NBH - another acronym used when your new EQ6 to 12"SCT mount bar is not right

[h0ughy]

:mad2: :mad2: :mad2: I have been waiting for this rotten thing since July 30 to get here. now that it is here I am bitterly disappointed. I still need to go out and source some hex head screws for the SCT to attach the bar. Ken Duzat may have packed them in the first place but the parcel was opened by customs. :sadeyes: :( :( :( :(

anyway I think you will get the gist of this item. It will be done before Kulnura:thumbsup: must be tested before then too. i also will need help to remove the OTA from the original mount - -Scott or Alan doing anything any night soon.........................;)

[Lee]

I recently had a similar problem - Supa Cheap Auto has a not too bad selection of stainless hex heads...... I picked up boxes of a few lengths, washers, nuts - anything that even *might* be handy one night! For my rings, 6mm threads seem to be the standard.....

[Dennis]

My local Mitre 10 and Bunnings have a small range of metric (5, 6 & 8mm) and imperial (1/4 inch) socket head cap screws. Not SS and lengths vary from 15 to 25mm.

If you really get stuck, and know exactly what you require, PM me as I have a small selection of metric & imperial in my spares kit. I find most of the stuff I get from the US tends to be imperial.

Cheers

Dennis

[h0ughy]

Thanks guys for the offer but I have found out what the thread is and what i need:

From: Ken Dauzat [mailto:sales@kendauzat.net]
Sent: Tuesday, 10 October 2006 11:59 PM
To: David Hough
Subject: Re: ken I got the bar unpacked it.................

Hi David,

The screws are called 1/4" x 20 meaning... 1/4" diameter x 20 teeth per inch............. they are not metric treads. since the plate is 1/4" thickness I would use about 5/8" length and then perhaps a flat washer...the heads can be slotted, Philip, or allen...it really does matter as long as the treads match.

Ken...
;)

[Dennis]

That's good news. In the shop you will probably find they don't have a 1/4inch x 5/8inch long. All the 1/4inch socket head cap screws I have seen state the length in mm - go figure!

So, 1/4inch x 5/8inch long would be 1/4inch x 16mm. Make sure you have a set of imperial allen keys too, as metric allen keys will not usually fit imperial socket head cap screws.

Cheers

Dennis

PS – ¼ x 20 UNC is the same as the 1/4 in Whitworth thread that most tripod heads use to screw your camera onto the mounting plate.
PPS – Are there any metallurgists out there who can advise on the effects of using a SS fastener on an Aluminium mirror cell? Will there be any adverse effects due to e.g. electrolysis?

[h0ughy]

:thumbsup:


the answer is here http://www.eaa1000.av.org/technicl/corrosion/galvanic.htm I think there would be but not sure what the SS fastner would be made of, if it is a SS close to Al then it would be minor but if it is up the other end of the scale then most definitely!:) Your a smart cookie Mr D:D
The Galvanic Table

Active (Anodic)

Magnesium
Mg alloy AZ-31B
Mg alloy HK-31A
Zinc (hot-dip, die cast, or plated)
Beryllium (hot pressed)
Al 7072 clad on 7075
Al 2014-T3
Al 1160-H14
Al 7079-T6
Cadmium (plated)
Uranium
Al 218 (die cast)
Al 5052-0
Al 5052-H12
Al 5456-0, H353
Al 5052-H32
Al 1100-0
Al 3003-H25
Al 6061-T6
Al A360 (die cast)
Al 7075-T6
Al 6061-0
Indium
Al 2014-0
Al 2024-T4
Al 5052-H16
Tin (plated)
Stainless steel 430 (active)
Lead
Steel 1010
Iron (cast)
Stainless steel 410 (active)
Copper (plated, cast, or wrought)
Nickel (plated)
Chromium (Plated)
Tantalum
AM350 (active)
Stainless steel 310 (active)
Stainless steel 301 (active)
Stainless steel 304 (active)
Stainless steel 430 (active)
Stainless steel 410 (active)
Stainless steel 17-7PH (active)
Tungsten
Niobium (columbium) 1% Zr
Brass, Yellow, 268
Uranium 8% Mo.
Brass, Naval, 464
Yellow Brass
Muntz Metal 280
Brass (plated)
Nickel-silver (18% Ni)
Stainless steel 316L (active)
Bronze 220
Copper 110
Red Brass
Stainless steel 347 (active)
Molybdenum, Commercial pure
Copper-nickel 715
Admiralty brass
Stainless steel 202 (active)
Bronze, Phosphor 534 (B-1)
Monel 400
Stainless steel 201 (active)
Carpenter 20 (active)
Stainless steel 321 (active)
Stainless steel 316 (active)
Stainless steel 309 (active)
Stainless steel 17-7PH (passive)
Silicone Bronze 655
Stainless steel 304 (passive)
Stainless steel 301 (passive)
Stainless steel 321 (passive)
Stainless steel 201 (passive)
Stainless steel 286 (passive)
Stainless steel 316L (passive)
AM355 (active)
Stainless steel 202 (passive)
Carpenter 20 (passive)
AM355 (passive)
A286 (passive)
Titanium 5A1, 2.5 Sn
Titanium 13V, 11Cr, 3Al (annealed)
Titanium 6Al, 4V (solution treated and aged)
Titanium 6Al, 4V (anneal)
Titanium 8Mn
Titanium 13V, 11Cr 3Al (solution heat treated and aged)
Titanium 75A
AM350 (passive)
Silver
Gold
Graphite
End - Noble (Less Active, Cathodic)

