Best topic for cleaning, adjusting chucks?

OK, I have an update. Ater reading Mikey's wonderful 3J Chuck Maintenance document, I stripped down the 5" that came with my lathe but which I haven't yet used (going back to the beginning of this post, I've been using the 6" that also came with the lathe), gave all the parts a good soaking and scrubbing bath in SuperClean (sadly, I forgot for one critical minute to wear gloves and have been applying my wife's aquaphore lotion ever since to restore the sandpaper-like skin on my fingers...). A ton of old grease and chips came out, one chunk looking like nothing so much as a miniature prime rib. Then, being alone for the weekend, I took over the kitchen sink and scrubbed it all whistle clean in Dawn and hot water, then blasted compressed air at it until dry dry. I didn't have Super Lube grease around (point 1 of insufficient advance planning), so reassembled on a trial basis with WD40 rubbed lightly everywhere as a rust preventive. It got back together OK but clicks and clacks a bit, which, in addition to one of the pinion screws not fitting as deeply as it should, tells me that something (the scroll?) isn't seated quite right. The jaws appear to be aligned well; but I'm not positive the .008 runout an inch away on a turned piece of 12L14 isn't the result of the jaw alignment. Runout is .003 on the chuck just off the spindle; wondering if it might not be threaded in all the way; that should be <.001, correct?

Next steps: get a tube of SuperLube grease on hand, remove and strip it all down, grease lightly and carefully reassemble. What should I be looking for? Or is it thought to just be not everything is in snugly?

How does one measure the jaw installation's alignment other than runout?

Many thanks.
Tim
 
A comment about polishing the scroll/pinions.

All sliding bearing surfaces require a small amount of clearance to function properly. As such, there will be a clearance at the bearing surface that the scroll rotates on. When you tighten the jaws, you do so by rotating the scroll by means of the pinion. There is friction between all the contact surfaces; static and dynamic with static being larger. As the tightening force increases, so does the frictional force. Movement will occur where frictional forces are least and will tend to push the scroll slightly off center as well as rotating the scroll which has the effect of moving one of the jaws slightly more than the others creating runout. Increased surface roughness will increase friction and tend to enhance this eccentricity.

I would suspect that is why some chuck manufacturers recommend only using a specific pinion for final tightening and why some individuals recommend a final tightening at all three positions. I would also suspect that better surface finish is one of the reasons why the name brand chucks happen to have better runout specs.

I have no scholarly writings to base this on nor do I have any empirical evidence. Just a thought to consider.
 
tmenyc said:
OK, I have an update. Ater reading Mikey's wonderful 3J Chuck Maintenance document, I stripped down the 5" that came with my lathe but which I haven't yet used (going back to the beginning of this post, I've been using the 6" that also came with the lathe), gave all the parts a good soaking and scrubbing bath in SuperClean (sadly, I forgot for one critical minute to wear gloves and have been applying my wife's aquaphore lotion ever since to restore the sandpaper-like skin on my fingers...). A ton of old grease and chips came out, one chunk looking like nothing so much as a miniature prime rib. Then, being alone for the weekend, I took over the kitchen sink and scrubbed it all whistle clean in Dawn and hot water, then blasted compressed air at it until dry dry. I didn't have Super Lube grease around (point 1 of insufficient advance planning), so reassembled on a trial basis with WD40 rubbed lightly everywhere as a rust preventive. It got back together OK but clicks and clacks a bit, which, in addition to one of the pinion screws not fitting as deeply as it should, tells me that something (the scroll?) isn't seated quite right. The jaws appear to be aligned well; but I'm not positive the .008 runout an inch away on a turned piece of 12L14 isn't the result of the jaw alignment. Runout is .003 on the chuck just off the spindle; wondering if it might not be threaded in all the way; that should be <.001, correct?

Next steps: get a tube of SuperLube grease on hand, remove and strip it all down, grease lightly and carefully reassemble. What should I be looking for? Or is it thought to just be not everything is in snugly?

How does one measure the jaw installation's alignment other than runout?
Click to expand...

  • WD-40 is okay temporarily but it is not a good rust preventative for the long term.
  • If one pinion does not fit properly then there is a fair chance there is something inside the hub blocking it. Take it out and clean out the hub.
  • Is the 0.008" TIR on a previously turned piece or did you turn it and measure this without removing it from the chuck?
  • You assess jaw installation by making sure all the jaws open and close in sync.
 
thanks to both of you!
RJ -- one of the best parts of this learning curve year I've had has been learning how and why things work, not just how to get them to work. Your paragraph is one of the best, thanks!
Mikey -- yes,
  • the WD40 was only for immediate use.
  • yep, what I figured is the case. It's going to come apart at first opportunity
  • The observed TIR was on a piece that was turned previously with a different chuck. I stuck it into the chuck post-reassembly.
  • yes, thanks; they did open and close in sync.
Clearly, next step is taking it apart and carefully checking for why it didn't go back together more easily.

Question: I've had a strong vote for using way oil instead of superlube grease inside the chuck. I read your views above about using the grease. What are your thoughts about way oil for this?

Many thanks,
Tim
 
You cannot glean any useful information about the accuracy of a 3 jaw chuck by chucking up a previously turned work piece, Tim. If you want to know how accurate the chuck really is, chuck something up and turn it. It should read zero run out. That is what 3 jaw chucks do; they allow for great accuracy on a first turning, aka a first operation.

I have not used way oil in a chuck. It does not have extreme pressure additives in it so I prefer a known quality lubricant. However, it's your call.
 
Ah -- I get it, finally... I may be slow but I get there.
And for the clarification on the lubricant. I'd rather do it right from the outset.

Tim
 
Use grease for the scroll and pinions, oil for everything else. The choice of these lubricants is up to you. I prefer Superlube because it does not cake or harden with time and it cleans up easily when you need to re-do your chuck.
 
  • Like
Reactions: Z2V
Mikey, not familar with Superlube. Which version are you using?
 
Chewy said:
Mikey, not familar with Superlube. Which version are you using?
Click to expand...

I use this one but my can is almost empty - thanks for the reminder, have to get more. This version is high temp with extreme pressure additives so it works for most things on a machine. I use the regular Superlube oil for ... oiling stuff.

You can use any EP grease. The only reason I prefer Superlube is that it doesn't dry out and cake. I hate cleaning that stuff out of my equipment.
 
  • Like
Reactions: Z2V
Thanks Mikey! Agree with you on getting hard and cakey. Really off the subject, would you use this on toolbox drawers? My Snap-on glides are hard and caked greae. Getting ready to take apart and redo.
 
You must log in or register to reply here.
Back
Top