Bearings and shims on a Delta 46-230

[Amr Hadi]

Hello folks, I've had this Delta lathe for a couple of years, bought it from a cabinetmaker who was retiring. Recently I decided I want to graduate from carbide tools, and simultaneously upgrade to variable speed, so I found a 3 phase motor off craigslist, and added a new VFD.

508332

I'm also going over the headstock, and wondering (Q1) how can I tell if these Timken cone/cup bearings need to be replaced? I feel like it has a very small amount of play that is only noticeable with a big chuck on it, whereI can nudge it a tiny bit vertically. The cones seem a bit ovoid when viewed axially, but the cups spin pretty freely on them.

And (Q2) how the heck do I get these bearings off? Because hammering them did nothing, nor did putting an adjustable wrench at one end and trying to lever it using a large bench vise. I sprayed down the spindle with PB blaster tonight, and I was planning on going to Harbor Freight tomorrow to get one of those 3 prong bearing pullers if that's what I need to do.


508328

508329

508330

508331

Then, (Q3) what should I do about these eaten up shims? How important are they to replace?

The manual lists a total of 8 shim washers as 'required', 2 x 0.003, 2x 0.008, and 4x 0.0010", but my lathe only had 3, and by my measurements I have a 0.001", a 0.003", and a 0.010" washer. Did they just get chewed up and get thinner over time? And if I replace them, do I shoot for the same overall thickness as I currently have, or maybe assume that I had one each of the ones listed and try to get that thickness? Total thickness now is 0.014", which is roughly 0.35mm. If they started out as what is listed in the manual, then I would have 0.021" which is ~0.5mm.


They are also a very hard size to find (2 1/16 OD, 1 21/32 ID) - McMaster did not have them, and I finally found a comparable size after converting to metric (52mm/42mm) from some company on Ebay, from the UK. With shipping, it's gonna cost me about 30 bucks to replace them. Necessary, or too precious?

[Jerry Bruette]

Q1. Yes they need to be replaced if you've tried to hammer them off. If you had radial movement the bearings probably needed to be adjusted.

Q2. You'll need the bearing puller to remove the cones. Be aware of how you mount the puller though. You'll want to pull against the cone and not the rollers. The jaws on some pullers won't alllow you to do that though, they're too fat to close far enough. You could try a bearing seperator if the jaws on the puller are too fat to close far enough. You'll also need something to go over the end of the shaft, it looks hollow.

Q3. You'll need a new shim pack. Every set of bearings is different. Even though they're precision bearings made with precision machinery they are made with tolerances. The bearings you take out will be a different size than what goes back in. I don't know your location but if you have a Kaman or Motion Industries near by they could help with the shim pack from the bearing manufacturer, no need to order from acrosss the pond.

My questions.

Q1. Have you given any consideration as to how you're going to mount the new cones on the shaft? They can be mounted with a bearing driver and hammer if you have the proper size bearing driver. Or you can heat the cones and slip them onto the shaft being sure they seat tight to the shoulder on the shaft. Use some oil on the shaft while mounting the cones.

Q2. Do know how to shim the bearings for a proper fit? You'll need a dial indicator to meaure the axial play of the shaft and then add the proper amount of shims to take out the play. You may have to do this more than once to get everything seated properly.

[Richard Coers]

Anytime you hammer on bearings, you create brinelling. That's where the rollers or balls make tiny dents in the races. Another issue is because of the extreme hardness of bearings you can knock a piece off that can really damage an eye. You should never, ever use a hammer around bearings. How to tell a bearing is bad? It screeches or rumbles. A quiet bearing is a good bearing. It's a very rare user that wears out lathe bearings. They just don't get the hours of use like other machines. Especially in a cabinet shop!

[Amr Hadi]

Q1. Yes they need to be replaced if you've tried to hammer them off. If you had radial movement the bearings probably needed to be adjusted.

Q2. You'll need the bearing puller to remove the cones. Be aware of how you mount the puller though. You'll want to pull against the cone and not the rollers. The jaws on some pullers won't alllow you to do that though, they're too fat to close far enough. You could try a bearing seperator if the jaws on the puller are too fat to close far enough. You'll also need something to go over the end of the shaft, it looks hollow.

Q3. You'll need a new shim pack. Every set of bearings is different. Even though they're precision bearings made with precision machinery they are made with tolerances. The bearings you take out will be a different size than what goes back in. I don't know your location but if you have a Kaman or Motion Industries near by they could help with the shim pack from the bearing manufacturer, no need to order from acrosss the pond.

My questions.

Q1. Have you given any consideration as to how you're going to mount the new cones on the shaft? They can be mounted with a bearing driver and hammer if you have the proper size bearing driver. Or you can heat the cones and slip them onto the shaft being sure they seat tight to the shoulder on the shaft. Use some oil on the shaft while mounting the cones.

Q2. Do know how to shim the bearings for a proper fit? You'll need a dial indicator to meaure the axial play of the shaft and then add the proper amount of shims to take out the play. You may have to do this more than once to get everything seated properly.
Thank you, sir.

This is the way I tried to hammer it, I don't think I did any harm, if that is what you were implying. But yeah, I suspect slight radial movement is present.

Edit: I guess there's definitely a possibility as Richard suggests that I did some damage just by hammering, since it couldn't have been perfectly axial. I had a feeling it wasn't the right thing to do, just had to try it.

508346

And yeah, there's not a lot of rim showing on the inside ends of the cones, so we'll see if a bearing puller will do the job. As far as how to seat the puller on the end of the shaft, I thought I'd use the spindle nut as a 'cup' and put a wide washer (or a couple) in there to let the end of the shaft of the bearing puller to have something to push against.

