The Kunama Reflector

[Kunama]

With inspiration from conversations with John Bambury (ausastronomer) and Pete Read (SDM Telescopes) I have decided to undertake another little DIY project ...............

Over the coming months (hopefully not years...) I will be keeping a log of my attempt to make a telescope on a Dobsonian mount. (Yes Col & Lewis .... a DOB)

I want to thank Pete Read of SDM Telescopes who has given me a great deal of advice and encouragement and has also agreed to supply some of his custom components. :thanx:
Pete has also offered to answer my questions along the way (an offer he may later regret ;) )
Thanks also to Les Sharpe and to Julian O'D for his recommendations on scopes.
Here is the plan for the 'Kunama Reflector'

Specifications:

Aperture: 18" (457mm)
Focal Ratio: F5.58
Focal Length:100.5" (2552mm)

Primary Mirror: Galaxy Optics 18" F5.58 by John Hudek (Thanks Les S.)
Secondary Mirror: Galaxy Optics 3.11" or 3.50"
Focuser: Feathertouch FTF2015BCR LW
Altitude bearings: SDM Cast Aluminium 23" ø
Mirror cell: 'Kunama Industries' 18pt with SDM Laser cut S/S Triangles

At the moment I am gathering the materials and components, and to that end, have now bought:
Galaxy Optics 18" F5.58 Primary, 2 secondaries, Novak Secondary holders
SDM Altitude bearings and assorted bits
Austral Hoop Pine plywood 2440x1220 @16mm
Aluminium tubing 32mm x 1.6mm wall 3 @ 6.5metres

Paints and varnishes and 2Pac Epoxy painting services are supplied by Fluid Painting Solutions of Canberra free of charge !!! Thanks Gabriel (my son-in-law)

[ZeroID]

TPIWWP...

And you better keep them coming ... ;)

[LewisM]

You need the De Grasse Tyson seal of approval

http://gifrific.com/wp-content/uploads/2013/03/Neil-DeGrasse-Tyson-Shaking-His-Head.gif

Too bad - better luck next time.

[FlashDrive]

Awesome Matt .....

A ' BIG ' Hand for :clap: ' Kunama Industries ' :clap:

Col......:D

[glend]

Wow! That's a few steps up to the focuser. Are you going to deflect the image back down with a diagonal, go electronic, or buy a ladder from Bunnings? Please take lots of photos.:eyepop:

And here I was about to sell my "16, might get inspired to keep it.

[Kunama]

A bit bigger than I initially planned so I will be enlisting the aid of:
Little Jumbo Safety Ladder 410B to get up to the eyepiece.

[FlashDrive]

Just watch you don't get ' altitude sickness ' :lol:

Flash.....:D

[Larryp]

Sounds interesting, Matt. I look forward to your updates on construction.

[MattT]

Is this going to be the 'Great Kunama Reflector' ????? Is see a steampunk inspired bolts and rivets everywhere type of thing….:question:

Only one thing better than a refractor is a BIG reflector….can't believe I just wrote that…. 18" is a good size.

Will be following as this is the sort of thing I have in mind later on…after the 2" PB and 8" r35 f9.

Matt

[glend]

Matt is that the 8" iStar objective? When does that start?

[Kunama]

Dear Diary: It is the 11th of June and the parts are slowly accumulating :D and the bank balance is a little smaller :sadeyes:

Thanks guys for the comments, and Yes MattT, there will be some resemblance to my prior DIY projects when this is finished, though not quite 'Steampunk' !!!
At the moment the plan is just to make something that will come to focus but also to make it presentable in the daytime. As we all know, all scopes look good in the dark, it's only in daylight that you see the differences.

At the moment I am playing a waiting game: :whistle:

Hopefully a parcel from SDM will arrive soon, in the meantime:

A custom Starlight Instruments Feathertouch FTF2015BCR LW lightweight 2" focuser is now being assembled for me in the USofA.

Picked up my Austral 16mm Hoop Pine Marine Plywood today. Turner's Building Supplies even let me go through the pack to pick out my sheet.

Mirror Cell Frame materials bought from Metal Mart in Fyshwick,
Due to the focal ratio of the scope combined with the 1.6" thick Galaxy mirror, the mirror cell will be made heavy duty. No wimpy hollow steel here, 25mm x 25mm solid mild steel bar with 32mm x 10mm side plates. I will no doubt have fun drilling and tapping holes into this !!!

Aluminium tubing should arrive tomorrow:
3 lengths @ 6.5m of 32mm x 1.6mm wall courtesy of Aluminium Warehouse, Fyshwick.

To kill some time while waiting to get started I thought I would use up some spare timber and make a storage box for the mirror to keep it safe till First Light:
(Sorry Les, the old original one will be retired to the long yard !!!)
Tasmanian Oak & Marine ply Box (555mm x 555mm x 90mm) with 3 coats of Estapol, tomorrow the foam lining, latches and handles go on:

[FlashDrive]

I might put my order in now .....;) ... while he's motivated ...!!

Yep ... that's a nice box there Matt.

Flash.....:D

[Kunama]

Postie brought me lots of goodies today Col, cast aluminium side bearings, laser cut mirror support triangles and lots of shiny bits. I'll be building the mirror cell over the weekend and starting the Upper Assembly next week. Found a friend of a friend who has a computerised saw table that can take a 2400 x 1200 sheet in one go and cut it up to the required sizes ........ probably for a couple of slabs of beer !!!!

Side bearings are going to the powder coaters on Monday. :thumbsup:

[Kunama]

Saturday 13 June
Spent an enjoyable couple of hours on the project today.
a. Cut and grind the mirror cell frame steel to size
b. Set out the hole pattern for Collimation bolts (PCD = 235mm)
c. Drill Collimation bolts (5/16") and Tap 3/8" UNC threads
d. Set out and drill holes for Mirror Sling mounting bolts (10mm)
e. Set out Cell mounting bolts and drill to 8mm

Time taken 2hrs 45 minutes

Consumables used:
1.6mtrs 25mm x 25mm Square Solid Mild Steel Bar
1.0mtrs 32mm x 10mm Mild Steel Flat Bar
1 x 125mm cutting disc
2 x Carlton Draught Stubbies and
some WD40.

