Interapid test indicator

f21sh said:
What type and size of boring bar does one use to bore the hole prior to chambering. This is the first time after viewing Gordy's method for chambering that I have heard of boring to clean up after pre-drilling the chamber, is this step truly necessary in creating a excellent chamber? :) Thanks Bill
Click to expand...

I'm cutting the counterbore in the photo, but the same one is used after drilling.

On advice i got here, I indicated some typical case tapers and made a tiny scribe on my compound angle scale.

All case tapers I've checked so far are quite close to each other.
 

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Setting Taper

Long ago, I set my compound up and indicated it to a straight bar to read the exact taper in 1 inch that a PPC and BR Case have. I etched a mark on the degree section, and I just place it there every time. Remember when you do this to allow the indicator to read 1/2 the actual taper. For instance, if the taper is .010 in one inch, set the compound to read .005 difference in a one inch length.

As far as the actual degrees, the compound is set just about 1/2 degree off of straight in to get this.

As far as it being required to bore after pre-drilling and then indicating the throat, I say if you want every criticle surface to run within .0003 after the final operation, yes, you do.

Does everything have to be that close?? Probably not. But this is Benchrest. If we have controle over an operation that will remove a variable, then do it...........jackie
 
jackie schmidt said:
Long ago, I set my compound up and indicated it to a straight bar to read the exact taper in 1 inch that a PPC and BR Case have. I etched a mark on the degree section, and I just place it there every time. Remember when you do this to allow the indicator to read 1/2 the actual taper. For instance, if the taper is .010 in one inch, set the compound to read .005 difference in a one inch length.

As far as the actual degrees, the compound is set just about 1/2 degree off of straight in to get this.

As far as it being required to bore after pre-drilling and then indicating the throat, I say if you want every criticle surface to run within .0003 after the final operation, yes, you do.

Does everything have to be that close?? Probably not. But this is Benchrest. If we have controle over an operation that will remove a variable, then do it...........jackie
Click to expand...

Jackie,

How many boring passes does it usually take you to get this runout.

I've been using 3 light cuts, and still seeing some runout through tool flex.
 
Vertical Interapid 312b-15V has .0005" graduations.

At an auction I got an Interapid test indicator with .0001" graduations.
It is too sensitive for dialing in a bore with the 4 jaw.

I prefer to dial in bores with .001" or .0005" graduations.
 
Clark said:
Vertical Interapid 312b-15V has .0005" graduations.

At an auction I got an Interapid test indicator with .0001" graduations.
It is too sensitive for dialing in a bore with the 4 jaw.

I prefer to dial in bores with .001" or .0005" graduations.
Click to expand...
Whatever you are indicating, you need to be real close before switching to a 0.0001" resolution indicator. Most 0.0001" indicators only have about 1/64" travel anyway.
 
indicator

Jerry I was able to pick both indicators mitutoyo and the interapid. Same reasoning get it close then get real close.:D thanks
 
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