Appropriate lathe?

[rvt]

Hello,

I'm looking for a small lathe for some metal work, details on previous thread[/ulr].

<snip>

a lathe to machine 4-5mm (roughly) off a camera lens adapter, as it is to thick. Not being a machinist myself, I am told it could be faced off in the lathe, the outside diameter (one example, they vary slightly) is (62 mm) and is (49 mm) inside and they are generally made out of quite soft metals, often brass. The adapter, excluding the mounting ring, is 10mm thick.

<snip>

I'm not sure if my uncle might have something lying around in an old garage yet, but anyway, would this ? be appropriate? I can't spend a great deal of money on it, but then it's not a very demanding task. Would I be able to fit the adapter straight onto the lathe listed above or would i need a different chuck?

Thanks for your time.

p.s. yes that's the cheapest I could find ! Are there any second hand sales on this website?

[andyf]

I'm sure it would do the jobs you describe just fine. It's a pretty basic machine, made to compete with the little Unimat lathe, and some examples are not of brilliant quality. Here it is at £191 inc. carriage from Arc Euro Trade, which is, like Axminster, a reputable dealer:
http://www.arceurotrade.co.uk/Catalogue/Machines-Accessories/Lathes/C0-Baby-Lathe
There's a link on that page to a review, which I've read. It might be a bit too enthusiastc.

Some cutting tools will be needed. You mentioned brass, which requires a particular profile on the end of the tool for best results. If  your camera work also involves aluminium, a different profile is needed. You would probably do best to grind your own tools out of HSS (high speed steel) blanks, which will involve getting a grinder (one expense leads to another with lathes  ) . For reasons too involved to set out here, it might be wise to avoid carbide tools.

You mentioned that holes might need drilling; looking at the shape shown in the photo you posted in the previous thread, I doubt if this lathe will be much help on that score.

As to second-hand stuff, someone may come up with something. Unfortunately I don't want to sell it, but I've got a baby lathe which would do the job perfectly:
http://andysmachines.weebly.com/perris-baby-lathe.html
40-odd years old, and still going strong, though I did have had to do major repairs on its headstock three years ago.

Andy
 

[rvt]

Thanks for the info Andy! Yeah, it seems about as basic as you can get, but then I think the work is pretty basic as well so hopefully it'll work well.

To be honest, I'm not great at identifying the metals in hand, but the supplier will list them when i purchase. The one i have to hand now is aluminium. Is there a basic guide for how to make the different cutting tools for different metals? I have access to a grinder, so that shouldn't be too much trouble. Can I ask why different metals require different profiles?

Drilling is no problem, we have a bench mounted drill for that. As I say, I've done loads of lens conversions in the past, it's just with making a 'kit' it requires making things 'fool proof' and so means I need a thicker piece of metal to work from.

Your mini lathe does look excellent. I bet it's expensive even if you were selling it! Looks very well made.

[andyf]

Hi rvt,

There are others on here who know far more about it than I (a mere amateur tinkerer) do.This might give you some insight, or it might just baffle you further:
http://www.mini-lathe.com/mini_lathe/tool_grinding/tool_grinding.htm
Aluminium and brass are touched on near the bottom of the page.

My baby lathe is still in production, in an evolved form, by Cowells Small Machine Tools, at a stratospheric price.

The Peatol (in the UK, Taig in the US) is a versatile little machine:
http://www.peatol.com/
You seem to be able to buy as much of it as you want - for example, you wouldn't need a tailstock for your immediate purposes.

In your related thread, you mentioned a feature which might make the work difficult to hold. The stepped outer part of the jaws on a 3-jaw chuck (see the Axminster and Arc Euro photos, not the Peatol one) could be used to grip the work from inside, with the protruding widget between two of the jaws, if it only takes up a quarter or so of the internal circumference. Alternatively, if all you want to do is reduce the depth or thickness of the piece down by a mm or so from its present 10mm depth, you could hold it by the outside with a chuck configured as in the Peatol picture, with one end pressed up against the steps on the jaws. Most 3-jaw chucks come with a second set of jaws for that sort of purpose, but it is as well to check that before buying anything.

Andy

[Jasonb]

The only thing to watch out for when holding those adaptor rings is that you do not distort the metal which would quite easily happen with a standard 3 jaw chuck. Ideally they should be held with softjaws machined to suit the job or better still a threaded arbour that the adaptor can screw onto. Unfortunately a chuck with softjaws will not come on these small machines, you will ned something bigger and then have to purchase the jaws to suit the supplied chuck or a complete chuck/backplate and jaws.

Jason

[rvt]

Thanks for explaining that Andy. Hadn't actually taken a look at the closer photos, I see how the chuck works now. The chip is just under a quarter of the circumference, so I think it'll be fine. I'll have to do a couple of tests though, as Jason says bending and warping the adapter to hold it tight would completely ruin it. As I have never used one before, I am unsure of whether this will be an issue or not.

A 'threaded arbour' is an interesting idea. The adapter I'm grinding has a thread inside it naturally.

The inside threaded diameter (the other side, where it would be attached to the lathe) is 45mm. So, I guess somewhere I could find or find someone who would make, a chuck that would fit where i could simply thread the adapter on?

However, that has to be a plan b. As if I go down that route I would have to buy the adapter and chip seperately (couldn't thread it with the chip there) which would add more labour time (and the point is to cut down labour time).

Thanks everyone for their input!

[Divided he ad]

(see the Axminster and Arc Euro photos, not the Peatol one)

Unfortunately a chuck with softjaws will not come on these small machines, you will need something bigger and then have to purchase the jaws to suit the supplied chuck or a complete chuck/backplate and jaws.

A bit of mis-information me thinks!

Peatol 3 jaw chuck comes with easily changeable machinable soft jaws as standard! Which can be made to fit the job perfectly!  I know, I own one!



I've already PM'd Rich with all this info.




Ralph.

[Dean W]

The Peatol three jaw chuck can also be had with full circle soft jaws, that  can be machined to lightly grip the entire inner or outer circumference of your widget. 

I have one too.  I've use mine to make camera parts for years.  Give it a look, RVT.

I'm not selling anything, but see my web page below my name for more info on this lathe, (goes by a different name in the USA, but made at the same factory).

Dean
http://www.deansphotographica.com/machining/projects/projects.html

[Brass_Machine]

Nice site Dean!

Eric

[Dean W]

Thanks indeed, Eric!

Dean

[Davo J]

Hi RVT,
Good to see you over here, Welcome.
I did tell you Madmodders would help you out.
Now your looking at buying your own lathe, a mill will be next.
Davo.

[Divided he ad]

As Eric said "Nice site Dean" 

I do like pretty much all of the innovations in the tooling department, the compound vertical milling slide and the indicator holder are both very simple and effective. But I love the lead screw idea, and the fact that you guide people through the process    

All things I'd have never thought of!    I don't use the little fella much any more, if I did I'd sure be making some of those mod's 


How do people find the time to make all this stuff, post on forums, run a website and earn a living?      





Ralph.