[FlashDrive]

What colour will she be ... Kunama Cream :D

Col...:D

[rrussell1962]

Sheesh Matt, at the rate you are going it will be finished before the book gets there!

[Kunama]

Sunday 14 June:

Colour yet to be decided Col :question:
I think your book will have plenty of time to get read before this job is done Richard. :thanx:

Very little progress (wife insisted on some gardening instead :mad2: )

I did manage to get the stainless steel mirror support triangles drilled.
Funny how you forget how much of a pain S/S can be .......

For those contemplating drilling stainless steel remember:
a. Just like most of us, drill bits lose their temper at 120º C / 250ºF
b. have a bowl of water nearby (better with ice in it) splash some water on the steel where your hole is to go
c. cut the drill speed to half but press down firmly, when you see steam your bit is about 20 degrees from being stuffed, COOL the BIT in the water
d. drill a pilot hole first, then go larger COOL the BIT

Note the DIY plate vice, easy to make, fast to use and cheap ! (The screws are set so the plate slips in and then rotate it clockwise till it engages under the screw heads)
Beats having it spin like a fan blade.

Anyway I only broke 1 bit today:

[FlashDrive]

:D ... slow down mate... :P your making me sweat ...:P

Nice going ..... more to come I guess...;)

BTW ...you should have been a ' Manual Arts ' Teacher ... teaching Metal Work and Wood Work.

Col......:D

[LewisM]

Colour.... cream and Tak green :) :P

I hope you at LEAST put a Tak 7x50 illuminated finder on it...

[Kunama]

Thanks to Richard (rrussell1962) I now have the Kriege book on Dobs, my new Bible !!! :thanx:
First thing I did after opening the parcel was to flick to the section on Mirror Cell design to see how my ad-lib cell compared. :question:
I was relieved to see that I am only 0.5 mm outside the Kriege recommendation.
This book will make things a lot easier (previously I was going off photographs on my screen and my trusty vernier calliper) :thumbsup:

I am going to mount the Tak FC76DC on the Mirror box Lewis. :D

Spent my lunch money at Specialty Fasteners, Fyshwick, today (in fact spent next week's beer money as well) This build is starting to remind me of my boatbuilding days, you skip meals so you can spend the money on shiny stainless steel bits.

Tomorrow I will be arc-ing up the welder once I build a jig to keep the bits in their places when the heat hits.

[MattT]

Ain't that the truth! Can't really tell how much I have spent on the Gaunt re-build but must be close to $1K...or more....but really it doesn't matter when you end up with a unique (in every sense of the word) bit of whatever you are building.

Tak green....sheeeeesssss :P

[rrussell1962]

If you get stuck for odd parts etc check out the website for the shop Small Parts and Bearings in Capalaba Brisbane. They have saved me on more than one occasion.

[Kunama]

Thanks Richard,
I have bought some stuff from there when I lived up at Mooloolaba.

[Kunama]

Tuesday 16 June......

Little more progress today on the cell ............. (slow progress at that :sadeyes: )
More drilling and tapping threads into 304 grade stainless steel :tasdevil:
Thankfully that part of the job is over :2thumbs: ...... looking forward to drilling into plywood and aluminium instead

Hardest part was drilling and tapping an M5 thread into the end of a 10mm stainless steel shaft ...... two 4.5mm HSS bits died in the process :(

Welding tomorrow hopefully ........

[sharpiel]

I'm glad the old girl has found a loving home Matt. And it looks like you're doing a fantastic job.

I did feel a little sad watching you both drive away.

Then I started to spend your money :D

[Kunama]

Thanks Les,
"It won't happen overnight .... but it will happen"

I was only allowed to spend 2 hours on the project yesterday, the Minister for War & Finance demanded I do stuff around the house :mad2:
but I did get the welding and painting of the tailgate done. Also added a few shiny bits .........

The mirror will be resting on 18 Nylon gliders 25mm ø x 5mm high.
Edge support will be a PVC coated s/s wire sling which will be attached to 10mm x 29mm s/s linear bearings running
on the two 10mm ø stainless shafts attached to the the 25x25 steel lugs on the side rails ( that's the theory anyway !)

Weight of cell/tailgate as pictured is exactly 12 kilograms with the option to add weight bars to the middle rung (where the 60mm s/s cap screw with acorn nut is)

[FlashDrive]

Looking good Matt ....a piece of Art

Col....

[rrussell1962]

If it's any help Matt I have a spare empty Obsession weight bar with end caps that clips to the mirror cell frame, unfilled, just needs lead shot or sand as a filler. If it's any use to you let me know and I will send it down.

[Kunama]

Hi Richard,
Thanks for the generous offer, I am hoping that the scope ends up being base heavy (and to that end am making a fairly deep mirror box) but if not, I will be in touch. I will a start on the secondary cage next week and will be trying to keep the weight down to an absolute minimum. The only finder going on will be a Telrad.

[rrussell1962]

I have a finder base on mine, but have never felt the need to attach a finder, the telrad works perfectly. I ended up cutting a couple of 3 inch lengths of aluminium square tube plus end caps filled with lead shot which velcro to the top of the lower ring on the cage assembly to act as counterweights if I need to use them. The counterweights on the mirror cell are useful for me because I have the argo navis cradle on the secondary cage, only because I am too lazy to make a stalk!

[GrahamL]

Looks great Matt ,what (D) truss poles are you using?

[Kunama]

Thanks Graham, the truss poles will be 32mm OD 1.6mm wall 6060 T5 Aluminium.

[Kunama]

Monday 22nd June

Finally got to make some sawdust today :D:D
A big thanks to Norbert's megabucks computerised table saw, the 2440 x1220 Austral Hoop Pine sheet was chopped up in no time at all.............. This beautiful saw cuts the programmed sizes to an accuracy of 0.2mm so after 20 minutes I was loading the panels into the Merc........

Mirror Box sides x 2
Mirror Box ends x 2
Rocker Box sides x 2
UTA panels ready for router x 2
75mm corner bracing


(I will be throwing my circular saws into the bin tomorrow !!! )

[FlashDrive]

Well done Matt.... wood pieces look good.

Col....

[Larryp]

Looking good, Matt!

