Group Project: Dividing Head - The Build

[Flyinfool]

The trunion can still be made with the original dimensions on the aux base and that end of the trunion, at this point I am not aware of the aux base also having a 3 inch hole already.

 

[Shotgun]

The split ring works.
I put a 15 degree taper on the end of the 3" round I have. Did not move the compound and put the same taper on the inside of a piece of thick walled tubing. Turned the outside of the tube so that it was a slip fit to the inside of the base. Cut slits on the tube down through the tapered portion. Put the parts together, and pressed them together using my mill spindle as a press. Got a tight lock.
Would have gotten a better lock if I had drill 1/8" stress relief holes at the end of the hacksaw slits. Also, a couple screws would give more mechanical advantage than using a mill as a press.

 

[Shotgun]

The trunion can still be made with the original dimensions on the aux base and that end of the trunion, at this point I am not aware of the aux base also having a 3 inch hole already.

Yeah. I milled them together.
However, the aux is just 1/8" plate, and doesn't have a lot of features. Rather trivial to make them again.

 

[Shotgun]

Another option to keep the original design.
A brass bearing. .125 thick. 3.000 diameter.

 

[rwm]

Hey guys I just looked back at this thread. In post 63 Lanagos indicates that his trunnion material is 3.25 inches diameter. Does that help us? Like what if we upsize the OD of the trunnion to 3.125 inches so that it can clamp against the 3 inch hole?

 

[Flyinfool]

Here is what I was thinking for the new end cap to mate with a 15° taper on the trunion.

 

[Flyinfool]

A brass bearing would work if it was flanged. Then the shoulder on the trunion would need to get pushed back by the thickness of the flange. Might have to add a pointer for the degree markings.

 

[Flyinfool]

Hey guys I just looked back at this thread. In post 63 Lanagos indicates that his trunnion material is 3.25 inches diameter. Does that help us? Like what if we upsize the OD of the trunnion to 3.125 inches so that it can clamp against the 3 inch hole?

That could work, I would prefer that it be kept as large as possible. Just machine as little as possible for it to clean up or even leave stock surface, but it will not be pretty.

At 3.125 that only leaves .063 of bearing surface and some of that will be lost in deburring the hole, and the trunion would need an undercut at the shoulder to maximize bearing surface.

 

[Flyinfool]

Yeah. I milled them together.
However, the aux is just 1/8" plate, and doesn't have a lot of features. Rather trivial to make them again.

The Aux Plate was supposed to be 1/4 thick??

 

[Shotgun]

Yes. That's right. 1/4". That's what it is. I mispoke.