Interapid test indicator

F

f21sh

Guest
Helloo all
I am about to purchase the Vertical Interapid 312b-15V ( jig-bore) is this correct for indicating the grove and lands. Newbie just doesn't want to make a incorrect purchase on this magnitude.:eek:
Thanks for the info Bill
 
Take another look ?

I'm a raw beginner an hope some of the more experienced guys will speak to you on this before you commit your money.

I think most of these guys are using the "horizontal" version of this indicator.

Maybe remove the "V" from the part number ?

A. Weldy
 
What is wrong with the Mitutoyo 513-504t .0001 indicator? The long reach stems sure bounce a lot when they jump from land to groove. I have the long reach Interapid also, but seldom use it.
Butch
 
interapid

Hello Butch I have an opportunity to pick up a interapid 312b-15V vertical for a reasonable price. However I don't know if there is a preference as to a horizontal or a vertical indicator? :D Bill
 
Hello Butch,

The decision of choosing between one of the two indicators definitely requires the purchasers perusal. On J. Sharretts suggestion, I studied the Long Island Indicator Site. Following that, I called them.

I was thinking Mitutoyo might be the pick, especially with the difference in cost.

The fellow told me that for awhile, Mitutoyo had discontinued replacement parts for them. However, they were currently restarted on replacement parts. Bad sign, back to good sign, you might say.

The fellow went on to say, that because Mitutoyo used certain plastic parts, that have been known to cause problems, especially if handled roughly or banged, would fail. He also told me, that the Interapid was, by far, the better choice.

He is in the business, not me. They also do repair work.

I am looking for the longest indicator needed, for chambering field guns, perhaps F Class soon. Problem with Interapid is it is a 0.0005" indicator, and the 5.5" probe turns it into a 0.001" indicator. Long stylus not available on the 0.0001" indicator.

So, my general consensus is, for durability and servicability, the Interapid is the choice.

I know that you and others will have differing opinions, due to experience.

Perhaps you could ease my concerns over purchasing the Mitutoyo.

Thank you,
longshooter
 
Longshooter,
What cartridge are you going to use? A Mitutoyo will reach 2" with a .625 probe. You need to try one with a long probe before you get one and watch what it does when it goes from groove to lands. Probably the longest Fclass cartridge normally used is a 6.5x284 and 2.5" will get you to the throat. Whatever indicator that you get make sure you get the shortest probe that will do the job.
The more people talk about chambering, the more anal people get. How much curve do you think you would have in a so called bad barrel beyond what you could measure .500 short of the throat? We talk about tenths, our equip. and abilities are not capable of doing it.
I'm not saying that you don't need to strive for perfection, but shooting and reading the wind is more important than being off .0005.
Butch
 
What cartridge are you going to use?
Click to expand...

For f class, I am not decided. Currently, 300 win mag in the field. And would like to reach the full length belted if necessary.

I agree with you on the degree of perfection needed (attainable).

And I don't know if older Mitutoyos are better quality than latest production, or not.

longshooter
 
I put a longer stem on an Interapid .0001" indicator. I realize it is no longer .0001" per graduation however it works great and is absolutely repeatable. We are not using them to measure just alignment. I can reach to the end of a 300 Weatherby Magnum chamber with mine. I also have a Mitutoyo like Butch uses but it's not long enough for the long chambers so I prefer the Interapid.
You don't want a vertical model for barrel alignment.
 
Indicators

Keep in mind, most of the chambers we deal with are for extreme accuracy use, I haven't chambered anything longer than a 6.5 x 55 Ackley in quite a while.

And also keep in mind, when we indicate that bore after pre-drilling, you must rough bore the chamber after indicating that throat.

The little Mitutoyo 513 will reach the throat of the 6.5 x 55, which is a tad longer than a standard 308 length.

I have a Interrapid with the long carbide stylus. It actually belongs to the Shop. But I just use the little Mitutoyo, it's handy, is dead on accurate, and does handle the jump between the lands and grooves with no difficulty.

Between skilled machinist and craftsman, much of this comes down to personal taste, and what works best with the equipment on hand. Always remember, the only thing that counts in the end is the finished job, and how well it comes out. And of course, how small the agg is........jackie
 
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I'm now using both the interapid with long stylus and the Mitutoyo Butch has recommended to me.

I just finished a 6,5x284 for a friend in South Texas. I played a while with both indicators in the throat, and pre-bored most of the case length, and had no problem reaching the throat.

Basically, at this point, it's 6 to 1, half dozen..I will say the Mitutoyo is less "sloppy" when it goes over the lands.

But I believe a superb chamber can be indicated with either.

See pics of the new rifle..
 

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Here's where if you just buy a GOOD .0001" indicator and indicate in the muzzle and chamber end, drill your chamber out, and get that gritter's type indicator rod out and indicate in the throat with a fitted bushing and a long indicator rod you'll be golden. Then bore to clean-up and chamber the barrel. I did just that last week on a 6.5X47 for myself and it didn't require any special long-stem indicator and worked like a charm. I have an intrepid 312 model 1 1/2" face horizontal .0005" indicator, and I can easily tell when I'm less than .0002", which is good enough.

I've been chambering some large calibers like 300 RUM and whatnot, and that gritter's rod with fitted bushings is a godsend and just makes sense.

Like Butch says, I'd imagine those Loooong stem indicators have a bit of sideplay and jump you won't need to contend with on the standard stem models.

I don't have near the experience as many that already posted but that's my take.
 
Boring bar

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
 
I just ground my boring tool from a piece of HSS, but I think one of the small diameter boring bars with the carbide tooling would work really well, or Micro100 makes a variety of boring tools of solid carbide.

I think the general concensus with boring is that after you drill out the majority of the chamber with a drill bit then recenter the throat (by whatever method), the hole you drilled will not be concentric to the axis of rotation anymore so a quick cleanup with the boring tool trues up the hole. The reamer will start out on the correct path since they tend to follow the hole made for them.
 
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...
Bill, there are off-the -shelf boring bars or you can grind one yourself. This one is ground from 1/4 x 1/4 HSSCo. Not a good photo but all I have at the moment.


2ibly5z.jpg
 
msalm

Yes, that is exactly why you single point bore the drilled hole after you indicate the throat.

I actually set my lathes compound to bore the hole to the correct taper as the reamer, that way the reamer goes in darned near 1/2 way before it cuts. I use the reamer for nothing but putting the final dimensions and finish in the chamber. 98 percent of the metal removal is accomplished with the drill and the boring.........jackie
 
Jackie,
I'd imagine it takes quite a few chambers to wear out one chamber reamer using your method heh??:) Also Jackie, what method do you use to set the compound to the same angle as the body of the chamber? Is it just a rough adjustment or do you get it within a gnat's hinder? What diameter to you bore to on the end? I've just bored the hole straight, and take it to .020 or so under the shoulder dimension 'just to be sure I don't screw it up'.

I've personally played around with 3 or 4 different methods in the last two years and have settled on the drill and pre-bore. I LOVE how quickly the reaming goes up until the reamer starts cutting the shoulder. Pulling out the reamer every .100 for the first half then .050 and smaller for the final 3-5 passes to clean chips and chambers draws it out considerably. Drilling and pre-boring doesn't allow me to get complacent or bored and cuts the actual chamber reaming to less than 1/2 the time I spent previously. AND it produces a darned fine chamber.
 
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If you want the angle perfect, mount your reamer in the tailstock and then mount your indicator on your compound. Keep moving your compound over until the indicator doesn't move as it indicates the reamer.
Butch
 
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