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thisguy65
02-11-2016, 01:34 PM
I found a post showing Jackie chambering a barrel on a P&W lathe which has a really wide headstock. In the thread ti mention alignment system but for the life of me can't find any details on the alignment system.

I tired to PM Jackie but your inbox is full.

Boyd Allen
02-11-2016, 01:58 PM
http://benchrest.com/showthread.php?59097-Jackie-chambering-a-Barrel-%28Pictures

thisguy65
02-11-2016, 03:24 PM
http://benchrest.com/showthread.php?59097-Jackie-chambering-a-Barrel-%28Pictures

Yes sir that's the thread I'm referring to, was hoping he had some pictures of the setup.

jackie schmidt
02-11-2016, 04:42 PM
I found a post showing Jackie chambering a barrel on a P&W lathe which has a really wide headstock. In the thread ti mention alignment system but for the life of me can't find any details on the alignment system.

I tired to PM Jackie but your inbox is full.

I just cleaned out my In Box.

What kind of lathe are you using. If the center hole runs true, you can use this method.

I actually bored that Pratt & Whitney true, it ran out about .005 inch. The hole started as a nominal 1 1/2 inch.

This method of chambering is based on the premis that you can only get the ID of a barrel dead true in two spots. So, you establish those two spots, (the muzzle and where the throat will be established), and single point bore the third spot, i.e. the chamber, dead true with these. You don't worry about everything in between.

That thread is pretty thorough, but if you have any questions, I will be happy to answer them right her.

B.Larson
02-11-2016, 05:00 PM
My opinion is on a ....long barrel...... it`s much easier to do in a steady rest.......... either method is only as good as the operator...........
let the flames begin.........
bill larson

Zebra13
02-11-2016, 05:15 PM
I just cleaned out my In Box.

What kind of lathe are you using. If the center hole runs true, you can use this method.

I actually bored that Pratt & Whitney true, it ran out about .005 inch. The hole started as a nominal 1 1/2 inch.

This method of chambering is based on the premis that you can only get the ID of a barrel dead true in two spots. So, you establish those two spots, (the muzzle and where the throat will be established), and single point bore the third spot, i.e. the chamber, dead true with these. You don't worry about everything in between.

That thread is pretty thorough, but if you have any questions, I will be happy to answer them right her.

Jackie,

Could you please describe your set-up for boring the spindle. I'd appreciate it.

Thanks,
Justin

Butch Lambert
02-11-2016, 06:19 PM
Bill, My matches are wet.

jackie schmidt
02-11-2016, 10:20 PM
Jackie,

Could you please describe your set-up for boring the spindle. I'd appreciate it.

Thanks,
Justin

First, I removed the chuck. I mounted a 1 3/8 boring bar 20 inches sticking out from the cross slide with a small carbide insert with only a .010 radius tip. I then simply made several small passes at about 100 rpm until the hole was true. It might take a while, but once it's done, it's done.

I can do up to a 27 inch long barrel.

One thing that I think makes this a very affective setup for doing barrels is there is no danger of putting the barrel in deflection when you chamber it. It also makes setting barrels back up for a set-back a very easy operation. I like this because I do set barrels back on a regular basis.

Dusty Stevens
02-11-2016, 11:13 PM
Thats wild jackie. Never even dreamed of truing a spindle bore. Of course i damn sure dont have one of those tugboat boring bars either! Love hearing your methods

NezRongero
02-12-2016, 04:22 AM
First, I removed the chuck. I mounted a 1 3/8 boring bar 20 inches sticking out from the cross slide with a small carbide insert with only a .010 radius tip. I then simply made several small passes at about 100 rpm until the hole was true. It might take a while, but once it's done, it's done.

I can do up to a 27 inch long barrel.

One thing that I think makes this a very affective setup for doing barrels is there is no danger of putting the barrel in deflection when you chamber it. It also makes setting barrels back up for a set-back a very easy operation. I like this because I do set barrels back on a regular basis.

Jackie,

When you set back 30 BRs, what criteria do you use on how much to cut off?

Thank you.

nez

jackie schmidt
02-12-2016, 08:10 AM
Jackie,

When you set back 30 BRs, what criteria do you use on how much to cut off?

Thank you.

nez

The first two times, I take it back about .025, just to re-establish the throat. After these first two times, the barrel will have over 1500 rounds. The final time, I will chop the entire straight part of the chamber off and treat it like a new blank.

I have two barrels I have done this to, both down to about 20 inches in length, and both shoot pretty darned good.

I don't buy into the 4000 round life of a 30 barrel for Benchrest without doing something to it. Yes, it will still shoot decent, but that means 17-18 X's. If you want to consistently get into the 20+ X count, you better keep a fresh barrel on hand.

NezRongero
02-12-2016, 01:01 PM
The first two times, I take it back about .025, just to re-establish the throat. After these first two times, the barrel will have over 1500 rounds. The final time, I will chop the entire straight part of the chamber off and treat it like a new blank.

I have two barrels I have done this to, both down to about 20 inches in length, and both shoot pretty darned good.

I don't buy into the 4000 round life of a 30 barrel for Benchrest without doing something to it. Yes, it will still shoot decent, but that means 17-18 X's. If you want to consistently get into the 20+ X count, you better keep a fresh barrel on hand.



Thank you!

Zebra13
02-13-2016, 11:23 PM
First, I removed the chuck. I mounted a 1 3/8 boring bar 20 inches sticking out from the cross slide with a small carbide insert with only a .010 radius tip. I then simply made several small passes at about 100 rpm until the hole was true. It might take a while, but once it's done, it's done.

I can do up to a 27 inch long barrel.

One thing that I think makes this a very affective setup for doing barrels is there is no danger of putting the barrel in deflection when you chamber it. It also makes setting barrels back up for a set-back a very easy operation. I like this because I do set barrels back on a regular basis.

Jackie,

I did the same thing on my old lathe. I got it running fairly true as I remember, but the finish was less than stellar. And I just did the last 6 or so inches. Did you bore the entire length of your spindle?

I used a sliding center affair to hold my muzzle.

Thanks,
Justin

DSM
02-14-2016, 09:11 AM
I used a sliding center affair to hold my muzzle.

Thanks,
Justin

Can you explain more on the above statement?

Zebra13
02-15-2016, 10:16 AM
Can you explain more on the above statement?

DSM,

http://benchrest.com/showthread.php?67472-Larger-lathe-barrel-work-questions&p=561027&highlight=#post561027

Here's a couple of pictures. I'm gonna go airgun some ground squirrels right now, so I'll give you an explanation when I get back.

Justin

DSM
02-15-2016, 10:39 AM
Got it...I just never heard the term "sliding center".