First off I want to thank Smokeywolf and Keith for pushing me in the right direction. They made me realize how helpful soft jaws can be for repetitive work on the lathe while also allowing for repeatability.
Bill asked about how I hold a lead bullet in the chuck without damaging it. Pretty easy really.
These are the 6061 Al jaws I made. A chunk of 1.5" diameter Al was cut roughly to length. Each piece had one end faced flat then reversed in chuck to face to length. They were then thru drilled for clearance of the bolt. I drilled and bored a flat bottom recess for the bolt head so it is just below flush.
The jaws do not have any keying to index off the bottom portion of the jaw, screw tension alone keeps them from turning.
I clamped them on a very small round rod in the rear of the soft jaw to provide inward tension when boring. I then bored until a .432 gauge pin would just slip in. That makes for a set of jaws cut to provide contact on the full circumference of the bullet. Force is distributed such that the bullet can't spin but isn't damaged by heavy point loads on a smaller jaw surface.
Notice the flat bottom to the bore. This lets the bullet bottom out in a repeatable manner. I can simply place a bullet in place, snug the chuck, and cut. No need to indicate each bullet for either length or concentricity. I can groove a bullet in under a minute including time to chuck and remove after cutting.
The other cuts you see on these jaws are for trimming 445 brass to length for the SRH. They are cut so the rim fits into the recess you see to indicate for length. Trims brass to .001-.002 repeatably. The jaws are reversed for trimming.
These cost very little to make and took maybe an hour to complete. Very helpful.
The first soft jaws I got were used for holding Star die blanks for drilling and boring. I was using a sleeve with some slots in it like a collet but it wasn't as repeatable or easy to use as these are.
These jaws are made from 1018 so they cut very easily. I purchased a couple sets online, I want to say they were 20-30 bucks a set of three. Each end can be cut for a specific job so the cost isn't too bad in relation to their usefullness.
Top photo shows how they were bored to just fit a Star die blank. Again I used a smaller object held in the rear of the jaws to provide an inward force on the jaws when boring to size.
The lower photo shows how these are made to indicate on matching surfaces on the lower jaw. Each soft jaw was stamped to make sure it is always placed on the correct jaw. You can also see the bottom of the cut that the dies bottom on.
I had to buy a new chuck as the one I got with the lathe wasn't equipped with 2 piece jaws. The chuck wasn't cheap but between the chuck running much more true and the ability to use soft
jaws it was worth every penny.
Hope this helps you understand the process Bill. This is such a simple concept but has amazing capabilities. The jaws are bored on the lathe so the bore in very true so parts will run true time after time. How I got by without these I don't know.
Bill asked about how I hold a lead bullet in the chuck without damaging it. Pretty easy really.
These are the 6061 Al jaws I made. A chunk of 1.5" diameter Al was cut roughly to length. Each piece had one end faced flat then reversed in chuck to face to length. They were then thru drilled for clearance of the bolt. I drilled and bored a flat bottom recess for the bolt head so it is just below flush.
The jaws do not have any keying to index off the bottom portion of the jaw, screw tension alone keeps them from turning.
I clamped them on a very small round rod in the rear of the soft jaw to provide inward tension when boring. I then bored until a .432 gauge pin would just slip in. That makes for a set of jaws cut to provide contact on the full circumference of the bullet. Force is distributed such that the bullet can't spin but isn't damaged by heavy point loads on a smaller jaw surface.
Notice the flat bottom to the bore. This lets the bullet bottom out in a repeatable manner. I can simply place a bullet in place, snug the chuck, and cut. No need to indicate each bullet for either length or concentricity. I can groove a bullet in under a minute including time to chuck and remove after cutting.
The other cuts you see on these jaws are for trimming 445 brass to length for the SRH. They are cut so the rim fits into the recess you see to indicate for length. Trims brass to .001-.002 repeatably. The jaws are reversed for trimming.
These cost very little to make and took maybe an hour to complete. Very helpful.
The first soft jaws I got were used for holding Star die blanks for drilling and boring. I was using a sleeve with some slots in it like a collet but it wasn't as repeatable or easy to use as these are.
These jaws are made from 1018 so they cut very easily. I purchased a couple sets online, I want to say they were 20-30 bucks a set of three. Each end can be cut for a specific job so the cost isn't too bad in relation to their usefullness.
Top photo shows how they were bored to just fit a Star die blank. Again I used a smaller object held in the rear of the jaws to provide an inward force on the jaws when boring to size.
The lower photo shows how these are made to indicate on matching surfaces on the lower jaw. Each soft jaw was stamped to make sure it is always placed on the correct jaw. You can also see the bottom of the cut that the dies bottom on.
I had to buy a new chuck as the one I got with the lathe wasn't equipped with 2 piece jaws. The chuck wasn't cheap but between the chuck running much more true and the ability to use soft
jaws it was worth every penny.
Hope this helps you understand the process Bill. This is such a simple concept but has amazing capabilities. The jaws are bored on the lathe so the bore in very true so parts will run true time after time. How I got by without these I don't know.
