Help with mini lathe/required tooling to turn a 20mm Cylinder from AL

Hi All

I have very little experience with metal-working, did some at college some years ago. I wish to buy a mini lathe solely for the purposes of turning a 20mm dia cylinder, stepped to 35mm, total length approximately 12cm. Aluminium or brass would be the material

I am just wondering which mini lathe might be recommended that comes with all required kit to accomplish.

Trying to keep purchase price as low as possible.

thanks

Hi where are you based it makes a difference different suppliers etc.

David

Dublin, Ireland

Finnian

There has to be someone in Dublin or thereabouts who would do that for you for a lot less than a lathe is going to cost, or even a kind competent sole on here. I would even offer myself but health limitations are in force at the moment.

Regards

Martin

Finnian,

Have a trawl around for Roche Engineering which is not a million miles from Dublin and speak to Fergal. I am sure he could knock that out in about 2 minutes for a small donation to the steam fund!

Paul.

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To answer Finnian's question directly (perhaps he wants to make several cylinders over a period, and doesn't want to rely on someone else):

Almost any mini-lathe will do the job. It could probably be done on a Microlathe (Seig C0 size), but I'm prejudiced against them - too small.

Cheapest way in the UK, not sure about Eire, is to order a mini-lathe direct from China. I wouldn't because of the hassle if the lathe turns out to be faulty, and because there's more risk it might be. Read the small-print, chances are you will be required to return a faulty machine at your cost, and this will be ouch expensive. The other issue is that some cheap machines are seconds or factory rejects. Safer to buy from a local vendor who you can talk to, preferably one with a reputation to protect.

You don't need an expensive mini-lathe - these have useful additions like hardened ways, more accessories, and brushless motors not needed for a simple turning job.

All mini-lathes I seen advertised come with a 3-jaw chuck, which is what's needed to hold the cylinder.

My advice, even though it's not critical, avoid very cheap. Something mid-range, about £500.

Brass is easy to cut dry, but don't get the swarf in your eyes!!! Aluminium isn't difficult provided you avoid the alloys that don't machine well. (For example the alloy used to make window frames is intended to be extruded. As such it's soft and sticky and it machines badly, yuk.) Other alloys are intended to be machined and are good to work with. Aluminium needs to be lubricated during cutting with paraffin or WD40 - splash it on with a brush.

An ordinary HSS RH Knife will turn the cylinder down to size. Likely you also need a LH Knife to 'face-off' the ends of the cylinder. 6x6mm or 8x8mm tools will fit the lathe, note they have to be shimmed so the cutting point is at the same height as the cylinder's centre. Occasionally mini-lathes come with a set of cutting tools, usually you have to buy them separately. Strictly speaking, you need a grinding wheel to keep HSS knives sharp. However, provided you don't let them get too blunt, they can be touched up with an ordinary oil-stone.

You could buy a parting tool to cut the cylinder off the stock. However as 'parting off' is quite difficult, especially on a mini-lathe, I'd hacksaw the cylinder off in a vice and return it to the lathe to be faced-off cleanly to size.

120mm is getting on the long side to be turned without support at the tail-stock end. But, with care you should be OK. If you can't hold the diameter (the lathe cuts a taper because the work bends during cutting), ask again.

For both Brass and Aluminium I'd run the lathe at about 500 rpm and take approx 0.2mm cuts. Experiment for best results.

Dave

Edited By SillyOldDuffer on 05/03/2019 10:26:43

Thanks to all, appreciate the helpfulness in offering to sort out this job for me. What Dave outlines above aligns well with my thinking. Would like to perhaps add a milling feature later on, but all work will be on a small scale and low volume of pieces. Looking at importing from Sherline in the USA.

I personally know little about any mini-lathes, but Sherline do have a few dealers in the EU, which might save on import taxes etc. as well as being closer for support issues.

Good luck with whichever way you go.
I'd probably be looking towards a used UK made machine, though transport to Ireland from the UK mainland might bump the price up somewhat.

Bill

The OP says stepped to 35mm, which might mean starting with 35mm diameter or so stock. No way you're going to be able to turn that down on a small lathe without tailstock support. I suspect a Sherline would be on the small side anyway as there's quite a bit of metal to remove.

Andrew

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Mini-lathe vs Sherline is an interesting comparison. I see the Sherline as more suitable for light fine work, mostly in plastics, brass or aluminium. The mini-lathe is a better option when power matters and the work not so delicate. The Sherline motor is 60W whereas mini-lathes are 450 to 850W depending on model. That's a big difference if you need to shift a lot of metal or drill big holes. A mini-lathe has no trouble with mild or silver steel.

I was disappointed by the mini-lathe's milling vice, too limiting and incapable of taking deep cuts. Sherline's milling attachment looks a lot better (and is considerably more expensive), but again I would see it as being for fine work only, not metal munching,

Quite important to understand what the lathe is for. For example a Sherline would be completely out of its depth making motor-bike parts. Likewise a clock-maker would do better with a Sherline than a Gear Head monster. I found the mini-lathe excellent for learning on, but after a while 'buy the biggest you can afford' turned out to be good advice. I'm not into clocks or model railways though!

Dave

Although a Sherline and U3 would do it the question is how long do you want the job to take as neither will shift metal quickly, I know my U3 would take a long time to do it which is why it's in a cupboard collecting dust..

So Mini-lathe / C3 size would be the better option particularly if this is the sort of size you are likely to be working in, different if other things you want to make will be substantially smaller.

I think if I reversed the jaws in my C0, it might *just*cope with 35mm, but it'd be a close-run thing. I bought it for use in a teeny-tiny house we lived in part-time temporarily, and - without prejudice - it's best used for teeny-tiny work.

C3 type mini lathe would be ideal.

Bundled brazed carbide tools are unlikely to suit the work you want to do.

A cheap set of HSS tools should set you up, and use a touch of cutting oil applied by brush for a good finish.

Several good books on using Mini Lathes, I'd recommend the one written by me, but I might be biased

Neil