What is fluting

[Kansas City Jack #9243]

A friend ask me why some guns are fluted and some are not. I didn't know. Can someone out there tell us?

[Rio Brazos Kid]

Sometimes fluting is done to lighten the weight of the barrel, and other times to aid in cooling the barrel as in Varment Shooting where many rounds are fired in short periods of time.

 

Fluting has no place or value in CAS.

 

RBK

[Mad Dog Jack, SASS #77862]

The fluting on barrels increases the surface area to dissipate heat, no idea why cylinders, some anyway, have them. Two of my varmint heavy barreled guns are fluted.

[Loophole LaRue, SASS #51438]

Sometimes fluting is done to lighten the weight of the barrel, and other times to aid in cooling the barrel as in Varment Shooting where many rounds are fired in short periods of time.

 

Fluting has no place or value in CAS.

 

RBK

 

 

Ain't them flutes on the side of my cylinder?

 

LL

[Buckshot Frank]

The fluting on barrels increases the surface area to dissipate heat, no idea why cylinders, some anyway, have them. Two of my varmint heavy barreled guns are fluted.

 

Fluted chambers aid extraction. It is mostly found on military firearms. I have an HK P7 with a fluted chamber. It will supposedly still extract reliably with the extractor removed. The fluted chamber makes it easy to identify your brass too .

[Jackson Rose, SASS #45478]

The fluting on revolver cylinders are for esthetics.

[Driftwood Johnson, SASS #38283]

Howdy

 

There are a couple of purposes behind fluting cylinders and barrels. With a heavy target barrel on a rifle, cutting grooves the length of the barrel will reduce the weight of the barrel without affecting the stiffness of the barrel. So a fluted target barrel may be just as accurate as a barrel of the same diameter without flutes.

 

Generally speaking, most revolvers today have fluted cylinders. If you look carefully at the cylinder on the right, it is a 'long flute' version of a SAA cylinder. The flutes are a bit longer than standard.

 

Cylinders with flutes

 

Flutes on a cylinder make the cylinder a little bit lighter without altering the strength, and they also give the fingers a little bit of extra purchase which makes it more convenient to rotate the cylinder by hand.

 

The flutes on this S&W 44DA are quite short because of the vertical clearance cuts on the cylinder. These flutes are very useful they make it very simple to line the cylinder up when closing the Top Break action. I simply pinch the 'top two' flutes on either side of the barrel as I close the action. Then everything is perfectly lined up. Not so easy if there are no flutes.

 

44DA Cylinder

 

Many Cap & Ball revolvers did not have fluted cylinders, although a few did.

 

cylinders without flutes

 

Fluting is also an architectural term meaning the same thing, radiused grooves running the length of an architectural element. In this case, they are added only for appearance, they have no practical purpose.

 

Fluted Column

[Fordyce Beals]

I think fluted cylinders are for:

 

#1 even out the cylinder expansion to keep the fired brass rounder

 

#2 make cylinder lighter

 

#3 Add decorative style with an easy to machine process.

 

#4 replaces the roll mark engraving of the cap and ball Colts

 

But then you didn’t really care what I think did you?

 

Fordyce

[Adirondack Jack, SASS #53440]

A fluted cylinder revolved is also a hair narrower, and at least in the instance of a six shooter, makes the front edges of the cylinder easier to reholster, as the round cylinder may catch an edge going into the holster unless the holster has a modern "stiff" flared mouth. My guess is it started in the late C&B days as a way to facilitate easy turning of a gummed up gun. They are also quite aesthetically pleasing. Look at a '61 Navy or '62 pocket police with a fluted cylinder. Very sharp lookin guns.

[Manatee]

They fluted guns cuz they couldn't saxophone 'em.

[Driftwood Johnson, SASS #38283]

Howdy AJ

 

I believe you are right. I cannot recall seeing anything made by Colt with flutes on the cylinder prior to 1860. Of course, I have been known to be wrong on occasion. There were a few 1860 Army Colts made with fluted cylinders, but they are rare.

 

Note how unusual the treatment of the flutes was on the 1860 Colt. The flute went all the way to the rear of the cylinder, unlike most modern revolvers where it only goes about half way.

 

 

1860 Army Colt Fluted Cylinder

 

Approximately the first 100 1862 Navies had fluted cylinders. I believe the 1862 Police revolver came standard with half fluted cylinders.

 

I agree, I believe the flutes were there to make the cylinder easier to turn, particularly with a badly gummed up BP cylinder. Plus, they lightened the whole gun without removing metal in any critical areas of the cylinder.

[Driftwood Johnson, SASS #38283]

They fluted guns cuz they couldn't saxophone 'em.

 

Still having trouble with your eye, I see, Manatee.

[Guest Tennessee Stud, SASS# 43634 Life]

I know's a place near Beale Street in Memphis... they do a fair job at skin-flutin'....

 

Just sayin'...

 

ts

[Driftwood Johnson, SASS #38283]

Yeah, it was only a matter of time until that subject came up.

