chambering without reamer!

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peterdobson

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We just spoke with Danny Busse of Blue Chip Precision who advised that he can chamber barrels without reamers by using CNC equipment. Has anyone heard of this and how it works? He was in the experimental aircraft industry and is doing manufacturing of various firearm products.
 
One of my gunsmithing manuals describes how to bore a chamber, rather than ream it. This on a manual lathe, not CNC. Using CNC would facilitate the process. Obviously requires exceptionally precise control.
 
Reamers are expensive. A boring bar is cheap by comparison.
Length to diameter ratio really becomes the only issue.
In a perfect world, one would rough the form with a boring bar, then finish with a reamer. This will make your expensive reamers last much longer between regrinds.
You have much more finite control over what a single point tool does vs a reamer as well.
 
If the chamber is cut with the same precision as what the reamer is cut using CNC machinery, why would you want to add the expense of cutting a reamer and then using it to reamer a chamber?
 
I also read about doing this years ago, must be the same book/manual. Very impressive and would save a good chunk of cash on reamers. And yes, in the book I read it was done on a manual lathe. Some people really have talent.
 
I have cut several chambers on a manual lathe, not too difficult if you take your time and having a digital readout helps lots, to date cut 303 British, 30-30, 3006, 9mm and 45 acp, I have also used the cnc mill to make a reamer from drill rod held in the spindle and cutting tool in the vice, I also make gauges this way
 
I believe some of the custom bullet mold makers are doing them with CNC and their customers expectations are within a half a thousandth. They are more complex with grease grooves and nose profiles.

If that's possible then chambering shouldn't be a problem.
 
A chamber is deeper, but the process is essentially the same. My Accurate Mold blocks are beautifully cut. And moulds can be produced with ever so slight custom variations in dimensions. This cannot be done if a cherry is used. The same with a chamber - slight alterations could be made to the program.
 
gstprecision said:
Definately doable. Quality of tooling plays a big role here. I would be worried about flex in such a long boring bar.
Click to expand...

skinny bar too... single point cutting the throat in a .17 caliber...

CNC is doable if you put enough money into it but not practical. Reamers are $100 and up... CNC's are how much? You may find a few with cnc already playing with chambering, but making any money in chambering - I doubt it.
 
Tokay444 said:
Reamers are expensive. A boring bar is cheap by comparison.
Length to diameter ratio really becomes the only issue.
In a perfect world, one would rough the form with a boring bar, then finish with a reamer. This will make your expensive reamers last much longer between regrinds.
You have much more finite control over what a single point tool does vs a reamer as well.
Click to expand...

Reamers are not expensive, they are cheap compared to CNC tooling ... I have reamers that have cut over 100 chambers and have never been reground... just the 'flats' lightly stoned with a flat India stone to remove buildup. CNC and CNC tooling are not cheap.


I rough out my chambers with drills and then under bore the body and then ream.
 
guntech said:
Reamers are not expensive, they are cheap compared to CNC tooling ... I have reamers that have cut over 100 chambers and have never been reground... just the 'flats' lightly stoned with a flat India stone to remove buildup. CNC and CNC tooling are not cheap.


I rough out my chambers with drills and then under bore the body and then ream.
Click to expand...

I have solid carbide picco bars that are under $60/piece.
 
dero338 said:
A reamer cost a lot less than a barrel blank and manualy cut a chamber probably takes hell of time. Its why reamers have been invented at first. Its just like cut your fire wood with a axe vs chainsaw
Click to expand...

A reamer is a form tool. You get what you get and that's what you get, unless you want to grind the tool to get something different, and even then, you're only able to remove material from it.
A boring bar can cut whatever you want so long as it fits in the hole.
You can also do a lot of reaming on an NC machine.
 
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Seriously - price out what the CNC machine and tooling would cost to chamber a rifle barrel. Figure in the hours to program it for one cartridge and one action... now figure out how many cartridges and actions you may have to fit... program them in too. You are into a pretty tidy sum... for what purpose? Just because it can be done baring no expense? You could set up few gun shops with all the reamers, conventional lathes, milling machines, etc for far less money.

Seriously - a CNC machine is for production work... making hundreds of things all the same...
 
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