Indicating off an indicator rod

Grizzlypeg · Oct 10, 2012

Watching a video on youtube from a guy named Viper giving a tutorial on chambering a barrel for a Rem 700.

http://www.youtube.com/watch?v=ErVOUVszFjY&feature=share&list=ULErVOUVszFjY

I see he has two dial indicators at different positions on the indicator rod. Is there a reason for doing that? If the rod is straight, what difference would it make indicating it at two different locations along the rod?

Cole2534 · Oct 10, 2012

You'd know if the rod was truly parallel to the line drawn between the two indicators.

Grizzlypeg · Oct 10, 2012

Cole2534 said:
You'd know if the rod was truly parallel to the line drawn between the two indicators.

Can't say I understand that. If the shaft is straight and rotates along its axis, it should indicate the same off any point, or so I reason.

Murf · Oct 10, 2012

To verify the bore is running dead true to lathe axis. Your indicator values would almost definitely differ from end of muzzle to say 4" beyond muzzle taking readings on your indicator rod. You have to remember they are probably tenths indicators not thousandths.

keydiverfla · Oct 10, 2012

I can see that this is going to get heated.......Chucker, where are you?

speerchucker30x3 · Oct 10, 2012

keydiverfla said:
I can see that this is going to get heated.......Chucker, where are you?

I like the You Tube one of the guy crawling the walls and all over his bench trying to get the barrel off better. But this one is OK too. I give it a 9.8 !

Cole2534 · Oct 10, 2012

Grizzlypeg said:
Can't say I understand that. If the shaft is straight and rotates along its axis, it should indicate the same off any point, or so I reason.

Yes, it should. However, I can't watch the video so I'm imagining things from a geometric perspective.

Anyhow, a worker-monitor setup is always nice for verification.

speerchucker30x3 · Oct 10, 2012

Cole2534 said:
Yes, it should. However, I can't watch the video so I'm imagining things from a geometric perspective.

Anyhow, a worker-monitor setup is always nice for verification.

Very simple. Put a perfectly straight pin into the barrel, run a couple .00001 mikes three inches apart on the rod, dial it in bang on and its bang on. No problem.

abarnsley · Oct 10, 2012

When dealing with 10ths, and JUST using a slender bore riding pin.... There is droop/sag,and indicator induced deflection on the pin.

Add in the lobed support the rifling gives a simple bore riding pin...

Considering that the OTHER end of the bore, most likely is nowhere near perfectly inline with the muzzle.....

I like to average between them.. The bullet does...

Cole2534 · Oct 10, 2012

speerchucker30x3 said:
Very simple. Put a perfectly straight pin into the barrel, run a couple .00001 mikes three inches apart on the rod, dial it in bang on and its bang on. No problem.

Ya, duh...at least in geometric land it will be.

speerchucker30x3 · Oct 11, 2012

Wweellll, I'm not a proponent of that setup mostly because its slow. But I have worked in shops with small lathes and I had to chamber like that for four or five years. It works OK but you need to use a floating reamer holder and take very light slow cuts or you can get some odd looking chambers. I prefer working between centers so there is no guess work. Its hard to dial in something 28 inches long over just 3 inches and I can crank the oil up to 40 or 50 PSI so I can get some flow through the barrel and take hard, 1/2 inch cuts if I work on centers. Taking .025 thousandths cuts would take a day and a half on a 300 ultra mag. LOL

ADD NOTE: I notice a lot of guys have to buy and use those reamer stops so they can tell how deep they are going. The 2 or 3 dozen lathes I have owned and worked on all had tailstocks that were graduated in thousandths of an inch and I lock down the apron as a stop for the tailstock so that the tailstock returns to the exact spot every time when I move it back and forth and I remember what number I stopped at on the dial or write it down if I have to go to the phone. Pretty technical stuff. I didn't understand the feeler gauges he was using either. Well yeah I did. He did have a GO gauge and a depth mic. I guess they are there for the camera. Oh well, the guys on Sons of Guns don't have a depth mic so I guess its not needed.

Bob Pastor II · Oct 11, 2012

Chambering

Speerchucker,

Thank You for the 9.8!!!

I only chamber about 50 barrels a year for top competitive shooters, so time is not an issue for me.
My method is a bit slower but being old and feeble it suits my time frame well.

Bob Pastor

Grizzlypeg · Oct 12, 2012

Thanks for taking the time to post up quality videos like that for no personal gain whatsoever.

polish avenger · Oct 14, 2012

the guys on Sons of Guns don't have a depth mic so I guess its not needed.[/QUOTE]

Should be Sons of turd polishers......lmbo

jglenn · Oct 15, 2012

Bob

really like your Viper oil

http://www.viperbench-rest.com/F Class Feet2.htm

Cole2534 · Oct 15, 2012

Well, it's cheaper than Moly-Dee

Jeff Walker · Oct 16, 2012

Bob,
Good to see you back.

Watch out for the baboon in the bean field !!!!!

------Jeff

rws · Oct 17, 2012

A couple of thoughts regarding aligning a barrel with a long indicating rod, taking the muzzle end out of running true.

I've done it, but I wouldn't do it unless the barrel is then threaded and "clocked" so it is pointed up. You can, in reality, create quite a point-of-impact difference in doing this. Don't just do it because, do it for a reason.

Chambering short range benchrest barrels by indicating both ends true, one barrel will print within a couple inches of another barrel, sometimes quite close. What I've seen in the past 10 years or so, deep hole drilling has gotten much better with barrel makers. Most barrels now days run quite true, where before you could almost get sea-sick looking down the barrel while it was turning.

An indicator rod, regardless of how long or short, will get you close. Nothing beats indicating off of the actual interior of the barrel, watching both grooves AND lands. Rods only show you the lands.

Bob Pastor II · Oct 17, 2012

Jeff Walker said:
Bob,
Good to see you back.

Watch out for the baboon in the bean field !!!!!

------Jeff

Hey Jeff,

It's Iowa's Big Foot but you and I have pictures!

Kiwi 'smith Dean · Oct 20, 2012

rws said:
A couple of thoughts regarding aligning a barrel with a long indicating rod, taking the muzzle end out of running true.

I've done it, but I wouldn't do it unless the barrel is then threaded and "clocked" so it is pointed up. You can, in reality, create quite a point-of-impact difference in doing this. Don't just do it because, do it for a reason.

Chambering short range benchrest barrels by indicating both ends true, one barrel will print within a couple inches of another barrel, sometimes quite close. What I've seen in the past 10 years or so, deep hole drilling has gotten much better with barrel makers. Most barrels now days run quite true, where before you could almost get sea-sick looking down the barrel while it was turning.

An indicator rod, regardless of how long or short, will get you close. Nothing beats indicating off of the actual interior of the barrel, watching both grooves AND lands. Rods only show you the lands.

Yep. But bear in mind that the pilot on the chamber reamer will follow the lands as well, unless you decide to chamber without the pilot or deliberately fit an under-sized pilot just in case there is a discrepancy between the readings off the grooves and lands.
Don't be fooled, plenty of barrels still turning up with bowed bores, even from some of the big names makers with VERY long delivery times as well.......

D.

Indicating off an indicator rod

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