View Full Version : Truing lathe head
12-27-2007, 04:38 PM
My lathe head needs to be trued up. I had a bit of off-center wobble and thought my jaws were worn, so I bought a new set. The new jaws wobble as well.
It looks like the 3rd jaw always locks "late" and lets jaws 1 and 2 push the work off-center.
I don't want to buy a new head stock, especially considering how much this little lathe runs to begin with.
What would be the best way to true it up? I'm thinking about using my old jaws, and using my dremel as a jaw grinder like what Varmint Al uses:
12-27-2007, 04:59 PM
I don't have an answer; But this is where I go for machining info:
Most there are more than willing to share & help.
12-27-2007, 05:52 PM
BTW; you can dump my previous post ,if I'm out of line mentioning another forum.
They were great help in setting up my antique South Bend 9" lathe.
12-27-2007, 06:46 PM
On my 9x20, I found the biggest thin round object that would fit in the very back of the jaws, dykemed them. I then did the grinding like Varmit Al and stoned the unaltered portion to not make contact. Take off just enough to true the jaws when you do this and no more. I also marked my chuck and backplate to ensure that if I take it off I put it back with the same hole orientation. The other option is to chuck up a very round rod and using a test guage figure out which jaw or jaws need material removed then remove material slowly with plenty of test fiting. I did this on my smaller quality three jaw that was only off 0.0003 and got it as close as I can measure. Al's method will also make the jaws parallel. The only thing is that you can not clamp anything the same size or larger than how far the jaws were apart when you preformed the grinding as the jaws are curved and contact in the center of the jaw will not happen otherwise. I redykemed the jaws and used a new stone for the last pass on the chuck with just enough contact to take off all the dykem. My cheap chinese chuck had almost 4 thou runout when I got it and this fixed it.
12-28-2007, 03:06 PM
Here is another way with the jaws loaded like holding a piece of stock.