Pre-Drill & Boring A Chamber

It's really quite amazing how easy it is for a barrel to actually bend. A dial indicator, a well suppored breach end of a blank, a little finger pressure applied on the opposite end and watch the indicator showing you just how easy it is to bend.
 
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alinwa said:
This I can totally get with.

And many setups I've seen and spoken with folks about they absolutely ARE bending barrels.... I'm simply stating baldly that I'm not. I've redone my methodology 10 times, I'm a ways away from "copying Gordie's method" but I give full credit to him both for coming up with a real way to indicate deep, and for thinking of the usage he's put it to.

It has been and will always be "Gordie's Method" to me.

My results have been startling... enough so that right now if I couldn't do my own work I'd feel seriously handicapped. And I have some seriously good stuff against which to compare.
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Enough. Where is the video? I am ready to learn. Please don't say, "adjust the outboard screw just a little bit" ........
 
Louis.J said:
It's really quite amazing how easy is for a barrel to actually bend. A dial indicator, a well suppored breach end of a blank, a little finger pressure applied on the opposite end and watch the indicator showing you just how easy it to bend.
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This is exactly I describe all steel as "rubber" and all fitments and pressure points as "changing the loading"

Something as simple as sucking the screws down onto AL pillars on a typical "bedding job" isn't so very-very simple to my way of thinking

And folks assuming that because a highly accurate 6PPC setup will shoot really good with less than a hunnerd thou abutment on the barrel shank, a 300WSM should do the same.

And I see some of the hideous setups folks use to clamp receiver rings for removing barrels and all's I can think of is "Chinese Finger Traps much??"

yup

steel=rubber


me
 
Chambering the Gordy method or at the throat and muzzle.

Here is how I see it. I know I am not even close to being a machinist. I see it like a teeter-totter if one indicates at the pivot (the throat of the chamber) TDC then at the muzzle end TDC and knows that the very breech end has runout. They say first drill out then boring corrects the lineament of the chamber. But like a teeter-totter if there is runout on one end (throat to breech for a couple inches) then there has to be run out forward of the pivot (throat) for the same amount as the breech had. Now if you use the Gordy method, indicate throat TDC then at the very breech end TDC you straighten out (chamber throat) of the teeter-totter and then bore in front of the pivot point is also straighten out but the muzzle end now has the run out and for myself I have never seen it to be a problem on target or sighting the barrel in. I know I am stepping in a puddle.

Chet
 
coyotechet said:
Here is how I see it. I know I am not even close to being a machinist. I see it like a teeter-totter if one indicates at the pivot (the throat of the chamber) TDC then at the muzzle end TDC and knows that the very breech end has runout. They say first drill out then boring corrects the lineament of the chamber. But like a teeter-totter if there is runout on one end (throat to breech for a couple inches) then there has to be run out forward of the pivot (throat) for the same amount as the breech had. Now if you use the Gordy method, indicate throat TDC then at the very breech end TDC you straighten out (chamber throat) of the teeter-totter and then bore in front of the pivot point is also straighten out but the muzzle end now has the run out and for myself I have never seen it to be a problem on target or sighting the barrel in. I know I am stepping in a puddle.

Chet
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OK.... maybe we agree here?

Even if "Gordie's Method" of teetering the totter is NOT USED. Even if a guy thinks it's silly to flop the muzzle around..... Can you tell me of a better, or even a good way to locate that pivot point on, say a 30-06? Or, for those of us who sometimes shoot beyond 300yds..... how would you recommend dialing in the throat on a big .338?

(This is the point where most guys go "h'rump, this is why magnums are stupid")

I submit that properly used, Gordies extension method is freakin' brillion't...... And it allows a mere mortal like me'self, with cheap equipment to make deer rifles that shoot like STINK!
 
alinwa said:
I'd guess you're right.... I'll go over and measure one here when I get off the mill
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So I measured some, only found 5 but..... evidently there's different rules for hammered barrels as they all measured substantially over 1.250 with prox 1.254 being common, one at 1.258
 
Can you tell me of a better, or even a good way to locate that pivot point on, say a 30-06? Or, for those of us who sometimes shoot beyond 300yds..... how would you recommend dialing in the throat on a big .338?

I use a grizzly rod and then check the runout if any with a Mitutoyo 513-512 with a long probe which allows me to take a reading up to 4" into the bore after drilling. I have checked the runout of the Long Probe Mitutoyo against a .0001 Brown&Sharp indicator and always get a runout reading of .0005 or less which I call good.:):)

Chet

Mitutoyo 513-512 (5).JPG
 
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What might the actual reading be in tenths or thousands when reaching in there four inches. Compared to a standard tenths indicator or am I missing something.
 
. I have checked the runout of the Long Probe Mitutoyo against a .0001 Brown & Sharp indicator and always get a runout reading of .0005 or less which I call good.
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That is what I have already done, I chucked up a Deltronic pin and then with long probe Mitutoyo zeroed it to where the dial (pointer) does not any longer move then check the Deltronic pin that I just zeroed with my .0001 Brown & Sharp indicator and the runout on the Brown and sharp is always .0005 or less so I just call that good enough. P.S Have used other .0001 to do the checking of the pin also. Something like the picture below.
Chet


Indicator Accuracy test (1).jpg
 
coyotechet said:
That is what I have already done, I chucked up a Deltronic pin and then with long probe Mitutoyo zeroed it to where the dial (pointer) does not any longer move then check the Deltronic pin that I just zeroed with my .0001 Brown & Sharp indicator and the runout on the Brown and sharp is always .0005 or less so I just call that good enough. P.S Have used other .0001 to do the checking of the pin also. Something like the picture below.
Chet


View attachment 23260
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Is that your picture? That’s got the making of a meme! Can I steal it, if it’s yours?
 
Build a chuck that will hold the barrel by itself without NEEDING a spider. Dial it in with nothing touching the muzzle end, THEN snug the spider up only for support. If the barrel moves when you loosen up the spider, well, you were bending it.
 
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It looks like Chet needs to invest in some better quality indicators.:rolleyes:;):cool:

Nice collection there Chet.

Joe Hynes
 
QUOTE=Rubicon Prec.=indicator Test.jpeg=QUOTE
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Some so called gunsmiths only have one indicator. And think they indicated in GOOD gun work. Take my word not all indicators READ any where near true. I have tested many high dollar Top Brand name indicators and sent them back to the supplier for exchange. I Tested them because I want to do good GUNSMITH work. :):)
With out GOOD ACCURATE indicators it is hard to do GOOD GUNSMITH WORK.:confused:

Chet.

P1010111 (2) (12).JPG
 
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coyotechet said:
Some so called gunsmiths only have one indicator. And think they indicated in GOOD gun work. Take my word not all indicators READ any where near true. I have tested many high dollar Top Brand name indicators and sent them back to the supplier for exchange. I Tested them because I want to do good GUNSMITH work. :):)
With out GOOD ACCURATE indicators it is hard to do GOOD GUNSMITH WORK.:confused:

Chet.

View attachment 23265
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There's a lot of good info on indicators here: http://www.longislandindicator.com/. I was surprised to find out that they don't think too highly of (newer) Mitutoyo or B&S. Their top pick is BestTest/Tesa/Interapid (all the same parent company). Also the place to buy extended tips for anyone who's been reading along and wondering about that.

GsT
 
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