Shopsmith Forums

I'm rebuilding my 1954 vintage Mark V. I've owned the machine since 1972 and it's been almost trouble free. But, nothing lasts forever... well, almost nothing. Time for new bearings.

Along the way, I've looked with interest on the double bearing quills available for the Polydrive Mark V's. During an email exchange with another user, a suggestion was made that a double set of bearings could be added to the outboard end of the quill on a Gilmer drive machine - seemed like a worthwhile idea - better lateral support, tighter runout.

I ordered 2 new Fafnir bearings for this project. But, when the quill was apart, the existing bearing was not too hateful. So, we decided to re-use it as a 'spacer' between the new bearings. What could be better than a 2-bearing quill? How about a 3-bearing quill! It's working great - easilygood for another 'half century or beyond.

The pictures tell the story.





The alignment washer is no longer necessary. My mentor suggested that it was necessary that the lathe to turn the quill have a 1-3/4" spindle hole. That's true, but some lathes with a smaller spindle hole but "thick" 3- or 4-jaw chuck can also do this job just fine. Finally, be aware that machining standards in 1954 were not necessarily the same as today (they're better today).

This seems too simple to be true and at the same time sounds logical. I'm waiting for the members who have rebuild experience to check in.

Their comments should be very interesting.

Welcome to the forum, dave.

dusty wrote:This seems too simple to be true and at the same time sounds logical.

Sort of my thinking as well... after I figured it out. As you probably know (but some other users may not), the splines on the Gilmer quills are slightly larger than 5/8" so you cannot readily slide a bearing on the splined end of the shaft. But, two bearings on the other end seemed like a good compromise, right? Spreading the bearings apart by a short space seemed like an even better compromise, because even a fraction of an inch separation provides very serious support and stability.

So, I was going through all sorts of mental gymnastics on how to make a spacer that would space both the inner and outer bearing races. Well, do'oh.

Even if your existing bearing was pretty far gone, it would still make a great spacer. Or, splurge and buy a third new bearing. And, with the two new Fafnir C1`s taking the load, the old bearing should have a peaceful and load-free retirement.

Since the bearings are together at one end of the quill, it seems like this still does not have all of the attributes of a two bearing quill. But, two new bearings and one old must be better than just one old bearing.

Before you did this over haul, did you take any run out readings.

I would hope that you have real good run out characteristics now. If you do, this could be a new found way to deal with run out issues in the old one bearing quills.

Hmmm, will three bearings work in a two bearing quill. I'll wait to hear from Bill Mayo on this one.

dusty wrote:Since the bearings are together at one end of the quill, it seems like this still does not have all of the attributes of a two bearing quill. But, two new bearings and one old must be better than just one old bearing.

Before you did this over haul, did you take any run out readings.

I would hope that you have real good run out characteristics now. If you do, this could be a new found way to deal with run out issues in the old one bearing quills.

Hmmm, will three bearings work in a two bearing quill. I'll wait to hear from Bill Mayo on this one.

A beautiful job. I never thought about a 3 bearing quill. Similar to the 10ER drive assembly where they used a spacer between two bearings. An excellant idea for the quill and I believe it is better than the double bearing quills Shopsmith or I have been offering. The latest Shopsmith double bearing quill does use larger front (40mm OD) and back (35mm OD) bearings which is a large improvement over any previous double bearing quills they offered.

I will try this 3 bearing idea on a Gilmer quill soon and test it. I have dozens of bad quill bearings so I will see if I can cut/knock out the center of a bad bearing to use as a spacer.

Of course, precision machining is required for the quill housing and shaft. I have placed a quill housing and shaft with a bearing at several local machine shops and waiting on the results to test how well they did the job along with their costs and see who I will use in the future for this task. I have a few dozen quills waiting.

I believe the Poly-V quill would greatly benefit from the stacked front bearings too. I have been placing the second bearing at the front of the shaft splines. I did a double front bearing Poly-V quill for my dedicated Shopsmith milling machine (x/y vise) a few years ago that is still working. The single front bearing on the quills I tried before did not hold up very long when I was doing this type of work. I have found a source for a higher quality (also cheaper) quill bearing that I am also testing at this time.

I must state that Skip Campbell, 10ER guru, did Gilmer double bearing quills long before I did and helped me get started doing this type of conversion.