[Kunama]

Slow progress at the moment guys, I did manage to make the UTA struts today and picked up a router & bits so tomorrow I will make a trammel for the router and cut the rings.
Wayne from Starlight has posted my focuser so should have that in about a week.
Picking up the Alt Bearings from the powdercoaters tomorrow so then the mirror box can commence as well. Going to buy a new plate-joiner this week. (If the scope doesn't work at least I will have a bunch of nice new power tools at the end !!! )

[LewisM]

Have to find which powertool forum you will be selling them on :P :P

[Kunama]

Alt Bearings are looking resplendent in their new coat of Aztec Gold ......
The castings provided by SDM Telescopes had the bearing surfaces machined first, then all non-bearing edges were draw-filed with a 2mm radius
then powder coated with Aztec Gold PC .........

[rrussell1962]

Those Alt bearings look nice Matt. Much nicer than the somewhat functional ones on my Obsession. I am getting the impression that you are going to end up with a lovely looking telescope.

[Kunama]

Sunday 28th June:

Thanks Richard. Cleaned the cobwebs out of the router today and cut the UTA rings ....... Made the trammel from one of Jennifer's chopping boards :D

16mm AA grade Hoop Pine Marine OD 580mm ID 488mm

[rrussell1962]

Pretty damn close to my 18 inch Obsession. No surprises there!

[Kunama]

Your book has been quite handy in that, although I worked out all the sizes before the book arrived, I have been able to get confirmation that my planned measurements were close enough to work.

Coincidentally the waste pieces from the cutting of the rings ended up being exactly the same size as the mirror, so I now have a dummy mirror for fitment checks. (this was as a result of using a larger router bit).

The waste pieces will also be the basis of the rings for the "Little Kunama Reflector" should I decide to make a 12.5" copy of this one later!

[rrussell1962]

I may end up picking your brains for a 6 inch copy. I have my lovely old Broadhurst Clarkson 6 inch F8 mirror here waiting for a telescope.

[Kunama]

Only a little progress today:

UTA struts seated and assembled (Weight as pictured 2129 grams)
Alt bearings mounting holes drilled
Mirror box corner braces cut and drilled

Bought a DeWalt Plate Joiner (local toolshop had a sale, resistance was futile :shrug: )

[LewisM]

NICE work so far Matt.

You'll home-build a FCT-250 yet :P

[FlashDrive]

At the rate your going Matt, you'll be having ' first light ' by next weekend.

Good workmanship ...:thumbsup:

Col...

[Kunama]

Alas we are now in a holding pattern Col......
Waiting for the focuser to arrive, in the meantime I better get started on the secondary spider .......

[Kunama]

Thursday 2 July:

A bit of work on the mirror box today:
Sides with bearings, front and back panels and corner gussets ready for the biscuit joiner tomorrow ..........

[Kunama]

Friday 3 July .......... Arachnids R Us !!!!

Araneae Kunamatis, the four legged spider is born,

Ingredients:
125mm x 480mm x 0.7mm Stainless steel sheet
12.7mm SHS S/S 1.6mm wall (fits 3/8th secondary holder perfectly)
4 s/s M5 turnbuckles ( only use the right hand thread end !!! )
1 cutting disc (1.5mm thick)
and 2 hours

The right hand threaded ends of the turnbuckle were first cut off, then a slot cut into the two prongs, the ends then filed round and crimped tightly.
The vane was then pressed into the slot ready for welding. Weight of components is 259 grams + a few spots of weld :D:D
Total cost: $11.85

Just need to build a little jig to hold everything in place and TIG it together :P

[LewisM]

You almost look like you know what you are doing Matt :)

WELL DONE - you'll give Alexander a run for his money :P

[Kunama]

After 40 years of DIY I feel I am starting to grasp the concepts :D .....
This 18" is a little project to prepare me for the mega lightbucket to come :thumbsup:

[Kunama]

Saturday 4 July (Happy 4th of July Scott et al )

Oh how nice is it to get parcels on a Saturday, my thanks to Wayne Schroeder at Starlight Instruments for the beautiful FTF2015BCR LW 2" Focuser, only 456 grams including the base and screws :):)

[troypiggo]

Oh my. That focuser is gorgeous!

[LewisM]

What, no custom engraving or titling like "The Great Kunama Reflector"?

Lovely though.

[Kunama]

Thanks Troy, turned out just how I wanted it :D



The engraving and gold leaf signage will be done by 'Yours truly', once I learn how...... (and buy a Dremel ;) )

[Kunama]

This has now become rather addictive :D , I find myself grabbing any excuse to cut more bits for the project ............ Jennifer is not always impressed :mad2:

On the agenda this afternoon:
Rocker box sides panels marked out and cut (freehand with a jigsaw as my router wouldn't fire)

I am making the rocker a bit deeper than really needed so I can install some Lithium Ion power packs inside the rocker rather than using external power.
( it works in theory ...... ) these two panels are the 16mm Hoop Pine marine ply outer panels which will be laminated to some 18mm hardwood marine ply for the necessary strength and thickness. The inner panels will rest on the base panel while these outer panels (18mm deeper) will join to the edge of the base for the ultimate in strong joins.

[LewisM]

Decided what colour to stain the ply, or leaving it au naturel? UV set marine varnish or ???

Be nice in Jarrah red-brown :)

[Kunama]

At the moment Black Japan by Feast Watson is the leader of that race Lewis, I also have antique walnut and a very dark Jarrah stain here, not yet decided though.

[LewisM]

Maybe Brown Japan? I use that one a LOT.

[Kunama]

I am doing a test piece with the FW sealer, two coats of Black Japan and three coats of clear over the top, sanding between coats and a final cut&polish. If I end up going with that, it will take a few weeks just to do the stain/varnish ..... glutton for punishment?

[FlashDrive]

oooooh ...how lovely is that...!!

Col...

[FlashDrive]

Come on ... spill the beans ....:evil2:

Col...

[Kunama]

PM sent !

[Kunama]

Made some more saw dust today:

1. Laminated the Rocker Box sides to a second sheet of marine ply and routed the edges to match. (the inner board on both side is 18mm shorter to allow for the sides to sit on the base panel rather than just being dowelled to it.

2. Cut the top baffle for the Mirror Box (6.5mm marine ply)

3. Cut the lid for the Mirror Box (9mm overlap to the baffle)

4. Cut an annulus from the waste piece to be glued to the lid to strengthening.

[Kunama]

Little bit more progress today .............