[h0ughy]

http://www.corrosion-doctors.org/Definitions/galvanic-series.htm and try this one too

[Astroman]

Gee tuff luck David with the screws hope you get some soon, am itching to see that monster on the EQ6 for a size comparison. Just out of interest, how much does the 12" OTA weigh?

[h0ughy]

40LB OR 18.1KG:D and then add a lumicon giant easy guider and a dslr:whistle:

[Lee]

1/4" by 20 threads is the camera tripod mounting thread IIRC - handy to have these badboys around in any case.....

[tornado33]

Hope u can get the screws soon.
Im wondering if its best to set it all up in the daytime first to make sure eveything is okay, balanced etc. Let me know when u have the parts all set and I will give you a hand to set it up. (except this friday or following wednesday)
Scott

[h0ughy]

I have just got the screws............................t ick tick tick

[h0ughy]

:lol: :D I had a little acciDENT!!!!!!!!:eyepop: :scared: I slightly scratched and dented the tube getting it off the fork mount. never use too much force, and never trust yourself in the first place. I should have gotten help. but thats only the cosmetics. it does need a better tripod, and the vibration supression pads. I took a few 25 second shots just to see what it would be like, no polar aligning, actually not muchat all really and it showed. I am happy now - all I need ia a few lessons........;)

the picture of m20 is very crappy and only a 23 second jpeg, you can easily see I had no alignment:rofl:

[Dennis]

Looks good Dave. :thumbsup:

What are the two blue and green astro-accessories in the 1st photo 2nd row? Are they Meade specific leveling devices? :P

Cheers

Dennis

[JohnG]

Hey David

Arn't you supposed to loosen the forks at the base before you take the tube off??? comes straight off without any drama's then.

Cheers

JohnG

[h0ughy]

:D

bit late now, I did a little bit but was frightened what might happen if I did it too much. it was all my fault. Wont matter much now, damage is done. the optics are still pristine!;)

[JohnG]

Tis a bit late now.

Way I used to do was by laying the tube and base on a flat surface with pillows to support it, loosen one side of the forks, remove the opposite side upper bearing screws, remove the bolts from the fork and lift away the base and one fork, remove the otherside upper bearing screws and you have the tube separated without any drama's. :)

Cheers

JohnG

[h0ughy]

no I had foam underneath the tube supporting it, then I backed off the left arm (encoders on right with motors still attached) then undid the tube. arm got caught on the thread when moving it back and then the unthinkable happened the tube slipped and rotated jamming it in the position that was very awkward to hold onto so it not only dented the tube it also scratched it.
Nothing at few Iceinspace stickers will not fix

[matt]

Wow. That looks big on that poor little EQ6.

Aren't you pushing it's load capacity???

[h0ughy]

getting close, but if you dont push things a little then you will never know your limits;)

[beren]

:eyepop: "tis a sad day/night" :P David what a sight to make a fork mounted LX user tremble at the knee's :screwy: [<<<only kidding] The 12" OTA looks huge

[h0ughy]

:)


Umm yes it does, and what a potential weapon it could be too. as yet is untried, weather and other things haven't let me use it yet, but when i get that lumicon geg going - i look forward to the results;) :D

[sheeny]

hOughy,

Any grade of stainless screw should be fine with Al. You won't have a significant corrosion problem there. Both Al and SS work by forming an impermiable layer of oxide on the surface to prevent further corrosion, so unless you have either a fretting motion that keeps destroying that oxide layer, or a chemical solution that does the same, it'll be fine.

Now on to important matters... NBH... hmmm... seems to me to be a technical term... whilst I seem to get the general vibe of the thing, the precise meaning evades me... let me guess...

no hope?
no help?
not hardly?

Ahh! By Jan, I think I've got it! Not Happy!!!! (Jan):rofl: Best to be specific about these things!

Al.