Stopping my chuck falling off

[John Rumm]

One of the "features" of my cheapy Ferm pillar drill is that the chuck has a habit of falling off the quill if one vibrates it too much or pulls on it too hard. While this is not usually a problem for drilling, for activities like drum sanding, or use as a poor man't lathe it can be a tad irritating!

Is there a recognised way of achieving a better interference fit between them? I have already made sure they were well degreased.

(Since the morse taper hole is in the chuck rather than the far more useful alternative of it being in the quill, I don't have any objection to it being a semi/permanent fix)

[dom]

First thing that springs to mind is one of the weak-bond thread locking compounds that allow the bond to break with moderate force.

But presumably the chuck slips off because the taper isn't very accurately machined, so would it be possible to gently grind in the joint with some lapping compound?

[Bob Minchin]

You could use real loctite as this can be broken if needed with gentle heat.

Wind the jaws into the body and bring the quill down to push the chuck body against a block of wood

NB the taper in the chuck is not a morse taper but instead will normally be a steeper taper possibly a jacobs taper. JT6 is common in 1/2"- 13mm chucks

There are some chuck tapers - "B series" that are short sections of taper with the same included angle as a morse taper.

Bob

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember John Rumm saying something like:

Lap them in a bit - most cheapy tapers will be a hit and miss affair, fitting where they touch.

[Walt]

Try putting Talcom Powder on the taper a remedy passed on to me many years ago and is what I find effective

[Ian White]

Loctite 203/204 worked well for me, in exactly that situation.

Even after grinding it in, it still needed the Loctite. (It was also some years ago. These days, I'd have formally rejected the goods, and sent the whole thing back at supplier's expense.)

[Gib Bogle]

My sister Sue was engaged to an Eskimo, but they broke it off.

[robgraham]

Interesting one and quite a coincidence. I bought an MT2 for a 1/4" chuck for my wood working lathe very recently and was somewhat puzzled when it turned up with a thread at the back end - some thing that doesn't exist on some half dozen other taper shanks I have. What I then found irritating about this was that it was 3/8" Whit or UNC and the backstock only takes a 9mm drive bar, which of course then jammed in the thead.

That I have now solved but the purpose of the thread I've since learnt is so that the taper can be pulled into the stock - or quill in John's case.

Probably no use in this case but interesting all the same!!

Rob