Rifling?
- Thread starter Dingoboyx
- Start date
There are several ways. After a hole is drilled in the barrel, 1) "Cut Rifling": a cutting tool is drawn through the barrel leaving a groove, indexed (turned), and cutter drawn trough again leaving another groove. Continued until all grooves are cut. 2) " Button Rifling": A hard "button" (a tool with the shape of the rifling in it) is drawn through the barrel leaving the shape of the rifling as it passes by deforming the metal into the desired shape. 3) "Hammer Forged Rifling": A mandrel with the reverse shape of the rifling is placed in the barrel and the outside of the barrel is hammered until the metal inside the barrel is forced into the shape of the mandrel.
For cut rifling, it depends on the number of grooves - one total pass per groove, but it takes many in-and-out passes to get all the way through the barrel; for button rifling, the button is drawn (or pushed) through only once (the barrel must be tempered again to remove the stresses left in the barrel by the process). Some land/groove lapping may or may not take place afterward - depends on the barrel manufacturer.
One of the major aftermarket barrel manufacturers had a good explanation of all the processes with images. I'll see if I can find it ...
Here's one, but it's not the one I was thinking about.
He reminded me that there is another type of cut rifling - broach cutting. A cutter tool with all grooves in it is used in a similar fashion to the single cutter, but usually in only one pass. It's fast and creates a stress free barrel.
This is the one I was thinking about- from Lilja, but it only covers button rifling.
One of the major aftermarket barrel manufacturers had a good explanation of all the processes with images. I'll see if I can find it ...
Here's one, but it's not the one I was thinking about.
He reminded me that there is another type of cut rifling - broach cutting. A cutter tool with all grooves in it is used in a similar fashion to the single cutter, but usually in only one pass. It's fast and creates a stress free barrel.
This is the one I was thinking about- from Lilja, but it only covers button rifling.
grymster2007
New member
I think the rifling broach is the modern, hot-whammy method. One pass, adding essentially no stress....it makes sense.
Not for rifling, but we've used similar purpose-built broaches for a number of operations in the shop here. Nice having a master tool & cutter grinder on staff!
Not for rifling, but we've used similar purpose-built broaches for a number of operations in the shop here. Nice having a master tool & cutter grinder on staff!
Bolosniper
New member
Both the single point box cutter method , and the broach cutting method (both referred to as cut rifled) of rifling a bore are NOT done in one pass. A series of passes will be used to remove the material to machine the groove to proper depth. Each pass will be, at most, a couple of thousands deeper than the previous pass, and will produce a nice fine curl of material at the end of the pass. It can generally be said that there is no stress imparted to the barrel by either process of rifling a bore.
The pulled button method is another method of producing rifling in a barrel, and the button cold forms the rifling as it is pulled and twisted at the specified twist rate through the bore. There is quite a bit of internal residual stress imparted into the barrel blank using this method of rifling, and the barrel needs to be stress relieved after the process is completed. The cold forming also work hardens the bore and about 1/16" of the material surrounding the bore the entire length of the barrel. I have never seen that to be an issue from the perspective of the ultimate accuracy of the finished product.
The rotary hammer forged method is the fastest and most economical method of producing a rifled bore, and it is the least likely method to produce quality bores, barrel after barrel after barrel. They also have quite a bit of residual stress left in them after the process is completed, and nothing is done to relieve the barrels. Again, very economical, but most definitely not the best method. A bore made this way that will shoot alongside of a bore using the other above methods of manufacture is an anomaly in my experience.
The pulled button method is another method of producing rifling in a barrel, and the button cold forms the rifling as it is pulled and twisted at the specified twist rate through the bore. There is quite a bit of internal residual stress imparted into the barrel blank using this method of rifling, and the barrel needs to be stress relieved after the process is completed. The cold forming also work hardens the bore and about 1/16" of the material surrounding the bore the entire length of the barrel. I have never seen that to be an issue from the perspective of the ultimate accuracy of the finished product.
The rotary hammer forged method is the fastest and most economical method of producing a rifled bore, and it is the least likely method to produce quality bores, barrel after barrel after barrel. They also have quite a bit of residual stress left in them after the process is completed, and nothing is done to relieve the barrels. Again, very economical, but most definitely not the best method. A bore made this way that will shoot alongside of a bore using the other above methods of manufacture is an anomaly in my experience.
