Thread: Can a chuck be straightened? Wobble in the bits

Originally Posted by Evanism

Anyway, I have a Trade Tools RI170 with a keyed chuck ( https://www.tradetools.com/products/RI1720 ). The whole shebang is second hand. I have good reason to trust it hasn't been abused as the dude I bought it off is an army engineer who made, well, everything metal for them.

I'm not saying they are all like this but I'm not convinced being an an army engineer is a guarantee of non-abuse. We have an ex-army engineer work for us for a while and he was right butcher of machinery. It sounds like the chuck might have been run without being tightened up sufficiently, a not uncommon problem with second hand DPs.

You could approach Tradetools and see if they have replaceable jaws (a quality chuck will have these) but if it was me I would replace the chuck with a keyless one.

Oh come on fellas..nobody fixes chucks any more.

If the shaft of the drill is straight, I recon you are looking down the spout of a new chuck purchase.

first thing is to see if the body of the chuck is running true.

If its not the morse taper may not be properly seated with crap in the gap...or the mandrel may be bent.

you can pick up a mew mandrel and a new chuck cheap enough.

h&f
carbatec
McJing

cheers

Firstly I would mark the chuck on the outside to identify thje position of one of the jaws for reference. Then insert staight pieces of round material of vaying sizes form maximum to minimum diameters the chuck can hold, and measure the runout of each one. See if the direction of the runout is always in the direction of just one jaw. That would indicate that jaw is worn. If it varies all over the place in relation to the chuck, you probably have a bent mandrel. Since you have nothing to loose then, grip a piece of steel the biggest size the chuck will grip, clamp it tightly and give the chuck body a whack with a soft faced or copper/lead/wooden hammer on the side of maximum runout. Take it easy, if the jacobs taper holding the chuck is small or the chuck is screwed on, it may not take much of a hit to over-correct! Once you have a sens of how much it moved - using a dial gauge or indicator, then keep at it gently until the runout is gone for that diameter. Then check again with a few other sized rods and see if you corrected it or if the chuck has internal runout in addition to the mandrel that you can't fix. In that case, then go and get a new chuck