Mini lathes - possible to turn stainless?

It's getting to the point now where I have to admit defeat & seriously consider shelling out for a mini lathe (her indoors isn't going to see the funny side of this one at all).

To justify the purchase to myself, I need to be convinced that it is possible to turn Stailness A2 rod.

i'm talking here, skimming (is that the right term?!) 2mm off M10 diameter ...to a length of about 20mm.

Someof the more recent mini lathes have decent sized motors (by mini lathe standards).

here's one at 400W I'm thinking about....

http://cgi.ebay.co.uk/Mini-Lathe-Bra...lenotsupported

or a slightly larger model for £50 more...

http://cgi.ebay.co.uk/Mini-Lathe-Bra...lenotsupported

In the main, I'll likely only be turning acrylic, aluminium & perhaps a bit of brass ...but just wanted to know if stainless is do-able in small bite size chunks approach?!

Hank

If all you want to do is turn small pieces i would consider second hand. Save yourself a fortune. i have a tiny unitmat that will only take up to 20mm in the chuck that does well enough. Decent cutters and cooling (bucket, small bore hose and a windscreen washer motor with sponge over the end) is priority. The lathe you see there is the same as clarke, axminster and sealey in the same clothing. I must admit i do have a bigger lathe but by the time you buy all the other tools to go with it-----phew fortune blown.

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Originally Posted by 2e0poz

Hank

If all you want to do is turn small pieces i would consider second hand. Save yourself a fortune. i have a tiny unitmat that will only take up to 20mm in the chuck that does well enough. Decent cutters and cooling (bucket, small bore hose and a windscreen washer motor with sponge over the end) is priority. The lathe you see there is the same as clarke, axminster and sealey in the same clothing. I must admit i do have a bigger lathe but by the time you buy all the other tools to go with it-----phew fortune blown.

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The problem is that I need to turn up to 3"-4" lumps of acrylic...so I do need the larger chuck size.

Have you a pic of that cooling system? I'm curious how the sponge fits into the equation (what's its purpose)

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Originally Posted by HankMcSpank

I'm curious how the sponge fits into the equation (what's its purpose)

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Filter, goes over the pump pickup.
Sounds overkill to me on a small lathe, ran one for years with nothing but a coffee can and a paint brush, at least you get it where you need it which isn't in your boots :heehee:

.

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Originally Posted by Kip

.tip's are expensive at around £18 for 10.

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That's cheap, not expensive, some of mine are nearly £10 per tip and only one cutting edge.

Hank i wish had one to show you as it was only a suggestion to improvise. Like John said it is to stop cutting being sucked back up. We have a chap here in Swindon selling a lathe for £150 from his business workshop, sounds great till you see it. Its huge and would require a forklift to shift it and no room for that???? One place people forget for cheap secondhand are the papers like 'Loot'. Hope you find one for the right price.

Hank,

Either of those lathes are the ones to go for (i'd go for the larger motor). They're a different manufacturer that the Axminster, Chester, Clarke, etc.

Differences (improvements) over the Chester, etc include:
Heat treated ways (if you believe the sticker)
Rectangular saddle (Chester etc has rough-cast "H" shaped saddle)
Way oilers in saddle
Way wipers
More powerful motor

I have a 4yr old Chester, and would buy the one you've linked to next time.

I've never cut stainless, but it work hardens so you need to take as big a bite as you can each time. I've turned 5inch diameter alu before (bolted directly to the spindle face), so they're pretty flexible. Motor power would be a problem if you tried steel in the same diameter.

It almost certainly won't cut stainless "out of the box". I was very disappointed with my lathe to begin with. I even struggled with (small diameter) steel until I'd done a fair bit of adjustment. With a sharp bit now though I can take 2mm off a steel diameter without too much bother (I changed the spindle bearings to taper rollers before doing this). They're great lathes as long as you treat them as kits for finishing, rather than production-ready.

Enjoy!