Jim Watson
New member
Several links to descriptions of rifling methods at:
http://www.thehighroad.us/showthread.php?t=408598
And, by the way, broach rifling is a single pass process with multiple cutters on one shaft. Pedersoli says they use two broaches to bring their rifle barrels to finished rifling specs, though.
There are now barrels being rifled by ECM, too. S&W uses it to get a gain twist in their monster magnums, for a recent application.
And if you want to go back about 75 years, Springfield Armory rifled match 1903 barrels by the "scrape" process. Operationally the same as single point cut rifling, the cutters were ground to take a lighter, smoother cut. It took even more passes to get to final depth of the rifling, but it was very smooth and even.
There are some hybrid processes, too. Colt finished revolver barrels by pressing a bore diameter ball through to burnish the finish on top of the lands. I once read that Kimber made their reputation with barrels cut or broach rifled, but completed for exact size and smooth finish with a button displacing very little metal. (It is hard to button rifle an asymmetric shaped barrel uniformly, which is why S&W did a lot of ribbed and lugged revolver barrels by broach.)
http://www.thehighroad.us/showthread.php?t=408598
And, by the way, broach rifling is a single pass process with multiple cutters on one shaft. Pedersoli says they use two broaches to bring their rifle barrels to finished rifling specs, though.
There are now barrels being rifled by ECM, too. S&W uses it to get a gain twist in their monster magnums, for a recent application.
And if you want to go back about 75 years, Springfield Armory rifled match 1903 barrels by the "scrape" process. Operationally the same as single point cut rifling, the cutters were ground to take a lighter, smoother cut. It took even more passes to get to final depth of the rifling, but it was very smooth and even.
There are some hybrid processes, too. Colt finished revolver barrels by pressing a bore diameter ball through to burnish the finish on top of the lands. I once read that Kimber made their reputation with barrels cut or broach rifled, but completed for exact size and smooth finish with a button displacing very little metal. (It is hard to button rifle an asymmetric shaped barrel uniformly, which is why S&W did a lot of ribbed and lugged revolver barrels by broach.)
grymster2007
New member
This is what I was thinking a rifling broach would look like and it looks nearly identical to broaches our tool maker has built for various purposes. Multiple cutters of increasing size, spaced on a common shaft. Definitely a single pass affair.
Rifle broaching
Rifle broaching
All interesting
The main reason I asked about rifling, was because I heard once of some folk in the mountains of Afghanistan some years back, I think it was, making great accurate rifles using pedal powered lathes and mostly by hand (no elecreicity) and wondered how that could be done?
Seems amazing, but supposedly true
The main reason I asked about rifling, was because I heard once of some folk in the mountains of Afghanistan some years back, I think it was, making great accurate rifles using pedal powered lathes and mostly by hand (no elecreicity) and wondered how that could be done?
Seems amazing, but supposedly true
Lothar Walther
These guys make the barrels for the Kahr and quite a few others.
http://www.lothar-walther.com/
And I just noticed they are located 2 towns north of me. Sounds like a field-trip is in order.
Ben
These guys make the barrels for the Kahr and quite a few others.
http://www.lothar-walther.com/
And I just noticed they are located 2 towns north of me. Sounds like a field-trip is in order.
Ben
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the old time methods still work
It is done the same way gunmakers of the 17th, 18th, & 19th centuries did it. Lathes and cutters run by hand, or by water power, or later, steam power. Belt drives from the power source to the machinery. Not as fast as electric motor driven tools, but capable of turning out a good finished product, provided the operators are skilled, none the less.
I do have to admit there is something impressive about a bunch of turbaned tribesmen, squatting on dirt floors in between prayers, turning out firearms tht not only work, but in some cases take an expert to tell that they didn't come from European factories!
It is done the same way gunmakers of the 17th, 18th, & 19th centuries did it. Lathes and cutters run by hand, or by water power, or later, steam power. Belt drives from the power source to the machinery. Not as fast as electric motor driven tools, but capable of turning out a good finished product, provided the operators are skilled, none the less.
I do have to admit there is something impressive about a bunch of turbaned tribesmen, squatting on dirt floors in between prayers, turning out firearms tht not only work, but in some cases take an expert to tell that they didn't come from European factories!