Some surgery on the spider today, the stainless legs are now TIG welded to the 12.7 SHS s/s stem and the M5 s/s 'nuts' ......

also made another bag of sawdust and in the process managed to finish the mirror box gussets and cut the internal corner braces (4 @ 200mm above the gusset and 2 @ 195mm and 2 @ 245mm for below the gussets.

Hardwood marine ply groundboard also routed out ( 602mm ø x 18mm )

[glend]

Matt that spider looks good, you could have a business there making those, I'd buy one. My hacksaw blade spider is too flimsy I think.:thumbsup:

[Kunama]

Thanks Glen, I am pleased with how it turned out. The vanes are now just 0.65mm ( I took the gloss off them with the belt sander to give some bite to the primer). Total cost will be $29.85 :D

[FlashDrive]

Beautiful work....

[Kunama]

Thanks Flash, I think it is time I got myself a workshop...... so far everything has been done on a 600x600 chipboard panel screwed to a bit of pine sleeper and locked into a Triton Superjaws out on my back patio. :(

[rrussell1962]

Everything looks good. Really good actually. But what did the reference to the light bucket mean?

[Kunama]

Thanks Richard, I am looking forward to some assembly this weekend, the boxes will be joined with biscuit and dowel reinforced joints.

I've had lots of great advice from the master himself, Pete Read, along the way.
He has volunteered great tips along the way that have meant I have not wasted materials or time.

'Lightbucket' ........... ;) now that will depend on the planets aligning 'just so' over the next few years .......... and also the success of this project. How much aperture is enough :question:

[Kunama]

Focuser board (210 grams) and finder board (124grams) made and installed:

6.5mm marine ply with 16mm returns with excess areas routed out to reduce weight.

[Kunama]

Monday Monday .........Mirror box assembly day .......

Mirror box internal width 517mm
Tailgate width 516mm

a. cut #20 biscuit slots at 100mm centres on joining edges
b. lots of glue into slots and joins then assemble box and install tailgate
c. check for square
d. check all panels are in full contact with bench
e. clamp loosely and recheck for square
f. tighten clamps and check diagonals
g. make cup of coffee and wait for glue to set .....

[GrahamL]

First light on the weekend ? :)

[Kunama]

Not quite Graham, but I did manage to get the internal corner braces and gussets glued in and installed the 'T' nuts for the Alt bearings today and at the moment the mirror box baffle has been glued into place and clamped down ........
Check measured the diagonals, I was out by 0.5mm so not perfect but it is my first Dob. :shrug:

Wednesdays are spent with my granddaughter :D

[Kunama]

Today's progress pics:

Corner gussets, braces, bearings and mirror box baffle installed:)

[MattT]

Progress looks good, not that I know anything about Dob's.
0.5mm out....I'd be pleased with that.
Your nearly steampunk focuser....very sharp :thumbsup:

So is it going to be a black and Red Cedar beauty with lots of brass scews?

[Kunama]

Thanks Matt, I am a lot further with this than I expected when I started but there is still so much to do. No first light at Mt Stromlo for the record attempt but certainly by spring :question:

I had a rest day today, spent the day with my beautiful little granddaughter, even managed a nap on the couch for a couple of hours. Back into it tomorrow with the mirror cell installation and rocker box assembly ..........

[Kunama]

Thursday 16th July:

Mirror cell/tailgate fitted today
Pole clamp mounting reinforcement plates installed (12mm hardwood marine ply) even bevelled the pieces for a more professional look - not that anyone will ever see them :shrug: , but I will know :P ! )
Mirror box lid and reinforcement annulus bonded together

[Kunama]

Friday chores are done:

Rocker box sides and baseboard are united :)

Rocker sides are 2 layers of 16mm Hoop pine marine ply
Base is a single layer of 18mm hardwood marine ply

The inside layer of the side panels is left 18mm short so the sides sit on the baseboard. Each side is the dowelled to the base with 10 hardwood fluted dowels and lots of polyaliphatic pva glue.

[FlashDrive]

Very good ... this is coming along very nicely.

Col....:)

[Kunama]

Thanks Col,
I am going to take a little break from it tomorrow. Heading off to Parkes tonight for the Central West AstroFest. I am pleased to have the bulky stuff almost finished. I am going to get it all set up and test drive it before pulling it all apart again for the final sanding staining painting and polishing etc.

[Kunama]

Well the mirror box fits inside the rocker box .............. :D:D

Even 4mm clearance on all sides and even managed to get the boxes square :P

[Larryp]

Great workmanship, Matt-looking really nice :thumbsup:

[FlashDrive]

Yeah I reckon ... very nice work ....:thumbsup:

Col...

[nobby2]

I have an appreciation for your work as I have just assembled my mirror box inside the rocker using construction ply.
Have taken note that your rocker box end boards, particularly the high one finishes snug against the mirror box at zenith, thus stopping any movement past Zenith. I made my rocker a little long and should shorten it with final version. Its all a bit trial and error at this stage, but fun!

[nobby2]

Can I ask some specifics?
Are you using T-nuts mounted on the inside of your mirror box to hold the Alt beams? What size are your using?

Are you using threaded inserts inside the end of your tubing to assemble the secondary cage? Can you tell me where you sourced these?

Impressed with your fixed wooden pole attachment block on the secondary. Will be interested to see what attachments you use.
Cheers
Neil

[Kunama]

Hello Neil,
The Mirror box actually has 4mm clearance on the sides and against the front, once painted there will be 4mm felt pads glued as gliders to stop excess movement.
Yes, M8 'T' nuts recessed so they end up flush (actually 0.5mm below the surface) you can use either zinc plated or stainless steel ones. The secondary struts have threaded inserts. I got mine from Peter at SDM but they are available from places like Specialty Fasteners. Lookie here: https://www.essentracomponents.com.au and search for ' spring threaded insert '
The truss poles will have a plate joining each pair of poles and a bicycle seat post quick release clamp as the fastener.

The wheelie handles will be attached to the rocker box with M10 T nuts similarly recessed into the plywood.

