Jackie Schmidts alignment method through headstock?

T

thisguy65

Guest
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.
 
thisguy65 said:
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.
Click to expand...

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.
 
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Long Headstock

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
 
jackie schmidt said:
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.
Click to expand...

Jackie,

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

Thanks,
Justin
 
Zebra13 said:
Jackie,

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

Thanks,
Justin
Click to expand...

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.
 
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
 
jackie schmidt said:
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.
Click to expand...

Jackie,

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

Thank you.

nez
 
NezRongero said:
Jackie,

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

Thank you.

nez
Click to expand...

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.
 
jackie schmidt said:
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.
Click to expand...



Thank you!
 
jackie schmidt said:
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.
Click to expand...

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
 
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