Elliot Unimat lathe renovation

Acquired an Elliot Unimat mini lathe, I have no immediate use but looking forward to renovating it then will get some practice in on it.

The motor works ok and spins the chuck.

The cross slide thread is seized and the chuck I canot open or close.

Any help appreciated.

Hi Stan, welcome to the forum, but you may have been better to include Elliot and or Unimat in your title as there are one or two on here that have them.

Regards Nick.

Thanks Nick unfortunately I cant edit the heading.

Hi, Stan, welcome to the forum. You should start by spraying the chuck liberally with Plus Gas, AC90 or WD40 and leaving it for a few days. Some taps with a soft hammer and a lot of patience is what it needs. Sooner or later, it will start to move a bit, and when its apart, then scrape the rust off with a penknife, rather than abrasives, a few blemishes are preferable to something that just looks pretty. Oily wire wool and elbow grease is good for rusty steel without loosing the tolerances.                                                                             

Edited By old mart on 27/08/2020 20:49:43

Welcome, Stan.

Plus-gas is better than WD-40 for freeing rusted parts. (It's what it's made for - WD-40 is actually what its name says, a water-dispersant, so it will work but less efficiently).

You''ll probably find the steel and iron will be pitted, giving a sort of mottled dark-grey patina once you've cleaned the rust off, but hopefully once refurbished the lathe will be once again a very serviceable machine.

old mart....I have dismantled much of it and will work now on freeing the seized parts.

I better get some more WD40 as it looks like I will need a load.

Edited By stan smythe on 27/08/2020 21:09:16

If your dismantled parts are small enough ,put them in a container full of diesel and leave them to soak.

This usually works.

Maurice

Hi Stan,

Welcome to the forum and congratulations with your Unimat SL. I have one labelled Emco and now use it to sharpen milling cutters. If you don't have a manual you can download it here.

Thor

As others have said, patience, good freeing oil and tapping with, say, a brass hammer or drift are the key to unsticking parts. I used an American product called PB Blaster which has good reviews. It can take days or weeks though. You may be able to use heat on some parts too but a lot of things on the Unimat are painted which may rule that out.

Mine was less rusted than yours when I got it but still needed work. The most stubborn bit was the nut holding the big drive pulley onto the spindle. Getting a decent spanner onto the nut is no problem but preventing the spindle and pulley from turning (without causing damage) is not so easy. I bought a big rubber strap wrench from Machine Mart to hold the pulley and that (along with heat, freeing oil and plenty of time) eventually got the job done.

Regards, Andy

Just had a quick look at my chuck to remind myself how it fits together. If you can unscrew it from the spindle you will see a circlip on the back. If you remove this then IIRC the scroll part can be taken off, then the jaws can be withdrawn from their slots.

Make sure you have some well fitting tommy bars or find the right size bar or the wrong end of a drill to use in the tommy bar holes. 4mm dia I think. Mine had none so making new tommy bars was my first job on the Unimat.

Have fun.

Thanks Andy, useful info.

I got the spindle nut off ok, I will have a look at getting the chuck off later today..

Thor, thanks for the links that is very helpful.

I have managed to dismantle most of it now.

Still stuck on the cross feed but hopefully get that freed before too long.

The reciprical jaws are stuck at the moment but should manage to free them ok.

So far I haven't done any further damage to anything so once cleaned up should go back together ok.

Glad to see you are making progress. Probably worth undoing the three screws and taking the backplate off the chuck too - will help with cleaning up. Probably best to mark it first so that you can keep the same orientation on reassembly but not sure if it matters.

The cross slide bars can be removed - IIRC they are held in by pointy ended grub screws but may resist even after removing the grub screws. Removing these may help 'divide and conquer' and will make cleanup easier. I put mine back in the other way up because what had been the underside looked better.

Looks like yours is a cast iron one like mine. Based on the info on lathes.co.uk I reckoned about 1961 for mine. Mine is badged 'Selecta Unimat' which may or may not be relevant to dating.

I also stripped down the spindle cartridge before putting mine into use. The ball races (aka magneto bearings) are easily replaceable and not expensive. I decided mine were OK but it was good to clean them and pack with fresh grease - I doubt it had ever been done before.

If you havent found it already, the Unimat group on groups.io is worth joining - there are both UK and US folks on there and some good stuff in the files section. They do like a Unimat SL on the other side of the pond.

https://groups.io/g/Unimat

Regards, Andy

Andy,

I tried the backplate removal but need to find a better fitting screwdriver as I don't want to strip the head, I have socked them in WD40 overnight to see if that helps.

I already have the grub screws out of the cross feed but still locked solid.

Thanks for the link will have a look at that.

Once I get everything cleaned up I will probably paint the main body parts as there is a lot of bare metal exposed, my tools are kept in a shed and with Scottish winters I normally wipe all my tools with an oily rag for winter storage to keep rust at bay.

Now sorted the cross feed, many hundreds of taps with a hammer, WD40, oil, wooden wedges, clamps, vice, heat gun....but got there in the end.

Just one more piece to free, the jaws on the chuck. Then the clean up begins.

I decided to get help before getting too brutal with chuck jaws so went to a local metal fabricator who does wielding, lathe work, milling etc. He took a quick look and had the jaws free in two minutes.

for future ref....

cut the top off a 5 gall drum and drop the big bits in.....after a week or so the Diesel will have worked it's magic.....

have used this method on rusted up n seized tractor engines....but then it's a 45 gallon drum.....

doesn't have to be full, just cover the parts and put some kinda lid on.....

works for me.....

that will be quite useful when fin.....

Coincidently the guy that sorted it for me said if not using the lathe for a while get a small container with lid and 50:50 diesel/old oil. and keep the chuck in that until required.

nice stuff! just in case you want one chronos has the unimat size QCTP back in stock (best thing i got for my unimat 3)

RE seized screw youve got plenty of good advice but i figure the collective might have some info regarding replacement? ive been tempted to replace my x screw with an m8x1 leadscrew.

Thats the clean up done and the lathe up and running, everything appears to be ok. I bought some of the Polyurothane belt stuff to make a couple of belts.

Question though is the smooth or rough texture belt better?