[Kunama]

Back in the holding pattern, waiting for Mr Postman to bring me more pieces ....
In the meantime I have sorted out the linear bearings for the mirror sling :P

The 10mm linear bearing just happens to have a 19mm OD so a short length of 19mm irrigation hose was cut and slid over the bearing and is held in place by two s/s hose clips ...... the 3mm 7x19 s/s wire rope will sit between the clips so that it cannot slip off the bearing. Should make for a very smooth movement and thus the mirror will always be supported at the centre of gravity (in my case 19.25mm from the back of the mirror.

Also scored a 1800x1200 sheet of postforming laminate in a nice texture for $40. The laminate is just less than 0.8 mm thick and after I sand the back a little to get it down to about 0.65mm, it will make a perfect light baffle for the UTA...... :question:

Another little item out of the way is a 12mm thick spacer for the focuser to prevent the draw tube intruding into the light path, cut from marine ply and sanded down to the right thickness ... fiddly bits :mad2:

Next on the agenda are the pole clamps, "Cut to Size Plastics" in Sydney are supplying the black acetal block cut to my specs for $6.05 cents each !!!! How good is that !!!!

[rrussell1962]

Well, my new mirror sling from Howie Glatter arrived yesterday. I was going to PM you to ask if the old one would be of any use to you, but you seem to have that base more than adequately covered!

[Kunama]

Thanks Richard, yes all the bits for the cell/sling/tailgate are now ready.
My Delrin blocks arrived for the pole clamps, just waiting for a TCT Forstner bit from Carbatec, then the mirror box will be ready for finishing.

Still waiting for some parts for the upper pole clamps and the pivot kit/encoders/DTC.

[Kunama]

Lower truss pole clamps cut & drilled today (still need to cut the split)

Delrin 80mm x 52mm x 46mm

The block will be mounted horizontally for aesthetic reasons so the 32mm hole was drilled at an angle of 7.5º from vertical. This stuff is hard as ..... but the TCT Forstner bit did extremely well.

[Kunama]

The devil is in the details ................. :D

Started painting the stainless steel bolts ...... :help: I think I have OCD :shrug:

First a rub down with 400 grit wet&dry, then a coat of SLS Etch primer and 2 coats of PPG White Knight Gold Metallic.

First batch of many curing :

[FlashDrive]

Good as Gold mate.....:D

[LewisM]

I thought I was anally retentivelly obsessively bad... Matt, you sure you aren't my father (cue Darth Vader theme...)

[Kunama]

Hey Flash, sent you a PM.

Lewis, I hope not .............

Job worth doing is worth overdoing !!!! Progressing ever so slowly as I am having to do the project while minding my granddaughter. When she sleeps I get out for 30 minutes painting etc.

Camera going in for service so no pics for a week or so .....

[Kunama]

Still waiting for the postie to bring some parts and it is too cold here to varnish anything so yesterday I started on the ground board (can't drill the pivot hole till the pivot arrives ...)

Oil based gloss black to keep moisture out .......
then the obsessiveness kicked in again so the base of the board got painted gold with an overspray of black flecks

That made the red wheel rims look out of place so they had to be dismantled, sanded, etch primed and then painted gold with PPG Gold Dust.

Also found time to install the Noctua NF-B9 92mm fan which pumps out 64.5 cubic metres per hour or 38cfm and is nearly silent. Noctua fans also come with a 6yr warranty !!

[FlashDrive]

:prey2: ... perfection at it's finest ..!!

Great Work .....

[Julian]

Nice job Matt, good work like a PRO!

[LewisM]

There are Dobs, that look like they have been made out of recycled cardboard boxes and cement pylon paper tubes, and then there is the Kunama Dob... a class in it's own right.



Only thing, not sure the gold fleck idea works. Solid gold, yes, but the fleck looks a bit off IMHO.

[Kunama]

Thanks Lewis, (only the earthworms and ants will see the speckled side !!! )
I have made a little bit of progress on the project, still sneaking out to do a bit whenever my dearly beloved isn't watching ................

Get my camera back tomorrow so hope to have a couple of pics to update the thread.......

Pole clamps attached .......... :thumbsup:
Timber work stained ........... :D:D
Mirror cell going in tomorrow ........ :):)
Still waiting for the azimuth bearing material .... :sadeyes:

The electrics and electronics will be done sometime in the future when the budget recovers ...

Thanks to those who have been following the thread and PMd ideas, opinions and so on :thanx: ( I think the next one will be a much lighter project ....... Sumerian Optics Canopus look-a-like :question: )

[Kunama]

After 11 weeks things are starting to take shape.........

Being an old design (some might say an obsolete one ;) ) I decided it had to look like it had been around for a while, so the colour and fittings have been selected with that in mind.

The finish is Wattyl Colourwood Jarrah with lots of black dye added for an instant 'patina'. The application involved 2 coats of stain on the flat areas, four coats on edges of the rings to darken them a little more.
The lot was then given two coats of pre-catalysed varnish to seal it. This varnish takes a week or more to fully harden but once set will last longer than I will.....

As brass tube is hard to come by these days, the struts have been painted in PPG Gold epoxy enamel. All gold coloured items were first sanded with 400 grit then etch primed with SLS and then 2 coats of finish coat followed by a satin clear coat.

Still have lots to do but here is a preview of things to come:

[glend]

Excellent workmanship Matt, really like the colour scheme and finish. You'll be giving SDM some worries. Have you kept track of the hours you put into this scope? When you get the inevitable question - "can you build one for me?", you will need to be able to price your labour. I don't think the average punter understands just how much work is involved in something like your scope.

[Kunama]

Thanks very much Glen. I have hidden all the receipts so my dear wife doesn't see them, as for the hours ........ I haven't bothered keeping track.
I dare say it would have been finished in far less time if I had a workshop.

There are some parts here that would not be feasible in a commercial operation so I think Peter Read and SDM are safe :D. Peter has been a huge help in getting this scope built, both with ideas and supplying materials. I think he and I will be enjoying some fine wines one of these days.

The other contributor of note to this project has been John Bambury, with lots of good ideas from his years of experience.

