Why is it acceptable

[mmcmdl]

In old machinist terms from the guys I used to work with, its a very light kind of hair as the amount that has to come out.

No doubt in my mind you're talking about an RCH . Yep , that's all it would take to remove to seat the chuck correctly .

 

[mmcmdl]

Any chuck leaving the factory should be checked with go/ no go taper plug gages . The blueing should be transferred to the shoulder that meets the lathe spindle , not the taper . If it doesn't , the taper is too small .

 

[Tozguy]

The issue of fit to the spindle versus pin adjustment should be cleared up.

A good fit; the chuck should slip onto the D1-4 spindle to full contact (or within .001) by hand pressure. To test this remove all the pins and fit the chuck on the spindle. If the desired contact is not evident then work needs to be done to get it. The first thing to check is whether the shallow tapered recess in the chuck is tight and prevents the chuck from seating to full contact. Do any work on the chuck and not on the spindle.

Once the fit test is passed install the pins using the rings engraved on the pins for guidance.

Proper pin depth; holding the chuck up to the spindle by hand the cams should turn clockwise the first 90 degrees easily to the first V mark. Then further turning of the cam will take up any clearance left and stop before passing the second V mark. If the cam does not get to the first V mark easily then turn that pin one turn out and try again. If the cam does not lock up before passing the second V mark then turn the pin inwards by 1 turn and try again. The cams do not all have to lock up at the same point between the V marks.

Please note that there is no need to be switching pins around to find a magical place for the pin. The thread pitch on my D1-4 pins is 1mm or .039''. The throw of the cam over the quadrant used is .045''. So it is easy to see that any pin can be adjusted to any cam and lock in between the V marks. It is designed that way. Once the pins are adjusted properly it is important to index the chuck to the spindle so that the pins return to the same cam next time around.

Taking up the clearances with the cams does not take a lot of torque and you should feel the cam stop sharply when clearances are gone. There is no need to wrench down on the cams too much and the usual T wrench offers plenty of leverage for bare hands. The ingenious design of the D1- system means that any pressure wanting to pull the pin out will only tighten the cam. Remember the cams are a lock as opposed to being a fastener.

 

[nighthawkFmobil]

The issue of fit to the spindle versus pin adjustment should be cleared up.

A good fit; the chuck should slip onto the D1-4 spindle to full contact (or within .001) by hand pressure. To test this remove all the pins and fit the chuck on the spindle. If the desired contact is not evident then work needs to be done to get it. The first thing to check is whether the shallow tapered recess in the chuck is tight and prevents the chuck from seating to full contact. Do any work on the chuck and not on the spindle.

Once the fit test is passed install the pins using the rings engraved on the pins for guidance.

Proper pin depth; holding the chuck up to the spindle by hand the cams should turn the first 90 degrees easily to the first V mark. Then further turning of the cam will take up any clearance left and stop before passing the second V mark. If the cam does not get to the first V mark easily then turn that pin one turn out and try again. If the cam does not lock up before passing the second V mark then turn the pin inwards by 1 turn and try again. The cams do not all have to lock up at the same point between the V marks.

Please note that there is no need to be switching pins around to find a magical place for the pin. The thread pitch on my D!-4 pins is 1mm or .039''. The throw of the cam over the quadrant used is .045''. So it is easy to see that any pin can be adjusted to any cam and lock in between the V marks. It is designed that way. Once the pins are adjusted properly it is important to index the chuck to the spindle so that the pins return to the same cam next time around.

Taking up the clearances with the cams does not take a lot of torque and you should feel the cam stop sharply when clearances are gone. There is no need to wrench down on the cams too much and the usual T wrench offers plenty of leverage for bare hands. The ingenious design of the D1- system means that any pressure wanting to pull the pin out will only tighten the cam. Remember the cams are a lock as opposed to being a fastener.

Such good information I just spent the last few days learning . Everything you said in that post is clear now and aligns with the logic I accumulated getting into this thing. Guess everything happens for a reason.

I got some 320 grit emery cloth last night and very lightly took a couple passes around the chuck taper. Just after like 30 second of very light "polishing" per section I can get a couple of the areas around studs to reject the .001 shim and sit a lot closer to the spindle flat. It's just the area around the stud I had mentioned wasnt seating as deep(stud#1). It also seemed to rub in that spot a bit when I'd do the prussian blue. It was late and I got food poisoning thursday night so I stopped.

I'll finish it today hopefully and post how it goes.