[Larsen E. Pettifogger, SASS #32933]

Howdy AJ

 

I believe you are right. I cannot recall seeing anything made by Colt with flutes on the cylinder prior to 1860. Of course, I have been known to be wrong on occasion. There were a few 1860 Army Colts made with fluted cylinders, but they are rare.

 

Note how unusual the treatment of the flutes was on the 1860 Colt. The flute went all the way to the rear of the cylinder, unlike most modern revolvers where it only goes about half way.

 

 

1860 Army Colt Fluted Cylinder

 

Approximately the first 100 1862 Navies had fluted cylinders. I believe the 1862 Police revolver came standard with half fluted cylinders.

 

I agree, I believe the flutes were there to make the cylinder easier to turn, particularly with a badly gummed up BP cylinder. Plus, they lightened the whole gun without removing metal in any critical areas of the cylinder.

 

On the photo you show, if you look right above the lead in you can see a little ding. That's why they quit full fluting cylinders. If the bolt dropped to early, the cylinder wouldn't turn since the bolt head wouldn't climb the slope leading to the locking notch.

[Driftwood Johnson, SASS #38283]

Thanks Larsen

 

Learn something every day.

[Mustang Gregg]

 

A machinist Pard of mine says that milling flutes into a barrel or shaft makes them stiffer.

 

Mustang Gregg

[Guest Tennessee Stud, SASS# 43634 Life]

Yeah, it was only a matter of time until that subject came up.

 

 

Been there, too? Ya know what they say... "Great minds think alike."

 

ts

[Adirondack Jack, SASS #53440]

 

A machinist Pard of mine says that milling flutes into a barrel or shaft makes them stiffer.

 

Mustang Gregg

 

Makes em stiffer POUND FOR POUND. They are not stiffer than a round barrel of the same full diameter. They are ligher, and almost as stiff.

[Smithy]

Certainly something to do with the strength of the chambered cartridge as my 44 mag Ruger Alaskan has a fluted cylinder whereas the 454 version of the same gun did not. Going over to my 44 mag Bisley hunter, its cylinder is not fluted yet the diameter of the cylinder diameter is considerably less than the Alaskan so maybe they needed the additional meat in the cylinder area? I'm sure that some of the fluting/non fluting was done for aesthetics but would also imagine that a fair amount of it was done for a mechanical need or necessity to beef up or strengthen the gun in general to contain the pressures of the chambered cartridge based upon the round it's chambered for. Another possible example of this might be the American Derringer. When I was ordering some less than common chambering's for that gun, initially in their M1 standard model I was told that for some I would have to order their M4 model which did not have the traditional figure 8 muzzle profile, but rather had the slab sided, much heavier, more metal barrel surface. This was done so that the bores could be done off center allowing for more meat between the chamber walls. (this especially with the 45-70 chambering), so the same thing may be true with the unfluted revolver cylinder? Smithy.

[Boss Hoss Fly #63711]

 

A machinist Pard of mine says that milling flutes into a barrel or shaft makes them stiffer.

 

Mustang Gregg

 

Thats kinda goin back to Studs reply---------------------------------------------------kinda

[Garrison Joe, SASS #60708]

Makes em stiffer POUND FOR POUND. They are not stiffer than a round barrel of the same full diameter. They are lighter, and almost as stiff.

 

Yep, exactly right. GJ

[H. K. Uriah, SASS #74619]

And just for giggles, don't forget that some cylinders were scalloped.

 

But never clammed, muscled, or oystered.

 

Only scalloped.

[Tom Bullweed]

Shooting Frontier Cartridge for a few months, I have learned that the flutes can aid in turning a very dirty cylinder that cannot be turned by just pulling the hammer. They allow extra purchase for the fingers of the offhand to reach over the top strap and help turn that cylinder. I have also grabbed the rear half of the cylinder (no flutes) and tried the same manuvuer with less success.

I think that the were originally added to reduce weight and add a finished look, but I am okay with this additional benefit.

[Lone Dog, SASS #20401]

Smithy, the weakest part of any revolver cylinder is at the bolt cuts. Metal gets very thin there on some 6guns. Never understood why ole Sam couldn't offset the cuts some (like Ruger does) instead of putting them right over the chambers where the meat is thinnest.

 

I don't think fluting the front part of the cylinder weakens it at all, but it is pleasing to the eye.

[Forty Rod SASS 3935]

If big cylinders are fluted, are little cylinders piccoloed?

[Red Hooker]

Howdy AJ

 

I believe you are right. I cannot recall seeing anything made by Colt with flutes on the cylinder prior to 1860. ......

I was thinking about just this the other day, in regard to getting unfluted cylinders for my guns, to provide greater scope for engraving them (if ever I hit the lottery). I realized that Colt stopped providing unfluted cylinders about then. I suspect that it had to do with the conversion from wrought iron as material for Colt's guns, to steel. Steel, with its greater strength, could allow lightening cuts. Steel had formerly been expensive and hard to produce but was now more affordable, due to the introduction of the Bessemer process at about this time. Unfortunately, I'm not sure of the exact dates of either.