Thanks for the posting and sharing your idea.

dusty wrote:Since the bearings are together at one end of the quill, it seems like this still does not have all of the attributes of a two bearing quill. But, two new bearings and one old must be better than just one old bearing.

The only attribute that might be missing is supporting the non-loaded end of the shaft. But the bearing are providing great support at the loaded end - particularly lateral support for bowl turning or shaping. There's little danger of the non-loaded end of the shaft moving about since it is inside the drive sleeve splines (which are very well supported).

Sorry, but I did not take run-out readings before. With the new bearings, the quill should be very tight. The C1 bearings are probably tighter than the bearings originally used by Magna.

I finally did get the machine put back together a few hours ago - it's running like a top. Very quiet and vibration free. While reassembling, I noted a few things that seemed worth passing on:

Reassembling Quill Feed: When I tried to reassemble the quill feed, I noticed that nothing wanted to slip together. Earlier, it had not been particularly easy to get apart. This also applied to ends on the way tubes, etc. The least bit of misalignment meant binding. Rather than get a bigger hammer, I considered lubricating these slipping joints but grease attracts dust (and sawdust).

Instead of grease, I used Johnson paste wax (which every true Shopsmith owner should have on hand, right?). Worked like a charm - the quill feed assembly slipped into place perfectly. Ditto for the ends on the way tubes. Liquid soap would have been another possible lubricant.

Drive Sleeve Assembly: I had changed both bearings in the drive assembly. It was a pain to get this part out in the first place and I did not look forward to reassembly. Then I remembered a suggestion from somewhere back in the dark recesses of this forum's archives. I put the drive sleeve in the freezer for a day. An hour before reassembly, I put the headstock casting in the oven (set to "warm" - about 175-200 deg.). The warm headstock casting and cold drive sleeve slipped together in a flash - zero effort - perfect! It's probably best to do this when you're home along (if you plan to stay married).

After the temperatures of both parts normalized, I noticed that the drive sleeve assembly was very tight, with zero play or movement.

Cleaning Aluminum Parts: There was a light brown crud film on most of my aluminum parts (e.g. various handles, speed dial, etc.). I thought about different ways to clean them, but the simple method which worked was liquid dish soap and a scrub brush. Everything came out bright and shiny.

Screws: The folks at SS must dearly love self-tapping screws. But the second or third time they're removed and reinstalled, the threads they cut tend to disappear. I replaced all the self-tapping headstock screws (motor pan, belt cover) with stainless button head Allen capscrews, either 8-32 or 10-24 (and re-tapped stripped holes to 10-24 as necessary). I replaced the 4 motor screws with stainless button head Allen capscrews.

While I was at it, I replaced the 8 screws attaching the casters with 10-24 stainless Allen button head capscrews. These are not an exact match to the original SS screws (which have over-sized round heads) but close enough. Strangely, the square nuts used by SS held up fine - no rust or corrosion - so I re-used them. The over-sized RH machine screws had mostly rusted heads.

While I was at it, I replaced the 10 screws holding the legs to the frame with 10-24 stainless Allen flat head screws. These also thread into square nuts which I re-used. The stainless screws were a better fit into the counter sinks than the original SS screws.

Along the way, I picked up a few packages of #8 and #10 'toothed washers'. Every Shopsmith is missing a few toothed washers, and every time it's disassembled it loses a few more. I'm at full strength, until the next disassembly.

All of the Allen head stainless screws came from a local Ace Hardware, from a Hillman Fastener Company merchandise display.

The Shopsmith is back together and should be good for another 50+ years.

Great job, Dave. This could result in significant improvements in the performance of a tired Greenie. Your effort here can do nothing but help as we strive to keep these babies going as good or better than when new.

Thank you too for your efforts in posting the results and findings of your work.

Your legs are held on by 10-24 (3/16-24) bolts. I would have expected 1/4-20.

You brought up a good point re self tapping scews - They are not intended to self tap but the first time. Subsequent reinsertion of the bolts should include realigning the threads to prevent cutting a new set(crossthreading).

JPG40504 wrote:Your legs are held on by 10-24 (3/16-24) bolts. I would have expected 1/4-20.

You're right - 1/4-20's. My mistake.