As an example of time consuming things, the Pole Clamps arrived as plain square blocks, they then had to be drilled at the correct angle, split using the slide saw, edges planed with a wood plane as you can't sand the stuff. Once attached to the mirror box, the clamping bolt (M8x 100 stainless steel) had to have the head polished to mirror shine, the lock nuts were cut in half to make them only 2.5mm thick. M8 'T' nuts were set into the reinforcing plate inside the mirror box. The knobs were sourced through Amazon and are valve handles, these had the powder coating removed prior to etch priming and painting ................ (exhausting just to type about it...)

[rrussell1962]

Stunning...Just Stunning. But what are the pipe clamp thingies on the UTA strut for?

[Kunama]

Thanks Richard, I knew you would notice them !!! I just could not bring myself to mount a Telrad with double sided tape or cable ties so these were fashioned from bicycle seatpost clamps and the Telrad will be bolted to them.

The eyebolts are there temporarily to stop the clamps moving and scratching the paint.

Thanks again for the loan of your book, I have now read it cover to cover at least 8 times.

[rrussell1962]

Very neat idea. I too read the book at least 8 times. But unlike me you used the book for it's intended purpose!

[MattT]

Ohh yeah...very nice. The gold paint does look like brass :eyepop:Mixing your own stain is the only way to do it.
Have to drag yours and mine up Mt Stromlo some day.
I specially like the gold knobs for the struts :thumbsup:

[Kunama]

Thanks Matt, a little touch in keeping with the theme of a 'classic' Dobson.

[LewisM]

Ahoy there matey. Arggggg.....

Or

Hello sailor....

;)

[LewisM]

That just simply tramples over 90% of DIY scopes I have ever seen. Just perfect.

No shortcuts, no blobs of glue sitting exposed like dog cojones, finished like a piece of expensive furniture... just mesmerising.

And enough steam punk too :)

[FlashDrive]

What can I say .... Magnificent ....:2thumbs:

Poppy ... :D

[Paul Haese]

This is a master craftsman piece of work. The images probably don't do it justice. I have followed this thread from the start and I am highly impressed with your results. Congratulations on a real achievement.

[Larryp]

Beautiful workmanship, Matt!

[DJT]

This really is a thing of Beauty! Top marks that man. Looking forward to seeing the finished item.

[Julian]

Congrats Matt, really nice work!!

[Kunama]

Many thanks Lewis, Poppy, Paul, Laurie, David and Julian. It is very nice to get such generous feedback.
The building of the scope is rather addictive, and very rewarding when things work out. I have only had a couple of "Re-Do This Bit" so far but it is all a learning process.
You have to have a predictable temper when doing so many different things, like tapping threads into stainless steel shafts and just when you are finished and removing the tap it breaks inside the shaft and you start again ........... :mad2::mad2::mad2:

I think I will need another 2 weeks to get it up and running....

[croweater]

Great job Matt! Really impressive. Just cause to be very proud. Love those steam valve taps too. Cheers Richard.

[Kunama]

Thanks Richard, I'll be heading your way later this year, a nostalgia trip to Nangwarry, Mt Burr and the Mount, to see how much has changed since the 70s. Hopefully my wife will let me bring the scope too.

[nobby2]

Embarrassing to be on the same thread as the Kunama Reflector. Beautiful work! Referring to the comparison of my posts on "First Stages of building a Portable Newtonian"

There is certainly an 'all consuming' nature about a scope building project. Not to mention the slow, creeping costs each time you visit a hardware store. I had been throwing my receipts in a folder and just did a spreadsheet add up. OK!

Finding the correct bolt and material is half the challenge. Very rewarding however when you find a solution to a task you doubted you could complete.

Matt has taken the time to point me in the right direction in the middle of his own build.
Thanks

[OzEclipse]

Matt,

A work of art!

Joe

[multiweb]

That looks terrific Matt. Too beautiful to use. :lol: The attention to details is quite extraordinary. Quite a showpiece. :thumbsup:

[Kunama]

Many thanks Neil, Joe and Marc.

It may well spend a large part of its life on the loungeroom floor as my granddaughter is keeping me on my toes, so I thought I might as well try to make it presentable.
Tomorrow is stainless steel drilling day to convert it into a wheelbarrow, then a little more time at the powdercoaters and the rest can be bolted together .............

The initial timeframe was for it to be ready for Christmas so I am really pleased to be ahead of schedule. ......

At this rate I will be able to start on the 8" F8.8 refractor before the end of the year !!!!

[Kunama]

I managed a little bit of detail work today:


Pivot bolt and brass bushing.......

The bolt was a vintage handmade 1/2" x 5" bolt looking to be put to use again .......
1. Remove the rust and scale
2. Extend the BSW 1/2" thread another 2" down the bolt and cut the bolt to length
3. Drill 1/4" hole into the head for the encoder shaft
4. Drill and tap M4 x 0.7 thread into the side of the head for lock screw
5. Make a base plate
6. Weld 1/2" BSW s/s nut onto the plate
7. Grind the welded nut round (ish ! )
8. Spray primer
9. Spray gold
10.Spray black specks
11.Turn and polish 1.25" OD, 1/2" ID x 1/4" brass bushing to be recessed into rocker box
12.Photograph for posterity

Sometimes I think the OCD is getting the better of me .........
Edit: In case anyone is wondering .... yes I did polish the end of the bolt to a mirror shine and then sprayed the threads with liquid Teflon.

[MattT]

Can't have enough OCD when it comes to building scopes….I should know :rolleyes:

Step 11 intrigues me….do you now have a lathe of sorts? Or is the drill in a vice 'lathe'? :lol:

[Kunama]

Re: Step 11 ..... unfortunately not mine :( but one I can now access for little jobs. :D

[Octane]

Trying to lift my jaw off the floor.

What a magnificent work of art.

H

[Kunama]

Thanks Humayun,
I did some calculations for the Teflon pads today so had to weigh the beast,
Alt bearing pads will be carrying 60kg, with the rocker adding 15kg to the azimuth bearing load.
adding the groundboard, wheels and handles, some electrics will see a total weight of 90Kg so it is still lighter than me !

Once complete, I will take it up to Stromlo for a few pictures .........

[Atmos]

I am loving the wood finish, to me it appears like a telescope that should be sitting on the deck of a polished 1800's boat :D
Why you'd put it there I have no idea though!

[Kunama]

Thanks Colin, as long as nobody suggests it would be better as a boat anchor I will be happy!

