Webster Whitcomb headstock setup questions

[mbwatch]

I'm getting my WW lathe setup, and have a couple of questions about the headstock (and one stupid snag).

Getting the snag out of the way first: I can't fully disassemble the headstock because the pulley grub screw socket is stripped out. Does anyone have a suggestion for attempting to extract this screw so deep in a recess? I was confused why none of my allen keys fit, until I can see it has no faces left inside. There's a crack in the bakelite pulley with some super glue, maybe related to this stripped screw. Is it possible this screw is only providing friction, and not set into any flat or recess on the spindle? And therefore I might just tap out the spindle against the pulley without worrying about it?

If I could get that out, I might be able to answer my other questions for myself. They are mostly about what parts should move and what should not move. I can get the spindle moving freely and smoothly, but it is somewhat touchy as to how much tension the cone bearings can be pressed in and that doesn't feel right.

The collet side I think everything is assembled correctly. The oil reservoir hole is positioned at the top. No problems here I don't think:

On the back end, I am a little more confused because parts I expected would be stationary are movable. In this photo, the oil hole is positioned at the top and aligned with another recess for the oil hole in the frame:

 

I assumed that oil hole would not turn. But I find that it does. Here it is rotated clockwise to the 1 o'clock position. Should this turn? If I thread on the locking nut tightly, this compresses the cone bearings in together and causes friction that prevents everything from spinning as smoothly. I need to lightly tap it to introduce about 0.25mm of play and then it spins freely again.

But the thing that is most surprising and makes me feel like this whole thing is assembled incorrectly is that this brass dust cover, when affixed to the bearing and covering the oil hole, spins along with spindle. I assumed this would need to be a stationary part. Again, if it is pushed all the way on it causes friction that impedes rotation. But if I leave a small gap then no problem. These brass dust rings do not have a split or threads - they just push on with light friction. Pictured, it is pulled away from the frame by about 1mm. If it touches the frame then motion is impeded. That can't be right, can it?

If I could get the pulley screw out, I would be able to disassemble the whole thing and it might make more sense to me. It does move, just  not if everything is pushed together as close as it seems like it should be. I would appreciate any insight the experienced lathe folks can provide here. I probably have this all prepared correctly, but it just doesn't feel like I expect and I don't want to damage it.

Edited February 3 by mbwatch

[caseback]

The headstock of my Wolf Jahn WW lathe looks very simular. Maybe @nickelsilver knows if it actually is.Here you see it it diasassembled:

It has a recess in the spindle for the grub screw, and if your pulley only has the one screw it is very likely your's will be the same. If it was friction fit I would expect 2 or 3 screws. Tapping is not advisable. It is possibly/probably what caused the crack in the pulley.

Edit: looking at your first photo: are you sure you're looking at a grub screw or are you seeing the recess in the spindle and is the pulley glued on?? 

If there is a grub screw:

You could try to superglue something in the grub screw as a first try, but I don't expect that will work if the screw itself is stuck/glued. 2nd option: get a LH thread screw slightly bigger then the hole I see in the grub screw and try screwing that in. If it "bites" you can pull/turn the grubscrew out. Third option: drilling and tapping in LH treads (also tricky but might just work). Fourth: carefully drilling it out. After removal drill and tap a new hole.

The oil hole on the back should be stationary. This is alarming.. If the construction of yours is indeed simular to mine (which I think it does), that part is the "outside cone" of the rear bearing and it should not rotate. A rotating oil hole would also be lubricating the area around the lathe including you: not a very sensible construction.

Edited February 3 by caseback

[nickelsilver]

Yes, the rear bearing in the headstock should not move. And the oil covers should friction onto the bearings pressed into the headstock, and not move with the spindle either. They are usually split, but it could be you some that are just a friction fit- but, they shouldn't contact the spindle.

 

As you can see in Caseback's photos, the spindle has a divot for the pulley screw; so no tapping out the spindle if that screw is in place. You could try an extractor for broken screws, it will hopefully grab on the (now smooth) hex opening.