508348

As far as putting them back on, I was thinking about putting boiling the bearing and and putting the spindle in the freezer.. I also have access to liquid nitrogen if need be. I hope that would be enough. The other concern is that it was hard to get the pulley off the spindle, I think due to the grooving/scarring of the spindle with the setscrews of the pulley, and I'm not sure if they're going to cause the bearings to hang up.

508347

I looked up bearing drivers, and I don't see how those would help me, because they do not have a large enough central opening for the spindle. The bearing cups on the other hand slid relatively easily out of the headstock, so that part I'm not worried about. Come to think of it, that might be the reason for the slight radial movement..

Thanks for setting me straight aobut the nature of the shim washers. At this point I almost feel like just living with it how it is! The expense to replace bearings is climbing...

[Amr Hadi]

Update: went to a machine shop, proprietor told me to come back in half an hour and charged me $10 to remove both bearings. He said they gave him no trouble and there didn't seem to be any hangup over the shaft despite the grooves. He used a bearing separator and press.

I asked for advice regarding putting new ones on, he suggested using the race/cup to press on the new ones with a punch, and said he didn't expect there to be any problems putting them on. To be on the safe side I'm going to try using liquid nitrogen and/or boiling the bearings.

I also ordered off ebay, because the Timken bearings cost around 35 bucks each with cup and cone combo, versus a bearing supply where they cost upwards of 90 bucks. The shims I settled for a 'close enough' from McMaster, they are 50mm OD 40mm ID and 0.1 mm thicknesses, I figure 0.1 mm increments should be fine.

Time to return the Harbor Freight bearing pullers..

[Jim Morgan]

"Boiling the bearings"? In oil?

[Amr Hadi]

Water is a bad idea? Risk for rust? I figured if there's no grease on them then it won't matter, compressed air and wd40 afterwards, and in the headstock they sit in an oil bath.

[Jerry Bruette]

The number one cause of bearing failure is improper mounting.

DO NOT take the machine shop proprietor's advice for mounting the bearings, unless you want to do it a second time.

No need for liquid nitrogen to be involved. Sounds dangerous.

DO Not boil the bearings in water. No need for water to be involved at all.

I used to use an induction heater at work to heat bearings no hotter than 240*F. Any hotter and you can alter the heat treating of the bearing. If you happen to have a toaster oven you could heat them in there being sure not to go over 240*. You could fill a "Nesco" roaster with oil and heat the bearings in the oil bath.

There's no need to cool or chill the shaft heating the bearing will be enough to get it on the shaft. Put some oil on the journal and you'll have to work in a timely fashion. If the bearing cools down before being seated it will shrink onto the shaft and you won't be able to move it, then you're hosed. Make sure the cones are pointing in the right direction while mounting. It's very aggravating to find out your bearings are facing the wrong way after you've mounted them.

You can clean the bearing journal with some steel wool before mounting, be careful with cleaning so you don't change to diameter of the journal.

[Bill Howatt]

I'm surprised that he didn't offer, for a charge of course, to press the bearings onto the shaft.
I generally agree with Jerry's comments above.
Having said that, when my father had a garage way back in the 50s we used to use the hammer method to put bearings on axles. However, the interface between the hammer and the bearing was a very large brass drift making errant blows impossible and the brass would not mar the bearing like a hard punch would. Obviously, care had to be taken for uniform "driving" around the bearing inner race.
Pressing is a better way of doing it.

[Amr Hadi]

Yeah after looking at all the options, baking in a toaster oven seemed to be the best. I just don't want to be stuck halfway. I think I can find some steel plumbing pipe that is just larger than the shaft but very much within the diameter of the inner race, to use to hammer on if worse comes to worst. Or I could take it to the machine shop for them to press it the rest of the way.

I don't consider liquid nitrogen dangerous, or any more dangerous than any number of other things that happen in the shop. But I was thinking that liquid nitrogen means any oil on the shaft is going to be a waxy crud and may not help the bearing go on. On the other hand, -200C on the shaft and +100c on the bearing gives me a much larger 'gap' between shaft diameter and bearing inner diameter.

[Jim Morgan]

Liquid nitrogen could make the shaft sufficiently brittle that it would shatter on impact. You should pursue less extreme alternatives.

[Jerry Bruette]

Many moons ago when I was a wee pup in high school we took a field trip for chemistry class th the UW Madison. They had a science expo that we attended. Saw some interesting demonstrations with liquid nitrogen. They dipped a toy rubber nail in the nitrogen and then drove it into a board, just like a regular spike. Then they did a demonstration with a piece of steel that was scored with an awl then dipped into the nitrogen and then place in a machine that would shake/vibrate the piece of steel. The nitrogen was used like a catalyst to speed up the fatigue of the scored steel. In a matter of minutes the piece of steel broke at the score line.

I've never learned the theory of cyrogenic metal treatment, but I know the physical properties of steel can be altered by using extreme low temperatures. Your lathe spindle is more than likely not the proper alloy for cyrogenic treatment. I'd leave the liqid nitrogen in the Dewar and just heat the bearing to 240* and slip it on.

[Amr Hadi]

Update: Y'all were right, a toaster oven was all I needed. Well, that and a 5" section of 1" pipe, because I did still have to hammer the bearings on, but it went on smoothly and evenly since the pipe only contacted the inner race of the cone bearing.


I still have a tiny bit of vertical play when the spindle is in the headstock, I get about a 0.010" deflection (from the bore of the spindle) when I move put vertical pressure on the outboard side, which is usually pulled down from the weight of the motor. Suspect that I need more preload on the bearings.

[Amr Hadi]

Final update: It just took a couple of 0.004" shims to take out all the play in the spindle. Hallelujah.