[rrussell1962]

90 kg may sound heavy, but the wonderful thing is that with the handles it is very easy to move about. Wheel the rocker box and mirror box out. Another trip for the truss poles and UTA. Quicker to set up than my Nexstar 8se. The Obsession takes around 12 minutes including collimation. Oh-and then 2 hours to cool down! but when it is cooled.....wow. Matt, seriously a work of art. I look forward to seeing the pictures of the finished telescope.

[Kunama]

Thanks again Richard, I hope to get the wheelie bars fitted this weekend. Pictures will follow in about 2 weeks when it is all put together .......

in the meantime I hope you like today's tidbit of detailing:

1. Take one ordinary looking Telrad finder .......
2. dismantle it
3. slice off raised lettering
4. sand flat surfaces with 180grit
5. prime with plumbers primer (very carefully !!!!! )
6. take a sheet of 0.6mm Hoop Pine veneer
7. cut infill for the Telrad sides top and collimation panel
8. stain with Wattyl Dark Jarrah
9. Clear coat with Cabothane
10. Put it all back together again ........

Now doesn't that blend in better with the Dobsonian box work???

P.S. The 4 brass screws are on order and will be fitted asap ;)

[LewisM]

OMG OMG OMG! (said with an Effie accent)

Seriously OMG!!!!!!!!!!!!!!!!!!!!

[Octane]

That is sensational. I can't even begin to imagine the amount of work you have put in. I know nothing of this craft!

H

[LewisM]

Imitation is the sincerest form of flattery...

I went with elm.

I just had to have one :P

[FlashDrive]

This is getting too much for me ...I gotta sit down and read this again...:rofl:
You should start a ' production ' run on this ...I'll be 1st to buy....:P

Well done...I like it....I want one.....:thumbsup:

Col......:D

[FlashDrive]

That's a good one....:lol:

Col....

[LewisM]

I can do Apricot in mahogany or silky oak if you like Col :P

[troypiggo]

Please tell me that was Photoshopped and not real :(

[LewisM]

What, you don't like it? :shrug:

:lol:

[Atmos]

I personally love Mountain Ash :)

[sn1987a]

I'm going to shamelessly plagiarise that Telrad idea.

:thumbsup:

[Kunama]

Thanks Col, et al,
I don't think I will go into production on a full scale, more of an 'ideas man'.



Go for it Barry !

Got my azimuth bearing and barrow handles yesterday, pictures tomorrow......

[Kunama]

Here is my take on azimuth bearing material, an idea I discussed with Peter Read and John Bambury ............ as it turns out it has been done before by Peter Read (Great minds think alike ;) )

Take one sheet of 3mm aluminium plate ........
Cut a piece 3mm smaller than the base of the rocker box ......
Draw file the edge to a round profile..........
Round off the corners...........
Sand with 180 grit in circular fashion for some bite ..........
Take to your local powder coaters .........
Powdercoat in Aztec Gold or Aztec Silver (Antique Silver is the same texture)
Allow a couple of days for maximum hardness of PC.
Glue to the base of the rocker box (can also add a screw in each corner )

[Kunama]

Time to wheel a barrow back .......... this design is from the mind of Peter Read ...... i have only copied what I have seen in his website images .....
A couple of custom touches that I have added are the powder coating of the stainless steel RHS tube, brass screws, and end caps for the tubing....

Wherever the bolts went through the tubing, a Delrin insert was placed inside the tube to prevent it being deformed when tightened. (see one in a pic ..)

Materials used:
4 metres of 25mm x 50mm 1.6mm wall 304 stainless steel rectangular hollow section
1 piece of black Delrin (acetal) 200mm x 165mm x 21.9mm
2 @ M16 x 120mm s/s fully threaded bolts with s/s washers, nuts & nylons
Loctite antiseize paste
4 @ M10 x 60mm s/s button head bolts with t-nuts
16 @ 3/16" x 1.5" brass round head bolts.
a couple of wheels

Tools:
4-20mm UniKut titanium step-drill bit
4" angle grinder
Makita slide compound saw

[Kunama]

Today's efforts ..............

[FlashDrive]

Superb...:thumbsup:

[Somnium]

This Is a fantastic work of art, congratulations

[LewisM]

OK, ban and slam me now, but I gotta say it...

That last picture looks like a commode on wheels :D :P :)

You know I love it Matt... just that picture reminded me of a finely crafted porta-pooper :)

[Kunama]

Thanks Col & Aidan !

Lewis, that is what Jennifer said as well .......... I guess if it won't come to focus, it won't have been a total waste of time, I can bolt it into the Mercedes.

[LewisM]

:rofl:Priceless.

[Kunama]

Wheeled my little project out for its first taste of the great outdoors today, due to the late hour there will be no first light tonight as the poles will need to be shortened by 70mm. (The alt bearing did not allow the poles to be lowered enough to focus at infinity, the best I could do was to get the nearby hospital, which is about 600 metres, away into focus)

Balance was good, once the filter slide and baffle are attached, I expect to need only 1Kg of counterweight on the tailgate .......

Tomorrow will be first star test ........

Jobs still to be done:

Design and build filter slide system
Install UTA baffle
Install Telrad
Install encoders and DTC

I am pretty pleased with my first proper ATM build :D:D:D:D

[LewisM]

DIBS! :P

Beautiful Matt.

[MortonH]

Just fantastic, Matt.

[Larryp]

Looks incredible, Matt :thumbsup:

[MattT]

:thumbsup:

So good it's nearly enough to make me give up Refractors....nearly

What's next?

[rrussell1962]

Looks fantastic, better than fantastic actually. I do like how you have done the wheelbarrow handles, much better than the clunky one piece ones on my Obsession. Are you planning to add any baffling to the UTA or is the plan to use the telescope at a sufficiently dark site that none is needed? I was also looking at the mirror box cover trying to make out whether it is hinged and folds up against the trusses which is an idea that I have toyed with but couldn't work out how to keep it there! Oh, and the obvious question - what is she called? Assuming it is a she!

[RickS]

Wow! Great DIY work :thumbsup:

[Kunama]

Cheers guys, I'm very happy with it.
I have to make a filter slide system before fitting the baffle to the UTA, this was more a test of balance and pole length measurement.