Hi 2E0poz ...alas whatever I buy has to go through a loft hatch!

Tom, thanks for the input - I think they're from the Real Bull factory in China (SPG tools is slioghtly cheaper, but out of stock for a week or two ...plus he's in the Midlands whereas this seller I linked to is only 20 mins drive away here in London.

The seller has been very clever with the lathe price points.

Yes The £340 lather is the better buy, but he also does a lathe with some useful accessories deal for a sneaky £395 (http://cgi.ebay.co.uk/Mini-Lathe-Bra...lenotsupported) ....it can all end up getting a little more than I'd expected to pay!

I spent weeks looking at what i could buy. Scoured Ebay etc and ended up for piece of mind going to Machine Mart and buying the Clarke 430. A lot of people would not rate it but for my needs it was fine. If it goes wrong i can pop round the corner and bang on their door. If you've ever pick one of these up (it take two very strong people) you would NOT even consider trying to get it through a loft hatch. pop along to a tool place for a proper look before you do. A hurnia would seem like a child's ticlky throat in comparison...........If you was to look at machine mart and compare the size between the models they have, at least you would be able to see what you et for your money. All said and done they are a good price for they can do. Ask about the version with the milling drill? do forget they dont always include a table though :-)

hank almost forgot, don't forget to check what the diameter of through hole is behind the chuck. If it is not wide enough it can be limiting. my friends small lathe has a good size chuck but can only fit up to 6mm diameter through.

yeah...I think I got that one covered....

Power 550W
Distance between centres : 350mm
Swing Over Bed: 180mm
Swing Over Cross Slide: 110mm
Taper: MT3
Tailstock Taper: MT2
Chuck diameter: 80mm
Spindle Speed: 50 - 2500rpm
Spindle Bore: 20mm
Cross slide Travel: 65mm
Chuck diameter 100mm (Integral spindle plate is 100mm no adapter plate required)
Range of Metric Threads: 0.5 - 2.5mm.
Range of Imperial Threads: 12 - 52 TPI.
Spindle Accuracy: 0.01mm.
Size with packaging is L: 81cm W: 30.5cm H: 31.5cm
Operating instructions enclosed.
American circuit board
230v 50Hz motor
Actual dimensions of lathe - 29in.x 10in.x 9½ in.
Net weight/Gross weight : 42/45Kg.


I'll dismantle it to take it up into the loft!

Having spent too long researching these over the past few days, I'd learnt that an independent 4 jaw was going to be the most useful, therefore I'll probably take the package & just flog the 3 jaw chuck on (most comments I've read suggest that you never go back to a 3 jaw after using an independent 4 jaw!).

I genuinely don't know what size tooling it uses yet (I'm hopefully going to see these at his premises tomorrow)

Here's my initial shoppinng list...

the lathe ith independent 4 jaw chuck.
tailstock chuck
A cutting set! (was just going to go HSS as I have a grinder and read that it's easy to maintain these youirself)

nice to haves...

lever tailstock
Quick change toolpost.
proper boring rod.

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Originally Posted by HankMcSpank

Having spent too long researching these over the past few days, I'd learnt that an independent 4 jaw was going to be the most useful, therefore I'll probably take the package & just flog the 3 jaw chuck on (most comments I've read suggest that you never go back to a 3 jaw after using an independent 4 jaw!).

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If you are worried about run out on your 3 jaw then get yourself a set of soft jaws for it and bore them out on the machine that it will be used on. I have done this many times before, its quick and easy to do.

Just a thought....

What a splendid idea....do these soft jaws cost much? (cos it may be cheaper just to buy a 4 jaw independent chuck!

Perhaps I need to hold fire on this as there's stuff popping up that I'd never considered (& it's stuff that'll save me outlay!)

Soft jaws should only be about £20-£30 a set depending on the chuck manufacturer.

