UCP Bearings for lathe spindle?

Hi chaps,

I'm rebuilding a home made lathe and having some difficuties with oilite bearings I've decided to rebuild the headstock and use pillow block bearings. I got hold of some 25mm UCP bearing pillow blocks from Ebay which arrived today and to my mind they seem rather stiff i.e. packed full with grease, but not binding. They are also spherical mounted (self aligning?).

Can anyone please advise if these will be ok for the main spindle on a lathe. If ok, would they need to be run in?

Here's a link to the ones I have. **LINK**

Thank you,
Ed.

Edited By Ed Duffner on 06/04/2013 17:58:53

Unless otherwise stated I'd expect such bearings to support transvers loads, but not be much good with axial loading - so for a lathe they would support the spindle, but may not cope with much end thrust.

Also not sure how you would get a precise alignment with the lathe bed, the self aligning nature is to cope with imprecise mounting - not what you want on a lathe.

Hi Ed,

My advice would be to look at either angular contact bearings or taper roller bearings.

Taper rollers are not the cheapest option, but it would not be unusual only to use one at the front of the headstock witha smaller angualr contact bearing at the back.

Neil

David and Neil,

Thanks guys, I'll look at those bearings and see what I can fit in there.

All the best,
Ed.

"UCP bearing pillow blocks"

Can't resist pointing out that, when I were a lad and dinosaurs roamed the earth, "UCP" referred to any one of a chain of restaurants, mainly in Lancashire and run by United Cattle Products, which specialised in such delicacies as tripe and cow heels.

Andy

"OCP bearing pillow blocks"

Where Robocop rests his weary head...

neil

Those new corduroy pillows are making headlines.

...sorry

Edited By Ed Duffner on 06/04/2013 21:53:42

Edited By Ed Duffner on 06/04/2013 22:15:09

Ed,
it would be interesting to see pictures of this home made lathe.

I expect you are looking at the pillow blocks because they are self contained with their mounting. Two options come to mind for the thust problem mentioned and both were used in the past on commercial lathes.
If there is room to put something behind the back of the spindle and it is not bored through you can put a pointed screw to bear on the rear and take up any slack.
Rather better will be to arrange for the spindle to go through a hole in a plate positioned just in front of the rear bearing. Then mount a thust race on that, possibly bearing on the pulley block on the spindle. The initial bearings arrangement will be adequate for the time it takes to use the lathe to make the necessary components because most ball races can take some end force it's just not good for them long term.

The fact that they are self aligning makes no difference to your ability to align the spindle with the bed. They may well run more freely when warmed up.

Hi Bazyle,

Thanks for the advice. I've actually just requested a return from the Seller. I'll add add some photos shortly.

Regards,
Ed.

Before.

After strip-down and repaint.

Here's one of the spindle and bearings. 1" oilite bearings held in the 0.5" steel plate, but the shaft is 25.3mm so I get a bit of judder when taking moderate cuts.

Another angle showing a thrust washer and spindle register.

Edited By Ed Duffner on 06/04/2013 23:14:34

That was quick.

You just need to split the bearings. I suggest you start with just one sawcut along the front bearing and invent a way of tightening it up. A jubilee clip around the bush will close it up but it will then be loose in the frame. So then you need a slit in the frame and a way of closing that up.

Lets see what others say.

Lol, these photos were taken some months back, it's not so shiny now I tried splitting the bearings already and wrapped part of a strap from an electrical earth bonding strap around the full circumference of the bearing like a circular shim and pushed the bearings back in with a clamp, so a very tight fit initially and no play in the bearings, but axial play has reappeared. So I was thinking to chop off the top section of plate on each side and add a flat base with the pillow blocks on.

I suppose another possibility is to use new oilite bearings and turn a new shaft to correct size.

I do like the idea of adding a clamp into the plate.

If the play returned after the split it may indicate that you really need more lubrication. Most plain bearing headstocks have oilers and it doesn't look as if you even have an oil hole.
If you are considering going as far as making a new spindle you could make a conical bearing which you might be able to add to the existing one anyway.

Is this the Len Mason design?

Getting solid bearings to mate with the headstock housing AND the spindle isn't easy

The bearing has to be drawn around the spindle so it revolves... then the same bearing needs to be locked solidly to the headstock housing

Drummond took a few goes before they sussed it out and it's not an easy adjustment to make

However, there are still many Drummonds still going on their original bearings, including my own

Drummond 31/2" Lathe Headstocks 1902 -1942

So if you have already split the bearings they need to be tapered slightly, bigger inside to outside, with a matching taper in the headstock housing

The outside draw nut draws them in and the taper squishes the bearing around the spindle

The bearing split is tapered, wide at the top, narrow at the bottom, and points directly up to the oiler hole

A long bolt goes through the top of the headstock oiler hole and pushes a teeny vertical wedge into the split in the bearing, forcing the outside of the bearing to lock to the headstock

It's fiddly to get things right but Drummonds have a good reputation for stiffness and once it's done it works well for ages

I over tighten the spindle bearings very slightly then the wedge opens things up when the headstock bolt drives it in and locks the bearing to the housing

It may still need tweaking once you get some heat during running

Most lathe producers took the easy cheap route and made pinch bolt headstocks

Edited By Ady1 on 07/04/2013 02:56:50

Thank you Bazyle,

To be honest I've no idea as to the design origin. My Dad (also Basil) made it years ago. He was a Fitter at Rolls Royce Filton, Bristol and I was always under the impression it was something he designed and made.

I added the base recently, made from two pieces of 100x100x10 angle welded together and have started converting the leadscrews to metric and delrin half nuts.

Thanks Ady,

Looking at the photos in the link you provided, the arrangement seems to be a bronze bearing with tapered OD and parallel ID so that as the threaded ring is tighetened it closes the bearing around the spindle to a sliding or running tolerance. To do it this way I'd have to make a tapered housing to accept a bearing and would the bearings themselves be made of ordinary bronze or some special type?

Regards,
Ed.

Edited By Ed Duffner on 07/04/2013 03:34:57

As far as I know, just ordinary bronze

The Drummond system will give you some ideas

The pinch bolt system for the headstock wouldn't be so dangerous on your headstock because it's 0.5 inch steel

Cast iron is prone to cracking if you tighten headstock pinch bolts up too much, whereas steel is safer for flexing purposes

So a system for squishing the bearing around the spindle

And a pinch bolt for squishing the headstock housing around the bearing

A good headstock pinch bolt may actually do both jobs if the bearing is split and the bearing fits snugly in the headstock housing

This would probbly be your easiest solution

gl

Edited By Ady1 on 07/04/2013 04:02:21

The biggest problem for you will be keeping your spindle aligned with your lathe bed once you start messing with the original system and setup, (something well beyond my own limited hacker abilities)

I tend to use the hail mary system when I muck about with old machinery

You will probably drastically reduce the headstock housing stiffness if you change over to a headstock pinch bolt system, the original enclosed headstock housing system he has used looks pretty professional and very solid

It's all a case of compromise and convenience

Edited By Ady1 on 07/04/2013 04:16:16

Hi Ed,

The lathe looks fundamentally sound, but also constructed in a way that you don't need to feel guilty about maing 'improvements' - it's just ongoing development.

One option that avoids upsetting the accurate holes in the headstock would be to turn up solid bronze bushes to replace the oilite bushes and fit proper oilers. I guess you would probably want to lap these to fit.

Oilite bearings may be long lasting, but they don't hold enough oil to craate the consistent oil fil you need for accurate work.

You could make the bushes on the lathe itself, but do you have access to another lathe?

Neil