Aluminium

[LewisM]

Gawd I hate working with aluminium!

Decided to fix my in-focus issue on the Tak FS-60C myself, rather than either spending a fortune on Tak bits, or purchasing off the shelf stuff, or getting Hugh to make me one. I already had a 56 to 2" converter (thanks Oasis!), and the short nose Vixen flip mirror, but what to do with the eyepiece...

I ascertained that I needed to lose about an inch of space - the Vixen flip mirror eyepiece holder is LONG, and I DARE not shorten it, so...

I removed the eyepiece spacer tube from the diagonal. I then unscrewed the base of it from the diagonal, and luckily found that Vixen's subcontractor used STANDARD threads. Already ahead.

I then went through ALL the adapters and extensions I had. I found an old prime focus adapter I NEVER use, checked it out, and, the Vixen base threads fit, so...

Tried the hacksaw first. I managed to make at least the pilot cuts/straight circumference lines! gawd aluminium is a pain, especially without a bench vice! So then, the Dremel...

9 cut off discs later (only shattered ONE - the rest wore down!), and about 2 hours of work cutting and I had the piece I needed. Threaded a retainer screw hole, finish sanded/filed/etc, which took a while. Acid etched it,(wonderful how HCl does not attack anodized surfaces), etch primed it, shot it with epoxy satin black paint.

It's 1 and a bit inches shorter than the Vixen spacer, so it WILL come to focus now :)

I could have bought a low profile diagonal, but I did this for the cost of my time, the original cost of the dremel wheels and paint, and the original cost of the afocal tube (I think it was free with my Maksutov).

I need a lathe, NOW!

[ZeroID]

You sure it was aluminium ? Hacksaw should easily whizz through that . I normally cut round objects in a 'V' block, they can't escape or move. One of those fine tooth hobby hacksaws then just a big sandng block to finish it off smooth and square, tidy it up with a small file on the corners\edges. 10 mins max. I normally wrap some tape around it to establish the cut line.

Etch and paint is seperate.

[LewisM]

Probably was duralumin. BLOODY tough thing! There was 5mm to get through each side (I had to make the cut at the 2"to 1.25" step down ring)

[leon]

I find aluminum a pleasure to use, but mind you need to secure it when working with it.

Leon

[LewisM]

It is, as you say, IF you can secure it. I don't have a bench vice, unfortunately.

[lacad01]

Not sure if something like pictured would have helped but I have one that I've used to cut aluminium tubing and angle, no prob. Object clamps in place and get perfect 90 or 45 degree mitres.

[Barrykgerdes]

I love working with aluminium.
I cut bar and tube chunks with my band saw:thumbsup:
and finish in the lathe.:thumbsup:
The lathe tools stay sharp?:thumbsup:

Barry

[ZeroID]

Yeah, the good old mitre box is an excellent option. I've even used an old tenon saw, nice fine teeth, on Alum. I think I cut all the alum struts on both my scopes that way.

[leon]

That's true Barry, many times i have cut aluminum of all shapes and sizes using just the drop saw used for timber, cuts lovely and the blade is fine, as long as one has a carbide tips of coarse.

Leon

[rat156]

I use a tubing cutter, just the business for 90 deg cuts.

Cheers
Stuart

[LewisM]

I tried using my tube cutter, but:
1. the tube cutter I have is too small (the O.D of the tube I used is 4.5cm)
2. the wall thickness is 0.7cm

So, as you can see, a tube cutter really would have had a hard time coping with it, even if it did fit between :) Even a hacksaw with the tube in a vice would have taken a while.

[2stroke]

I use a brobo coldsaw http://www.brobo.com.au/coldsaws02.html at work which cuts tube perfectly and clean, so if you had to do it again just yell out to your local small metal supplier who will probably do it for $5 if not free lol. God do i need a lathe to, but money holds me back :(
Good work with the drem, lol i hate using the things for cutting because of disc breaking and flying miles.

[brian nordstrom]

:DTakahashi use good quality Aluminium Lewis , not Die cast ! .
Brian.

[LewisM]

I am not a complete moron Brian - I would NEVER cut a Takahashi part!!! The part I cut/modified was some no-brand Chinese adapter.

[brian nordstrom]

:shrug: Moron ,, WHAT??? settle Grettle ,Geez Bro .
Had me worried there .
Yea Chineese Alloy is carp . Its melting point is around 370 degrees , and it clogs cutting discs and is dangerous .
Brian.

[John0z]

LewisM,

Aluminium is easy to cut, especially if you have a bandsaw. On the subject of needing a lathe etc - it isn't quite that simple. In 2007, I also decided that I needed a lathe to do things around the house and for astronomy. Then to do a particular thing, I needed another tool or cutting bit - and now 5 years on - I realize that I have spent $7000 and still haven't quite made my first spur gear as yet, but did make a few things along the way. Right now I am restoring an old Tasco 5VTE that I picked up the other day. It needs a few pieces to fix up the mount, so am designing and making parts to make it functional since I don't know what the original parts looked like.

I could buy a lot of gear for that $7000, but I am almost there - just have to make some T-nuts and then my dividing gear will fit and I can start making a spur gear. (Soon, except that I had my calculations wrong and ended up with involute gear cutters that are a bit large - another $249 will fix that!)

-John

[brian nordstrom]

:) Bang on John , cold cuts are the only way to go with this "Plastic Steel" .
Brian.

[brian nordstrom]

:thumbsup: We have 2 Brobos at work , one for cutting steel and one for Non Ferrious , eg. Aluminium and stainless .
Cold cuts Lewis .
Brian.