Chuck Cleaning & Maintenance.

[mu38&Bg#]

I'm cleaning an old chuck for my Clausing 4904. I've taken it apart and cleaned all the parts. Some were cleaned in the kitchen sink with Dawn Power Dissolver others in outside with parts cleaner. The Dawn works great but strips every last bit of oil off the parts and they literally rust right in front of you as you dry them. I should take the time to polish the body, but I only cleaned up the face.

Now I need to reassemble. Is there a preferred lube for chuck parts? I saw something about lithium grease for the scroll and gears. I suspect I would oil the slides and pinion bearings. I have white lithium or bearing grease.

 

[cobra428]

Hi Greg,
I use 3-1 oil on mine. I think (dangerous thing) that a grease would tend to hold chips and be hard to blow off. Just my opinion (another dangerous thing)

Tony

 

[Brian Rupnow]

I cleaned my lathe chuck in gasoline, wiped it dry and then reassambled it.

Diymania---Given your luck with gasoline, I think you should find a less volatile cleaner!!!

 

[mu38&Bg#]

Hi Greg,
I use 3-1 oil on mine. I think (dangerous thing) that a grease would tend to hold chips and be hard to blow off. Just my opinion (another dangerous thing)

Tony

I was thinking the same while reading that web page. I'll use grease on the inside and oil the scroll. The oil eventually finds it's way all over the wall and my shirt, but I'd rather not take it apart again too soon to clean it.

DIY, I like the idea of having some lubricant in there to help it last longer. It probably is already 40 years old, but I hope to keep it for as long as I can use it.

 

[Stan]

I use white lithium grease on the pinions and back of the scroll that dirt never gets to. On the front of the scroll and the jaws I use whatever oil is handy, sometimes way oil and sometimes the hydraulic oil that I use for general lubrication of machine tools.

 

[deverett]

The scroll and adjuster space in the back of my GripTru chuck was filled with a graphite type grease from new. If it was good enough for Pratt Burnerd, then it is good enough for me and so I have always refilled it with grease during cleaning and have not experienced any problems with it. I always oil the jaw slides lightly before use.

Dave
The Emerald Isle

 

[JMI]

Dow Corning's "Molykote"

Jim

 

[Russel]

I clean my chucks (as well as just about all my tools) with Break-Free CLP and lubricate them with Super Lube synthetic oil. The Sherline stuff comes from the factory with grease, but I find that oil seems to lubricate better and makes cleaning easyer. I'm not shy with the oil, I apply a few drops every time I'm done with a chuck.

Russ

 

[cba]

Oils or greases will fly in your face. It happens slowly, by centrifugal force. But sooner or later most of it will creep out of the chuck and cover your face and shirt (and glasses) in small oil dots. On a CNC lathe it may not matter since its all enclosed and anyway flooded with oil or coolant. But on a small manual lathe you do not want to use oil or lithium grease for the chucks.

Dry graphite powder is a good old time high pressure lubricant for chucks. It will not fly in your face. Nor will chips and metal dust stick to a scroll lubed with it.

I personally use a very thick paste called "Molykote G-Rapid plus high performance assembly and running-in paste". I bought it 25 years ago in a 50g tube and its still half full. I apply it very very sparingly. It will not fling off.

There are also special chuck greases, these look and feel like tar and are very very thick. Unfortunately only sold in quantities far too large for a home shop.

An alternative that I have not tried, but believe it should work very well, is thread anti-seize compound. Usually a thick paste, and available in very small tubes from most bearing shops. Use very sparingly.

Chris

 

[Stan]

A quick note on oil flying off chucks. Oil or grease cannot escape from the back side of the scroll. The problem with oiling the front of the scroll and the jaws is that you cannot apply the small amount required, so you put on to much.

The solution is to oil the chuck and then with the spindle at it's highest speed, run the lathe while holding a rag to catch the flying oil. When you slow the spindle down to normal operating speed it will have sufficient oil for lubrication and doesn't lubricate your shirt.

 

[cobra428]

Stan you the man :bow:
Tony

 

[Hal]

Gas should not be use as a solvent inside of a shop or building.
There is to much of a chance of FIRE..... it only takes once.

Hal

 

[mu38&Bg#]

I ended up using the white lithium I had. I do have some moly grease for brakes, oh well maybe next time. I might even make some chips with the 4904 today. Now to clean the four jaw.

 

[mu38&Bg#]

Now the tricky part. The jaws need to be cleaned up. When I put a bar in the chuck the outer tip of the jaw is not touching the bar. This results in the material chattering on any cut. The jaws don't look worn however. I have to look at things more closely.

