Lathe convert to bearings

[surfdabbler]

I have a very old lathe that I'm wanting to convert to bearings. The lathe is an old 1890s pedal lathe, converted to motor by my wife's grandfather, about 40 years ago. I've restored it with a complete tear-down, de-rust, and rebuild, and I've used it for a little bit of woodwork and metalwork. The headstock shaft runs in oiled slides, and I'm wanting to put some bearings into the headstock shaft, for several reasons...

1) Oil makes a big mess of the headstock, dribbling everywhere, and sawdust sticks to the oil when I'm turning wood. It also can spray oil up the wall and up my arm when I turn it on.
2) It has oil feeds added to it, but these drip through, such that if I don't use it for a few weeks (quite common), the oil is empty next time I want to use it - which means I have to remember to put oil in it most times I use it.
3) And most importantly, if I am turning between centres, and put much pressure with the tailstock, the mechanism binds up to the point where the drive belt slips. This greatly limits turning between centres - with the minimal pressure applied at the tailstock, I often find that the bearing tailstock is not even turning, because the tailstock couldn't be turned up tight, and slips back loose during turning.
4) If I re-machined the radial load area of the shaft, and found a really good suitable machine oil from somewhere, most of these issues would probably improve, but bearings would just be so much nicer.



Having pulled apart the gears in the rebuild, I'm happy to do it again, and I have done so in the picture above (some pieces are missing, so you can see the important bits), and I'm trying to figure out how to add a bearing setup to this.

On the right hand end, the original setup has a sleeve that fits in two halves around the shaft, and is oiled. I'm having trouble working out how to fit bearings into this, as there is a large flange on the end of the shaft. I was originally thinking about turning this off, before realising that the chucks seat back against this flange! So, I can't take that off. At the other side of the bearing is the big gear, which looks like it might not be a single part with the shaft, but there are no screws or anything else fitting the gear to the shaft, so I can't get it off.

Anyone got any ideas how I can fit a bearing onto this shaft? Any secret tricks to removing and refitting the gear on the shaft?

At the other end, the pulley wheels and back gear mechanism take up almost all the space to the left end, leaving almost no room for a bearing at that end, but perhaps I can fit a smaller bearing inside the tail end, to just take the radial load of the drive pulley. Originally the tail end took all the axial load from the shaft, but I'm thinking if I put a tapered bearing into the right hand end, then the left end can be smaller and simpler.

I'm happy to explain more details and give measurements, photos, etc, but I wanted to start with the overall picture and see if there are any ideas/interest out there, or whether people will slap me a say "Stop that!". Any thoughts?

 

[12bolts]

Hi surfdabbler,
Sorry I missed your intro post.
As far as oiling goes it should be habit to oil the spindle everytime you use the lathe anyway and depending on model, various other points too. On my hercus the oil runs out almost as fast as I put it in so I just keep the oil up anyway.
I fitted a thrust bearing to replace the washer on mine.

Its nice and thin and takes up almost no extra space. you should be able to do similar to your lathe I imagine. Still pondering about how to retro fit main spindle bearings.
For the price of a cheap wood lathe now should you consider just buying one? Wood lathes run at much higher RPM's than metal. You will enjoy wood turning more with a wood lathe.

Cheers Phil

 

[Cadillac STS]

Does the gear come off the shaft to let you slide a bearing all the way to the spindle and touch that?

Could measure and fit a tapered roller bearing at the spindle side, maybe even get one with a flange on the front of the race that will keep it from pulling through.

Turn down the tail side of the shaft to allow another tapered roller bearing there. Again, flanged race to hold it from pulling through.

Thread the end of the shaft to be able to tighten the roller bearings together with some preload so the shaft is supported on bearings.

Drill and thread above each bearing for grease for those roller bearings.

