Home Forums Hunting & Shooting Long Range Hunting 50 millionths man

I had questions on a post in one of the sniper's forums and got comments from another forum. What are your thoughts.
http://benchrest.com/showthread.php?74550-Another-50Millionths-Man
Read all of the posts.


Butch

Interesting read. Answers where about what I figured.

Hell Fulton Armory still sells guns to the unknowing too...

I am guessing he must charge a lot for his rifles as the tools required to read the tolerances and surface finishes are not cheap. Also neither are machine tools that hold those tolerances.

By the way for a good lapping machine 50 millionths is a easy to obtain tolerance yet this person is down on lapping.

ENorton

And if bullschitt were music they'd have a brass band..

to hold .00005 = Bullshit

1 degree of temperature = .000006 per inch

We fight temperature in my shop constantly (No A/C) trying to hold 2 tenths .0002

The thing that made me go hmmmmm was the Beverly Hills CA address.

I have seen and put my hands on parts that were lapped to a tolerence of 70 millionths.

A gentleman that I knew long ago was an engineer at Catepillar that designed the mechanical fuel injectors for Cat's diesel engines. It was a barrel and piston assembly that relied solely on the precision fit of the components to act as a seal.

The barrel and piston were lapped to almost a mirror finish. The coolest thing about it was if you seperated the piston from the barrel it was a struggle to reinsert the piston. You could fiddle with it for minutes trying to get it perfectly aligned. Once you aligned it would slip in with ABSOLUTELY no play - even with piston only minimally inserted.

This was all accomplished with ultra high dollar state of the art machining and lapping processes at Catepillar.

I wonder if there are any machinists who rough out the chambers with a boring bar on a CNC lathe and then EDM to finish the chamber? I think that would give good results.
It would be interesting to see this guy check concentricity
because the tolerances on the rifled bore aren't nearly that close.

We talked about this topic during our first break Friday morning.

Many laughs, a couple bullshits, and one "who cares what they say they can do" from the toolmakers at Revere Plastic.

You can hold a 2" part in your hand for a couple minutes and change it's size up to .0004

He does.

I have and operate three Waidia Jigbore and Jiggrinding machines at our shop. They are in their own room with climate control. We keep it at 70 degrees +/- 1 degree at all times. So I know alittle bit about holding close tolerances.
I think they are full of [bleep] even talking about holding 50 millionths tolerances. Holding true position of a hole to .0005" and diameter to .00001" ,your doing something. Let alone .00005". I was working on a part one time that was 36" dia with a .500" wall thickness. I was having trouble holding true position of a series of hole on the face of this dang part. A engineer from the company that we were make the part for happened to be there watching the part being machined. He said the reason we were having trouble holding the tolerance was because the work light on the machine was heating the part enough to throw the tolerance out once the part was taken off the machine. Oh and by the way I wasn't trying to hold .00005" tolerance.

I worked in a place once where the parts had to sit in an air conditioned room for eight hours prior to machining.
Then they had to sit for another hours after machining before they could be checked. There were two machinists ready to fight over who was making the parts with the oversize bores. Luckily they were working 12 hour shifts so there were only two people involved. My manager wanted me to check the part and I could hardly get the air gauge in the bore it was such a tight fit.
I think the total tolerance was 20 microns or something like that. They went out of business eventually. Good times!

Butch,

We routinely hold everything to an absolute zero. We decided to go this route so no one could ever make a better rifle.

Half a tenth is for pikers.

First liar never stands a chance!!!

John,
You are a piece of work!
Butch

John,

Now that's funny!

But why don't all the bullets from your rifles go in the same hole at a mile?

'Splains it all now!

The one up game is always fun. You killed a 6 pt bull I killed a 7. You caught a dozen steelhead I caught 13. Your rifle shoots quarters mine shoots in the tens. It's all good...

I just loved John's response. I hope no one took it differently.
Butch

..anyone can work to a tenth of a thou.......the hard part is hitting the right tenth...:-)

As a being a grinder/machinest for 25 years,it's been my experence that most people in the trade who like to "say" they work in the world of the micron have little to NO experence actually cutting metal...

Usually it's engineers and paper shuffler's who are the culpruts..

Where I work we grind and hand lap bores and diameters to +/- 1 micron match fit clearences..

The amount of hoops we have to jump through to acually accomplish this is mind blowing!

If this is the ONLY tolerence you work with,"absolute zero"..
The costs of doing so will eventually eat your lunch!

That's is what our challenge is where I work..Everything is so ridiculously tolerenced that once we are ready to take something to production,venders that we solicite to have work quoted usually take one look at the prints and refuse to quote...

This is the only work we do here and I feel as a result we are never a "stable" place to work and are always on the brink of closing the doors...

The bottom line is, talk is cheap and actually doing it is another thing all together! IMO