Gilmer double bearing machining

holsgo · Post by **holsgo** » Fri Jul 13, 2012 8:37 pm

Some of you had seen that a couple years ago I did a multi bearing upgrade to a 54. I have now taken the machine back apart and machined the quill and spindle to fit the 6202-zz-10 5/8 bearing...or in other words multiple stock bearings for the quill.
Here is the quill in the 3 jaw with the parting off blade.
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Used the DI to find .431 to then used the parting off to set the shoulder for the second bearing.
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Shoulder cut.
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Brought to .624
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And bearings slip on. Well press on actually.
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holsgo · Post by **holsgo** » Fri Jul 13, 2012 8:45 pm

Now I move to the quill. Switched to the 4 jaw chuck and dialed in the quill at the headstock end. Then moved down the quill to the tailstock and set the steady rest with brass between the fingers and the work.
Here is the quill mounted and ready to machine.
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The qill chips. I used the DI again to find the original shoulder and then set the carriage stop once I found .431 back from it to machine space for the bearing.
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Worked the machine about .003 at a time to get a friction fit. One more pass at .001 gives me a tight slip fit.
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Clip in and the fit is good.
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To the shopsmith where it's all finally fit and running. I already know I'm going to have little runout. My issue is whether to put the third bearing towards the spline end. Probably will. Just machine the spindle back about another 2-3 inches. Machine the quill back the same. Then set a bearing on the spindle with a sleeve of about 2 inches between it and the front 2 bearings.
We'll see but it's fun to fit the machine up a bit more.
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billmayo · Post by **billmayo** » Fri Jul 13, 2012 11:09 pm

It took me 5 years and trying 5 different machine shops before finding someone who could machine the quill housing to a .001" accuracy. I have available on Ebay both the Poly-V and Gilmer double bearing quills that I had machined this year. My machinest (retired and with a well equipped backyard machine shop) advised me to space the 2 bearings apart using the inner race from a front bearing. I find my results shows little less runout then when years ago, I was placing the 2 bearings together. I believe the Drive Sleeve bearings supports the quill shaft spine end to where no additional bearing was needed at that end.
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holsgo · Post by **holsgo** » Sat Jul 14, 2012 5:44 am

I was going to space them as well. Like I said, probably going to put one further back. I must say that holding the quill is a challenge, especially that far out from the chuck.
I did see these for sale. They look great Bill. I thought you were a machinist way back? Are you just not tooled up as much anymore or specifically wanted a through hole over 1.75 for the quill?

pennview · Post by **pennview** » Sat Jul 14, 2012 6:39 am

I modified a couple of these quills to accept three bearings using techniques similar to your methods, holsgo. I simply put them adjacent to one another, rather than using a spacer between. I've never put them to good use yet, but one of these days I'll get around to repairing a Greenie that could use the gilmer quill I modified. This should make for a much stiffer spindle, particularly when using the lathe. I used cheap Chinese-made bearings, so longevity may be an issue. In any event, quill bearings are easy enough to replace.

My steady rest is actually from a wood lathe, but it seemed to give adequate support when turning the quill housing.

holsgo · Post by **holsgo** » Sat Jul 14, 2012 7:26 am

Great pennview. Practice makes perfect and I am probably just going to stack all three. Part of me just wants to load the quill but I can only go so far with my boring bars.

peterm · Post by **peterm** » Sat Jul 14, 2012 9:46 am

Impressive machining, holsgo!

holsgo · Post by **holsgo** » Sat Jul 14, 2012 2:25 pm

Thanks Peter. I just got done adding the third bearing. I now have 3 stacked just like my original mod, but now using OEM bearings same size as stock. I just put the machine back together so if someone wants a pic I'll go take it apart. The only thing different is a large washer, turned on the lathe to be quite thin and drilled to .625. This slips over the shaft down to the shoulder. Then the bearings go on with the first bearing against this washer. I found some binding without it but now smooth with little to no heat.

billmayo · Post by **billmayo** » Sat Jul 14, 2012 10:36 pm

holsgo wrote:I was going to space them as well. Like I said, probably going to put one further back. I must say that holding the quill is a challenge, especially that far out from the chuck.
I did see these for sale. They look great Bill. I thought you were a machinist way back? Are you just not tooled up as much anymore or specifically wanted a through hole over 1.75 for the quill?

Yes, I am a self taught machinist but only have a HF 7X10 metal lathe and a Shopsmith I modified as a metal lathe. The original machinist who machined a batch of quills for me went out of business about 7 years ago. It took me 6 years to find another accurate machinist. I tried 5 different machine shops in 5 years without success.

So I ended up with around a dozen sets of quill housings and shafts from these 5 machine shops. The 2nd bearing area in the housing and/or shaft was machined .001“-.006" off specified tolerance. I think the metal chuck in each case had some minimum play or the person doing the machining was less than accurate.

My retired machinist wife is a long arm quilter, the same as my wife. When we met at a quilting show, the machinist and I found we had common interests. He has a very large South Bend lathe in which the quill housing is supported entirely in the chuck. He is a perfectionist when machining. To salvage the off-center machined quill housings/shafts I have, he suggested adding a spacer and machine deeper/longer for the second bearing location. He also has a large Bridgeport milling machine which he done some joiner tables for me.

I have found about 10% of the about 200 quills I have dealt with have been bent. I have a modified headstock with a dial indicator and V-blocks on top that I use to check if the quill shaft is bent. I found I have less run-out at the shaft end with using the spacer between the bearings. Also, I noticed that Shopsmith moved the second bearing from the rear of the housing up to close to the front bearing on their latest double bearing quill.

nuhobby · Post by **nuhobby** » Wed Jul 18, 2012 9:14 am

billmayo wrote: Also, I noticed that Shopsmith moved the second bearing from the rear of the housing up to close to the front bearing on their latest double bearing quill.

That's interesting... any pictures of that? (Maybe I should take apart my 2010 quill to look at that.)

Holsgo: Looks like you're an unstoppable shop now!