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D1-4 Spindle Saga and Bison Chuck ShoutOut

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rpmMan

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#1
A few years ago i bought a clausing 1500 lathe... i initially spent many hours cleaning up rust, dirt etc... not to mention dealing with vari drive issues which i have finally solved... knock on metal....

Anyways i recently was using the 10 in 4 jaw pratt burnard chuck it came with and while running it at about 500 rpm or so noticed that the dang thing is wobbling...whoa.. started investigating.. it is not easy to measure but the back surface of the chuck had 15 thou or so runout...checked it by indexing thu all 3 cam positions...no help...

Double checked my spindle which previously showed <1 tenth runout on the taper, the face of the taper end (which should never contact anything, and the spindle face.. all are less than a 1/10 thou measured with my only tenths indicator..

now this chuck required a lot of cleanup when i got it .. jaws were rusted up, jaw ways were rusted etc...so i thought ok.. lets try something else.. i next tried the 7 in D1-4 drive plate the lathe came with...now it was obvious ... when mounted and slowing turning by hand one section of the plate has a gap between it and the spindle face.. in fact i can fit a 6 thou feller gauge in there..indexing it around does not help..

Time to do some research.. duck duck go searches led me to several treatises on pm and other sites about the D1camlock system and what may or not be the issue.. some have even mentioned placing shims between the chuck/plate and spindle etc...
Fortunately i managed to stumble on my root cause.. mainly since i was working with an easily handled drive plate and not struggling trying hoist a 10 in 4 jaw in place..

It appeared that one or more of the cam lock pins were bottoming out in the spindle recess... a quick check with a depth gauge confirmed this..2 of the pins when adjusted to be between the spindle marks were just to long and not allowing the back plate to contact the spindle face evenly.. a quick check of the 10 in chuck showed the same thing...

Time to fire up the boyar shulz surface grinder i have just got running...

IMG_0002.JPG

took approx 15-20 thou or so off the offending pins and now things look much better..
What is interesting to me anyways is that in all of my searching i do not think anyone has mentioned checking this.. and of course i had just assumed that my problem was a defect in my spindle and or other hardware..

In the process of going thru all of this i decided it was time to get a new chuck... i was tempted to go with a d1-4 backplate plus chuck as i wanted to be able to eliminate and or control runout issues...instead i took a chance on a brand new bison forged 8 in 4 jaw with 2 piece jaws...

First step was checking the pins.. no worries .. install the chuck and a quick runout test shows spot on..but need to take it off and adjust all the pins 1 turn out to get my cam lock indicators right.. do that, double check their length .. still ok.. remount and check the runout.. maybe a tenth or so..

The next step was how to confirm the radial runout... turns out i was able to lightly grab a starrett 1/2 x 6 in parallel and sweep it with one of my better indicators.. maybe a tenth!!! i am very happy with this...

IMG_0001.JPG

So now i can get back to work ... still need to check the pins on my old 8 in scroll chuck and the 12 in backplate...

rich
 

pstemari

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#2
Interesting.

I've found that seating chucks on the D1-4 spindle benefits a lot from careful procedure and use of an indicator to check that everything is where it should be. Lightly snug each cam, and then work around and gradually tighten them a bit at a time.

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Dabbler

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#3
When I use my friend's lathe (D1-5) I always go around 3 times: lightly snug, full on, then a check that all the cams are equally tensioned. I get great accuracy that way...
 

ddickey

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#4
I made a wrench made out of 1.5" conduit the full length of each hand. Really helps to snug the camlocks down.
 

rpmMan

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#5
A quick check of my 8 in scroll and 12in faceplate show no issues.. it was only the 10 in 4 jaw and 7 in drive plates..note that it appears that on my clausing there is 20 or 30 thous clearance or so for properly adjusted pins.. I did see more than 1 post about the inability to draw up against the spindle face but nothing about the pins potentially bottoming out ...

I am very impressed so far with the bison chuck.. with the exception of the spring loaded wrench.. perhaps i can get used to it, but it is a pain having to put the wrench down somewhere while fussing with a piece in the chuck..

rich
 

Doubleeboy

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#6
on that Bison spring loaded wrench you can take a vise grip and rip the spring off and be happy. Spring loaded wrenches are dreadful. I have a couple Bison wrenches, both were fixed in less than a minute.
 
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