Jacobs Chuck

[rmancini]

I have a Jacobs (18N) chuck on a R-8 adapter on my mill/drill.
For several years it worked just fine but a few wekks ago, the chuck loosened from the JT and dropped off while in use (UGH!!)
Since that time it tends to loosen again every now and then (More UGH!)
The surface of the adapter looks fine - no scratches/dings, etc but I don't quite trust it like I used to.
Is there any tricks to reattaching it?
I thought about freezing the adapter and leaving the chuck at room temp for a tighter fit.
Any ideas?
Rich

[JCHannum]

Clean the mating surfaces with a good degreaser such as acetone or lighter fluid to remove any oil or grease, heat the chuck in the oven to around 250 degrees and install the arbor. It helps to give the arbor a good swat with a lead hammer to fully seat it.

[thistle]

while the chuck is in the oven stick the arbor in the freezer,then give it a clout together.

[banjoallen]

One other thing I do is very carefully hand lap the two mating part's with very fine lapping compound(400 grit maybe).And then do as above.Works real well for me. It's something I learned when I raced kart's years ago.Used it for mounting the clutch's. It seems to work for me.

Allen