Resettable handwheels for the Unimat 3.

Resettable handwheels are, as far as I'm concerned, a must on a lathe. Others will no doubt disagree, but when you've used full sized lathes with indexable handwheels you do wonder how folk manage without them. The ability to 'zero' the dial in any position is very usefull either when taking a cut on a diameter or when turning to length as the position of the tool can be marked by setting the dial to zero, then when the tool is moved the original setting can be easily returned to.

I bought a set of 3 'precision' handwheels from an ebay seller. These are genuine Emco products, part number 171900, and are sold as suitable for the Unimat 3, 4 and Basic. They are made of plastic with metal handles (which model engineering theorists will no doubt hate) and cost me the princely sum of £48 including postage. Other aftermarket handwheels are available from time to time, usually made from steel and of course more expensive.

Note the cover has been removed on the handwheel on the right, easily done by inserting a knife blade into a small slot.

The first job is to remove the existing 'wheel,using an 8mm spanner;

The new 'wheel is just a straight swap,but you do need an 8mm socket fitted to a ratchet or spinner to re-fit the nut.

Once the backlash is set, a trial and error job involving tightening the nut, checking the movement by turning the handwheel back and forth, loosening the nut, moving the handwheel slightly, tightening the nut etc. the cover can be clipped back in place.
I fitted the second handwheel onto the longitudinal shaft;

I didn't bother to swap the tailstock handwheels over as I rarely feel the need to set a zero when drilling.
The machine with both 'wheels fitted;

And a comparison between the old and new;

Initial impressions are good despite the divisions being printed rather than moulded. Time and use will of course confirm whether these are a good investment or not.
Now I should really get my finger out and make something on this machine!

Paul.

Unimat 3 ER16 collet chuck.

I've been looking for a collet chuck for my Unimat 3 for a while now. It seems that new examples are available again. I found mine on eBay, very reasonably priced;

The collet in the above photo is one of a number that I've aquired over the years and didn't come with the chuck.
Its a genuine Emco product, part number 171140, which will also fit the Unimat 4, Basic and PC, having an M14x1 mounting thread.

This chuck uses ESX16 collets, otherwise known as ER16. These collets have a release groove which locates in the locking nut, so that when the locking nut is undone the collet is withdrawn from the body of the chuck. The locking nut is threaded M22x1.5.

I mounted the chuck on the lathe and used a lever type DTI (dial test indicater) to check the chuck for concentricity. With the lever bearing on the ground bore the chuck was spun by hand and the DTI showed a run-out of .0005", perfectly adequate for my use although model engineering theorists might argue otherwise...

Here it is again holding a length of 4mm dia. brass;

Collet chucks are often preferable to the usual 3 jaw type when turning for several reasons. Firstly they hold the work truer than a 3 jaw, secondly they don't mark the surface of the work (important when holding a finished diameter), and thirdly they are safer than 3 jaw chucks when using hand tools (files and gravers) on the lathe as there are no protruding jaws to hit.

Paul.

Recycled tramway rail.

I've been nosing around the Goyt Valley (just outside Buxton in Derbyshire) these past two weekends looking for remnants of the railway built to serve the construction of Fernilee Reservoir. The railway lasted from 1932 to 1937 and was 3' gauge (although a short 2' gauge line was initially built to aid the laying of a pipeline). As for railway relics, there isn't much to find. The course of part of the trackbed survives, as does an incline up to a quarry. I also located the puddle field, where clay was extracted to seal the dam wall. Now the field is home to several lagoons, the most northerly of which is supported on two sides by an embankment;

Note the metalwork sticking out of the ground to reinforce the bank, this is in fact redundant tramway rail;

Note the railhead with the give-away groove.
Some narrow gauge track can be seen as well;

Now I realise that this isn't the most interesting discovery, but it does show that odd relics do turn up in unusual places. I can only assume that tramway rail was cheap and plentifull at the time, possibly coming from Stockport as Fernilee Reservoir was built by Stockport Corporation.

Some photos of the construction of the reservoir can be seen here. And an account of the railway can be found in Harold Bowtell's 'Reservoir Railways of Manchester and the Peak', now long out of print.

Paul.