 

The rear spindle bearing is usually a light press fit on the spindle and is keyed. You will almost always need to knock the spindle out with a brass drift- just be careful not to damage the key, which is usually integral with the bearing. Also be careful to line the key up with the keyway when reassembling.

 

The loose rear headstock bearing needs to be addressed. Once it's all apart and clean get it in place and tap it home with a soft faced hammer, if it seems secure it should be alright, but in the event it still wants to move, you can use a little bit of Loctite sleeve retainer like 638 to hold it. Just the smallest amount evenly distributed, a band maybe 2-3mm wide. If there's too much it will almost certainly not fit all the way in the opening correctly.

Edited February 3 by nickelsilver

[mbwatch]

@nickelsilver If I am understanding you, the part with the red arrow should be firmly attached to the frame but it moves very smoothly. What I am finding confusing here is that if the part with half of the oil hole marked red is not supposed to rotate, then it would mean that these must be two separate parts so that the piece keyed into the spindle's groove  can move independently. But these do not look like two pieces to me, it looks like one piece at the green line unless they are so perfectly seized together. And the motion is so smooth it doesn't feel "wrong", unless the brass caps are pushed all the way against the frame, adding a little more friction. Now if the green line should really be where the rotation occurs then these must be 2 parts seized together.

Since there is an oil hole in the shoulder of the frame (light blue) that can align with the little scoop in the part that does rotate, the oil does have somewhere to go without spilling out. That scoop just funnels the oil in (to @caseback point about flinging oil out in rotation).

If I give the spindle a little tap, I can shift that piece (which I think is one piece) about 0.5mm and I believe if the pulley could be removed I would be able to tap it all the way out. So my primary task needs to be getting that grub screw out.

11 hours ago, caseback said:

Edit: looking at your first photo: are you sure you're looking at a grub screw or are you seeing the recess in the spindle and is the pulley glued on?? 

Yes there's a screw in there. If the screw is superglued, I wonder if I can get some acetone in there. But first I would have to find out what effect acetone has on bakelite (probably not good). I might first try to glue the tip of an allen key in there and back the screw out. Difficult without accidentally getting glue onto the threads though and making this worse. I suppose if I just put a tiny bit of CA glue in with an oiler I would have good control.

[caseback]

I do hope you're right, but they look very much alike.. 

Fingers crossed then...

[Dell]

I have seen headstocks with two alen screws one locking the other I have also had them with butchered alen screws & the only way I got the screw out was to drill hole ( carbide drill bit ) and use an easy out but that had a steel pulley .

[mbwatch]

@caseback They sure do look alike. Where is the rotation occurring on yours? Red I suppose? It almost looks like you have a weld right beside your oil hole.

Edited February 3 by mbwatch

[caseback]

46 minutes ago, mbwatch said:

@caseback They sure do look alike. Where is the rotation occurring on yours? Red I suppose? It almost looks like you have a weld right beside your oil hole.

Well spotted, that was a bit of dirt. It needs cleaning. Mine rotates along the red line. Looking at the differences in surface finish, I'm afraid that's where yours need to rotate as well...

The oil hole connects to an oil groove:

If you're removing the pulley, don't worry too much about it possibly getting damaged. If needed, I can make you one in aluminium or steel fairly easy, including the hole pattern on the back.

Edited February 3 by caseback

[mbwatch]

1 hour ago, caseback said:

Well spotted, that was a bit of dirt. It needs cleaning. Mine rotates along the red line. Looking at the differences in surface finish, I'm afraid that's where yours need to rotate as well...

In person, a difference in surface finish is not really perceptible but I am pretty convinced you're right. I will figure out how to get that pulley off and pull this thing apart. I'll also put some penetrating oil on the "red line" and see if I can something to grip the two parts to attempt rotation. Thanks for all your input (and machining offer! if it comes to that)

[mbwatch]

Progress! I removed the grub screw by pushing into it with an allen key while turning. It's now stuck on the allen key but I'm not worried about that.

Yes, the cone is seized into the bearing, which was not firmly attached to the frame. I suspect this is actually how the previous owner was using it, because it actually does spin pretty nicely in this wrong state. Next issue will be to figure out how to separate these without damaging the surface of the bearing where it should mate with the frame.

I put a lot of penetrating oil on the outer joint where they meet and on the inner joint and will leave it overnight. Maybe if I can clamp the bearing part in a vise surrounded by grippy rubber I might be able to twist it off. Or a dowel of exactly the right diameter to rest on the edge of the cone inside and tap them apart. Maybe I try to drive a razor blade into that seam with a brass hammer. I'll give the oil some time to work.

Note the little fleck of blue here. That was possibly loctite used for, I don't know what.

In theory, unless someone glued these together they should just be two conical surfaces touching and gripping something like a morse taper, no?

[caseback]

55 minutes ago, mbwatch said:

Or a dowel of exactly the right diameter to rest on the edge of the cone inside and tap them apart

A brass dowel, a bushing for the outside so you can apply even pressure on this small ridge 

and perhaps a bit of heat for the outside part. Fingers crossed that they're morse-tapered together..

You want even pressure, forcing in a razor blade won't get you that.

But first try some light taps with a brass hammer on the outside diameter while holding the part in your hand (to avoid any "crushing" action). Perhaps that will jarr them loose.

Edited February 4 by caseback

[mbwatch]

6 hours ago, caseback said:

You want even pressure, forcing in a razor blade won't get you that.

But first try some light taps with a brass hammer on the outside diameter while holding the part in your hand (to avoid any "crushing" action). Perhaps that will jarr them loose.

Thank you. I can't test it right now. But also failing any of these, I am thinking the same thing I would use to remove a seized on caseback - a bead of superglue on the outer rim to attach a socket to one end and maybe glue the other end to a flat metal surface so I can twist them apart.

[AndyGSi]

If you had a pipe of the right size could you drift it out?

[mbwatch]

UPDATE: Yes I could spare the 30 seconds to test a brass hammer before I go to work. It worked! They jarred apart and separated, the surfaces look pretty good, no damage and a tiny bit of surface on the outer flare. And lot of oil.

Thanks very much for your generous help @caseback. 

[mbwatch]

On 2/3/2025 at 3:28 AM, nickelsilver said:

The loose rear headstock bearing needs to be addressed. Once it's all apart and clean get it in place and tap it home with a soft faced hammer, if it seems secure it should be alright, but in the event it still wants to move, you can use a little bit of Loctite sleeve retainer like 638 to hold it

After cleaning up, I find that the headstock bearing is a very close, smooth fit with no holding friction at all. It could be that it was run this way with the cone seized inside. It is a perfect fit, no play at all, but no friction so I have some Loctite sleeve retainer on the way to affix it. I just have to be cautious about not getting any into the oil reservoir so I will probably try to apply it only toward the inner 1/4 of the bearing length, and skip the area in front of the reservoir to minimize how much adhesive spreads near there

The bearing and the spindle cone fit well and rotate, but do want to bind up slightly in one spot.  I do not think either is out of round, but there's a high spot possibly at or near the oil groove. I don't have the equipment to measure it accurately but if I can pinpoint it and try to reduce it by a couple microns with fine grits I think it will stop binding. I just don't want to put it back together and then find it seizes up in the bearing again so i'll try to attack this before I affix the bearing with loctite.

Edited February 5 by mbwatch

[nickelsilver]

The bearings on these are a double angle, with both angles contacting at the same time. If things get worn, for example the short steep taper (which takes the axial loads, and will wear faster over time), the long taper will make too much contact and lock up. Regrinding something like this is basically impossible without very special machinery and skills.

 

But- they can be lapped to darn close to like-new condition. I remember one of my teachers in school was an ex-toolmaker, and he had me lapping some of the beat up school lathes using silicone carbide lapping compound. This works on spindles like this where everything is nice hard steel, but it's still a pain cleaning out all the lapping compound with a lingering fear that there will be a lingering lapping effect over time.

 

Years later I found out about Timesaver lapping compound, which if you read up on it appears to possess some truly magical qualities, but the really magic thing about it is it breaks down into a non-abrasive product and doesn't imbed. You can use it on steel as well as softer alloys safely. There are two types, green and yellow cans, the green being for steel-on-steel.

 

If you get it all together and find that it binds a bit, I think it would be totally safe to use some of that product to "bed in" the bearings.

[caseback]

One way to locate high/contact points is to clean both surfaces and treat one with a dye. In machining, a blueing compund is used, but here a white board or permanent marker will do fine. So colour one part and fit them together and twist slightly (no full rotations). Then take apart and study the transfer pattern and rubbed away dye.

[mbwatch]

34 minutes ago, caseback said:

a white board or permanent marker will do fine

I had been thinking this over, because I have seen a lathe restoration project where the guy did extensive manual scraping using blueing compound. I was thinking I would try Sharpie since I could clean it off with alcohol. Thank you!

 

(addendum: It was Chronova Enginnering of course, don't know why I didn't remember that at first)

[caseback]

7 hours ago, nickelsilver said:

Years later I found out about Timesaver lapping compound, which if you read up on it appears to possess some truly magical qualities, but the really magic thing about it is it breaks down into a non-abrasive product and doesn't imbed. You can use it on steel as well as softer alloys safely. There are two types, green and yellow cans, the green being for steel-on-steel.

@nickelsilver: Thank you for the tip. I have another lathe with some lightly scored bearing surfaces that I'm going to try this out on. Fortunately I found a supplier for this in the Netherlands, saving me about $110 in shipping and tax..

[mbwatch]

Evening 4 progress report:

I did another cleaning of the spindle and bearings, and especially went over the outer edges of the bearing and spindle cones where they touch with 00 steel wool. This seems to have cleaned off whatever microscopic crud was still on there causing binding when they were pushed all the way together.

I installed the rear bearing with Loctite 638 - can't believe how fast it works. I barely had time to straighten the oil channel before it set. But it is firmly in place now and the oil channel isn't blocked. I tested a good amount of 3 in 1 oil to see it flow through into the bearing. I'm only beginning to read about what lubricants everyone prefers for cone bearings so i expect I may end up flushing the 3 in 1 to use something else. Tested the spindle and I get good motion once I had a lot of oil in there.

The last thing before I can reassemble is to get a new grub screw. The one in there with the stripped socket threads right down through the bakelite pulleys, and has stripped out the hole in the pulley. I will need to get a slightly larger grub screw with enough length that I can grind off the last 2mm of threads to fit down into its recess on the spindle. Maybe it isn't necessary to remove those threads, but that was apparently done on the screw that I pulled out.

[Dell]

The grub screw is usually dog point  & the lubrication is the total loss system designed to flush through, use high speed spindle oil.

[mbwatch]

4 hours ago, Dell said:

dog point

Thank you @Dell, I did not know this term and it looks like my previous screw was modified to "dog point". I am going to look for a slotted head screw instead of hex.

I have started reading the debates on spindle oil vs light motor oil on all the old watch & clock forums.

[mbwatch]

@Dell if you don't mind, what metal must the pulley set screw be? I have found options in alloy steel, stainless, brass. Nothing labeled as hardened, though hard steel seems like it would be prone to shearing for an application like this. Thanks for addressing newbie questions - I knew almost nothing about machining or metal composition before this week.

[Dell]

11 hours ago, mbwatch said:

@Dell if you don't mind, what metal must the pulley set screw be? I have found options in alloy steel, stainless, brass. Nothing labeled as hardened, though hard steel seems like it would be prone to shearing for an application like this. Thanks for addressing newbie questions - I knew almost nothing about machining or metal composition before this week.

I wouldn’t worry too much about it as it’s not under any stress all it does is lock the pulley to the spindle, on my Pultra they are just alloy steel.

[caseback]

On 2/6/2025 at 4:01 AM, mbwatch said:

I'm only beginning to read about what lubricants everyone prefers for cone bearings so i expect I may end up flushing the 3 in 1 to use something else. Tested the spindle and I get good motion once I had a lot of oil in there.

10 watchmakers: 15 opinions on lubrication 

I use a synthetic 5w-30 motor oil in a syringe to lubricate my lathe.