question on rechambering

[racesnake]

My first try at rechambering. Barrel is in the lathe and old shank has been cut off. The problem I'm having is when I roll the barrel to a high spot my indicator will show it and then start drifting back with out me turning the barrel away from the high point. I've used a indicator rod and a range rod. Tried a different indicator and several bushings. Nothing seems to help. Has anyone else had this problem?

 

[jscandale]

Dave,

Since the tenon is already cut off, a good way to dial in that barrel is by using a last word gauge and indicating what is left on the chamber wall on one end and indicating the center of the bore on the other end with a rod.
It would be assuming that the existing chamber wall is properly in line with the center line of the bore, but you do what you have to do when necessary.

JS

 

[Erik Cortina]

Are you using a 4 jaw and spider? Are all the jaws snug against the barrel or are you leaving them loose?

 

[racesnake]

I'm using a 4jaw spyder on both ends. The indicator movement has something to do with eroded bore which is what I'm trying to eliminate.

 

[Cigarcop]

Get yourself a long stylist indicator that will reach up where the new throat will be and dial it in right there.

What your saying doesn't make sense, even if the bore is eroded it still has a high and low spot that won't move .

 

[racesnake]

I don't have an indicator with a long tip. You hit the nail on the head, pal -it doesn't make any sense! I took John Scandales advice and dialed the barrel in easily. I would still like to know what the hell is going on!

 

[hogpatrol]

Headstock bearings?

 

[racesnake]

No apparent play in the headstock bushings.

 

[Erik Cortina]

I don't have an indicator with a long tip. You hit the nail on the head, pal -it doesn't make any sense! I took John Scandales advice and dialed the barrel in easily. I would still like to know what the hell is going on!

The issue with JS advise, and he mentioned this, is that you do not know if the previous chamber was concentric. If it was off, the new chamber will end up the same way.

You will need a long reach indicator. It's ok, the Interapid is only about $300.00. Don't you love how much money we save chambering our own barrels?

 

[hogpatrol]

Have you tried two indicators, one on the OD of the barrel and one on the range rod to see if you get the same drift?

 

[racesnake]

No drift on barrel od - just on the rod.

 

[Erik Cortina]

No drift on barrel od - just on the rod.

There is your answer.......

+1

 

[racesnake]

Guess I'm a little slow. What's the answer?

 

[ridgeway]

Guess I'm a little slow. What's the answer?

Your rod is the culprit. You need to pick up a long reach indicator...

 

[DCRYDER]

With erosion it's tougher to pick the right bushing since the bore is larger toward the breech end due to wear. I just wonder if the bushing you picked is actually getting tight and not allowing the tapered rod to to solidly fit in the bore. I'd twist the rod and feel if it's making good contact. Our possibly carbon build up at the old throat gave you a false reading and the bushing is actually too small causing loose fit farther in the bore.?.?.? A good JB scrubbing may help.

 

[jscandale]

Dave,

When you use a range rod to indicate a fresh cut barrel, you can expect pretty uniform results, however, then you place the same rod in a throat that has a good deal of wear in it, you can expect to funny things to happen that are only explained in theory or even opinion.
My advice of using a last word gauge inserted as far up the existing portion of the chamber is a pretty good one, and the advice that others gave you of using an indicator with a long stylus is better provided that you don't go all the way to the throat. If you are able to get the tip of the stylus in the neck area, you'll be assured to get a pretty reliable reading.
I have some Starrett long reach indicator sets that I am selling for an old retired machinist buddy that would help in you project. If you would like, I can send you one.

JS

 

[racesnake]

John..I'm sure you're right. I think that the lands are worn at an, ever-so-slight, taper and one bushing was too tight and the next size up was too loose.
My " last word" indicator has a short stylus ( about 3/8") so was only able to reach to just short of the shoulder. I'll email you about the indicator.

 

[eww1350]

You can buy long stylus for just about any indicator..look on Ebay first...I purchased a used mixed set and had some for several different brand of indicators..my favorite indicator for reaching into the throat area is a Mitutoyo like in the link below you can ad a long stylus to it...which is a very good deal..

Eddie in Texas

http://www.ebay.com/itm/Mitutoyo-No-513-104-Dial-Test-Indicator-0001-1-Range-As-Photo-/221423608179?pt=LH_DefaultDomain_0&hash=item338de02173

http://www.ebay.com/itm/Mitutoyo-513-112-Dial-Indicator-/251508920911?pt=LH_DefaultDomain_0&hash=item3a8f19924f

 

[338 Mollett]

Dave if that barrel is still chucked I'll bring one of my indicators to see if it drifts also,be glad to help but after I set posts tomorrow.

 

[MDSpencer]

I can modifie your rod. Set it up to use two pilots. $12.00 plus shipping. This way you have two points of contact in the barrel.