My Unimat Metal Line

(or something like that)

For a little while now, I've had one of these funny Chinese lathe kits made of extruded aluminium and castings, mostly held together with wedges and M4 bolts. Suitable kits can be reconfigured in various ways and there are a few extensions.

It's hard to come up with a name or designation for these. Lacking that, I'm calling this a Unimat (1) ML as that's the closest resemblance.

Which unit do I have?

Mine is an all-metal kit with the 50 mm riser blocks (no lower ones) and a four way toolpost plus possibly an upgraded motor ("power line"?). It has endcaps marked "Tool The First" and which is nonexistent but searching turns up which has similar logos. Other parts are marked "Extraordinary Maker".

Unimat used to be a line of small desktop lathes from Emco. Supposedly the name was eventually sold (possibly with other assets) to a far east manufacturer. The Cool Tool may be the one and they make a set called Unimat 1 (Possible US site) and a few others plus a Metal Line of similar modular machines. They apparently also sold Sherline lathes and mills branded as "Uniturn" and "Unimill". There's also some Austrian branding on the site as well as contact address for The Cool Tool GmbH in Mödling, Austria.

There seem to be some different colours and finishes on hand wheels and tables. Mine seem to be metal plated or certainly shinier than the dull grey one or certainly shinier than the dull grey oness.

What it's for

So far, hard to say, other than something to explore on a whim. It cuts wood, plastics, brass and even stainless steel with varying levels of success. I will need to test and document materials and tasks later.

It seems to run needlessly fast, but doesn't seem to be short on power or stability. Accuracy isn't very good and there is clearly some more setting up that I need to do.

I'm hoping it can fit some shafts and spinning things together for me. I also intend to try the feeds and tables with a die grinder and/or drill in case they let me do interesting things I can't do freehand. Likewise, something here should make an easy indexing or dividing setup.

Prices and opinions

The various kits are priced between $100 and $1000 or so and even with the resemblance, don't necessarily seem to come from one manufacturer. At least there seem to be a few different brandings. I would not invest the kind of prices most are asking and probably would recommend getting something else if at all feasible. There are numerous sellers and resellers of various models, kits, and setups around the world.

I think it's a far cry from an old Unimat, let alone a Sherline, Taig/Peatol, or the much larger Sieg/Sumore mini lathes. It probably also isn't as nice or accurate as old Geneva or WW watchmaker's lathes, but might well be more versatile than a basic one.

Mine was much cheaper to me than any of those. Most of the alternatives are also much bigger and used ones, especially the watchmaker's lathes, are usually missing parts. Used prices also seem be high on anything not completely covered in rust. Other benchtop lathes are extremely rare and have even less parts available.

This one is much smaller than most of those (see tech section), including Unimat DB/SL. Fit and finish are surprisingly functional, but aligning the parts and the chuck may be a lot of work. Sherline was long my dream machine, but it's still much larger and the costs including tooling, import, and customs would be quite high.

Anywhere it turns up in forum discussions and the like, there will be some vocal bullies voicing loud and obnoxious opinions about them and very few people own up to owning one. I guess they could be called stigmatized.

The Nano series of Sieg machines also gets a lot of criticism about the manufacturing quality. The C0 and especially C3 and up get more praise. There's even been some occasional improvements (not available from all dealers) such as brushless motors and improved tailstock. Even these supposedly need a bit of work and at least CLA to get working.

Many of the parts also make interesting building blocks that are hard to come by. I expect that for CNC conversions, it's pretty much worthless because of the structure and arrangement of the feed screws. Factory configurations exist, though, but might have quite different structure.

I don't expect the build quality to be consistent. Mine might be particularly bad or exceptionally good. It's not very good out of the box. Certainly not up to the advertised standards but also certainly not just something that looks like the picture but doesn't work. It also did not come new in a box, so it might be used but not much.

