How many cuts ??

[Frank in the Laurels]

I've often wondered how many chambers do the BIG manufacturers cut with one reamer ?? Like w/w, big green, savage etc....I've never had a chance to ask anyone who worked for any of them who would actually know instead of guessing..and what the amount in .001's, what the wear and tear would be after that amount of chambering...just wondering if anyone really knows the answer..

 

[shortgrass]

Until it doesn't work as it should or breaks? Impossible to answer. Reamer made of what material, carbide or high speed steel (probably carbide), feed rate per revolution, how many RPM, how many 'pecks', was a roughing reamer used, what's the barrel made of, 4140/4150 or stainless, the consistancy of the barrel steel, what coolant used, was it mixed per the coolant manufactures recommendations, how is the coolant supplied to the tool, muzzle flush or externally, is the machine program capable of "constant SFM" as most reamers taper from smaller at the shoulder to larger at the head? This is not taking into consideration the ridgidity of the machine or the tool holder or the skill of the operator. Too many variables to give any kind of educated answer...... I have HS reamers, used on my manual lathe with a muzzle flush, with 15+ chambers on them and still cutting 'strong'.

 

[J E Custom]

Until it doesn't work as it should or breaks? Impossible to answer. Reamer made of what material, carbide or high speed steel (probably carbide), feed rate per revolution, how many RPM, how many 'pecks', was a roughing reamer used, what's the barrel made of, 4140/4150 or stainless, the consistancy of the barrel steel, what coolant used, was it mixed per the coolant manufactures recommendations, how is the coolant supplied to the tool, muzzle flush or externally, is the machine program capable of "constant SFM" as most reamers taper from smaller at the shoulder to larger at the head? This is not taking into consideration the ridgidity of the machine or the tool holder or the skill of the operator. Too many variables to give any kind of educated answer...... I have HS reamers, used on my manual lathe with a muzzle flush, with 15+ chambers on them and still cutting 'strong'.

+1

Normally, machining is done on a 100 run schedule. (Parts are checked and as long as they meet specification, all tooling is re done at 100 parts). If the part goes out of spec. , tooling is replaced or re sharpened at that time. Modern CNC machines have multiple tooling and can replace worn tools without shutting down and loosing production.

Reamer quality has a large bearing on tool life also.

J E CUSTOM

 

[Trickymissfit]

I've often wondered how many chambers do the BIG manufacturers cut with one reamer ?? Like w/w, big green, savage etc....I've never had a chance to ask anyone who worked for any of them who would actually know instead of guessing..and what the amount in .001's, what the wear and tear would be after that amount of chambering...just wondering if anyone really knows the answer..

You can re-sharpen a typical reamer many times over. The O.D. rarely wears out, but when you do this the throat lengthens a few thousandths of an inch. Of course you can also re-grind the throat to.

With a CNC grinder like a Starr, you set the program and re-grind everything again. Not very hard to do.
gary

 

[Trickymissfit]

+1

Normally, machining is done on a 100 run schedule. (Parts are checked and as long as they meet specification, all tooling is re done at 100 parts). If the part goes out of spec. , tooling is replaced or re sharpened at that time. Modern CNC machines have multiple tooling and can replace worn tools without shutting down and loosing production.

Reamer quality has a large bearing on tool life also.

J E CUSTOM

with the advent of statistical process control, and precision measuring on the fly; you monitor the reamer wear as it goes. Normally nobody wants to change out the reamer, as you get to start all over with everything in that hole (no two reamers cut exactly the same). Ultra critical multi step holes (like a chamber) can be cut with a Mapol reamer, and you may see four hundred holes off the reamer (I've seen six hundred and still holding less than three tenths). The down side is the cost of the reamer. About $5,000, but worth every penny when it has to be right.

