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- Dec 20, 2012
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I can understand the reluctance, Bill, but as David said, it is the right move to make ... every single cut you make with a tool held in an R8 collet will be affected by that spindle. Besides, its an opportunity to learn how to remove and replace the spindle, check the bearings and make sure your bearing preload is good. If you can, put the new spindle on V-blocks and check it with a tenths-reading DTI so you know it is straight and that the spindle taper runs true. If you do the same thing at each step of the installation then if one component is off you will know exactly what it is.
To clarify, check the spindle first. Then install it in the quill and check the run out of the spindle in the quill with the quill locked down on the work bench. This tells you that the spindle bearings are aligned and the spindle runs true in them. Then install the quill and check it again. If run out is consistent with what you got before then you're good; if it increases wildly then your drive sleeve bearings are suspect. Get it?
I'm not sure how you're checking your spindle concentricity but this procedure from an older thread works well:
Just thought I would give you a simple procedure for checking concentricity with reasonable reliability.
To clarify, check the spindle first. Then install it in the quill and check the run out of the spindle in the quill with the quill locked down on the work bench. This tells you that the spindle bearings are aligned and the spindle runs true in them. Then install the quill and check it again. If run out is consistent with what you got before then you're good; if it increases wildly then your drive sleeve bearings are suspect. Get it?
I'm not sure how you're checking your spindle concentricity but this procedure from an older thread works well:
Just thought I would give you a simple procedure for checking concentricity with reasonable reliability.
- Clean everything - the thing to be checked, any tapered thing, the indicator base and indicator tip. No oil anywhere.
- Always check the foundation. If you're checking something that fits in the spindle then you have to check the concentricity of the spindle first. If mounting something that contacts the spindle register, check the register. If mounting something inside the Morse taper then you have to check that, too.
- Use a Sharpie and mark the thing that is being checked and another reference mark in line with it that is on something stationary. This is really important. Try to make your marks in such a way that you minimize parallax. That is, when they line up, you're sure they line up.
- Mount the indicator correctly (angle of the indicator arm correct for that indicator) and preload it so there is some tension on the internal springs. I usually preload to at least 0.050", then zero the dial. If I tap the indicator and the needle jumps around and doesn't return to exactly where I set it then I know I need to re-configure the holder so it is solid. When you zero the needle, it needs to be dead center on some unit so you know exactly where your starting point is; no guessing allowed.
- With your reference marks lined up, manually turn the thing you're measuring one full revolution and be certain the indicator needle returns exactly to your starting point when your Sharpie marks align. If they do, this tells you your set up is repeatable and you can rely on it. If they don't then you need to reconfigure it more solidly or change indicators.
- Now, make one more revolution manually but slowly and note the maximum deviation of the needle. If you can, Sharpie mark the turning thing so you know where that deviation is. Come back to your reference marks and check that you hit zero. Now repeat to see if the deviation is in the same place and of the same magnitude. If it is, then that is the amount your concentricity is out.
- It is a good idea to check a thing in multiple places - at least three spots on a spindle or taper (near the outer end, a bit of the way in and way in). That way you are sure the defect is over the whole surface and not at one spot.
- When using a D1 camlock attachment, like a chuck, it is a good idea to check your run out in all of the possible mounting positions so you know which one is the best and then put a witness mark on the chuck so you can always remount it for best accuracy. This assumes the run out is acceptable and you're going to keep it.