Question about Barrel Threading

[ddickey]

For an OD threading operation, what is a good way or acceptable way to align the inside bore to the center axis?

 

[LEEQ]

for some visual help, try searching range rod or chamber reaming. You will see how to indicate off of a rod stuffed in the bore to find the axis of it so that your work will be concentric. Workholding should also be covered. Things like an outboard spider that work like an independent 4 jaw, and an independent 4 jaw allow you to hold the work concentric to the bore and align it to the machine.

 

[Balor]

There are a number of good videos on YouTube "Barrel threading on a lathe".

rngr1

 

[Tinkertoy1941]

Easy way is to use the bore on both ends no indicating, no barrel marks, no special jaws,
I threaded two barrels while the customer was standing watching me
His comment the last guy charged an arm and a leg
He did not realize how easy it was the previous fellow had to make specials jaws and special tooling.
Another happy customer

 

[ddickey]

Easy way is to use the bore on both ends no indicating, no barrel marks, no special jaws,
I threaded two barrels while the customer was standing watching me
His comment the last guy charged an arm and a leg
He did not realize how easy it was the previous fellow had to make specials jaws and special tooling.
Another happy customer

What do you mean by using the bore on both ends?

 

[Tozguy]

two examples with barrel through the headstock and outboard spider
1) range rod
2) indicator

 

[dulltool17]

What do you mean by using the bore on both ends?

I was puzzled as well... I'm thinking he means using the bore Between Centers.

Not that I've threaded all that many, but I use inboard and outboard spiders.

 

[ddickey]

Between centers would definitely be the easiest but is that accurately aligning the center of the bore?

 

[Tinkertoy1941]

If you have a cylinder and you want the machining concentric with the bore what would be the easiest way to get them in line on a lathe.
A rifles bore is nothing more than a cylinder you want something concentric with.
Working between centers means no fancy spiders, no fancy fixtures, no indicating
The old toolmaker I learned from beat into us "SIMPLEST IS ALWAYS THE BEST"
He said you can screw around a half a day for a half a thousandth and miss it a half an inch!!

 

[Tozguy]

If you have a cylinder and you want the machining concentric with the bore what would be the easiest way to get them in line on a lathe.
A rifles bore is nothing more than a cylinder you want something concentric with.
Working between centers means no fancy spiders, no fancy fixtures, no indicating
The old toolmaker I learned from beat into us "SIMPLEST IS ALWAYS THE BEST"
He said you can screw around a half a day for a half a thousandth and miss it a half an inch!!

Well I guess if you are going to miss the mark by half an inch then you might as well do it quickly. Anyone who thinks that a modern rifle barrel is just another piece of pipe must be a flintlock fan.