Jaws too tight on a 4 Jaw chuck

[November X-ray]

I took mine completely apart and cleaned everything while apart and I did find a little bit of grit in it. Anyways, once disassembled you can easily clean it once you get thru filing/sanding/polishing, etc. Just use a good lubricant upon reassembly, I believe I used spray on lithium grease on mine in areas where chips cannot easily get.

 

[Dranreb]

I had this problem with what looked like a new but mucky three jaw Burnerd chuck that came with my lathe, the jaws really where very tight, it took ages to get them to run free, the tiniest burr or ding can have a big effect.

I gave up the fight with the last jaw and put a small dab of fine grinding paste where it seemed to be rubbing and knocked it through with a soft hammer, all it took was one pass, no need to repeat or lap, it's fine now.

Had the same with a used four jaw Pratt, in perfect condition except one jaw that had a tiny ding, the PO had just forced it, quite a few times by the look of the cracked socket in the end of screw! A couple of strokes with a stone and it is good.

Bernard

 

[PurpLev]

I've done that when I originally got the chuck, and just took the tightness to be normal for a supposedly unused chuck. I guess it's time to take it apart again and give it a closer inspection.

FYI, I use dry graphite for lubricant on chucks and jaws to keep it from attracting any debris during use.

 

[November X-ray]

Graphite, now that's a good idea and should last well enough and never attract swarf. Thanks for the tip and Good Luck with your chuck!!!

 

[E.MARQUEZ]

As previously posted, I would check that the jaws are fitted to the correct slots first. Failing that, I would check the actual surface finish. It may be the case that a little lapping compound might solve the issue and free up the jaws a little. The only issue with the lapping compound is the clean-up necessary to avoid premature wear.

Paul.

THIS ^^^^

Exactly what I did for mine.
Disassembled, cleaned, measured, checked, coated the sides of the jaws with fine lapping compound. reassembled, and used my 3/8 drive air ratchet that is set up at the lathe for machine tool accessory attachments, opening, closing ect.. and ran the chuck open and closed about 30 times, tried by hand, and it was smoother and a bit more free. Knowing there was still lapping grit in there.. I assumed it would free up more once cleaned and lubed.

Disassembled, cleaned, lightly lubed with Molybdenum Disulfide Solid Film Lubricant and reassembled.

Tight still, no slop.. but free to move smoothly. Perfect

 

[rafe]

Graphite, now that's a good idea and should last well enough and never attract swarf. Thanks for the tip and Good Luck with your chuck!!!

I took my three jaw apart and cleaned it, It still had tight spots I sprayed it down with a good graphite spray it has a mixing ball in it like paint ...that really did the job

 

[darkzero]

Where can I find this graphite spray (possibly locally, bike shop?) & what is it originally intended for use with/on?

I normally don't like to use grease in my chucks, just oil but I hate that it gets on the walls.

 

[E.MARQUEZ]

molybdenum disulfide solid film lubricant
https://www.google.com/search?q=sol...796,d.b2I&fp=9610ee3d36cde05&biw=1366&bih=643

or if you prefer Graphite Dry Lubricant
https://www.google.com/search?q=sol...796,d.b2I&fp=9610ee3d36cde05&biw=1366&bih=643

Graphite Dry Lubricant in a solvent base for dispersal is used for bike and motorcycle cables and locks.

molybdenum disulfide solid film lubricant I found as part of weapon maintenance in the US Army. Im sure it has other uses with as many suppliers as Google finds

Where can I find this graphite spray (possibly locally, bike shop?) & what is it originally intended for use with/on?

I normally don't like to use grease in my chucks, just oil but I hate that it gets on the walls.

 

[GK1918]

I resently went through this, I was given a new but wwII surplus 4 jaw about 12" real heavy. Was not
dirty but It had its years of its shelf life. I could barely budge any jaw just stiff. So I put it in a bucket
of gas and left it for (I forgot). Then I dryed and blew it out, just a little better but still no go. Didnt
want to but 1/2 impact spraying back and forth finally got them out, dryed cosmoline or something,
more like dryed tar, then lacquer thinner. Works perfectly. this is the one I just posted in the rotary table
reply-- its for or going to be for my mill. someday

 

[macrnr]

Where can I find this graphite spray (possibly locally, bike shop?) & what is it originally intended for use with/on?

I normally don't like to use grease in my chucks, just oil but I hate that it gets on the walls.

I had a lockset on my back door that was sticking and I went to a locksmith and bought a product called "Key Lube". It is an aerosol graphite product and it works very well. Locks don't like oil because it attracts dust and grit, so this product would work well for you.