AmericanLongRifles Forums

General discussion => Shop Made Tools => Topic started by: Hank01 on June 10, 2023, 02:45:15 PM

Title: Round to octagon barrel grinding jig
Post by: Hank01 on June 10, 2023, 02:45:15 PM

There’s been some discussion on the Gun Building forum about grinding octagon flats on a round barrel. Here is a jig built in our shop for grinding flats using an angle grinder. It’s easy to build and easy to use. It’s a simple machine made of scrap lumber, angle iron and steel plate. The steel top plates help to guide the grinder to keep the flats even side to side and from going too deep. Wood blocks the plates are fastened to have a slight amount of swamp.

(https://i.ibb.co/f2yP80w/DSCN3593.jpg)

The barrel blank is held in place by V block clamps on both ends.

(https://i.ibb.co/qBVL6Jv/DSCN3595.jpg)

V block height is adjustable up and down to provide taper of the flat.

(https://i.ibb.co/2v57WDS/DSCN3591.jpg)
(https://i.ibb.co/HpZNyzn/DSCN3603.jpg)

A scrap piece of octagon barrel fits in one V block to serve as the flat index.

(https://i.ibb.co/FHTz9vK/DSCN3597.jpg)

It is welded to a full length mandrel threaded on the opposite end. A nut and washer keep it tight. It is kept centered by a turned insert. That's the brown thing between the washer and barrel.

(https://i.ibb.co/8cb18xN/DSCN3624.jpg)

To use all one has to do is set the angle of taper, clamp the blank to the jig, grind one flat, index the blank to the next flat and grind.

(https://i.ibb.co/cJ32XHp/DSCN3599.jpg)
(https://i.ibb.co/6th0TvJ/DSCN3600.jpg)
(https://i.ibb.co/Ct4r5Lf/DSCN3607.jpg)

Repeat until all flats are ground to shape.

(https://i.ibb.co/f1qHtht/DSCN3613.jpg)
(https://i.ibb.co/Lndf871/DSCN3614.jpg)

Draw filing and sanding is all that’s needed to finish a new barrel.

Hank

Title: Re: Round to octagon barrel grinding jig
Post by: Osprey on June 11, 2023, 12:22:38 PM

I'll give that a nifty!

Title: Re: Round to octagon barrel grinding jig
Post by: P.W.Berkuta on June 12, 2023, 07:52:20 PM

Very clever and may be useful for some - good idea. ;)

Title: Re: Round to octagon barrel grinding jig
Post by: 2 shots on June 13, 2023, 04:59:55 AM

 :) nice

Title: Re: Round to octagon barrel grinding jig
Post by: Dan Fruth on June 17, 2023, 02:02:58 AM

Very clever way to accomplish a tough job> Hats off to you!

Title: Re: Round to octagon barrel grinding jig
Post by: Hank01 on June 17, 2023, 07:44:09 PM

Thanks guys. A physics professor one time said "Mr. Hank, why do you constantly try to reinvent the wheel?" My reply? "I don't. Just trying to find a better way to make it go 'round and 'round."

Hank