# Chuck and Arbor divorcing!



## Pmedic828 (Oct 2, 2014)

Does anyone know how to prevent a JT-33 chuck and arbor from separating?  Upon receiving my tooling, I placed the arbor in the freezer after cleaning and degreasing  it in preparation for use.  For about a year,I have not had any problems with them as they were a match - All of a sudden, one doesn't like the other and continues to file for separation and divorce.  
After attempting to clean and degrease it again, determine if any burrs exist and use metal cloth to rough up the surface slightly on both arbor and chuck, giving one the "cold shoulder" and mate them back together, they continue to have bad feelings for each other.
I originally thought that I had a "bend" drill but after swapping this bit out for others, it starts to cut (2 threads), then separation.  I predrilled the hole at 1/4 inch, increasing about 1/16 diameter to full depth.  When I get up to around 3/8, it starts it's problems.  I am feeding moderately, not forcing, using cutting oil, appropriate speed, retracting after about 20 thou....   placed dykem and no gaps or scrapes on the arbor or chuck are noticeable.    The last time, I even attempted to back the jaws out from the chuck and using a hammer and wood, strike gently on the arbor to attempt to "set" it.  Any thoughts?  Solutions?:noidea:


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## JimDawson (Oct 2, 2014)

I normally ''set'' the chuck by slamming the back of the arbor as hard as I can on a solid surface, like a vice anvil or other solid, large chunk of steel.  Mind your hand when you do this.  The only time I've ever had one come off is when I tried milling with and end mill, chucks are not made for that operation.


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## darkzero (Oct 2, 2014)

First thing that came to mind was checking the tapers' mating surfaces with bluing but you have already done that. The chuck I use on the lathe broke free when I was using a 1" drill. I used a decent size brass hammer to seat the arbor in. Hasn't came loose yet but if it does I would then try freezing the arbor.

Right now I have the opposite problem. I have two 14Ns that I haven't been able to get the arbors off yet. They just laughed at using the Jacobs wedges. I'll be heating them on the next attempt & hopefully that's all they need. Just need to get some time to play with them again.


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## 12bolts (Oct 2, 2014)

Rather than cooling the male part, I prefer to get that part degreased with turps, dried and wipe over with acetone or metho to make sure its really clean. Degrease, dry and wipe over the female as well. then warm the female part and assemble with loctite retaining compound. Still smack them together hard tho'

Cheers Phil


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## awander (Oct 2, 2014)

Pmedic828 said:


> ....and use metal cloth to rough up the surface slightly on both arbor and chuck,.....



You don't want to rough up the surfaces. You want them as smooth as you can get them(assuming they keep their original geometry). A rough surface will not stick anywhere near as well as a smooth one.


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## darkzero (Oct 3, 2014)

awander said:


> You don't want to rough up the surfaces. You want them as smooth as you can get them(assuming they keep their original geometry). A rough surface will not stick anywhere near as well as a smooth one.



Agreed, I've never heard of anyone recommending to roughen up the mating surfaces, definitely don't want to do that. This is not epoxy.


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## NEL957 (Oct 4, 2014)

Loctite the hardest on they have. Loctite works in the absents of air but it will not with stand using it as a milling machine. The bearings are made for forward thrust and not sideways or the thump thump of a milling cutter. 
Nelson Collar


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## benmychree (Oct 4, 2014)

I bought a chuck (on E Bay) with 30 taper adaptor for my Fray vertical mill and my B&S #2 universal with all angle head; when I tried using it, I quickly found out why the dude sold it ---the chuck kept falling off the shank; I tried some really hard smacks on it with the chuck jaws retracted on the anvil with a copper hammer, to no good result.  I finally suspected that the arbor was bottoming in the taper hole in the chuck; I then ground off a bit of the length, and problem solved -----


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## PatMiles (Oct 6, 2014)

benmychree said:


> I finally suspected that the arbor was bottoming in the taper hole in the chuck; I then ground off a bit of the length, and problem solved -----



Good catch!


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## benmychree (Oct 7, 2014)

PatMiles said:


> Good catch!



bad beer does not deserve the name in my estimation "I wanted a beer, but all they had was "Bud"


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## bfd (Oct 30, 2016)

I have had good luck with heating the chuck 200-250 degrees abd then slaming it home while still hot. bill


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## NEL957 (Oct 31, 2016)

They make a set of wedges for removing chucks that work very well. You will find them at: https://www.mcmaster.com/#chuck-wedges/=14u6q8d


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## 4GSR (Oct 31, 2016)

Wedges sometimes works.  For me, I drill a 3/8" or 1/2" hole thru the center of the chuck from the jaw side.  Once you do this, set the chuck on a piece of tubing with an ID slightly bigger than the chuck arbor is.  Take a drift, insert in hole (drift pin does not need to be any longer than about 1/2" sticking up above the chuck) strike with a 2 lb. hammer.  If it doesn't pop loose, strike again.  If after a few strikes, it doesn't come loose, put back in lathe, drill hole deeper into arbor, about 1" to 1-1/4" deep and try again.  It should come loose after relieving the center of the arbor.  If not, cut off arbor and drill completely out from opposite end.


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## NEL957 (Oct 31, 2016)

I think the biggest factor is get the impact to the taper and not loosing any in the vice, bench or else where. Make sure you have a nice solid work area. And a bigger hammer might help.


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## Christian Poulsen (Oct 31, 2016)

As someone said above use "blue" (a very light, even coating!) to check the mating of any ID to OD (especially tapers) ifn' they are supposed to match....ifn' at least around 70% or more doesn't match (around 100% at "top and bottom") lapping compound can be used to "hand grind" them in....then just a solid,hard, straight "knock" or press and the 2 mates will be hard to get apart (note: using some various set ups and an indicator yoose' can knock the chuck around to get it dead nuts on center...another note: Probably chucks, jaws, and collets in lathes and mills, even in professional shops, get the most abuse due to wrecks and tool "spinning", galling...


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## kingmt01 (Oct 31, 2016)

JimDawson said:


> I normally ''set'' the chuck by slamming the back of the arbor as hard as I can on a solid surface, like a vice anvil or other solid, large chunk of steel.  Mind your hand when you do this.  The only time I've ever had one come off is when I tried milling with and end mill, chucks are not made for that operation.


End mills are one heck of a way to remove a stuck one tho.

I'd also suggest lapping them.


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