 

[bollie7]

surfdabbler
Unfortunately I dont think there is any easy option to reduce the oil. The machine was designed to have a total loss oiling system. It would have had either a split bronze or white metal bearing at the front of the spindle. More than likely this bearing had a flange on the front that acted as a thrust bearing. I'd make a guess and say it had just a bronze bush in the tail end of the spindle.
You might be able to fit a needle roller bearing to the tail end but the spindle might not be hard enough for that and it would still need lubrication. You could possibly fit a ball race and thrust bearing to the front or even a tapered roller but adjusting would be trickey. Again would still need lubrication unless you used a sealed bearing but I dont know how that would go in this application.
If it was me I'd be just sticking with a split bronze bearing with flange at front, a bush at the back and put up with the oil. You could fit auto oilers to it which would ensure that the bearings get lube whilst you are using it. (provided you remember to turn them on before starting and turn them off when finished) Its an old machine - it is what it is.
I'm not trying to put down your ideas here. I went through this very head scratching exercise myself about 20 years ago with an old lathe I had. I came to the conclusion that it was easier to keep oiling it and cleaning it.
Re the gear. Cant really tell with your pics but I'd guess and say its pressed on, possibly fited with a drive key as well but I might be wrong. (I'm usually more wrong than right.)
All the best with it
bollie7

 

[bollie7]

I fitted a thrust bearing to replace the washer on mine.
View attachment 84010
Its nice and thin and takes up almost no extra space. you should be able to do similar to your lathe I imagine.

Phil
Am I looking at the pic correctly? Have you fitted the thrust bearing on the outboard end of the spindle between the bearing and the nut on the spindle? If so, then unfortunately I think it wouldn't be taking any thrust from cutting. It should be on teh other side of a bearing.
If I'm misinterpreting the pic then my apologies.
regards
bollie7

 

[12bolts]

Bollie,
Sorry, yeah my post could/should have been clearer

They come with an existing thrust bearing on the inboard side, but just a washer under the take up nut. So about the best adjustment you can get is 0.0005-0.001 thou spindle end float. With the new bearing you can get zero.
Was just showing that a thin thust washer could be employed.

Cheers Phil

 

[bollie7]

Bollie,
They come with an existing thrust bearing on the inboard side, but just a washer under the take up nut. So about the best adjustment you can get is 0.0005-0.001 thou spindle end float. With the new bearing you can get zero.
Was just showing that a thin thust washer could be employed.

Cheers Phil

After I posted my last, I was looking at your pic thinking that, what you have now labled as the existing thrust washer, looked like a thrust washer to me also.
It would be a big job to convert your lathe to roller/ball bearings. If you could get access to a horizontal borer or a big enough lathe you could probably bore the existing bearing housings out to take a race but you'd still have to come up with an oil containment system or put up with a total loss system.
I seem to remember reading somewhere, some time, ago that std ball/roller or taper bearings are not too good for a lathe as they influence the surface finish when taking a cut. So the bearings have to be super precision. Something like that anyway.
I might be getting my memories of what I read mixed up as well.

all the best
bollie7

 

[surfdabbler]

@bollie7 - your picture labels are pretty much correct. At the tail end is a bronze bushing, and this might be the easiest place to put in a thrust bearing, although it will have to be pretty small.

The big end has a 'white metal' bearing bushing. Haven't heard that term before, but after a quick websearch, it seems to match up. Being from the 1890s, I had suspected that my bushings probably have a lead component in them to aid with lubrication, which I'm not super keen on either. There is no thrust bearing in there - that function is shared between the side of the white metal bushing and the bronze bushing at the other end.

@12bolts - I wonder...perhaps I can machine off the flange at the chuck end of the spindle, and then make a little split ring like you have on your tail end to replace it. It would probably have to go on tight enough to hold some of the axial thrust, but a second thrust bearing at the tail end would help.

Thanks for your thoughts. I'll mull on this some more...

 

[janvanruth]

first and foremost: leave the spindle as it is!!!!
You will never be able to get back to original after the spindle is changed.


You will not be able to put a rollerbearing in the headstock as there is no room for it.
The gear is probably pressed on with a key which should be visible or heat shurnk without a key.
It should come off in a press.

Where exactly does the spindle bind when pressure is applied?
Something must be wrong beause even a pre 1900 lathe should have a way of taking the axial thrust.

Oil spillage can be decreased by adjusting the bearings clearance to minimum or by taking a heavier oil.

 

[SWARFEATER]

get some thrust bearings in there and put some small valves on the oilers, though they should not really be needed unless the bushings are shot. you cant turn this machine into a new state of the art engine lathe no matter what you do, new bushes, thrust bearings and good oil. have fun using it instead of working on it.