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Single Bearing Quill better than Double Bearing ...?

Posted: Tue Mar 19, 2013 2:27 pm
by WmZiggy
I recently replaced the original single bearing quill in my 73' SS 500 with a double bearing quill I bought on eBay. It runs just fine, thank you.

However, the single bear quill that I removed looked so nice I wondered if it could be fitted with another bearing to keep as a back-up. While researching what would need to be done I contacted a SS repair individual to see if he did this type of work. He told me that double bearing quills create more shaft problems, even breakage, and you are better off with a single bearing quill than a double bearing quill. That's hard for me to believe!

Has anyone here ever heard of this? And is there anyone out there who machines quill housings and shafts to take an additional bearing, doing so at a reasonable price. What's reasonable? Cheaper than a new one, and less than what one generally goes for on eBay (usually $75 - $90 dollars).

Posted: Tue Mar 19, 2013 2:34 pm
by joshh
Shopsmith cut the center shaft into two halves to create their double bearing quill. It is still more accurate (in good condition) than a single bearing quill. The other alternative is to create a real double bearing quill, which is what your original question is...

MKC tools does the exact work you are looking for, and does EXTREMELY good work.

Watch this and read the video description.
http://m.youtube.com/#/watch?v=2S7ICFrS ... S7ICFrSttA

Then go here and look at the first two items
http://mkctools.com/mark%20v%20parts.htm

Posted: Tue Mar 19, 2013 3:00 pm
by WmZiggy
Thanks joshh. I knew about the youtube video and had watched it and it enabled me to take the bearing out of my old quill. I didn't know about mkctools, so appreciate the source. I also didn't know the factory two bearing quill, which is what I have on my 82' SS 500, was a split shaft affair. Good to learn that as I figured SS did what mkc is doing. Thanks again.

Posted: Tue Mar 19, 2013 3:01 pm
by terrydowning
That being said. Nothing wrong with the single bearing quill for wood working. Check the runout with a dial indicator. It may need to have a bearing replaced. Don't settle for cheap shoddy bearings on the quill. Pay a few dollars more and get quality.

Posted: Tue Mar 19, 2013 3:20 pm
by holsgo
I posted the machining of the quill and spindle. Look up a past post of mine and you'll see how it's done. I'll look for the link.
Edit..found it.
http://www.shopsmith.net/forums/showthread.htm?t=10834

Posted: Tue Mar 19, 2013 3:27 pm
by reible
If I recall at last count there are 3 different 2 bearing quills. One early version has the split shaft, the rest are all one piece.

I haven't taken the time to match part numbers of the new quill that comes with the powerpro upgrade, that could be one they just provide because they don't want any issues with the "old" one you might have or it could be they have upgraded bearings/specks for 10K operations.

The run out spec's on the two bearing quill are better then the single bearing, if you happen to notice that or not, well you would have to tell me about that.

I replaced the single bearing on my 1976 model while it was in OK condition and put in a two bearing. It was noticeable to me. When I replaced the quill on a used machine with a "bad" quill (meaning one that had a bad bearing) it was even more striking an improvement. In defense of those who like the single bearing I still have one of my machines with one, but it has had the bearing replaced.

If you want more information I'd use the search function, this has been discussed many times.

Ed

Posted: Tue Mar 19, 2013 10:29 pm
by WmZiggy
Thanks all for the additonal resources and insights. I use my SSs often for routing and shaping, and biscuit cutting which puts more lateral stresses on the shaft. I thought it best to have double bearings on both machines, especially the oldest one. I was suprised how good everything was on my 73' after 40 years - the bearing in great shape. On my 82' I had a factory replacement right after SS came out with it. The 73' was my brother's and he didn't use it very much, the reason he sold it to me.

Posted: Wed Mar 20, 2013 12:35 am
by billmayo
Shopsmith has made 5 different versions of the double bearing quill. I find only the latest to be a quality item that I recommend (bigger bearings, one piece) but it is expensive ($150). I have offered several different versions of double bearing quills that I machined for the second bearing. I have done extensive testing in this area with test jigs and finally arrived at what I found the most accurate version (less than .001" runout) that I offer on Ebay (billstoolz) at various times. It takes a really good machinest and a really tight metal lathe to machine to these close tolerances. I am currently adding a 11mm spacer and the second bearing behind the front bearing. I have Gilmer quills available ($90) and have 2 three bearing poly-v quills ($100) for bowl turners. I use the early Shopsmith 2 bearing quill and add the spacer and third bearing behind the front bearing. I have done several of these quills for bowl turners without any come back after a few years. I currently have 5 poly-V quill shafts and housing being machined for the spacer and second bearing but have not received them yet. Under extensive testing my quill shaft had less deflection less than the Shopsmith ones. I spent hours insuring that I am selling a quality product.

Posted: Wed Mar 20, 2013 8:01 am
by WmZiggy
Thanks Bill. I have a Delta lathe. It is a wood lathe fitted with compound slide rest and countershafted for slower rpms. But I've got no training as a machinest and the tolerances are not good enough for this level of work. I am interested in the work you are doing.

Double and Triple Bearing quills

Posted: Tue Mar 26, 2013 12:29 am
by billmayo
My latest shipment of Poly-V and Gilmer Drive housings and shafts arrived today at my shop. I will be offering 2 bearing quill ($90) a 3 bearing quills ($100) for the Poly-V drive, a 2 bearing quill ($90) for the Gilmer Drive. Contact me or visit Ebay (billstoolz)