Here s an easy way to true your chuck. The milling machine I used was my first vertical machine. A Grizzly column mill. I already had a Burke #4 with a vertical attachment for many years. Small but useful little mill. These days I also have an older Enco 6 x 26 knee mill. Real nice older machine 1985. Not a Bridgeport but I couldn't fit one in my small shop if I wanted to. I had to do some work to the Grizzly to really make it usable. No complaints, I bought it very reasonably. And it served well. I thought I would sell it but I soon realized how nice it is to have 3 milling machines to choose from. If one has a particular set up on it sometimes I can just use another. Almost always one mill with a vise and one with a rotary table mounted. Sometimes I have a vise on one end and a rotary table on the other end.
So see how I made notches in a piece of pipe with my rotary table . See how it fits the chuck. Loads the jaws while you grind. It's an older Westcott chuck that came with my very nice 1947 South Bend 9a. I've had it almost 35 years . Still no nicks on the ways or crash marks on the compound. The chuck was in decent shape but the jaws were bell mouth and one was out about .002 or 3 more than the others.
I did this a few years back and I didn't have a tool post grinder then. So I rigged up an air die grinder held in the compound. After I had the grinder in place I dressed the stone and gave it a try. Came out really well. I was really pleased. Years later It still turns with very little runout. I haven't put an indicator on it lately. And the jaws are still square.
Too much work, Id just buy a new one. Im just kidding, I have this barrel coming and spent almost $400 on accessories to machine it. If it goes well Im looking at rebarreling 3 other guns. Rather than spend good money on an accurate rifle out of the box.
Wellllll, I can't seem to find a similar quality new chuck for less than $400. That's a Bison from Poland. A Burnerd from England is over $800. That's what came with most Atlas lathes. And Myfords. You can find good used ones on eBag if you are patient and win the bid. When you get the used chuck and mount it on your spindle you are likely to find that it doesn't run as true as you'd like. So you are going to have some work to do. Some spindles have a larger diameter register area so you may have to open that up a bit for your back plate to meet your spindle face.
When you buy a new chuck you have to face and Accurately turn the back plate to fit your new chuck. If it's a cheap chuck you might still have to true the jaws...........?
The chuck I trued is about 73 years old. Well taken care of and the jaws still fit the slots accurately. It only took a few hours to do. Maybe 2 or 3.
Picture is of my other South Bend 9. I found the Burnerd chuck on it at a hobby machinist show. Surely came with an Atlas lathe originally. It's in excellent almost NOS condition. I bought it form a nice elderly gentleman for his price of $70. The outside jaws are missing. I have my eye on eBag for them. They made many thousands of these chucks for Atlas so I'll surely find a set. Outside jaws aren't normally used much so condition is often like new. I had to open up the register a little for it to fit the South Bend. Doesn't have much runout but I might just kiss it with the grinder as well. Should only take an hour since I already have the tools. Just repeating the set up.
Wellllll, I can't seem to find a similar quality new chuck for less than $400. That's a Bison from Poland. You can find good used ones on eBag if you are patient and win the bid. When you get the used chuck and mount it on your spindle you are likely to find that it doesn't run as true as you'd like.
This.
My $600 Logan 10x24 came with a $700 Bison, +$2k-3k more worth of goodies.
Certain things aren't worth messing with on Ebay, used Holley carbs for example.
They should give a free lathe to anyone that wants one, tooling prices are obscene.
The Chinese lathes should come with a grinder and indicators.
It should be noted that a "Buck Chuck" can be adjusted somewhat without grinding.
Back when I was a newb on mini-lathe, I almost started grinding and probably would have ruin't my chuck like a dummy. Wow, what a dummy! I'm not saying that anything you did was wrong, you seem competent.
Could you please remind us (me) what the concern was with taper in the jaws? Taper tending to remain even when ground as such? Was it the jaws titling in the chuck face? I've totally forgotten now.
It's been a while, and I never did grind anything, thankfully.
John, Logan are good lathes. My father got one for me when I was 15.(1974) It was from the local high school Vo Ag shop and it was hammered. But it was mine and it kept me from making boo boos on his rather nice lathe. It came disassembled and we had to put it together. I had to make a spacer for the end gears and a lead screw support bracket. I made the bracket on his Ammco shaper out of aluminum. At Christmas he gave it to me. That's how/where I learned to grind my tool bits. Many mispent hours. You couldn't keep me out of the shop. Unless you wanted to go hunting,trapping, or fishing!
Quite a few makers offer (Adjust Tru)(Set Tru) chucks these days. Typically higher end. Look at the price of just a back plate for one.
The biggest issue with my chuck was the typical sprung jaws. Years of use and clamping at the front edge of the jaws eventually causes it. Makes them bell mouthed. Can allow some wiggle under heavy loads. Try parting operations with one.
Lightly tighten your chuck on a bar then grab the far end and see if it will wiggle a little, tiny bit. If it does your jaws are sprung. You can live with it somewhat. Until you try parting! Parting tool will suddenly hog in and hopefully only stall the lathe. Maybe scrap your part.
Be safe and healthy all! Give thanks for all we receive today
