Rotary Table Woes

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OlCatBob

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Hey Guys,

When I bought my Nichols Mill, the accessories that came with it were few; but it did come with a D60 Kurt and a Troyke 9" rotary table.
I had to clean 'em up of course, but hey! they were valuable pieces. Anyway, I thought I could use the rotary table for a project I was working on, so I took it apart to clean and paint it. When I took it apart, the nut underneath was a lot looser than I thought it should be, but I figured I could adjust it when reassembling. Well, upon reassembly, I tightened it up to what I thought would be good, and when I went to try turning the table with the crank knob the table turned until it just tightened itself up. It was then that I determined that a prior owner must have dropped it at some point. I put an indicator on it, and sure enough, it's bent at the spindle.
Does anyone know how to get it back square to the table?

Any help would be appreciated.
Bob
 
Loosen the nut, shim up the low side, and smack the high side with a big hammer? It might work, it's about the only way I can think of the straighten it out, short of making a new spindle.
 
Might be easier to make a new one rather than attempting to straighten. You're a lucky guy - that Troyke is a real score as you clearly know and well worth investing some TLC !
 
Jim, I never even thought of that approach; that just MAY work, and I really don't have a lot to lose by trying it. What about "tightening the bolt" it may help pull it into position better... it would also be easier to check, just start turning the handle, it would tell me something immediately.
I'll give it a try this weekend, and report back.
Bob
 
I should note here that when smacking with a hammer, you need to protect the table with a chunk of oak or hickory if you have it, a chunk of 1/2 inch thick aluminum or steel would work too. Or use a big dead-blow hammer. Another option might be a press rather than a hammer.
 
You could try heat to straighten it. keith Rucker on YouTube had a good video on it.
 
OlCatBob said:
Jim, I never even thought of that approach; that just MAY work, and I really don't have a lot to lose by trying it. What about "tightening the bolt" it may help pull it into position better... it would also be easier to check, just start turning the handle, it would tell me something immediately.
I'll give it a try this weekend, and report back.
Bob
Click to expand...
Years ago, I purchased a 12" Enco rotary table which also had a bent shaft but it was the worm shaft. As you rotated the dial, it would bind up at a particular spot and the interference was visible. To use the table, I had to loosen the nut on the shaft. I unsuccessfully tried straightening it by the method described in earlier posts and finally just shimmed the dial so it wouldn't touch when rotated.
While I have never straightened a rotary table spindle, I have straightened bent crankshafts on B&S lawnmower engines after running into immovable objects. It is important to try to duplicate in reverse the conditions that caused the bend. Otherwise you end up with an "S" bend which may have zero runout at one position but will not at any other position.
I made a fixture to support the far end of the shaft and a split bearing to clamp the shaft at the same point as the lower mower bearing. This was all set up on a long piece of I beam. A long piece of pipe was placed over the end of the shaft and leverage applied to straighten the shaft. A dial indicator was used to check for runout. The process allowed putting the shaft back into service. I would think a similar process using a hydraulic press and properly located supports would work for you.
 
JD, yeah: that goes without saying. I would likely place the RT on a solid surface, place a piece of hardwood on top of RT to protect it from the blow. My initial thoughts were in fact to use a press, just couldn't think of a way to accomplish it.
Arknack, do you have a URL for the Keith Rucker piece? I'm open to anything, although I'm not sure if there would be a way to utilize it.

thanks to all so far, still open to other suggestions though.
Bob
 
Sakowski,congratulations on straightening the bent crank shafts if you really got them accurate!!!
 
george wilson said:
Sakowski,congratulations on straightening the bent crank shafts if you really got them accurate!!!
Click to expand...
They were serviceable to the point of eliminating vibration. As I recall, I couldn't get them totally straight but stopped "adjusting" when I was down to a thousandth runout.

I have also done some archery in the past and found out how hard it is to remove a bend in and arrow by visually sighting straightening. Invariably, you would end up with the "S" curve rather than a straight arrow. As I recall, I past times, the blacksmiths who could properly straighten shafts were at the top of their profession. It is a true art and one I have not yet mastered.
 
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