Lost post -- please help me find

[Dirtlaw]

I'm looking for a tool that was recently advertised on the board. It has a rotary dial with holes for measurements from the bullet ogive. The tool was sold before I could buy it, but can someone identify the manufacturer and the name by which it is known? I want to scavenge the rotary part for a measurement device which I hope to build. I've searched buy I can't find the post.

[divingin]

I think you need to talk to Frank Guffey. He keeps all the datums.

Ogive measurements are made using a hole about the size of the land diameter of the bore. They are not exact, but are made so you can compare one projectile to another. If you know the caliber(s) you're trying to measure, you should be able to come up with the diameter hole(s) you need to get your measurement.

[five.five-six]

I think you need to talk to Frank Guffey. He keeps all the datums.

Ogive measurements are made using a hole about the size of the land diameter of the bore. They are not exact, but are made so you can compare one projectile to another. If you know the caliber(s) you're trying to measure, you should be able to come up with the diameter hole(s) you need to get your measurement.

[Dirtlaw]

Actually I was looking for the measuring tool because the holes were already drilled on a piece that would work for what I'm thinking about. The older you get the more you look for shortcuts!

[ptmn]

Are you looking for a bullet comparator?

https://www.hornady.com/reloading/precision-measuring/precision-tools-and-gauges/lock-n-load-bullet-comparator#!/

[mtenenhaus]

this one perhaps? this is what i use and am very pleased with it

https://www.forsterproducts.com/product-category/inspection-measurement/datum-dial/

[Dirtlaw]

Have a Hornady, but this was a bit different. I'm kicking myself for not printing out the post, but the tool sold quickly and I was in the midst of other things.

[Dirtlaw]

this one perhaps? this is what i use and am very pleased with it

https://www.forsterproducts.com/prod...nt/datum-dial/

Thanks!!! You found it! I thought it was Forester and I looked on their site but couldn't find it.


Thanks again!!!

[ar15barrels]

The sinclair hex comparator is easier to use with calipers.

https://www.sinclairintl.com/reloading-equipment/measuring-tools/bullet-comparators/sinclair-hex-style-bullet-comparators-prod83792.aspx

The the forester would be easier to use on a surface plate with a drop indicator.

[smoothy8500]

The older you get the more you look for shortcuts!

And obviously the more money you have to spend on the shortcuts...$175 kit?

[Dirtlaw]

And obviously the more money you have to spend on the shortcuts...$175 kit?

Seriously, God has blessed me beyond my wildest dreams. After a lifetime of trials, training and wearing the dunce cap in the school of faith.

[fguffey]

I think you need to talk to Frank Guffey. He keeps all the datums.

Ogive measurements are made using a hole about the size of the land diameter of the bore. They are not exact, but are made so you can compare one projectile to another. If you know the caliber(s) you're trying to measure, you should be able to come up with the diameter hole(s) you need to get your measurement.

Divingin, thank you for the kind words.

I understand I do not have the luxury of disagreeing; I do not find is necessary to purchase tools that have holes in them that are drilled by someone else; but if I did the holes would not be drilled they way they drill them.

If we were talking about a 30/06 barrel we would be talking about two diameters, one would be .300" and the other would be .308". That changes when the hot high pressure metal cutting gas starts to eat away at the rifling.

F. Guffey

[Dirtlaw]

Divingin, thank you for the kind words.

I understand I do not have the luxury of disagreeing; I do not find is necessary to purchase tools that have holes in them that are drilled by someone else; but if I did the holes would not be drilled they way they drill them.

If we were talking about a 30/06 barrel we would be talking about two diameters, one would be .300" and the other would be .308". That changes when the hot high pressure metal cutting gas starts to eat away at the rifling.

F. Guffey

Mr. Guffey, I've heard much about you. You are a legend on a couple of boards. I'm curious when you say you would drill the holes differently. In what way is that? Would you use anything special as a drill? I more interested in learning from people like you than whether a particular idea is accepted by others. Sometimes the best thinking is found in the view held by the minority.



Thanks in advance,


B.W.

[divingin]

Divingin, thank you for the kind words.

I understand I do not have the luxury of disagreeing; I do not find is necessary to purchase tools that have holes in them that are drilled by someone else; but if I did the holes would not be drilled they way they drill them.

If we were talking about a 30/06 barrel we would be talking about two diameters, one would be .300" and the other would be .308". That changes when the hot high pressure metal cutting gas starts to eat away at the rifling.

F. Guffey

You're welcome. You're free to disagree, as is everyone on this forum. I just wish you'd be clear on why you disagree rather tangentially mentioning some anecdote completely unrelated to the discussion.

We weren't talking about barrels. So yeah; like that.

[ar15barrels]

I'm curious when you say you would drill the holes differently.
In what way is that?
Would you use anything special as a drill?
I more interested in learning from people like you than whether a particular idea is accepted by others.
Sometimes the best thinking is found in the view held by the minority.

The most accurate holes are drilled, then reamed, then honed.
This is of course talking about cylindrical holes.

A datum is usually a combination of diameter and length and it's location on an angled surface.
The problem with making a datum with a cylindrical hole and a sharp corner is that the corner is subject to wear and the wear would cause inaccuracy.
A far more accurate datum would be made with an angled surface which would match the angled surface being checked.

With some simple math, ball bearings can also be used as a contact to verify a datum instead of measuring to a flat face.
A ball bearing is not subject to wear like a sharp cornered datum is.