They do have more uses than just boring out the inside diameter to prevent runout, you can also bore out the face's with a shoulder for holding larger dia items. Say you had a 100mm dia circular bearing holder with a finish width of 20mm then you could bore the jaws at 100mm dia down to a depth of say 15mm, cut the 100 mm dia material a couple of mm's oversize in a saw and then when you put it in the chuck and tap it up to the shoulder it will run true and will be easy to get the width parallel.

Also if you bore them to the size of the part you are machining then it helps prevent marking of the workpiece that hard jaws can sometimes leave, specially on soft material like aluminum.

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Originally Posted by Kip

If you're using 10mm tooling I have a "gret handful" of brazed carbide tooling (new) you can have as I never use it.

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Wow, what a kind offfer, I'm starting from zip .....I'd like to take you up on that if the lathe turns out to take 10mm tools - thanks! (these will no doubt weigh a little bit...obviously I'll pay the postage!)

I'll let you know later!

You'll get a flavour for why I need a lathe from this set of photos, I've just completed this -

http://img21.imageshack.us/img21/6344/26752070.th.jpg


http://img31.imageshack.us/img31/1180/36950560.th.jpg
(those lines are on the lower surface - top is nice & smooth. That centre circle looks a little odd as I haven't come all the way through to the top surface with it . - also those little holes are meant to be different - there are two sizes of DIY pickups I need to mount, both of which have different pole spacings)


The cheapest/quickest traversing pickup winder I can dream up....

http://img160.imageshack.us/img160/6553/14811707.th.jpg


"What I learnt today" - biggish circular stuff is painful to do on a mill and doesn't look so neat after either!

(& I dare say not that 'true' either!)

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Originally Posted by Kip

But did you leave a little bit for finishing? A lot of the things I make I don't bother with a finishing pass as it's more a functional than aesthetically pleasing thing.....I just bought an Alimaster milling cutter made by Mitsubishi....just to see if it's better than the Alu Power I got given to try....Amazing finish by comparison to an old Hydra Al cutter....With a finishing pass it left a mirror finish! :beer:

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Oops pressed the thanks button there by accident - have one anyway (for the offer of the tools!)


No I didn't use a finishing pass...1. becuase I've never used them (!) & 2. I've not bothered to work out how finishing passes would slot into my workflow!

This was just to get a cheap & dirty coil winder wheel in situ PDQ.

Couldn't get over there today (it's further than I thought & this is London!).

Called the seller - it seems it does take 10mm tools ....Kip I'll PM you!

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Originally Posted by HankMcSpank

"What I learnt today" - biggish circular stuff is painful to do on a mill and doesn't look so neat after either!

(& I dare say not that 'true' either!)

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To do circular stuff in a mill, mount the workpiece on the spindle and clamp the lathe tool(s) to the bed using a vice or purpose-made jig.

See [ame="http://www.youtube.com/watch?v=wbfXXeiSHsw"]YouTube - Taig mill turning bushings[/ame] as an example

Quote:

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Originally Posted by HankMcSpank

Having spent too long researching these over the past few days, I'd learnt that an independent 4 jaw was going to be the most useful, therefore I'll probably take the package & just flog the 3 jaw chuck on (most comments I've read suggest that you never go back to a 3 jaw after using an independent 4 jaw!).

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Hank,

If you go the 4 jaw independent route, consider getting a larger chuck than standard. Standard is 75mm.
100mm and 125mm are both options. 125mm uses up a fair bit of bed length, but i've found myself boring holes in sheet that I wouldn't have been able to hold in a 100mm chuck. Also the large spinning mass has smoothed some of my cuts out (not to mention making the lathe significantly more DEADLY :twisted:)
:biggrin:

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Originally Posted by Kip

PM returned matey.. :beer: 12mm shanks..... might still "fit"

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A judiscious amount of googling has confirmed they will still fit - I'll paypal you now.

Cheers!!!! :beer:

thanks Tom...I'll likely just buy it with a 4" 4 jaw independent. I did look into 5" chucks the other day...but they seemed fairly scarce (maybe I was looking in the worng places!) & very expensive

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Originally Posted by Kip

PM returned matey.. :beer: 12mm shanks..... might still "fit"

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Got any more Kip?

