# Jaws too tight on a 4 Jaw chuck



## PurpLev (Apr 22, 2013)

So a while back I got a 4 jaw chuck from someone on the net that had it laying around unused. I got it, cleaned it up and put it together and noticed that the jaws are REAL tight - but seeing that it was supposedly never used took it for just that, and assumed it would loosen over time.


I tried using this chuck a few weeks ago - this time with the jaws reversed, and as before all the jaws were real tight to close with 1 jaw on the extreme to the point I could not close it past a certain point no matter how hard I tried. I decided not to break it and ended up using a different chuck for that project, but it got me thinking - maybe it's not that it's NEW - maybe its just defective?

I tried filing the edges of the jaw(s) to make it(them) fit smoothly to no avail.

Is there anything I can look for or do to regain use of this chuck+jaws or am I better of chucking it (pun intended) and getting a different chuck all together?


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## Ray C (Apr 22, 2013)

Sharon,

Have you tried systematically checking each jaw in a different slot to see if there's a good fit for each one?  If it were mine, I'd try that first followed by complete disassembly and careful measuring (with telescoping gages etc) each slot and jaw.  Determine which ones are the closest match and make whatever adjustments are necessary.

My 3 and 4 jaw chucks are about one year old now.  They were tight when I got them and still are -and I'm darn happy about it.  A chuck with wiggly/sloppy fitting jaws can be a nightmare in some circumstances.


Ray




PurpLev said:


> So a while back I got a 4 jaw chuck from someone on the net that had it laying around unused. I got it, cleaned it up and put it together and noticed that the jaws are REAL tight - but seeing that it was supposedly never used took it for just that, and assumed it would loosen over time.
> 
> 
> I tried using this chuck a few weeks ago - this time with the jaws reversed, and as before all the jaws were real tight to close with 1 jaw on the extreme to the point I could not close it past a certain point no matter how hard I tried. I decided not to break it and ended up using a different chuck for that project, but it got me thinking - maybe it's not that it's NEW - maybe its just defective?
> ...


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## samthedog (Apr 22, 2013)

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.


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## toag (Apr 22, 2013)

both really good suggestions,
my old really used and abused 4 jaw has numbers on the face and each jaw, just like a 3 jaw, might check the jaws, face, back for some markings


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## PurpLev (Apr 22, 2013)

Thanks for the replies.

the jaws and chuck are marked 1-4, and I have been matching the jaws to their respectable slots. I've also lapped the jaws to try and smooth it out. I will go over these again though to see what else it could be.


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## toag (Apr 22, 2013)

how much movement do the screws have in the chuck body?  one might have something that has moved it out of ilignment, or allowing it to move and bind


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## Tony Wells (Apr 22, 2013)

Is it the screws, or the slots? Could be burrs on the threads on either the jaw or the screw if it is the threads. If it is the slots, you'll just have to lap them in.


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## RandyM (Apr 22, 2013)

Some clean lube can do wonders also.


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## November X-ray (Apr 22, 2013)

I had a similar problem and after I verified the jaws were parallel, I noticed the chuck slots were not. It took a fair bit of filing with some small files but I eventually got it to work fairly well, not perfect but way better than it originally was. If I remember correctly, the chuck was made in India.

Good Luck with yours!


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## PurpLev (Apr 22, 2013)

Thanks for ideas. I'll check screw movements and slot parallelism - those makes sense to me as the culprit based on what I've tried so far.


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## November X-ray (Apr 22, 2013)

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.


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## Dranreb (Apr 22, 2013)

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


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## PurpLev (Apr 22, 2013)

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.


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## November X-ray (Apr 22, 2013)

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!!!


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## E.MARQUEZ (Apr 23, 2013)

samthedog said:


> 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


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## rafe (Apr 23, 2013)

November X-ray said:


> 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


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## darkzero (Apr 25, 2013)

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.


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## E.MARQUEZ (Apr 26, 2013)

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 



darkzero said:


> 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.


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## GK1918 (Apr 26, 2013)

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


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## macrnr (Apr 26, 2013)

darkzero said:


> 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.


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## E.MARQUEZ (Apr 26, 2013)

macrnr said:


> 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.


 ANy big name auto parts store, most any big fishing places that have lots of reels and supplies, stores that sell bike tools and repair parts, and of course the mentioned locksmiths.
 They should all have graphite products in a dispersant.


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## PurpLev (Apr 26, 2013)

I got dry graphite at the BORG, where they have the oils, and WDs and PB products


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## Bill C. (Apr 26, 2013)

PurpLev said:


> I got dry graphite at the BORG, where they have the oils, and WDs and PB products



Try hobby shops or stores that sell pinewood derby car supplies.  We use it to lube axles.


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## Bill Gruby (Apr 26, 2013)

I gotta tell ya Sharon, it sounds like those jaws do not go to that chuck. Have you checked the fit up of the jaws to their respective screws with the chuck apart?

 "Billy G"


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## darkzero (Apr 26, 2013)

E.MARQUEZ said:


> 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_
> ...



Thanks. While searching online for a local supplier, I read that the graphite spray damages paint so I didn't like that if true. Went to my local Grainger & picked up the moly dry spray. They had the graphite too but it sounds like the molybdenum disulfide is a better product. I'll give it a try tonight.


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## E.MARQUEZ (Apr 26, 2013)

The carrier in "dry lubes" will often damage paint.

And graphite is a very fine particle in these lubes, it gets into pores of metal, paint, ect.. and ,yes it does "stain" 

So Im careful where I use it, door locks especially, as you don't want to get that stuff on a nice wood door.

 ,,,





darkzero said:


> Thanks. While searching online for a local supplier, I read that the graphite spray damages paint so I didn't like that if true. Went to my local Grainger & picked up the moly dry spray. They had the graphite too but it sounds like the molybdenum disulfide is a better product. I'll give it a try tonight.


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## Ray C (Apr 26, 2013)

Hey Will, maybe try some tri-flow which is a teflon (PTFE) lube that comes in spray cans and is available at Lowes.  The carrier is a very light oil that basically evaporates.  I used it on the magazines of my target pistols.  Did a fine job of lubing and didn't collect soot.


Ray


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## darkzero (Apr 26, 2013)

Ray C said:


> Hey Will, maybe try some tri-flow which is a teflon (PTFE) lube that comes in spray cans and is available at Lowes.  The carrier is a very light oil that basically evaporates.  I used it on the magazines of my target pistols.  Did a fine job of lubing and didn't collect soot.
> 
> 
> Ray



I didn't get the graphite spray so there's no worry of solvent damage. I did try the moly dry on some painted surfaces to test & it diesn't seem to be harmful. But regardless I don't like it for using on the scroll & jaws, I don't like how it applies. I do have other ideas for it including the open gears so it's not a total waste. I'll just stick with what I have been using for a while that has always work fine on all my chucks.


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