- Joined
- Jan 10, 2014
- Messages
- 200
Greetings everyone,
I am having a problem with runout on my 4 jaw chuck (Chinese). When I dial in the work with the dial near the jaws, then take a reading 4 or so inches away from the chuck, the runout is about 0.010. Before I mounted the chuck to the backplate, I took a facing cut across the front of the backplate and marked the position relative to my spindle. I dug through the forums and happened upon JimDawson's Asian 4-jaw Chuck Adventures:
http://www.hobby-machinist.com/threads/asian-4-jaw-chuck-adventures-re-post.33311/
I decided to use the methods he described to track down my problem.
I measured the runout on the face of the chuck, and got a reading of 0.007". Next I removed the chuck from the backplate and measured the runout. Same reading. I took the backplate off to make extra sure there was no chips or anything causing the error, and when I went to put the backplate on the spindle, I noticed a thin little sliver of light coming from between the spindle face and the backplate. Without tightening any of the mounting lugs, I am able to wiggle the backplate around on the spindle in the same way that would cause the runout reading on the face (if you catch my drift).
Its like the backplate is sitting on that conical surface (surface 2) but won't go on far enough to seat against the flat surface (surface 1)of the spindle face no matter how hard I push on it. See my crude drawing below for reference.
My question is, the backplate should sit flat on surface 1, shouldn't it? If so, then the taper inside the backplate is too small and needs to be widened out slightly it would seem. The best way to do this would seem to be to duplicate JimDawson's setup where he was machining the rear of the chuck, except set to bore the taper instead (with the mounting pins removed). That sound about right?
Thank yall for the help..hope everyone has a happy Thanksgiving!
I am having a problem with runout on my 4 jaw chuck (Chinese). When I dial in the work with the dial near the jaws, then take a reading 4 or so inches away from the chuck, the runout is about 0.010. Before I mounted the chuck to the backplate, I took a facing cut across the front of the backplate and marked the position relative to my spindle. I dug through the forums and happened upon JimDawson's Asian 4-jaw Chuck Adventures:
http://www.hobby-machinist.com/threads/asian-4-jaw-chuck-adventures-re-post.33311/
I decided to use the methods he described to track down my problem.
I measured the runout on the face of the chuck, and got a reading of 0.007". Next I removed the chuck from the backplate and measured the runout. Same reading. I took the backplate off to make extra sure there was no chips or anything causing the error, and when I went to put the backplate on the spindle, I noticed a thin little sliver of light coming from between the spindle face and the backplate. Without tightening any of the mounting lugs, I am able to wiggle the backplate around on the spindle in the same way that would cause the runout reading on the face (if you catch my drift).
Its like the backplate is sitting on that conical surface (surface 2) but won't go on far enough to seat against the flat surface (surface 1)of the spindle face no matter how hard I push on it. See my crude drawing below for reference.
My question is, the backplate should sit flat on surface 1, shouldn't it? If so, then the taper inside the backplate is too small and needs to be widened out slightly it would seem. The best way to do this would seem to be to duplicate JimDawson's setup where he was machining the rear of the chuck, except set to bore the taper instead (with the mounting pins removed). That sound about right?
Thank yall for the help..hope everyone has a happy Thanksgiving!