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Craftsman head stock question .

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westsailpat

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#1
This blog on the 6" I find helpful , http://www.deansphotographica.com/machining/atlas/spindle/spindle.html
My question is why are the bushings not split on one side and the oil hole hasn't been drilled ?
On my machine the bushes have been split and oil holes drilled , I have reason to believe my machine's bushes were factory issue .
Thanks , Mark .
 

wa5cab

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#2
There us one error in the blog. The Atlas Tech Bulletin on the 6" headstock was actually written for the Timken bearing models. One of the ways in which those and the sleeve bearing model differ is in how you set the spindle end float. The instructions he gives to tighten the collar on the left end of the spindle two gear teeth really applies to the Timken version. The ball thrust bearing takes thrust toward the headstock. Thrust toward the tailstock is only taken by the gear spacer rubbing against the left end of the left bushing. My take is that this should be set to zero initially and checked and reset after the first 8 or 10 hours of running.

On the bushings themselves, the factory ones are porous to allow oil to pass through them. They have no oil hole and no longitudinal slit. The clamping screws are tightened to hold the bushing and prevent it either spinning or moving longitudinally. The factory's take on adjustment to compensate for a worn spindle is to replace the spindle.
 

westsailpat

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#3
Thanks Robert , so noted about the end play . Also about the bushings . Although I find it hard to understand they could pass enough oil , but if that's the deal then that is what I shall do . So I would say that on my machine the original owner split and drilled the bushings so he could do the tighten up without having to buy new bushings .
 

wa5cab

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#4
Well, one has to assume that the original designers knew what they were doing. Mostly, anyway. :confused 3: One fairly quick way to confirm that enough oil is getting through is to run the spindle (tumbler in OFF) for a while and note the temperature rise of the casting right over the bearings.

Unless the spindle showed much wear, I would have to guess that it was the bearings that he didn't want to replace. But it appears that that wasn't the original intent of the split bearing retainer.
 

westsailpat

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#5
Haha , yes original intent . Right now I have to do the tighten up way more than I'm comfy with to get proper bushing tension . However I'm able to get the spindle run out down to almost nothing and I get a decent finish too , and it runs cool . Last time I had the head stock apart for inspection the bearing surface did not look great , I think on next disassembly I will make a set up on the drill press (think vertical lathe) and polish it out , that could be done but on second thought a new spindle might be in my little 6" 's future .
 

wa5cab

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#6
The down sides of polishing are two-fold - the entire circumference gets polished, not just the side or spot that needs it, and polishing involves material removal which increases clearance. You may be better off leaving things as they are until such time if ever when you do get a new spindle. And if you ever do get a new spindle, unless it's very soon, I would again install a new bushing or bushings. Fortunately bushings are cheap relatively speaking.
 
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