What most folks fail to realize, is that a typical CNC lathe (kept in good shape) is quite capable of cutting the chamber without the reamer. The process takes much longer (about five passes), and will be in the .00075" range.
gary

 

[Frank in the Laurels]

Thanks.. As always... Ask and ye shall receive information from the guys !! Thanks

 

[J E Custom]

with the advent of statistical process control, and precision measuring on the fly; you monitor the reamer wear as it goes. Normally nobody wants to change out the reamer, as you get to start all over with everything in that hole (no two reamers cut exactly the same). Ultra critical multi step holes (like a chamber) can be cut with a Mapol reamer, and you may see four hundred holes off the reamer (I've seen six hundred and still holding less than three tenths). The down side is the cost of the reamer. About $5,000, but worth every penny when it has to be right.

What most folks fail to realize, is that a typical CNC lathe (kept in good shape) is quite capable of cutting the chamber without the reamer. The process takes much longer (about five passes), and will be in the .00075" range.
gary

Thanks Gary, Never to old to learn.

I know that some of the custom dies are cut this way (Without a reamer) and it makes sense that chambers could be cut this way also. But I had no idea that chambers were being cut this way, And If that many chambers can be cut (600+) maybe that's the reason that they are so bad in some cases. It becomes a quality control issue.

Chambering the way I do I can expect 15 to 20 chambers with quality reamers (The most any reamer I have has been used is 11 times) and it will still cut you if you drag it over your hand the wrong way, so I have no first hand knowledge of a reamers life if used properly and taken care of. I would like to think that 25 to 30 uses would be reasonable.

J E CUSTOM

 

[Trickymissfit]

Thanks Gary, Never to old to learn.

I know that some of the custom dies are cut this way (Without a reamer) and it makes sense that chambers could be cut this way also. But I had no idea that chambers were being cut this way, And If that many chambers can be cut (600+) maybe that's the reason that they are so bad in some cases. It becomes a quality control issue.

Chambering the way I do I can expect 15 to 20 chambers with quality reamers (The most any reamer I have has been used is 11 times) and it will still cut you if you drag it over your hand the wrong way, so I have no first hand knowledge of a reamers life if used properly and taken care of. I would like to think that 25 to 30 uses would be reasonable.

J E CUSTOM

JE; two things to remember:

* your almost always reaming pre-hardened steel. Not so much that the metal is super hard, but it's abrasive. Actually a sharp reamer is not as accurate as one that's done a few holes. I had several reamer sets, and never allowed anybody to use them, but myself. Most never were re-sharpened. I had one set of .001" over and under reamers ($$$) that had the leads and reliefs cut to my spec. They stayed locked up!
I'll honestly tell you that when in doubt, I'd make the call to somebody else I knew to be ontop of the game.

* coolant is really a lubricant. Learn to be selective. I still like Trim CE in it's raw state foe threading, and reaming. Still there are cases when something else is better. The life of a reamer is built around surface speed and lubrication ( my Dad didn't teach me this, I learned the hard way). When we ream by hand, we also violate all the rules. That's why a hand reamer is ground a little different. Your typical chamber reamer is ground for a very low surface speed, but all could be designed better.
gary

 

[shortgrass]

Most chambering reamers used outside of the 'factories' get "rubbed to death". The muzzle flush for gunsmith chambering changed a lot. I still don't turn at calculated SFM because of the small relative size & weight of the lathe. It's not a 'production machine', like a W&S #3 is. But with the flush, RPM is up around 200 depending on 'what chamber',,,, and let 'er eat just as fast as it wants to cut. Feeding by hand, it's easy to find that feed rate and not be 'pushing it'. Dark threading oil mixed with Tap Magic Pro-Tap w/EP Extra is my preferred coolant/lubricant. And, that's the key. Those higher RPMs can be turned because of the forced coolant/lubricant so the work and the tool don't heat-up. Flushes the cuttings, which if left in the flutes, would generate heat,,,, one of the main enemies of any cutting tool, be it a simple turning too, a twist drill or a chambering reamer. Larger production machines could turn for chambering faster and with 'peck cycles' reducing the time it'd take to finish a chamber. They must run those reamers, in the factories, pretty hard 'cause some of those production cut chambers look pretty rough!