Site Notices
10/24/2014 2:42:22 PM
Author
Message
Bloencustoms
Offline
Posts: 15904
Feedback: 0% (0)
Posted: 11/21/2013 1:20:37 AM
Here's the situation. Barrel dimpling jigs are $$ and I would rather spend the time than the money.

I don't have a mill or a decent drill press, but I do have a little bench top lathe.

Could this be as simple as getting some 1" stock and mounting it in the chuck sideways and cross drilling it and tapping it first, then mounting it lengthwise and boring it out to fit the barrel?

I'd then be able to tap one side of the hole to take a pointed setscrew to index it on the gas port, which would allow me to dimple the barrel 180 degrees opposite and centered on the gas port, correct?
Boostinjdm
Offline
Posts: 21
Feedback: 0% (0)
Link To This Post
Posted: 11/21/2013 5:07:30 AM
That would be fine as long as you can hit dead center when you cross drill.
SigOwner_P229
Member
Offline
Posts: 3304
Feedback: 100% (16)
Link To This Post
Posted: 11/21/2013 9:52:22 AM
[Last Edit: 11/21/2013 9:52:59 AM by SigOwner_P229]
[Jump To Reply]Originally Posted By Boostinjdm:
That would be fine as long as you can hit dead center when you cross drill.

This ^^^

Nothing wrong with doing it on the lathe, you just have to be sure you get it indicated in properly. That is a classic case of using "the wrong tool for the job". Sometimes using the wrong tool will still work, but most of the time it is a lot more difficult and challenging. If you're up for it I see no problem with trying...
Bloencustoms
Offline
Posts: 15908
Feedback: 0% (0)
Link To This Post
Posted: 11/21/2013 9:47:20 PM
Would using a dead center in the tailstock to pinch a ruler against the work piece in the chuck work for finding center? Or do I need to use indicators?
Bloencustoms
Offline
Posts: 15909
Feedback: 0% (0)
Link To This Post
Posted: 11/21/2013 9:50:42 PM
I wish I had a decent drill press. I have a tiny little ryobi that has plenty of wobble. I use it for all kinds of things, but nothing that needs to be precise. And by the time I bought decent V blocks I could just buy the dimpling jig itself from brownells.
SigOwner_P229
Member
Offline
Posts: 3311
Feedback: 100% (16)
Link To This Post
Posted: 11/22/2013 1:35:37 PM
[Jump To Reply]Originally Posted By Bloencustoms:
Would using a dead center in the tailstock to pinch a ruler against the work piece in the chuck work for finding center? Or do I need to use indicators?

That depends how precise you want your holes located for the dimpling jig. Your holes will only be located as precisely as all of your errors combined. If you have a sloppy old lathe you will have a .005-.020 error (depending on technique and how bad your lathe is) just on getting a drill-bit started in the work-piece. If you add on another .050" by using only a ruler to locate your work-piece into the 4-jaw you could end up with a total tolerance stackup of .140" (over 1/8"). Are you ok with that? How close and how repeatable can you get a workpiece into your 4-jaw using a ruler?
AeroE
I Was Free Born
Offline
Posts: 49382
Feedback: 100% (2)
Link To This Post
Posted: 11/23/2013 8:49:15 AM
Use a piece of square stock to make the set up simple.

A tailstock vise is an option, but you'd have to fabricate that. Southbend is the only lathe I've seen that supplied one in the accessories.

A Palmgren milling vise for the cross slide is another option.

It is not easy to explain Liberty to those that are not familiar with Liberty. Kevin Jamison, on explaining firearm regulation to a Massachusetts lawyer. Jeff City, Mo 18 Apr 13.
SigOwner_P229
Member
Offline
Posts: 3315
Feedback: 100% (16)
Link To This Post
Posted: 11/23/2013 12:41:15 PM
[Jump To Reply]Originally Posted By AeroE:
Use a piece of square stock to make the set up simple.

A tailstock vise is an option, but you'd have to fabricate that. Southbend is the only lathe I've seen that supplied one in the accessories.

A Palmgren milling vise for the cross slide is another option.



From my understanding he has the stock already to size, he just needs to drill the 2 dimpling holes into it in a precise manner.

Your post does bring up a good point though. You can "clamp" the stock to your cross-slide and use the cross-slide to get the holes precisely spaced. Use shim-stock under the work-piece to get it to the right height, drill first hole, crank cross-slide the right distance and drill second hole (with drill bit in the head-stock).
AeroE
I Was Free Born
Offline
Posts: 49400
Feedback: 100% (2)
Link To This Post
Posted: 11/24/2013 10:45:54 AM
It's clear in the first post that the stock hasn't been bought.

This is a simple job in a milling machine.

Machining two of the holes in a four jaw chuck is also simple, then a decision has to be made about an offset hole for a clamp screw similar to the jig sold by Brownell's, or putting clamp screws on the centerline of the side flats of the jig.

It is not easy to explain Liberty to those that are not familiar with Liberty. Kevin Jamison, on explaining firearm regulation to a Massachusetts lawyer. Jeff City, Mo 18 Apr 13.