Mounting D1-3 Three jaw chuck

Look at the lower left of this pic, as cam 3 is turned clockwise, it will pull the pin number 4 to the left. Also, keep in mind, that number 3 is a cam, not a pin like on the chuck.

Don't look at the 1,2, and 3 in the upper right.
spindle1.png
 
Thanks guys.
I am the thing that is wrong! Went out last night and turned the cam locks clock wise and they held. Loosened them again to where the chuck moved out about 1/4 inch then turned them clock wise at which point the chuck started moving towarrd the spindle plate and I could feel the cams sliding on the pins. Took two turns of the chuck to bring it tight and square, Took a short 0.015' deep cut for a short distance, no vibration or loosening of the pins. I can still see light between the spindle plate and the chuck back plate. although the crack seems smaller. A piece of paper 0.0035 thick will go clear in to the taper in one spot and opposite that spot the paper will not start into the groove between the two plates. I believe the chuck back plate is not true and a light pass across the back plate might help to bring the chuck into better alignment. No cutting is going to happen until the spindle side of the chuck back plate is checked with a dial indicator and a definite "wow" is found.

Guys the alternator on my pickup quit working so I will have to work on it tomorrow so I may not be around for a couple of days. Your help in this discussion has taught me a lot about cam lock chucks and find written information. Your contributions to this thread? have been outstanding and greatly appreciated.

Thanks again and have a good day.
Ray
 
From the readings you got with the paper shim stock, you are VERY close to seating against the spindle face. Fitting the spindle nose taper to the backing plate very carefully and slowly until it seats will allow the chuck to be held repeatably in the orientation and radial location where it needs to be. If you want to, you can do that fit up with the back plate only, removed from the chuck. That will make it easier. After the back plate fits snugly and with no radial or axial play and is drawn down tight to the spindle face and spindle taper, you can then indicate the face of the back plate where it mounts to the chuck for runout. Try mounting it to the spindle at all three clock positions to see what the differences are. When the back plate is correctly fitted to the spindle, you can then take a skim cut off the back plate chuck mounting surface, just enough to get it running true. Then, mount the chuck to the back plate and check the runout of the chuck itself. It is again well worth trying it at multiple clock positions to find the best fit before making any needed corrections. When finished and happy with it being true, make witness marks on the spindle (there may already be some), the back plate, and the chuck so any future disassembly can be returned to the optimum clock positions. In doing this kind of work, careful thought is needed before any cuts are made. Make sure you understand the whole picture before doing anything.
 
I can still see light between the spindle plate and the chuck back plate. although the crack seems smaller. A piece of paper 0.0035 thick will go clear in to the taper in one spot and opposite that spot the paper will not start into the groove between the two plates.


rock_breaker, I am working through a similar situation on a new chuck, and the advice in this thread has been very helpful. My situation is very similar to what you describe, except I've confirmed that both the chuck and spindle face mating surfaces are very flat.

It finally started to make sense to me after looking closely at the middle picture in post #25 by JimDawson, where it points out the mating surfaces.
The taper centers the chuck on the spindle, and the large flat face ensures that the chuck is not installed at an angle.

In my case, I'm nearly certain that the bore where the spindle taper seats into the chuck is very slightly undersized. The taper seats before the flat spindle face is in full contact with the back of the chuck. I could fit a 0.005" feeler gauge between the two, but only on one side. The back of my chuck and the spindle face are both very flat. (Better than I can measure with a 0.001" indicator, certainly better than 0.005".) The location of the gap moved depending on which cam I tightened first. If I understand correctly, I am able to pull it out of square with the camlocks, since it is such a short taper and the flat spindle face is not in proper contact with the chuck.

I am working on the procedure Bob Korves described in post #26 to fit the chuck to the spindle taper. I'm currently on the "try again, and again, and again, little by little" step, but I am seeing definite slow improvement as I test fit and lightly sand the high spots. (I'm using finer sandpaper than Bob recommended, since I'm new at this and really don't want to overshoot. I only had time to mark and sand a few times last night, but now I'm down to a 0.004" feeler gauge.)

I wanted to share what I think I've learned, in case it helps. (If I've misunderstood, someone please correct me.)
 
The location of the gap moved depending on which cam I tightened first. If I understand correctly, I am able to pull it out of square with the camlocks, since it is such a short taper and the flat spindle face is not in proper contact with the chuck.
That is very well described, Sheather, and the small gap at the spindle face causes relatively major chuck face and O.D. runout when you measure it. It is also not repeatable, as you described. There is no way to do accurate work when that problem exists. I suspect that it exists unknown on many D1 series spindle/chuck fits, with many users wondering why the accuracy is so poor and unpredictable.

Note also that every chuck, faceplate, collet chuck, or anything else that mounts to the spindle needs to be separately fitted to the spindle taper and face. It is really not that difficult, but mildly fussy, to do. Just requires understanding of how the parts fit together. Don't mess with the spindle at all except to very carefully remove any burrs that may exist there. Thanks for the additional take on it, Sheather.

BTW, when I learned of this I was warned about taking a cut with the lathe to try to improve the taper fit. It is very likely you will overshoot and end up with radial runout between nose taper and chuck or back plate taper, and the chuck will fall free when loosening the cam locks, which is not correct. The sandpaper and blueing method is much slower, but much more likely to achieve success and avoid failure.
 
I found the guide put out by Jacobs to be useful. Check page 2 of the attached file for instructions on mounting D-.
 

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Thanks guys, yes Sheather this has been a real learning experience; you have described the problem much better than I. Bob Korves has hung in there to keep me from screwing up and gwade has gone the extra mile for written instructions. Each contributor to this thread has made valuable and important comments that are appreciated.
I took measurements on the chuck today, found 0.005 high spot on the chuck taper and each pin has approximately 0.001-2 bumps as they pass by the indicator. Lots of work to do, starting with finding the best mounting position then sanding the high spots as described. <This maybe my lifes work as the 4 jaw and the face plate exhibit the same problems. I am going to practice mounting and tightening as I believe that is my first problem.
I mounted the chuck as per Jim Dawson's post and pictures., except between centers. As an after thought I checked the dimeters of the support shaft to determine the taper, approximately 0.0005" difference over 5.5 inches. Then checked the run-out on the chuck back plate, approximately 0.002" I think this means the mounting problem is causing a drastic run out.

On the lighter side the neighbor to the west said while he was doing his health walks he came across bear tracks in the county road between the houses. David said the "rear paw tracks are about 6" long so it must not be to big".

Have a good day
Ray
 
It's done! I lightly sanded 2 short streaks of blue dye out of the chuck taper then replaced the chuck. The chuck was stuck to the spindle and required a light bump on the shaft it was mounted on. I left the true between centers shaft in the chuck for ease of handling. Inspection of the second dye application showed a ring on about 1/3 of the circumference. Lightly sanded again and the chuck stayed on the spindle.
Thanks to all the contributors to this thread, you prevented a disaster.
Have a good day
Ray
 
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