Chambering short barrels in the headstock

[Jake P]

Ken, what did you bore your ID to on yours?

 

[LVLAaron]

I went with a 2 inch bore. That'll hold any action or barrel you run across.

 

[Ken226]

I take it then that rigidity with something with this mass is not enough of a difference then to worry about. Thanks!

Exactly.

Steel actually has a shear modulus (rigidity) that is 3 times higher than aluminum, but in this application a lathe doesn't generate nearly the force needed to effect the aluminum fixture.

This hitch is rated for a 10,000 lb trailer.


Visualize the stresses involved with a truck towing a 10,000 trailer, hard stopping at a stoplight, then taking off again. His fixture is probably even more rigid than that hitch due to its much larger diameter.

 

[Ken226]

Ken, what did you bore your ID to on yours?

2"

I mostly work on flat bottom Winchester and FN receivers. I needed a bigger hole that would have been necessary for Remington's.

 

[LVLAaron]

I went down a rabbit hole of determining thread strength in aluminum and various steels because I was concerned about having cam pins or bolts in an aluminum fixture. I forget what the exact numbers were but it was many thousands of pounds (Think, guys testing threads with 20 ton presses)... at that point I quit worrying about it.

 

[Jake P]

I went down a rabbit hole of determining thread strength in aluminum and various steels because I was concerned about having cam pins or bolts in an aluminum fixture. I forget what the exact numbers were but it was many thousands of pounds (Think, guys testing threads with 20 ton presses)... at that point I quit worrying about it.

 

[Jake P]

I went down a rabbit hole of determining thread strength in aluminum and various steels because I was concerned about having cam pins or bolts in an aluminum fixture. I forget what the exact numbers were but it was many thousands of pounds (Think, guys testing threads with 20 ton presses)... at that point I quit worrying about it.

I meant to ask what you settled on for your set screws (or what ever the truing bolts are called on a jig like this)?

I am considering 3/8x24 as I feel a finer thread should aid in fine adjustments.

 

[LVLAaron]

1/2-20 on the fixture.

I have 3/8-24 on my outboard spider and I'm sure that would be fine (and certainly less money in hardware)

 

[pontiac428]

I went with 5/16-24 on my receiver fixture. It was my intent to make its pitch similar to a 4-jaw. I'm content with it.

 

[Jake P]

Cutting the slots for bolt handles. It’s a slow process. Sure glad I am not making this out of steel!

It’s 5” OD and 2” ID x 7” long. With the backplate it’s about 8” overall.