A very useful material

[centroid]

For making adapters, and extension tubes etc, Delrin (aka Acetal) is an ideal material. Its tough and versatile engineering grade plastic.

It machines easliy, and as such can 'turned' in the lathe, drilled/bored, and threaded etc. It usually comes in rod form, and is available in a good variety of diameters. Although its available in black or wight, the black is eminently suited to astro work, as it gives a nice matt black finish, when machined. If you like it to look 'posh', you can always buff-up the outside surface. .

Unlike aluminium, it doesn't need anodising of course, which makes ideal for DiY projects.

Its relatively cheap, I have just bought a piece 500mm long and 40mm dia, for £8.75, of which I'll be using a piece to make a focuser extension tube for the ZS66..

I've seen it available in 15, 20, 30, 40, 50, 60, 80, 90, and 100mm diameters. There maybe other sizes, but I'm not aware of them.

I've also found a very reliable supplier, that sells it it small cut lengths, e.g. in some cases, a 100mm length.

There's a couple of pictures below, one showing the Delrin rod, as supplied, and another (albeit a lousy picture, sorry), of an extension tube I made for the ED80/DSI combination, a few years ago.

Hope this info is useful, to anyone contemplating' making any 'bits and pieces'.

I can provide the details of where I buy the Delrin, if anybody needs to know.

Dave

[jcm]

Yep , good stuff for making telescope bits. The only problem I have found is you must not make the "walls" of anything you make too thin or they will deform when you put pressure on them.

John

[Doc]

I've seen this on e-bay alot and have often wondered whats it like.

Only problem is I need a machinist as well and thats where it comes expensive.

[PhillyDee]

I know what you mean. I am a miller/turner and unfortunatley the place I am currently working doesnt have much provision for doing 'guvvy jobs'. Especially threads on turned materials. Plenty of taps, but nothing fine pitched. Everywhere else I used to program machines that worked with bar/billet materials such as aluminium and you could always find a spare 15 minutes to knock up your own project. Its a shame my current machine has a 1 metre horizontal chuck.

[centroid]

A 1 metre Chuck :shock: , now that's a serious piece of 'kit' .

Nothing like that here, just a 'hobby lathe' with a 3.5" chuck, 300mm between dead centres, and a max work dia of 180mm, but is does all that I need it to do.

As a retired RF/electronics/EMS engineer, this was a whole new 'skill set' to try and learn :scratch: , but with practice and a lot of reading, I now manage quite well.

It was astronomy that made me buy the lathe. I needed an ext/adapter made, as a 'one off', and although it was quite a simple piece engineering with a lathe, it cost £50.

So, I thought, "why not buy a small lathe, and make things for myself". Its going to be long time before it 'pays for itself', but I quite enjoy using it.

John, yep, you've got to leave a reasonable thickness of 'wall' to ensure rigidity, but that said, its not proven to be any problem, as far as vignetting etc is concerned.

I could 'work' in Aluminium, but it then needs anodising. I know it is possible to do this at home, using 'Dylon' dye, etc, but it involves the use of reasonably concentrated Sulphuric Acid, which 1. is not easy to obtain, and 2., is not the nicest of materials to have laying around, especially with grandchildren.

Dave

[beamish]

............. but it involves the use of reasonably concentrated Sulphuric Acid, which 1. is not easy to obtain, and 2., is not the nicest of materials to have laying around, especially with grandchildren.

Dave

:shock: tell me about it, I've still got bottles of conc Nitric and Sulphuric from when I was a jeweller, Had to carefully wrap them and cossett them before hiding in the voids under the floor boards via the basement to avoid ANY accidents.

If anyone knows how/where I might be able to legally and safely get rid I'd be grateful for ideas.

Karlo

[Psychobilly]

I do most of my prototyping in SpeedAL very nice to machine...but would be interested in your source for the Black Delrin...

I Have a Myford ML7 , Centec 2A universal Mill, 12 Speed Drill Press, Metal cutting Bandsaw , Mig, Arc and gas welding etc in the garage ... it hasnt seen a car for the last 5 years....

Billy...

[centroid]

Karlo, I'm sure that you local council (environmental health dept, maybe), could dispose of it, or at least tell you where you can.

Pre 1964, prior joining the GPO Telephone Eng, which later became BT, I used to drive articulated tankers, carrying, Sulphuric, Nitric, and Hydrochloric Acid, from one end of the country to the other.

In fact those days, you could go to the likes of your local Halfords, and buy a bottle of battery acid (Sulphuric Acid diluted to a 'specific gravity' of 1.30 or 1.27), but still quite capable giving a nasty burn.

Not possible to buy it so readily now though, with all the restrictions that are in place.

Dave

[centroid]

Peter, your 'kit' is in a 'different league' to mine.

I've got the 7x12 Mini Lathe, a Pillar Drill, and a Grinder, and that's it. Albeit I thinking about buying a vertical slide for the Lathe, to give some limited milling facility.

I'll PM you the details on where to buy the Delrin.

Dave

[beamish]

Cheers Dave.

Yup I had to buy mine from a specific source in Hatton Garden.

[Psychobilly]

I better hang on to my full winchesters of conc Hydrochloric, Sulphuric and Nitric acids then... and some other more "exotic" stuff

[Wobbly Bob]

Dave, I was looking for just such material a couple of weeks back, you WILL have to let me know of your secret supplier next time we meet.

[ChrisEdu]

:shock: tell me about it, I've still got bottles of conc Nitric and Sulphuric from when I was a jeweller, Had to carefully wrap them and cossett them before hiding in the voids under the floor boards via the basement to avoid ANY accidents.

If anyone knows how/where I might be able to legally and safely get rid I'd be grateful for ideas.

Karlo

Contact your local high school - they might well appreciate having some for use in chemistry lessons.

[Black Shuck]

Karlo, I'm sure that you local council (environmental health dept, maybe), could dispose of it, or at least tell you where you can.

Dave

Agreed. The Environment Agency would direct you to your local council to advise.

£

[astro_dt]

Hope this info is useful, to anyone contemplating' making any 'bits and pieces'.

I can provide the details of where I buy the Delrin, if anybody needs to know.

Dave

Hi Dave

I would like to know your source (PM if you want). Luckily I have a relative who build clocks and steam engines so he machines stuff up for me.

Cheers

Danny

[centroid]

Bob/Danny

PM sent.

Dave