Mini Lathe vs. Watchmakers Lathe

Hi,

I was pondering the subject of do I need a watchmakers lather or a mini lathe. I looked at some of the discussion groups and on the whole the thinking was that the watchmakers lather would provide greater precision and / or would provide better feel when using the tailstock for drilling.

Well I firmly agree with the level of feel from the tailstock while drilling, but as for accuracy I am no so sure, here is what I think...

The 'graving' method of material remova' that the watchmakers use would not be safe on a mini lathe. Yes, it would be possible to add a tool rest. But just look at the saddle and cross slide on a mini lathe. On a mini lathe these parts of the machine are (more or less) non removable and full of sharp corners and edges.

Also if you look at the collet options on a mini lathe I don't think that these would be suitable lots of edges to engage a C wrench all more or less designed to remove the skin on ones knuckles.

So in my humble opinion the reason for the watchmakers lathe is to enable safe use of the graver.

I also worry about the stall torque of comparison, the stall torque of the mini later is too high while the rotational speed is much too low.

Graeme

The cross slide can be removed from a Mini-lathe just as it can from most lathes. This gives you a nice flat surface to mount a hand rest which is something I have done a lot on my larger lathes mostly for turning wood but also metal. However most of the time when I want to use a hand held tool I just stick a bit of bar in the tool post and use that as a rest.

Mini-lathes have the option to use finger collets just like you use on a watchmakers lathe so you don't have to worry about hitting your knuckles on a chuck jaw or collet nut. If you do want to use an ER type collet then smooth nuts are available or easy enough to make your own or ft a simple 3D printed cover.

Not even sure stalling comes into it at watch making sizes a mini-lathe will have ample power to take the small cuts associated with a graver. The small work size sizes also mean you will be running at a high spindle speed where the electronically controlled motor speed will be high so the motor is putting out it's full power.

And if you want more "feel" when drilling from the tailstock, make or buy a small lever-operated sensitive drilling attachment that plugs into the existing tailstock taper. There will be an article and drawings to make one come up in MEW at some point in the not too distant future.

I use a graver on my Super 7 with no problems at all. I built the George Thomas hand turning rest (Hemmingway do a kit).

regards Martin

this is my setup best of both worlds for me , I use the graver a lot but I can also use the crosslide 

Edited By Dell on 31/01/2023 09:20:12

Edited By Dell on 31/01/2023 09:22:49

The answer depends very much on what the lathe is used for!

If the hobby is delicate watchmaking type work, then a watchmakers lathe is super for that: plain turning, collets, and hand-graving etc. They're for small objects that turn best at high speed, which is also needed for drilling holes less than 2 or 3mm diameter.

Mini-lathes are more general purpose. Compared with a watchmakers lathe, they're more powerful, able to handle considerably bigger jobs, screw-cut, and auto-feed the carriage. They come with accessories suitable for 'next size up' work - steadies, 3-jaw chuck, and a sturdy tailstock. Mine was excellent for learning 'big lathe' technique on, and I realised fairly quickly that it's chief fault was being a shade too small for the sort of work I do.

It's usually good advice to buy the biggest lathe you can afford. It's because big machines can be cajoled into doing small work, but small machines can't do big. But the advice assumes the owner does a wide range of work and isn't a specialist. Doing tiny turning on a giant lathe soon gets frustrating.

Workshop size is often a problem. I think one reason Myfords are so popular is that they're the perfect compromise size for a small workshop. They can be squeezed into a tight space but are big enough to tackle serious work. I think WM250 size Far Eastern lathes are popular for the same reason: more capable than a mini-lathe, but not monster big.

One way of deciding is to think about how much swarf your hobby will produce. A watchmakers lathe is a precision tool that takes forever to produce a significant amount of swarf. Lathes used by a busy hobbyist to make 5" scale locomotives or do repair work can create a bagful of swarf in a single session.  Which best describes the work you want to do?

