Lathe chucks

[marazzi59]

Also the fine thread bolts compared to the coarse thread on the 4 jaw chucks makes adjustments so amazingly easy and fine

 

[Konocti's Wigwam]

One thing I wanted to mention, in regard to 4-jaw chucks. It helps to have 2 small chuck keys so you can adjust front/back at the same time. Don't forget to harden them if you make some yourself. I made a set a few years ago and broke the key off gorilla handling it. Many of the old chucks used fairly small keys.

 

[LVLAaron]

I’ve got another question, I use the Gordy method dialing a barrel in with that said how tight of a bushing do y’all?
Thanks ACSR

If it's dialed in straight, you don't need a pilot.

 

[xr650rRider]

If it's dialed in straight, you don't need a pilot.

I think he's trying to dial in straight and if using Gordy rods, you need a pilot bushing.

This old post on same thing references Gordy's book.
https://forum.accurateshooter.com/t...ate-your-chambering-job.4081657/post-38520090

 

[LVLAaron]

Ah, yeah... just make sure nothing is binding up.

 

[DR_2297]

In my quest for ever improving I am currently at at like iteration 4 and that is inboard and outboard spider that are detailed throughout this thread.

In order to be able to do short barrels through the head stick I ended up buying a D1-5 backing plate, removed 2 of the pins and D&T 4 holes normal to the spindle. I have been making brass tipped jack screws and it works OK but they have their issues and I am about to venture toward iteration 5 and making pivoting pads and jack screws with ball bearings in the end as seen here.

The real issues I run into is the fine balance between enough clamp pressure to have a rigid setup and too much that locks the barrel up and you just end up bending it between the spiders rather than articulating at the inboard end. If you use too much clamp load and you are clamping in the throat area you get bore distortion and direct indicating becomes a PITA.

Otherwise I pretty much do what most here are doing. Rough in OD, pin bore to fine indicate both ends and then go to a long stem interapid to direct indicate the throat.

I was at a friend’s place yesterday and he showed me his setup with a stirrable Buck 6 jaw and an outboard spider. He uses a wrap of aluminum between the jaws and barrel about an inch or so wide. I haven’t wrapped my head around how that setup gets you a bore (in the throat area) coaxial to spindle though. When you clamp down with 6 jaw on the OD you get what you get since there is no ability to pivot and therefore you can stir only in one plane to indicate a “curved” bore at one single point. Trying to adjust with outboard spider would really do nothing but bend the barrel.

 

[Sniperhandle]

In my quest for ever improving I am currently at at like iteration 4 and that is inboard and outboard spider that are detailed throughout this thread.

In order to be able to do short barrels through the head stick I ended up buying a D1-5 backing plate, removed 2 of the pins and D&T 4 holes normal to the spindle. I have been making brass tipped jack screws and it works OK but they have their issues and I am about to venture toward iteration 5 and making pivoting pads and jack screws with ball bearings in the end as seen here.

The real issues I run into is the fine balance between enough clamp pressure to have a rigid setup and too much that locks the barrel up and you just end up bending it between the spiders rather than articulating at the inboard end. If you use too much clamp load and you are clamping in the throat area you get bore distortion and direct indicating becomes a PITA.

Otherwise I pretty much do what most here are doing. Rough in OD, pin bore to fine indicate both ends and then go to a long stem interapid to direct indicate the throat.

I was at a friend’s place yesterday and he showed me his setup with a stirrable Buck 6 jaw and an outboard spider. He uses a wrap of aluminum between the jaws and barrel about an inch or so wide. I haven’t wrapped my head around how that setup gets you a bore (in the throat area) coaxial to spindle though. When you clamp down with 6 jaw on the OD you get what you get since there is no ability to pivot and therefore you can stir only in one plane to indicate a “curved” bore at one single point. Trying to adjust with outboard spider would really do nothing but bend the barrel.

Your friend's method is the Darrel Holland method from 20 to 25 years ago, Darrel would put the barrel through the headstock in a 6 jaw chuck, And then dial in the muzzle end using a range rod with the outboard spider and an indicator.

So whatever the 6 jaw chuck end is, Is what it is as far as runout. There are much better ways of doing it now.