Gritter's chambering video

Gordy it was a pleasure meeting you in person at the show. I wish I had more time to go over the technical points. One thing I have a difficult time with is the accuracy of the 12" (or longer) rod which has clearance in the pilot/bushing. I don't see how you can get proper readings with this inherent float/pivot.

Wouldn't a ground gage pin 12" long provide the best indicator for alignment?
 
Gordy. Don't know if you rembemer me, but we shot BR50 together when you ran the matches up there. I would be interested in the classes.
 
Hi, Kurt. I sure do remember you. I've often wondered if that was you when I'd see your name on a forum. We sure had fun back then, didn't we? Call me at my shop - 641-628-3044 - and we can set a date up for the class. (I only answer my phone from 2-5 pm, Central time, Monday to Friday, so call then if you can - or leave a message and I'll get back to you).

Joe, I sure enjoyed meeting you at the SHOT show also. It's always great to put a face to a name of someone I've only met on the phone or the internet.

I would think a close-fitting ground gauge rod 12" long would work great, but you'd have to have a great number of them to fit all the different size barrels in each bore size, which would be expensive. Bushings are inexpensive and work great!

Dialing it in initially with a range rod works extremely well for getting the bore running straight and true for purposes of cutting the shank and threads. But if you remember I drill out the hole for the chamber and then go in and get a direct reading off the lands ahead of the chamber with my long reach indicator to double check the range rod readings before I do the chamber. Sometimes I have to adjust it ever so slightly to bring it to as close to .0001" runout as I can get - it's almost always within a couple tenths or so - no problem at all for aligning and cutting the shank and threads.

Then I bore the drilled chamber hole so it's running true to the bore, and then ream the chamber, constantly checking for runout as I go. Done this way the chambers/throats always come out true and aligned to the bore like the ones I did at the SHOT show.

Thanks!
Gordy
 
Gordy

I watched your video and although I use different methods, I'd think I could be happy using yours, provided a 20" to 22" barrel could be done in my lathe using yours. I use a 16X40 Victor and have to utilize a dead center inside my spindle to catch the muzzle of the barrel.

My question: I use the Mitutoyo indicators and mine came with a .6"(approx) long indicator point. Your's seems to have a point that looks to be about 2" long. Doesn't that cause the resolution to be diluted? I chamber several point blank BR barrels per week and with the short cartridges, I don't need a longer point but if I did use a longer point, wouldn't .0001" runout on the dial mean that I actually had about .0003" in the barrel?

The specs on the big Grizzlys show normal runout at the spindle nose to be .0002". That's the same measured runout that my lathe has. And, sometimes I get chambers that show an honest .0001" so I know it's possible but, with the factory point on my Mitutoyo indicator, my .0002" capable machine usually produces .0002" work.

Shelley
 
WSnyder said:
Shelley

One thing I noticed while watching the video is that many times when Gordy is using the indicator with the long stylus he chokes up on the stylus point when running it against the rod. It looks to me like he turns that long stylus point into a short one (~the same length as the original short one) when dialing in with the rod. I assume he may do this because he then has the option of using a long stylus albeit a less accurate one when indicating up in the bore but more accurate on the rod without changing indicators.
Click to expand...

My guess is that he does this only in the rough dial in portion of the process and it is so that the straight side of stylus can ride on the radius of the indicator rod without the ball point trying to track around the radius of the rod as it wobbles in the large rough dial in movements.

He than switches to the ball point end of the stylus for fine adjustments on the rod or barrel groove when trying adjust to .001 or less movement where the ball point radius of the stylus has little or no affect when riding a radius contour, where little change movement is involved..............Don
 
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Indicator tips

Shelley, depending on the size of the hole in your lathe spindle, it's not hard to make up a sleeve that slips over the end of your barrel a ways and either tapers to fit like a Morse taper or set screws in place. This makes the barrel long enough to reach out to the end of your spindle allowing it to dial in easily like a longer barrel.

My Mitotoyu indicators come with a .7" tip, and I use a 1.5" replacement tip available from MSC. This essentially halves the readings, so to measure .0001" I can easily "read between the lines" when measuring with the long tip, or "choke-up" on it 1/2 way up the stem like WSnyder says to get true .0001" readings. Works very well.

Remember I use the range rod to reach in much farther than the long tip will reach to initially dial the bore in as straight as possible for threading the shank and fitting the action. Then I pre-drill the chamber, which allows me to run the indicator in to give a direct reading off the bore itself to "fine-tune" the range rod readings, getting the bore to run even more true than the range rod can before boring the pre-drilled hole true and cutting the chamber. This gives very accurate and repeatable results.

Gordy
 
Halves?

Gordy Halves? or doubles the read out? For example if it is reading .0001 now what will the indicator read with the longer probe?

Ralph
 
"Halves" - I guess it depends on how you look at it - sorry, Ill try to clarify this.