The lid is hinged with a large Parliament hinge and will have a brass window latch fitted to keep prying fingers out.

Being a refractorian, I had nothing to collimate it with so ended up having to trust my builders eye and stood back a couple of metres from the scope staring into the empty draw tube while my dear wife adjusted the two collimation bolts. End result was actually pretty good out of focus donut on A Cent. It has been a long time since I collimated a scope so will have to practice that art.

Going with the Nexus DSC this time around.

The three part handles are another SDM Telescopes idea of Pete Read, shamelessly copied by yours truly from photographs on Pete's website.


Name to be decided.......

[LewisM]

"Tähtitieteilijä n lipasto"?

:scared3:

Maybe "Karin"

[ZeroID]

That thing should pull in enough photons to stop the universe from expanding anymore !!
Beautiful workmanship ... I do approve.

[Kunama]

Thanks Brent, been doing some fine tuning tonight to get it to focus. I cut 70mm off the poles and now have almost all eyepieces achieving focus. I will have to take another 15 off them to get the 42 and 50mm grenades to focus.

I did however get to spend 30 minutes mesmerised by the view of the Jewel Box in my LVW22. I had forgotten how much more you see with the extra aperture.

[Kunama]

Installed the UTA light baffle today.........
With the exception of the DSC/Encoders, the build is now complete !

3 months and 1 day....

Edit: now how do you collimated these again ?

[FlashDrive]

Matt .... go to the ' top ' of the class :thumbsup:

Well done indeed ....:D

Col...

[Kunama]

Hey Poppy, thanks again, just ordered some ramps for the van and need to find a decent ladder, thankfully we have 9' ceilings so I can assemble it inside the house.

The Big 50mm sits nicely up there!

[Kunama]

To bring this thread to a close here is the finished scope:

"Sweet Guinevere"
(a reference not only to Gordon Lightfoot's song but to my beautiful and very patient dearly beloved Jennifer)

features a Galaxy 18" F5.58 primary Sn # 0411
Galaxy Optics 1/20 wave 3.11" secondary
Novak secondary holder
Kunama stainless steel spider 0.7mm s/s
SDM Alt bearings in Aztec Gold PC
Kunama Az bearing (3mm Al with Aztec Gold PC)
Kunama Half-moon offset pole pivot/clamps with QR skewers
Kunama Delrin pole clamps with valve handles, brass screws and stainless lock bolts
Noctua cooling fan (Lithium power pack)
Linear bearing cable sling mirror support
3 pieces stainless steel wheel/handles powder coated in Aztec Gold
etc etc.......

Thanks for following the build and for your comments/compliments along the way :thanx::thanx::thanx:

[rrussell1962]

Just beautiful Matt. Love the matching Telrad, very nice touch.

[CJ]

Wow! A fascinating thread and a hugely impressive piece of craftsmanship!
Thanks for posting.

[sharpiel]

Great to see the old girl collecting light again after years of storage. So, very keen to know: How does it perform under the stars???

[ZeroID]

Between this and the Gaunt project in another thread IIS could put on an Artisans show. Fascinating and impressive to watch from start to finish. Especially as they are both extremely functional and beautiful.
I applaud ...

[Kunama]

Thanks guys, just got some ramps yesterday so I will be able to take the scope out this weekend. Six streetlights around my house mean no viewing from home.....
Got to learn collimating again!

[N1]

Hey Matt, great project and a great result! :thumbsup::thumbsup::thumbsup:

[nebulosity.]

A stunning telescope with superb craftsmanship and taste.

Congratulations on building a masterpiece!

Cheers
Jo

[Kunama]

Thanks Mirko, I must admit I am thrilled with how it turned out. There were a few times along the way I had some doubts.



Thanks Jo, much appreciated. I started out wanting to build a scope that looked as though it had been around for a while, and with that in mind I was pleased with how my colour scheme and the time taken to paint all the stainless steel hardware paid off.

[ausastronomer]

It looks superb Matt and all finished in super fast time. Great work.

Cheers
John B

[astroboy]

Fantastic looking scope Matt , well done.

[Kunama]

Thanks very much John for all your advice along the way, it was great to be able to bounce ideas off experienced people like you and Pete Read. I doubt the result would have been as successful without you and Pete chipping in so generously with your time and knowledge.



Thank you Zane, now I need to learn to use it. Cheers.

[FlashDrive]

Gee ..... that's a bit ' flash '

:P

[Kunama]

Finally got around to making a mount for the Telrad today:

[Kunama]

Trying to find somewhere to house the scope I came upon this unused dome, now to find a key to get in .......

[issdaol]

Does that beast shoot out gold cannon balls ?! :-)

Looks like the perfect home !!

Loved the opportunity to see this piece of art up close .... attention to detail across all areas makes all the other dob manufacturers look a but 2nd tier by comparison :-)

[LewisM]

I was not going to pass final judgement til the zip ties came off the Telrad.

OK, the score is 100%.

To quote Mr. Ellis (:P), SUBLIME, EXOTICA LEVEL telescope :D

[Kunama]

Great to meet up yesterday Phil, I ended up taking it to Peter Bobroff's place last night where Peter and I set our scopes side by side, alas, the sky and clouds conspired to ensure no viewing was undertaken. We spent the evening chatting over a nice cup of coffee. Maybe next time!



Thanks Lewis, the Ultra Premium zip ties are a distant memory :D
Thanks for sending down the Vixen adapter, I might have to make a couple of copies while it's here !!!

[Kunama]

After thirteen months the "Guinevere 18" is going strong and giving beautiful views...... Its outreach events total tally now exceeds 1000 people who have climbed my ladder to see the views....

I have taken Phil's advice and replaced the only component that was temporary (though looked increasingly like a permanent fixture) the DSC/Eyepiece holder made from plastic has finally been retired to the rubbish bin and in its place is this Eucalyptus marginata (Jarrah by another name) tray that will hold the Nexus DSC and the Nagler 31T5/Nagler 22T4 pair.

[Atmos]

You've replaced the plastic chopping board :lol: Looks a lot nicer, suits the rest of the telescope.

[Kunama]

Yes the chopping board was an eyesore from the start. I'll fit the Nexus retaining lugs as soon as I can get to the lathe, I thought I would turn some brass pins for it. The OCD comes in bouts......