Dave

Edited By SillyOldDuffer on 31/01/2023 10:00:10

Go for a watchmakers lathe if you want extreme accuracy. I have a BTM watchmakers lathe with compound slide and lever tailstock. Based on the dimensions of a German Boley lathe

BTM watchmakers lathe

The drawback of the watchmakers' lathe for model engineering is that it's less suitable for making the small batches of identical or similar components that projects quite often require. They're more suitable for the replication of random individual components as needed than working to drawings. You can't set an accurate depth of cut with a toolrest and graver - you just have to put the time in to creep up on the needed dimension.

Watchmakers lathes are also often too small. I started with a Unimat3, which is a bit bigger than most watchmakers's lathes, and even building a Stuart 10V needed a bit of design variation to machine it on there.

As others have said, it depends what you want to do.

I've done a lot of turning in a hobby lathe with work held in an ER32 collet in a collet chuck. Some of it using a graver. Check out what Clickspring on youtube can do with a graver in a largish lathe!

On the other hand I am in the process of doing some very detailed work (M1.2 threads in an1.5mm cylinder and I think I will struggle due to the low speed of the lather (max 2000) and the inaccuracy of the tailstock. I'm expecting to buy / make various tools (such as a sensitive drilling attachment) to attempt to get close.

At some point I want to buy a watchmakers lathe to do exactly that sort of thing, but I'm under orders to wait until our (hopefully) upcoming house move.

Also, I've been trying to wortk with 1 and 2mm end mills in my mill and they break very easily - I think they should be running at around 30,000 rpm and not 2000!

Horses for courses.

Iain

As Dave (SOD) says it mainly depends on what you want to do with the lathe, but it also depends on how deep your pockets are, and what level of precision you are aiming for.

A decent watchmakers lathe in excellent condition is expensive A second hand one is cheaper, but the bits come expernsive - 8mm collets can run £10 each second hand and you need one for every 0.1mm - and the precision is questionable.

Can I suggest - if you are in between the mini lathe or watchmakers lathe - that you look at something like a Sherline, Taig or with deeper pockets one of Cowells. They are a good compromise between the two.

My Taig (with an ER collet headstock and shop made power feed) works well and is safe enough with a graver (I would not want to use a graver with a 3 or 4 jaw chuck!) and I can turn up to 6" diameter using riser blocks if needs be. Many of the professional clock repairers use Sherline machines.

Thread cutting at over 2000 RPM sounds Interesting!

Not entirely sure why you say that unless you refer to having a plain bearing headstock?

regards Martin

Gah! I meant drilling at 2000 (of course!). Threading will be nearer 2 rpm I suspect (and consume many taps )

Iain

Yes I'm in agreement with the taig/ sherline thing as mine are capable of very accurate work and I'm happy using a graver on that and the S7 with a GHT rest. On the point of speed I get my tags up to 9000rpm with no ill effects and it does help when working with small diameters or with tiny milling cutters

I was going to suggest a Sherline I know it’s American but there is a company in the uk that sells everything from Sherline and all accessories are easily available, I see there is one for sale in the classifieds on here.

I know I only repair antique clocks but if I hadn’t found the Pultra I would’ve purchased a Sherline.

Dell

Maybe compare a ‘clock maker’ lathe with a ‘mini lathe’. I reckon making watch parts are likely just a too-fine job with a mini lathe. But I daresay those with only a min lathe would likely dispute my opinion.

If you get a mini-lathe you might well at some time want to make a small drilling spindle for it (rather than cobbling up a holder for a Dremel) that can also help with gear cutting either for milling or for acting as a dividing head. If you make this in a suitable way you can also make it work as a watchmaker's lathe headstock.

In regards to your concern about the danger of hand turning with an er collet chuck, check out these totally smooth collet nuts:

https://a.aliexpress.com/_EvPbRBT

I'd be tempted to go with a Cowells 90CW if you have deep pockets. It's kinda halfway between a watchmakers lathe and a mini lathe. 😎

I agree with the Sherline option. It's so adaptable with a huge range of accessories.

You can single point cut threads down to M1 x 0.25 and 5 minutes later be turning down 3" bar.

It is as accurate as you can set it up to be and great for hand graving.

I usually use 8mm watchmakers collets with mine as I already had a good selection.

Also, if you have the Sherline mill, it can share the headstock and motor assembly and loads of other accessories.

I was not worried about hand turning with an ER collet chuck. It was doing so with a standard 3 or 4 jaw!