I mean the needle on the indicator dial will move 1/2 the amount with the long tip as it will with the short tip. So each .0001" graduation on the dial with a short tip is .0001", and each graduation on the dial with the long tip is about .0002". So to get a .0001" reading with the long tip, just go 1/2 way between each graduation if reading off the tip, or "choke-up" on the tip 1/2 way to give normal readings.

Hope this makes it more clear!

Gordy
 
Ok

Here's my range rod. 18" Drill rod is on order, but I'm trying brass first.

The length is 13" the tip is .220 the shaft is .235. Tapped 4-40.

Need to fit bushing and try tomorrow.
 

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I tried to get Shiraz's two helpers to shrink the mill and one of the lathes so it would fit in my RSR cart. Those darn guys would'nt do it unless I gave them a big pile of greenbacks........:D:D:D
 
rang rod

the same results can be had with dave kiff range rods.

if you measure the amount the rod goes into the barrel then place ( 2 )
dial indicators on the rod one up close to the barrel and the other one
the distance that the pilot end is in the barrel tweak the cat end
to get both running at zero. you are doing the same thing as you do
when you are setting up in a action truing jig only on a bigger scale.
yes you are only truing a smaller amount of barrel but then you can do
as gordy does and go in with dial indicator and check after you have
drilled the chamber.??

regards tasy_ted:rolleyes:
still can spell ( range rod )
 
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The longer probe should be more accurate ?

The longer probe will (in my humble opinion anyway) tend to magnify the reading, so this should be even better than a shorter probe.

Rob Carnell
Sydney, Australia
 
Rob Carnell said:
The longer probe will (in my humble opinion anyway) tend to magnify the reading, so this should be even better than a shorter probe.

Rob Carnell
Sydney, Australia
Click to expand...
Rob, if the probe were 2 inches long and the tip traveled 0.002", then 1 inch down that probe toward the pivot, that 1 inch spot would be traveling 0.001", so, the longer the probe, the less is indicated on the dial for a given amount of measurement.

If that indicator were designed for a 1 inch long probe, then a 2 inch long probe would only move the dial half the amount that a 1 inch long probe would for a given amount of tip travel.

Did I make this sound confusing or do I need more coffee?
 
JerrySharrett said:
Rob, if the probe were 2 inches long and the tip traveled 0.002", then 1 inch down that probe toward the pivot, that 1 inch spot would be traveling 0.001", so, the longer the probe, the less is indicated on the dial for a given amount of measurement.

If that indicator were designed for a 1 inch long probe, then a 2 inch long probe would only move the dial half the amount that a 1 inch long probe would for a given amount of tip travel.

Did I make this sound confusing or do I need more coffee?
Click to expand...

Clear to me Jerry,

What do you think about using a teeter totter? (I call them).

I have a Starrett one that is 2" on either side (4" total)

My test indicator has a short stylus. Or..Should I just buy a different indicator?

Ben
 
Bnhpr said:
Clear to me Jerry,

What do you think about using a teeter totter? (I call them).

I have a Starrett one that is 2" on either side (4" total)

My test indicator has a short stylus. Or..Should I just buy a different indicator?

Ben
Click to expand...
I think you are talking about the probe bar that comes with a standard Starrett? Like the thingy in the middle of this picture?
http://cgi.ebay.com/STARRETT-196-DI...ryZ25272QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

If you are, that entire package is not as precise as I would recommend for barrel bore alignment.

What dial indicator do you have now?
 
I have an interapid test indicator, Starrett test indicator and Starret dial indicator/mag base.

The probe bar is the same as you show, but longer, I believe. (I'll get a pic) It's quite old but in good shape. I was just wondering if I could use it, with my interapid test indicator.

My thoughts were that the spring in the test indicator would keep the slop behind you in the probe bar.
 
contact info

Can someone here send me an e-mail with Gordy Gritters contact info.

Thanks
 
Contact info

Rolandr, My contact info is as follows:

e-mail: gordy@wildbluepella.org

Phone: 641-628-3044 (I'm normally in my shop all day, but I'm very busy so I only answer the phone in the afternoons from 2-5 pm Central time, Mon-Fri)

Address: Gordy's Gunsmith Shop, 1648 Cordova Ave, Pella IA 50219
 
Ben...

You can buy a longer stylus for the Interapid test indicator from MSC - no need to purchase another indicator. I bought a 2.75" stylus for my 312b-3 and a 2" stylus for a B&S bestest .0001" indicator (actually, the 2" B&S stylus was one of the two free contacts that they're giving when you purchase a bestest indicator from Enco). I've also got one of the Mitutoyo test indicators with the round body like Gordy uses in the DVD, but haven't purchased a longer contact point for it yet. Guess I should get cracking on that little detail, as it would fit into the rough-drilled chamber and allow me to check for bore runout before boring the drilled hole true.
 
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