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D1-4 spindle issue

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songbird

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Hello everyone. I recently purchased another used lathe, a “Tida” TD 1236 E, clone to an Enco or Rutland. I got a super deal, but noticed that the 3 jaw chuck had excessive runnout. I removed the 3 jaw, cleaned it, re-installed it and had more run out. I then purchased a collet chuck but had the same problem. I checked the spindle which was less than a half a thousand, and found that I could improve the run out considerably by the way I would tight the 3 key holes. The run out started at about .020 and could be brought down to about 002. It makes me think that the “nose” section of the spindle mount must be worn out. Has anyone else had this problem and come up with a solution? Obviously the cost of removing the spindle to have reground or replaced is out of the question because of cost. Thanks in advance, Jim
 

john.k

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I have noticed that careless people get swarf caught and crushed between the taper and the chuck..........next operation is said careless person takes a file and files off the burrs from the spindle taper........pretty soon,taper undersize,chuck loose ,and moving under load.....Assuming the spindle nose is not glass hard( in which case it shouldnt dent).....you would need to face off the flat face ,to allow the taper to seat deeper........If you recut the taper,a lot will need to be removed from the face ,and then the rotary locks may be wrong,causing all sorts of trouble............Incidentally ,I have fixed this type of problem,by converting to the "J" type mount............same taper ,but chuck retained by four studs ,with a special quick release securing ring......Sometimes called the "Lang" spindle nose after John Lang and Sons of Johnstone ,Scotland.
 

JimDawson

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While it's not impossible that the spindle nose is not correct, from what you describe, it sounds like the chuck mounting plates may be out of spec. It is very rare that the spindle would be worn or ground wrong. Assuming that the spindle needs to be reground, it is easy to do in the lathe, but you are a long ways from doing that.

First let's take a look at the chuck mounting plate and get some measurements'

1548091876339.png

Make sure the spindle nose is not bottoming in the taper.
1548091907621.png
When the chuck is pulled in with the cams, there should be no gap between the chuck and the spindle nose.
1548091935975.png

If you have a gap, then the chuck needs some work rather than the spindle.
1548092495948.png
 

Bob Korves

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Look for light between the the spindle face and the backing plate (or chuck face if integral mount) with a flashlight on the far side. It is very common for this to be the case, and the chuck then tilts on the mounting taper cone as the camlocs are tightened. It takes very careful work to fix the issue correctly. Ask how and understand well before removing any metal. You can easily turn a precision spindle into a piece of junk, and/or damage a chuck or back plate so it will never be correct again. If this turns out to be the problem you are having, it is quite fixable to a good result. Please report back with what you find.
 

warrjon

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In post #3 has a lot a of good info.

The first picture shows the cam index mark, If the studs are not in the correct position (either too far in or too far out) when you lock the cam the index mark must be between the two limit marks. I had a Chinese lathe with a D1-4 and when I got it it had a lot of runout, one of the studs was one turn too far out so the cam was not locking it. Also as some else said use a feeler gauge between the chuck and spindle nose to ensure the chuck is seated. It must seat on the mating surface.

Check the spindle nose for burs and stone them if there are any. Mine had a bur on one of the holes on the mating surface.

If there is no index on the chuck and spindle as my lathe had none. Mount the chuck in the 3 different positions and check runout also check the cam index is correct, then mark the chuck and spindle with a perm marker to start with. My chuck also had no marks to identify which was the slot for jaw 1 so I moved the jaws around until I had minimum runout. Re-check the chuck by re-mounting on the spindle in different positions once you have minimum runout and if it is acceptable then mark the chuck and spindle so you can re-mount the chuck in the same position every time. When I did this on mine the runout went from 0.020" to 0.003"
 

songbird

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While it's not impossible that the spindle nose is not correct, from what you describe, it sounds like the chuck mounting plates may be out of spec. It is very rare that the spindle would be worn or ground wrong. Assuming that the spindle needs to be reground, it is easy to do in the lathe, but you are a long ways from doing that.

First let's take a look at the chuck mounting plate and get some measurements'

View attachment 285349

Make sure the spindle nose is not bottoming in the taper.
View attachment 285350
When the chuck is pulled in with the cams, there should be no gap between the chuck and the spindle nose.
View attachment 285351

If you have a gap, then the chuck needs some work rather than the spindle.
View attachment 285352
Now that you mention that, I measured and don’t believe that the “nose is bottoming out but there is a gap, (.003-.004) between the backing /mounting plate and the flat surface (outer ring) on the spindle. I wondered about that. If the nose is not bottoming out, then does it stand to reason that section on the mounting plate that receives the nose needs to be cut a little larger?
 

JimDawson

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then does it stand to reason that section on the mounting plate that receives the nose needs to be cut a little larger?
Maybe. Measure everything carefully and make sure you know where the problem is at before you start cutting. You can remove the mounting pins, and hold the chuck in place with the tailstock and see if it will register properly without the pins. When everything comes up tight, the spindle nose should clear the the bottom of the tapered socket in the back plate by a few thousanths.
 

Bob Korves

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Maybe. Measure everything carefully and make sure you know where the problem is at before you start cutting. You can remove the mounting pins, and hold the chuck in place with the tailstock and see if it will register properly without the pins. When everything comes up tight, the spindle nose should clear the the bottom of the tapered socket in the back plate by a few thousanths.
If you are going to remove material, go VERY slowly and easy at it. It is quite easy to remove too much from the mating surface and then you have a chuck with radial runout, and no good and easy fixes available. I used high spot blue, marked it up, and then just sanded off the high parts of the chuck (or back plate) very little at a time until the camlocs just pulled the chuck to the spindle face with some light/medium pressure on the chuck wrench required. It does not require much metal removal to make about .005" of face clearance go away.
 
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