Massive Runout on my new D1-4 5C Collet chuck. Suggestions???

CNC Dude

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Hi Group,

Recently acquired an import D1-4 5C Collet chuck for my 12x36 lathe and am experiencing massive runout and wobbling to unacceptable levels (about 12 mils!). I am wondering if there is any adjustment that you can think of or whether I am wasting my time with this guy here. The eBay seller told me that how deep I screw the D Lock cams will determine runout. I tried dozens of combinations and with all of them I got basically the same 9 to 12 mils worth of runout.

Here is a picture of the screws that I have on the back:

ChuckScrews.jpg

The intriguing thing is that if I measure runout at the base of the chuck, I get less than 1 mils worth of variation. The way this chuck is constructed is that there are two halves, so the base would be the first half. When I measure the second half, which is where the collet goes, then I see the variation of up to 12 mils. If I place a part on the collet, I get the same variation.

Any idea on how this can be brought to usable levels? Thanks!

ChuckScrews.jpg
 
The seller doesn't seem to understand the D lock system. Each stud has one, and only one position that is acceptable for use. You have the option of one turn too deep, correct, or one turn too shallow. When you engage the locking lug, it draws the chuck body tightly against the spindle face. If you have the stud too deep, the locking lug will not engage correctly, or if the stud is too shallow it will not. I suppose in an odd case that all of the studs were one turn shallow, there would be a visible gap between the chuck base and the spindle nose, but It would be unlikely that all three were wrong. Can you see any gap? With the locking lugs not engaged, can you seat the chuck base firmly against the spindle?
 
I was able to find a D Lock position in which all three locks are engaged. The chuck is super firmly attached to the spindle and no gaps are visible.

The chuck half closer to the spindle measures true. The second half, where the collet goes, is where I see the wobble. Hence, somehow this half is not set up correctly. I am wondering if there is any technique to set it up correctly.

Or do I have a big fishing weight?
 
First things first... Remove the cam lugs completely by removing the cam position/lock screws then, unscrew the lugs themselves. Now, take the chuck and press it up against the spindle nose fitting and check to see if it sits flat (or comes anywhere close to sitting flat) against the face of the spindle.

On almost all backplates, the tapered hole that the spindle nose fits into, is cut small in diameter. That tapered hole must be the proper size to allow a perfectly flush fit when the cams are locked. Check this first and we'll go from there.


Ray
 
Ray, I am positive the back plate is super tight against the spindle. There is no play here. In fact, when I use an indicator on the back plate, this thing is as tight as you would expect from an import chuck. I measure less than 1 mil wobble.

I think I need to explain this further so here is another picture:

ChuckPartition..jpg

Notice the chuck is divided in two sections. This is very hard to notice, but if you look at the wrench key hole (yellow square), you will notice the partition line.

When I fully engage the three CAM locks, if I place my indicator on what I am calling Half 1, I get practically no runout. This holds true as long as the indicator is between the partition line and the lathe spindle (i.e. anywhere on the Half 1 region). As soon as I place the indicator after the partition line, I start seeing 12 thousands of an inch of runout. This includes the part on the collet.

If the entire chuck was not sitting properly against the spindle, then the chuck would form the hypotenuse of a triangle and I should be seeing the runout increasing as I move the indicator farther away from the spindle. However, that is not the case, Hence, the only plausible conclusion I can reach at this time is that Half 2 is not sitting properly against Half 1, but there is no way (that I can see) to get this corrected.

I am starting to think that indeed I have an alligator jaw breaker on my hands...

ChuckPartition..jpg
 
Carefully wipe a very thin coat of high spot blue onto the empty face of your lathe spindle. It is of the HIGHEST importance to get this blue in an exceedingly THIN coat on the surfaces,or you will get readings no better that the thickness of the blue. Then,without tipping the chuck any more than you can,mount the chuck onto the spindle and tighten down the cams. NO NEED to get the blue into the cams!!

If all seems to mate up well,loosen those socket head cap screws that hold the front part of the collet chuck on. See if there is any room inside the mating parts of the chuck to slide the chuck's front part sideways If so,replace the screws,leaving them snug,but not tight. Then,put on a collet of KNOWN ACCURACY(collets can be bad too!) into the chuck. Hold an end mill shank (NOT DRILL ROD! it is not accurate enough) in the collet. indicate it and tap the collet sideways with a small plastic or brass hammer. Take your indicator probe OFF the end mill while you do this. You can ruin the indicator by shocking it with taps. Mess around until you get the end mill to run .0001". Then,CAREFULLY remove the chuck and progressively tighten the screws. This may throw it out some. You have to keep on till you get it right.

If the mating surfaces do not mate up well,remove the chuck and look where the blue has transferred to the mating surfaces on the chuck. This will tell you if the chuck's tapered hole is too small or too large,and if the other surface is not going down flush.

If the tapered hole in your chuck is too small,you probably ought to just send it back. Otherwise,you must put it back side out in a 4 jaw chuck and with a good dial indicator,carefully get all the surfaces to run dead nuts true. Then,you must take a GOOD tool post grinder and grind a bit out of the hole. You can go by degrees. Undo the cam pins on the back of the 4 jaw chuck AFTER marking one pin and which hole it went into. Without bumping the chucks,and with blue on the spindle again, press the back of the collet chuck against the spindle. You don't need to install the pins to do this. Check where the blue touched,and find out if you need to take another slight grind off the back of the collet chuck. This is the simplest way I can figure to get your chuck to properly match your spindle.b If you don't get the collet chuck to run true on all surfaces before you grind anything,you will likely screw it up for good.

If you do a good job of fitting the chuck to the spindle and it still runs out of true,the hole and taper where the collet goes may be ground off center. You really should try loosening the cap screws first and see if the chuck can be adjusted sideways.

I always do this exercise when I get a new chuck,to get it to run as true as it possibly can.

When I got my new 16" Grizzly,I kissed the surfaces of the spindle with a tool post grinder,including the tapered hole. There was a bit of runout on the surfaces. Not a lot,but I'm a perfectionist. I don't advise anyone to try doing this unless they really know what they are doing. You can't take metal off once it is removed.

Once the surface had been ground,I put on each chuck and faceplate with blue,to make sure everything mated up perfectly.

If you got the chuck cheap,or if you like to overcome problems,time no object,you can keep it and try to get the problems worked out.


Not to confuse you,but here is a list of things I can think of that COULD be wrong with the collet chuck:

1. Problem with the chuck not mating up to the spindle nose

2.The front of the chuck may just need to be adjusted sideways. I have a Cushman collet chuck that takes much larger type collets that I need to adjust. A Cushman was an excellent chuck,so I'm sure it just needs adjusting.

3. The hole and/or the tapered hole that holds the collets may be out of true. The straight part of the hole could be too large. The hole could be ground at a slight angle to the centerline of the chuck. The tapered part could also be ground askew.

4. The back side of the chuck could have been ground at a slight angle to the centerline of the chuck. The tapered hole could also be ground askew.

These imperfections need only be slight so that you cannot detect them by eye,and they must be determined by indicating everything in a methodical manner.
 
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OK... We need to diagnose this front to back. BTW, the problem could still be in the back of the chuck but, lets look at some different things...

What happens when you indicate off the C5 taper as shown? This location, by the way, is the only important place you need it to be zero/little runout. The side body, nose -and all other locations are meaningless.

Note that on mine, I have a non-integral backplate. The backplate fits the spindle perfectly. This allows me to adjust the position of the chuck on the backplate until there is no runout on the taper. This particular chuck always zeros.

In your case, you might try making witness marks in ink, and rotating the backplate to different positions on the spindle. If any particular position is zero, always use that position.

Try these things and let me know...

EDIT: I just saw George's post and he's (of course) correct on all points. I'm dragging you through the steps to isolate what the problem is.



InidcatedColletChuck.JPG

Ray

InidcatedColletChuck.JPG
 
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Recently purchased same D1-4 5c collet chuck. I had to install/adjust the cam pins to mount. IT had .030-.040 runout at the collet nose, without the collet inserted. Sent it back for exchange. New one is .008. Have not made adjustments yet to see if I can make it better.
RIchard
 
Start by inserting the chuck in the best Cam lock location. The chuck halves screws is where I would start. Loosen them up just enough so that the nose of the chuck can be tapped around with a soft face hammer. Indicate and spin the chuck and tap to adjust. Sometimes theres enough play in there to get the nose set right. If not, , It's time to machine, file or return the chuck. These things should run within .0005 if your spindle is running true. What's the point of having a collet chuck if it won't hold better than a 3-jaw.
 
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