Greg

 

[websterz]

Now the tricky part. The jaws need to be cleaned up. When I put a bar in the chuck the outer tip of the jaw is not touching the bar. This results in the material chattering on any cut. The jaws don't look worn however. I have to look at things more closely.

Greg

That's called "bellmouthing". Over-tightening a part that is shorter than the full depth of the jaws can actually deform the scroll and cause the jaws to sit cockeyed like that. There is actually no damage to the jaws themselves. Change to the outside jaws and you'll see a mirror-image of the problem...the ends of those jaws will contact first.

 

[Russel]

A quick note on oil flying off chucks. Oil or grease cannot escape from the back side of the scroll. The problem with oiling the front of the scroll and the jaws is that you cannot apply the small amount required, so you put on to much.

The solution is to oil the chuck and then with the spindle at it's highest speed, run the lathe while holding a rag to catch the flying oil. When you slow the spindle down to normal operating speed it will have sufficient oil for lubrication and doesn't lubricate your shirt.

I apply oil with the tip of a small flat blade screwdriver and let the oil wick into the joint that I'm trying to lubricate. That way I don't over oil it. I never have had any oil fly off the chuck from lubricating it. Of course, I've had cutting oil fling off the work, but that's a different story.

If the chuck is getting adequate lubrication, I don't think it really matters if it is oil or grease. What works for one person may not work for another. That is not to mention the differences between different chucks. I lubricate with oil because, with the chucks I use, it makes cleaning easier. But by the time I'm done cleaning the chuck, it needs more oil applied. Also, at least with the little chucks that I use (2.5” to 3.5”) they feel smoother, giving me the impression that the oil is doing a better job of lubrication that the grease I used before.

Russ

 

[Stan]

Unless you live in such extreme climate conditions that the lubricant degrades in the back half of a scroll chuck, it would only need re-oiling once every twenty years or so. Cleaning and oiling the front of the scroll could occur two hours after the last time if you get a chip stuck in the scroll.

 

[mu38&Bg#]

Well the excess oil is out of the chuck and into the rag, the wall, and my shirt. I haven't had it up to full RPM yet so I'm sure there will be a repeat.

After a closer look it does appear that the jaws and top jaws show the same thing. They are worn though. If I grind the jaws what are the chances this chuck will be somewhat accurate? Is it not the slide ways that carry the load of the jaws? I can't imagine the scroll takes any load other than closing the jaws.

This lathe is out of a high school so it has more than it's fair share of nicks.

How much of a problem for the scroll is the dust created from turning? I try to keep it out of the chuck, but the vane action of the jaws tends to pull the dust into that area, especially when turning IDs through parts.

 

[cba]

Each set of jaws can held a workpiece in 3 ways. That is 6 separate runouts on an ordinary self centering 3-jaw chuck with two sets of jaws.
When people talk "regrinding the jaws" they usually only think grinding the inside of the inside jaws. But the same jaws can be used to hold a donut shaped workpiece from the inside. Moreover, this donut can have a turning AND a facing runout. Grinding the long inside of the jaws can help, if only this edge is worn. But if the jaws have play within the chuck body, its a waste of time.
A scroll gets locally worn by overtightening. Such overtightening is a common problem at schools, as students still have to learn how not to abuse a machine. It means that the chuck will develop different runout errors at different scroll settings or workpiece diameters. That makes it a challenge to decide at which diameter to regrind the jaws, its clearly going to be a compromise. There is a point, where it makes more sense to consider getting a new chuck.

Yes, the dust created by turning is an abrasive problem. That is the second reason (beside said shirt) that you should not use grease to lubricate a chuck. The dust and fine chips stick to the grease, and as you turn the scroll this dust gets compacted onto the scroll and onto the rear teeth of the jaws. Once thoroughly rolled into teeth and scroll, it becomes very hard to remove. You then have to take the chuck apart and use a wire brush. You can avoid all these problems, by only using a dry lubricant such as graphite powder.
Chris

 

[mu38&Bg#]

I should have been clear. I did mean grinding the inside of the jaws. I will rarely if ever use the outside of the jaws. I can always grind them if I need. The jaws are tight in the chuck. I suppose I have nothing to lose. I'll try truing the jaws today. If I get .002" TIR over the clamping range I normally use, I'd be happy. I'll be using a collet chuck for most of my smaller parts. I'll end up transferring the chuck from my old lathe at some point.