Unless you get very lucky, it won't be working to spec right out of the box. That may well be true for all cheap and many very expensive machines, too. With better ones, it should be fairly routine adjustment instead of finishing work that the factory neglected to do. An exception might be buying a second hand machine straight from use. It might be an interesting project, though, and I like that. Maybe it will get me to decide I want a better machine when one comes along or decide that I don't need one at all.

Technical stats and bits

The spindle and tailstock are probably at least very close to the same dimensions as the old(er) Unimat lathes before they changed. That is, M12x1 (extra fine pitch!) thread with a center hole of 7 mm IIRC. 6 mm bar goes through with space to spare, and a 7 mm bar (drill bit) goes most of the way, but snags on something near to the chuck side. An 8 mm bar from the chuck side will pass in about 14 mm before stop and from the drive side, 7.5 mm will not pass in at all. I think there's a bit of larger bore in front that can take collets.

The body sections are 50 x 50 mm box sections with dovetails on all sides. Some parts like the long slide and motor are a bit different. That means stacking up no extensions, center height is 25 mm and skips up 50 mm with another box on top or with the motor below the spindle. There is also a lower version of the riser in some pics of other models. One thing to note is that without a riser, the chuck jaws don't actually fit to open very far.

The bed is 280 mm including endcaps, the tailstock 50 mm plus 15 mm to end of spindle, and the headstock 75 mm plus at least 10 mm to end of spindle. That mostly sets the distance between centers to somewhere below 125 mm minus the centers and mounting hardware unless you overhang.

With the riser blocks, tallest point (headstock) would end up four sections high, or 200 mm. Quite small machine, then. I'm planning on fitting mine on a piece of floor laminate 390 x 200 mm to start with.

Power is fed from a DC motor (12 V, supposedly) by a timing belt with some reduction. Motor powers in ads range from 35 to 125 W or so. This one should be near the top of the actual range. I'll need to profile the current draw a bit. I'm planning on making better motor controls and possibly a different power supply than the included 12 V @ 5 A (which is 60 W) SMPS brick.

The supplied tool is 3.80 x 4.01 mm square-ish. Even end to end, though. 4x4 mm stock should do well. Heavier might work with less shims and/or different toolholders.

Indications and set up

Spindle runout is quite small (need to measure this again sometime) and three jaw chuck body isn't much worse. My jaws are off by quite a bit, though. This chuck also doesn't have or mount to a face plate, but the scroll is the same piece of metal that threads onto the spindle.

Headstock and tailstock don't line up properly. I measured the spindle and I think it's slightly off-centre. It could be adjusted a bit by loosening the screws on the headstock plates and moving but might still be off. I think I can shim the tailstock for a better alignment and work with this. The spindle is probably fairly well in line with the bed now.

Feeds use simple threaded rod (some LHT, some RHT). The long one mounted next to the bed should be well aligned, but a cross slide would need the base aligned carefully to ensure it travels at right angles to the spindle.

Without risers, the 4 mm tool can be clamped to the cross slide surface with a roughly 1 mm shim under it (need to measure this one better as well, especially if I get the jaws running more true).

The toolpost height, though, is funny. I think it's meant to be used with the lower riser blocks, but I don't have those. I do have a topslide and a rotator (need to find a name) for it, but the height with those and a toolpost is even higher than the spindle line with 50 mm riser section. This should be clearer if I get the CAD model done.

So, I haven't explored those extra parts enough to have working configurations yet.

More parts

Acquired dividing plate and collet set. Tried to true up the jaws. Success on some material sizes, not others. Collets aren't too hot either, but one will hold a center drill in the tailstock, so that's a win.

Made a backplate of a sort using brass bolted to a bit of floor laminate and M12 tap. Turned the plate to round and flat. Well, not quite flat. It's somewhat dished out as the headstock alignment is probably off. Haven't found use for it yet.


Headstock and power:


Tailstock and drilling/boring:

Tools and holders:

Related things: