Need help with drill spindle!

[RobinHood]

From the manual on Vintage Machinery dot Org, the chuck is a #6A Jacobs. The male taper on the spindle is a #33 Jacobs Taper. (File is too large to attach here).

Great work Peter.

Did you have a chance to measure the spindle and confirm the 0.620” OD for the bearing seat areas? Using a 0.625 ID bearing, there should be a way to get 1 thou shims all the way around the shaft. It would still leave a sloppy fit. 3 thou theoretically. More like 2 thou with for a 1 thou sliding fit.

 

[DH930]

From the manual on Vintage Machinery dot Org, the chuck is a #6A Jacobs. The male taper on the spindle is a #33 Jacobs Taper. (File is too large to attach here).

Great work Peter.

Did you have a chance to measure the spindle and confirm the 0.620” OD for the bearing seat areas? Using a 0.625 ID bearing, there should be a way to get 1 thou shims all the way around the shaft. It would still leave a sloppy fit. 3 thou theoretically. More like 2 thou with for a 1 thou sliding fit.

Thanks for the chuck info. I was searching for the info and also searching for the original box last night. I can't believe that I would have discarded the box. I bought the chuck on Ebay from a fella in UK couple years ago. The chuck was NOS.

 

[DH930]

I looked into my purchase history on Ebay and found the chuck. It is #6A.

Jacobs # 6A Drill Chuck/Key, JT33 Mount, 0-1/2" Capacity

 

[PeterT]

Did you have a chance to measure the spindle and confirm the 0.620” OD for the bearing seat areas? Using a 0.625 ID bearing, there should be a way to get 1 thou shims all the way around the shaft. It would still leave a sloppy fit. 3 thou theoretically. More like 2 thou with for a 1 thou sliding fit.

I think the 0.620 came from Dai originally. He didn't say if it was mic'd or calipered, he can chime in. But maybe the best he could do with the tools he had. I measured the shaft with my good mic & like I was saying kind of varies a bit depending on the orientation, but on average seemed a bigger than 0.620. I'll check my notes. The spindle body has been cleaned up a bit so there are some micro flats here & there which may influence a particular region between the anvils measuring across the diameter in a certain orientation.

But the takeaway point is I can only push a 0.001" shim in from one side of the inner race to shaft & obviously the other side of bearing is in tangent contact with the shaft. If I cut a shim of about 1/3 the diameter it fits in. if I cut it to say 1/2 the diameter its already tightening up on the shim ends & easy to curl getting in. If I try to make a full diameter shim loop around the shaft (0.001 shim = 0.002 diametric difference) the bearing wont go on at all. So I think the real annular gap is maybe more like 0.0007... 0.0008" just as a guess. Which in my mind puts the situation in the range of some kind of shaft 'coating' just to get the bearing centered with no play. I didn't measure the bearing IDs but assume they are pretty accurate & what we have to work with anyways.

What was trying to say a couple posts above is - maybe I could find the happy position for the shim on one preferential side to minimize runout as much as possible. But the random position I chose just for a looksee gave me 0.002 DTI deflection. That still pretty decent. But I'm not quite sure the quill/bearing/shaft assembly can be put together as a sub-assembly like this & installed into the rest of the drill body. Dai can elaborate. But this particular chuck is adding 0.010" to whatever we achieve so that's the dominant issue.

So I think we are getting closer. Just need to figure out an easy to apply 'gap-goop' that will preserve the spindle runout & take up slack. By guess is an even coating will achieve something close to 0.002"

 

[PeterT]

I looked into my purchase history on Ebay and found the chuck. It is #6A.
Jacobs # 6A Drill Chuck/Key, JT33 Mount, 0-1/2" Capacity

I'll check tonight. Thought I tried my 1/2" dowel pin & it was too large so guessed 3/8 capacity. Anyways Jacobs makes a lot of different models & they have varied over the years & been outsourcing for a while. For example some of these medium grade are showing 0.004" runout catalog spec. That whole subject is a discussion unto itself IMO but I know when you start getting into precision range (0.001) the cost goes up pretty dramatically. But I also know there are some good Asian chucks that are decent. Thats why I was asking if you were married to Jacobs for nostalia or just wanted a good chuck. (I am personally fond of keyless). And Rudy makes a good point that maybe the existing chuck can be rebuilt, but not anything I've attempted.

I have a similar issue on my to-do list with a mini 'precision' chuck that is a runout POS. But the jaws close nice. I've been thinking of creative ways to modify it to give me something equivalent to SetTrue adjustability like a big lathe chuck & use epoxy to lock it home. But seems like a misguided plan. Better to reverse hold a pin it & attempt to regrind the seat. The issue is there just isn't much taper material to work with assuming it has to fit a standard arbor.

 

[DH930]

I think the 0.620 came from Dai originally. He didn't say if it was mic'd or calipered, he can chime in. But maybe the best he could do with the tools he had. I measured the shaft with my good mic & like I was saying kind of varies a bit depending on the orientation, but on average seemed a bigger than 0.620. I'll check my notes. The spindle body has been cleaned up a bit so there are some micro flats here & there which may influence a particular region between the anvils measuring across the diameter in a certain orientation.

But the takeaway point is I can only push a 0.001" shim in from one side of the inner race to shaft & obviously the other side of bearing is in tangent contact with the shaft. If I cut a shim of about 1/3 the diameter it fits in. if I cut it to say 1/2 the diameter its already tightening up on the shim ends & easy to curl getting in. If I try to make a full diameter shim loop around the shaft (0.001 shim = 0.002 diametric difference) the bearing wont go on at all. So I think the real annular gap is maybe more like 0.0007... 0.0008" just as a guess. Which in my mind puts the situation in the range of some kind of shaft 'coating' just to get the bearing centered with no play. I didn't measure the bearing IDs but assume they are pretty accurate & what we have to work with anyways.

What was trying to say a couple posts above is - maybe I could find the happy position for the shim on one preferential side to minimize runout as much as possible. But the random position I chose just for a looksee gave me 0.002 DTI deflection. That still pretty decent. But I'm not quite sure the quill/bearing/shaft assembly can be put together as a sub-assembly like this & installed into the rest of the drill body. Dai can elaborate. But this particular chuck is adding 0.010" to whatever we achieve so that's the dominant issue.

So I think we are getting closer. Just need to figure out an easy to apply 'gap-goop' that will preserve the spindle runout & take up slack. By guess is an even coating will achieve something close to 0.002"

The tool I used was a caliber and I am with Peter that it is a smidgens bigger than .620".

Peter, yes you can assemble the quill/spindle unit all put together up to the lock collar. Even the chuck can be installed on the spindle prior to installation to the drill head. In short answer, the bearings can be installed securely to the spindle and the quill and locked in place.

 

[DH930]

Is this the right chuck and is it a good one to get?

http://www.jacobschuck.com/jacobs-chuck-9682d-jkp-130-j33-high-precision-keyless-13mm-chuck.html

 

[PeterT]

Yes that's a good one for sure but going to be spendy. Not sure if same model number but in this order of $ magnitude.
https://www.kbctools.ca/products/search/?Keyword=precision drill chuck

The Taiwan? keyless model one I got for my mill was very accurate & reasonably priced, but that was a while ago. Sometimes its just luck I feel with the offshore stuff, but when I got a similar model for my lathe tailstock, it was again good. I hate endorsing things just in case they vary. It might be worth going through a dealer so if its an obvious issue compared to spec, you have some exchange recourse.

Mine looks conspicuously like GS (its marketed under different labels). I have some other GS tooling & its decent value. SOWA is a retailer but you can get through Calgary via DMH & Thomas Skinner I believe.
http://www.sowatool.com/Product/8/312/1338

Looks like they sell Rohm & Jacobs too, but always pays to shop around. KBC is flat fee 9$ to your door or whatever the current rate is.
http://www.sowatool.com/Catalogue/8/312?Category=Drill+Chucks&Drill+Chuck+Type=Keyless+Chucks

I'll do some digging

 

[DH930]

Yes that's a good one for sure but going to be spendy. Not sure if same model number but in this order of $ magnitude.
https://www.kbctools.ca/products/search/?Keyword=precision drill chuck

The Taiwan? keyless model one I got for my mill was very accurate & reasonably priced, but that was a while ago. Sometimes its just luck I feel with the offshore stuff, but when I got a similar model for my lathe tailstock, it was again good. I hate endorsing things just in case they vary. It might be worth going through a dealer so if its an obvious issue compared to spec, you have some exchange recourse.

Mine looks conspicuously like GS (its marketed under different labels). I have some other GS tooling & its decent value. SOWA is a retailer but you can get through Calgary via DMH & Thomas Skinner I believe.
http://www.sowatool.com/Product/8/312/1338

Looks like they sell Rohm & Jacobs too, but always pays to shop around. KBC is flat fee 9$ to your door or whatever the current rate is.
http://www.sowatool.com/Catalogue/8/312?Category=Drill+Chucks&Drill+Chuck+Type=Keyless+Chucks

I'll do some digging

Thanks Peter. I have been doing research on chuck today and found out a lot of info. Albrecht is another top-end brand. Many peoples love that chuck for precision.

 

[PeterT]

I tried the primer trick. The shaft OD on the lower bearing area was nominally 0.6223" For reference the bearing ID is 0.6242-0.6245 according to my mics.
By adding a single coat of primer the OD goes to 0.6243-0.6246". It took away all the play. I assembled the spindle fully just to take some more measurements. When I disassembled & pulled the bearing off it shows the rub off in one area & shiny in another. This could be bit of eccentricity on the shaft assuming the bearing is ground pretty accurate.

The primer method is interesting but my preference would be a more hard surface mechanical solution. If one were to use the primer as kind of gap filling tool with the intent of wicking in retainer than it might be OK. This particular assembly doesn't lend itself to that IMO because after the lower is bearing goes on, the spacer tube & quill & upper bearing has to go on. Which means one has to spray the upper band in, masking off etc. Yellow pencil tip shows the upper bearing seat on the quill body.

 

[PeterT]

Now that I have more confidence on how much annular gap we are dealing with & the variation, I think the best solution is using 0.001" shim stock like so & just skip the Loctite. The way the parts go together the shims completely removes radial & axial bearing play. I think the shims just need to be spotted into position during assembly & cant really go anywhere once the assembly is tightened up. So it still gives a lets call it 80% constant annular gap because they are mostly still on either side of the shaft, just spaced out a bit just as they find the natural low. If I took some material (light sanding) off the shaft I could get a full annular ring of shim, that's another option. I almost prefer the 2 segments as-is when its disassembled, they dislodge a bit easier. The shims get kind of crumpled & damaged each disassembly which is no big deal. They are expendable. But I think they might jam up requiring some extra tapping effort. This assembly got me within 0.0010 - 0.0015" on the taper end, so quite good.

I could assemble this way with brass & call it good. But I think the steel shim John has might be better to try only because its hopefully a tougher material. The brass is quite fragile & folds up easy just trying to insert whereas steel may allow something like a full annular ring if I take the shaft down just a smidge. The steel material might offer another advantage, maybe a drop of Loctite on the shim would keep it stuck but still release with no effort, whereas I think I'm convinced the brass just does not like to bond very well.

 

[PeterT]

Here is the set screw collar which prevents the shaft from sliding within the bearing races. It was a bit distorted & you can see prior bite marks on the shaft & skid mark coincident with raised burr. I stoned down the shaft & chamfered the collar threaded edge with diamond ball. Then subsequently cleaned up the collar ID. Its an easy sliding fit on the shaft now but my I took it just a bit further with emery & now the collar can go over top the extended shim from the bearing & set screw bite down on that & protect the shaft.

 

[PeterT]

Here are the chuck pics, Dai. It is 1/2" capacity according tho this so maybe my pin was pushing the limits. Now that I have some more play eliminated total runout is maybe 0.008-0.009". Not sure what you were intending to do with the drill accuracy wise, but personally might be worth assembling as-is, measure runout with everything assembled. If its ok for your purposes, live with it. Or if you want to upgrade one day, it should be easy to remove & mount another completely independent of the 'upstairs' components. I forgot to mention I dont have a key that size so I could only hand tightened on my edge finder, so maybe not super tight. Some people have claimed their chuck 'break in' & improve a bit but who knows.

 

[DH930]

Wow Peter, you have done so much to investigate the best possible solution to the bearings mounting method. I really appreciate this. I think the steel shim is probably the best solution to this and I completely trust you to choose whichever method you think is best, either 2 halfs or one continuous shim. As for the chuck, I have bought an Albrecht chuck from the US for $300CAD. My intent for this drill is to be my main drill and I want to be as accurate as it can be. The chuck is being sent to my friend in Chicago and then he will ship it to me later. The chuck is still 3-5 weeks away from now. Peter, if you would like, you can hold on to that until I have the Albrecht chuck so that you can measure it with spindle. Since you have spent so much time with this that I thought you might be interested to see this to the final step, with the chuck mounted. Let me know what you preferred to do.
I want to thank you for your efforts that is beyond my expectation. I will make sure you will be rewarded in the end.

 

[PeterT]

Nice chuck. Sure no problem. I've learned a lot through this project too.

I meant to comment on CA glue - my test on my scrap steel shaft. On the plus side
- it actually forms a pretty tough buildup coating that has more adhesion than primer & thicker than primer
- I think it could be completely removed with solvent or CA de-bonder so it wouldn't be destructive to the metal
- it cures quick so the treatment could be done in several minutes vs waiting for primer or paint to cure

On the minus side
- getting it even is kind of a feel thing. I just q-tipped a single layer, let it flash, then another
- sanding makes the surface smoother & flatter but because its clear, kind of hard to see whats going on
- still a bit of jerry rig solution, but in certain applications OK maybe

 

[PeterT]

Dai bought a variety pack of steel shim from Amazon to cover the bases. Maybe he has plans to buy a lathe or some other restoration project next lol. (Thanks for the shim offer Johnwa, we will find a use for that!).

The steel is a bit firmer than brass but its still a pretty delicate 'foil' in the 0.001" thickness. If you push it with your thumbnail & the entry too firm, it will crumple. I found it was better to position on a slight angle, get the bearing started on a corner & kind of work it on. The material can be cut with a new blade or scissors. I wanted to do the assembly with no adhesive if possible. I'll do some bond testing separately on my scrap shaft because I'm still curious about steel vs. brass. The assembly is pretty straightforward but the upper (second) bearing is a bit fiddly because at this point the bearing OD is being contained by the quill ID seat & its about an inch deep in the quill, so getting the shim slid into the ID in is a bit constrained. The trick at this point is get the shim in but not allow the first (lower) bearing move on the shaft or it will lose its shim & back to square 1. This is where pre-bonding the shim would be ideal. I also put a separate ring of shim stock under the set screws of the race collar so it wouldn't mar the shaft.

Anyways all back together. There is no play axially or radially now. I consistently measure 0.001" runout at the wide part of arbor cone and 0.0015" near the tip. So if the new chuck is reasonably accurate this will be awesome. I tested the old chuck again for old times sake & get the same +0.008" runout on a chucked pin. I get the same runout value on the chuck body no matter how I mount it. If I nearly close the jaws I can can see some gap discrepancy. I'm not sure if this is a valid test or which is the predominant culprit. But my 'good' chucks jaws mate up very close together & the nose body is within a thou of the pin.

 

[DH930]

Very nice work Peter. You have gone beyond just helping me out here. I truly humbled at your patience, and your dedication to exploring the best possible solutions. I am surprise to see the photo of the Jacob chuck's jaw being so far off. And, I thought that Jacob makes good chucks. Anyway, the new replacement chuck should be here in two weeks. I will drop off the new Albrecht chuck for you to see, and for you to do your testings.
You are correct that there will be a lathe in my future. Now that I belong to this awesome forum, I will be tapping into this community for recommendations when I'm ready to buy one. I love old machines so I'm not sure if an old lathe is a good choice.

 

[Tom O]

And now for something completely different!
Just found these while browsing.

https://www.euro-bearings.com/tol1.htm

 

[Brent H]

@Tom O : we used those before for a fan housing that the bearing spun in - outside bearing diameter and had to machine the housing bore to accommodate the ring. I did not think they were available for an inside diameter shaft press fit - I think you would need to machine the shaft for the ring to be fitted.....not really my cup of tea for a press fit ID repair

 

[Tom O]

It’s hard to say I’d think that being steel they would be strong enough, the use would have to be taken into consideration for loads but a drill has no real side loads.