Cam tightening on D1-4 chuck

[Dean Head]

Newbie question...
How tight should the cams be. I have them slightly past the 3 o'clock position. Is this just a feel I will develope to know when I've turned the cams far enough. Reason I ask is that I was fitting a back plate to my collect chuck when I realized that one of the three cams was turned less than the other two. My lathe HF 12x36 came with a short right angle tool to turn the cams. I used my t-handle chuck key to turn the cam to basically match the other two. Well, my back plate run-out jumped up. Obviously tightening the cam "pulled" the bplate in somewhat. So, with all the discussion about D1-4 and runout how do I know when the cams are set right? Will I reach a point that the bplate is in full contact with the spindle and not move any further?
Thanks for any help,
Dean Head

[metal mite]

Dean,
I just snug them all, than tighten them all, working the opposites, like tightening down an engine head.
I only use the chuck wrench provided, and no pipe, but do pull them TIGHT.
The pins are adjustable and locked with a set screw.
Pulling out the setscrew, and rotating the pin a revolution will change where she locks up.
I set mine so they lock at 4 to 6 o'clock.
Haven't lost one in 33 years that way.
If you're warping your plate, maybe there's a nick on the taper, or something is machined wrong (probably the plate, from China?).
best of luck
mite

[halfnut]

Dean,

When the cams are tightened up they need to fall somewhere between 3 and 6 Oclock, 4 and 5:30 best.

I'll have to get up on a soap box here, when mounting a chuck, clean, clean and then reclean. Don't want any foriegn material betweem precision mating surfaces. Blow it off, wipe it off with a rag, then use your hand. Little fine particles of metal will stick to the skin that can't be wiped off with a rag nor blow off with air.

Harbor Freight, highest quality control standards right. But it's yours and we all aren't rich and can afford a new Clausing or such. We have a newish Asian made machine at work, chuck registers just aren't quite right. Whether it's the Taiwan lathe spindle or the Flung Dung Chinese chuck who knows.

On this machine I mount the chuck about like putting a Dayton wheel on a truck. Snug up topmost cam almost snug, the turn and tighten others alternatively. Then go around and really tighten with the short tee wrench which came with machine. If you don't do some bearing down on these cams on this machine you will have problems, almost scary.

Our Clausing one can just tighten them up in any order and not that tight really, no problems.

Don't try to turn cams to any particular position, you tighten them to tightness. If cams don't tighten to the correct position the cam lugs on chuck back are adjustable, keep the pointer when tight between the 3 an 6 Oclock position.

[wmgeorge]

Dean, Halfnut more or less covered it all, but after you get your D1 pins set so all tightned at 5-6 o'clock position here is something else. Mark the top of your chuck with a magic marker or something. My D spindle mount has a - mark, mark the chuck to this. Then try your chuck in each of the three or four positions it can be clamped down at. I bet you will find one that is right on the money or very, very close. Then I marked my chuck with a punch mark so I can mount it the same place every time. B.G.

[wierdscience]

Mount the plate and see if a feeler gauge will slip in between the two mating faces.If it will then somethings wrong with the tolerence between the two because the taper is suposed to maintain the plate concentric with the spindle and the matching faces are to maintain runout with the spindle face.In other words the two are suposed to bottom out at the same time.This is the reason that the short taper design is suposed to be superior,quick,repeatable changes with little runout.

[Don Clement]

Either the taper registers the chuck or the flat back registers the chuck, but not both.

Don Clement
Running Springs, California
http://www.clementfocuser.com