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Originally Posted by HankMcSpank

Couldn't get over there today (it's further than I thought & this is London!).

Called the seller - it seems it does take 10mm tools ....Kip I'll PM you!

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So what have you bought?

Pity I'd have swapped you for 5 ballscrews and 4 stepper drives, too late now ........................

.

If you can file something then you can turn it, as simple as that. Some stainless is "free cutting" and is much easier to cut but all stainless can be turned. Cutting speeds are important and HSS will cut although not as good as tipped tools. Size of lathe is unimportant so buy one that you have the space for. Remember, don't try too big a cut on too high a speed. One answer states that ss hardens as you cut, not true. The only time it will harden is with excessive heat generated from a tool that rubs stock away rather than cut it and you should always use a small amount of coolant anyway as the cutting action itself will generate a certain amount of heat. When I have finished turning anything I can touch it with my bare hand so the heat generated is only minor. Your turnings should be the same colour as the stock, this is always a good guide on how much heat is being generated. All the above is a general rule and by no means definitive.

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it almost certainly won't cut stainless "out of the box". I was very disappointed with my lathe to begin with. I even struggled with (small diameter) steel until I'd done a fair bit of adjustment. With a sharp bit now though I can take 2mm off a steel diameter without too much bother (I changed the spindle bearings to taper rollers before doing this). They're great lathes as long as you treat them as kits for finishing, rather than production-ready.

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Hi Tom

Are you saying the cutters fo these mini lathes won't cut the steel or the machine is not up to it?
Thanks.

Hi. Not sure about the cheaper ones but a Sherline will handle anything that'll go in the chuck up to it's full capacity. I've turned a lot of 45mm dia cast iron and mild steel without any problems at all. Made stainless parts and the od bit of silver steel. If you want to turn down rod the chucks are very accurate if you keep the scroll clean, mines less than 0.25 thou run out.
Tom

Before building up your hopes too much, I suggest you talk to whoever is supplying the lathe about a few of the items that have been mentioned.

The chuck backplate that usually comes with a minilathe is usually a standard sized one that takes specific sized chucks, so any thoughts of larger ones will require a chuck backplate change. Also, you will have to take into account the mass of a larger chuck will have on the fairly frail gears in the headstock. So changing out for metal gears would be a recommended option, and while you are there, you may as well fit tapered bearings to the spindle, and they will require to be preloaded correctly.

Also soft jaws are not as universally available as you seem to think. The chuck manufacturers use all sorts of different measurements when making their chucks, width of jaws, scroll size etc. So just going in and asking for a set of soft jaws for a 100mm chuck will most probably get the reply, which manufacturer? You might be lucky and the retailer knows if they are available for the chuck on your particular mini lathe, but don't count on it. I don't buy 3 or 4 jaw self centring chucks unless I can buy soft jaws at the same time, because trying to trace ones to fit later can be a real PITA.

Also, as mentioned before, the mini lathe comes ready assembled. That means it has been put together in a rough order. The final tuning depends on yourself.
Having done set up tuning on a fair few of these machines, I would say at least four or five hours to get it to a machining ready state, if you don't know what you are doing, get someone in who does know. The way the saddle, cross and compound gibs are set on these machines really does take some very fine tuning to get them right, and if they are not done correctly, you may as well kiss goodbye to fine finishes and close tolerances. Even the leadscrew usually requires tuning into position.

I am definitely not trying to put you off, I am just preparing you for what WILL be required before you can do any serious machining with it.

But once done correctly, they will usually cope with most things you can throw at them.

Also don't forget, the correct slideway oil must be introduced to all gibbed slideways before attempting to adjust, and the correct oil is NOT engine oil or WD40, use a correct way oil, usually it has a 68 in the name somewhere, it is designed to do the job properly.

Bogs