View Full Version : D-1 chuck mount question

04-19-2005, 07:54 AM
Hey guys! I have to clean up all the packing goo (fishguts/poggy) from a four jaw and adaptor. Was thinking of replacing the bolts with Grade 8. And of course checking for any burrs etc on the mating surfaces. On the three jaw, I don't see any referance marks. Does it matter? Do they usually go together spot on?
I've never had one of these apart before. I'm assuming there is some sort of cam that holds these to 4 studs on the spindle. There is a T wrench in the tool kit for the square bolts in behind the chuck. Loosen them and it should pop right off. Correct?
Anything else I should be aware of? Thanks!

04-19-2005, 10:54 AM
Torker, your chuck should have 3 pins if it is a D1-3 or D1-4, or 6 pins if it is D1-6. Some chucks require a slight tap with a soft hammer to release from the taper and others will simply come off when you release the camlocks. I was totally ignorant of the operation of camlocks when I recently got my new (1959) Sheldon lathe with a D1-4 spindle. I did a search on this site for "D1-4" and there is a ton of good advice on the operation of camlock systems. For safety sake I would highly recommend doing this search and look at the wealth of information so many fine folks have put on this site.

I would always mark the orientation of a backplate when removing it , however when you reinstall after cleaning any burrs off, I would try each different orientation and use the one that results in the least runout.

I have a love affair with grade 8 bolts and use them whenever strength (or appearance)is an issue but I don't think there would be any real advantage in this application.

04-19-2005, 10:57 AM
There may be a set screw on each of the cam sockets. Loosen them and then unlock the cams with the T wrench.

Mine was not indexed either. Before I removed the 3 Jaw chuck (factory installed?), I checked the runnout. Mine was acceptable, so I indexed the chuck with some number punches at that time. I then installed the faceplate and found the best clock position for it and indexed it as well. I have not installed the 4 jaw as of yet and I don't know if it will matter much where it is clocked on the spindle. Plus, I really don't know how to check the 4 jaw.

BTW, on my similar lathe, the tourque on each cam lock affects the runout. I have to "play" with the tightness on each cam while indicating the chuck in. So changing a chuck out in this lathe is not as simple as the cam lock system looks. I don't know if this is supposed to be this way or maybee this is a "feature" of these off-shore lathes.

But the indexing helps get me in the ball park quicker. I'm glad I did it.

That's my story and I'm sticking to it...

[This message has been edited by smurph (edited 04-19-2005).]

04-19-2005, 12:43 PM
Hey guys, Thanks for the great advice! Yes...I should have done a search but I was too busy writing about how good I am to my better half. http://bbs.homeshopmachinist.net//biggrin.gif
I'll do a search later today to add to what you have said. Thanks for your time!

04-19-2005, 01:20 PM
I can vouch for smurphs' observation that the
torque on the camlock sockets can indeed
affect the runout by 3 to 5 thousandths and
there frequently is a preferred position to
put the chuck on. Go over the taper on the
spindle and on the chuck carefully for burrs and dings and look for shrapnel also. Be sure you are rotating the locking sockets the correct way: they will "lock" both ways but one way is 'loose', the other tight.
Chuck won't fall off if tightened the wrong
way but can shift under load in my experience. There is considerable controversy over the appearance of daylite
between the chuck and the flat part of the
spindle flange. Consensus appears to be that it would be nice if there were no daylite but the chuck registers on the taper, not the flange. Steve

04-19-2005, 02:07 PM
There should definitely not be daylight anywhere on either the flat or taper seats of a D-1 mount. If there is, something's wrong. There may be a chip caught somewhere, a ding, or the male or female taper (or both) are out of tolerance with respect to the ASME B5.9 standard. Both the taper and flat should be seated. Cam torque variations should not affect the runout anywhere near 3-5 thousandths if the assembly is to the standard.

04-19-2005, 03:33 PM

IMO the tension will affect runout. Best way I've found is to use something of known roundness (drill rod that's ground & polished works well) and indicate on the end about twelve inches from the chuck.

By trying different positions & different torque settings you'll find the one that gives the least runout. Then it's just a matter of making witness marks so you don't have to do this again!

Barry Milton

04-19-2005, 04:33 PM
Thanks guys! So am I to assume that I should be using a torque wrench for this? Or is it that critical? It's almost sounding like it is. I'm glad I asked you all. Probably saved myself a whack of time looking for the run out problem it sounds like I could have http://bbs.homeshopmachinist.net//biggrin.gif

04-19-2005, 04:38 PM
Rich: appreciate the response. My experience is with lowend chinese and
midrange Taiwan origined Southbends.
About 10 lathes overall, all the chinese
and some of the Southbends had daylite
between the chuck and the flange, usually
in the few thousandths clearance range.
It make sense that there would be no daylite
when the chuck is fully seated. Probably the reason why cam torquing has such an
influence on the runout. Steve

04-19-2005, 05:33 PM
There's a standard for the airgap between chuck and spindle flange when the chuck is held against it uniformly (not tightened). I think the limits are something like 0.0008" min to 0.002" max.

04-19-2005, 08:03 PM
Russ! Here is a thread about this subject.


I don't fuss with trying the chuck in different positions, infact the instructions in the manual recomend having a datum on the chuck and installing it the same each time. This was not for runout but camlock adjustment.

I believe if you are having runout problems then there is dirt (chips) causing this or the tapers don't mate properly.

I asume that the import lathes that don't have the open datum and locking arrows work the same. I think it is poor that they don't put them on because if you work them the wrong way they will come loose.


04-19-2005, 08:09 PM
John, thanks for the link!
I'm HOPING to get the goo cleaned off the 4 jaw and the adaptor sometime tonight (I have far too much junk piled on my parts washer http://bbs.homeshopmachinist.net//biggrin.gif). Then I can see if there are any indexing marks. I kind of doubt it though.

04-19-2005, 08:26 PM
One little tip someone came up with is to put a clean rag down into the center of the chuck when you have cleaned out for mounting. This will hopefully prevent any erant chips droping out of the scrolls of the chuck at the last second only to get jamed betwen the tapers causing runout.


charlie coghill
04-19-2005, 08:36 PM
My three jaw needs to be taken apart now and then to clean the scroll of chips. I punched marked the backing plate and the chuck so they go back togeather the same way each time. Also the chuck and lathe spindle are marked so they go togeather the same way. I don't worry much about the four jaw.

I wished I had this BB when I purchased my lathe, I would have known how to adjust the camlock pins. Than the chuck would not have fallen off the spindle while the lathe was spinning. http://bbs.homeshopmachinist.net//frown.gif Scared hell out of me.