Gunsmithing thread for home made gun smithing jigs

[LRI]

Here's my new fixture for accurizing Winchesters. My intent here is to securely register the action while keeping the front ring completely tension free. This way there's no risk of the fixture distorting the action.

Shown is my pride n joy: A 2nd year production M70 action.

First step is qualifying the bottom of the receiver. In order to fixture it this way, the mating surface has to be dead nuts flat. Otherwise the clamp will distort the action and this will cause the bushings/arbor shaft to give a false indication of center/concentricity/location, etc.

This is done in a separate fixture in a previous operation.

The trick in all this has been to build a fixture that'll adapt to the entire legacy/spectrum of Winnies built over the last 79 years. So far, were in good shape. Every action run through it has been spot on. I was fortunate enough to have a couple receivers given to me a few years ago by a gun shop nearby. The two actions had been in a house fire and were ruined. Perfect candidates for proofing out code and ensuring this was going to work.

We've got four different machining operations to take these actions to the level I wanted. The forward edge of the lug has a 2* draft angle machined so that the receiver will "peel" out of a well bedded stock a bit easier and reduce the risk of tearing stuff up.

Same accurizing fixture is used to interpolate (helically bore)/thread mill the base holes.

Might be a little out there for some as this requires a 5axis machining center to work as I intended, but it's suits our needs well.


My coolant is starting to leave a rather strange green/shit/brown patina on the fixture. It's not rust, not sure what it is exactly. Will have to start pickling it with Marvel oil once were done with it.

Fun stuff.

C.

 

[deadmilkman]

Very cool fixture! Looks like you machine the bottom of the receiver as well?

Wes

 

[LRI]

Yes. Have to. Bottom of the action has to be dead nuts flat otherwise it'll distort the entire receiver in the fixture.

 

[Glenn]

Nice jig Chad!

So the bottom of the action is surface ground before any of the other machining takes place?
Is the bottom of the action ground parallel to the bolt raceway?
Just trying to get my head around it!

Glenn

 

[LRI]

Yes. Parallel to the raceway. That's the 1st op fixture. In reality though it being parallel really doesn't matter from the fixture perspective. With the 5 axis trunion you can't orient the bore center to vertical regardless of what the rest of the action is doing.

it's kinda like working on a 700. Nobody worries about where the outside of the action is going.

 

[Glenn]

Thanks Chad.

Glenn