[Driftwood Johnson, SASS #38283]

Smithy, the weakest part of any revolver cylinder is at the bolt cuts. Metal gets very thin there on some 6guns. Never understood why ole Sam couldn't offset the cuts some (like Ruger does) instead of putting them right over the chambers where the meat is thinnest.

 

I don't think fluting the front part of the cylinder weakens it at all, but it is pleasing to the eye.

 

Howdy Again

 

That is correct. Leaving a cylinder unfluted does not increase its strength. It is also correct that the thinnest cross section on any Colt style cylinder is the section between the outside of the cylinder and the bolt locking slot. A cylinder will fail at the thinnest point of the metal. Adding metal somewhere else does not make the cylinder stronger, it will still fail at the thinnest point.

 

Here is a photo showing views of the front and rear of a 2nd Gen Colt cylinder. The rear view of the cylinder is not perfectly in focus, but I can tell you that the thinnest section between chambers on this cylinder is only about .043 thick. The cross section between the chambers and the outside of the cylinder is about .055 thick, or about .012 thicker than the space between chambers. Looking at the front view, there is a whopping .120 of metal at the thinnest section between the chambers and the flutes. Even allowing for the slightly smaller diameter of the chamber throats, there is still far more metal at the flutes than there is at either of the other two locations. Leaving the steel in the flute area will not strengthen the cylinder at all.

 

cylinder

 

The bolt locking slot has been cut about .030 deep into the cylinder, and one edge of the slot is within .010 of the centerline of the chambers. Doing the math that tells us that there is only about .025 of steel between the deepest part of the bolt locking slot and the chamber wall. Ruger did indeed shift the location of the bolt locking slot on their cylinders away from dead center on the chambers, in order to help strengthen the cylinder.

 

When a cylinder fails, that thin cross section at the bolt locking slot acts as a stress riser. It lets go first. A few years ago, Rusty Marlin, who was a line engineer at Ruger at the time, put an ‘original model’ Vaquero to the test, putting higher and higher pressure loads through it until the cylinder did indeed blow up. He filmed the destructive test with high speed video. Playing the video back in slow motion he clearly saw the cylinder fail first at the bolt locking slot. The crack then propagated both forward and back along the center line of the chamber. Rusty’s comment to me at the time was it was just like watching a zipper open up. Once the crack reached the front and back of the cylinder, the thin sections of the cylinder between the chambers on either side began to fold until they too failed. Once those walls failed the remaining steel separating the two chambers from the outside of the cylinder failed.

 

That is why when a cylinder fails, the outsides of three chambers are usually ruptured. First, the overstressed chamber fails at its center, starting at the bolt locking slot. Next the two adjoining chambers are ruptured, and finally, two big chunks of steel go flying.

 

When Ruger first started developing a revolver for the then new 44 Magnum cartridge, the first prototype revolvers used cylinders having the same standard dimensions as their then current 357 Magnum revolvers. They quickly realized they would need a more massive cylinder, so they made up cylinders .053 larger in diameter and 1/8” longer. This meant the frames needed to be larger than the standard Blackhawk frames, to house the larger cylinder. They also made the decision at that time not to cut flutes in the chambers. But this decision was not to make the cylinder stronger, it was to add a little bit of weight, to make the gun slightly heavier because of the massive recoil of the new cartridge. The new gun also had a steel grip frame, instead of the aluminum grip frame used previously on the Blackhawks, also to add weight.

 

Deleting the flutes on the Super Blackhawk also added to the mystique of the new revolver, harkening back to the appearance of the Colt Dragoon with its square backed trigger guard.

 

When Ruger chambered the Vaquero for 44 Magnum, despite the fact that the cylinder was the same size as the Super Blackhawk, they added flutes to the cylinder. The cylinders were just as strong as the unfluted Super Blackhawk cylinders.

 

I was thinking about just this the other day, in regard to getting unfluted cylinders for my guns, to provide greater scope for engraving them (if ever I hit the lottery). I realized that Colt stopped providing unfluted cylinders about then. I suspect that it had to do with the conversion from wrought iron as material for Colt's guns, to steel. Steel, with its greater strength, could allow lightening cuts. Steel had formerly been expensive and hard to produce but was now more affordable, due to the introduction of the Bessemer process at about this time. Unfortunately, I'm not sure of the exact dates of either.

 

Howdy Red

 

What became known as the Bessemer process was discovered in 1851 and Henry Bessemer patented it in 1855. However, Colt was still using malleable iron for their frames and cylinders well into SAA production. Colt did not begin using low/medium carbon type steels until approx SN 96,000, which would have been sometime in 1883. Flutes were standard on the early SAA malleable iron cylinders.

[Lone Dog, SASS #20401]

DJ, on behalf of revolver afficionados everywhere I want to thank ye kindly for that impressive tutorial. You are an altruistic treasure and I tip my hat to you. Bang up job, keep it up.

[Adirondack Jack, SASS #53440]

Howdy Again

 

That is correct. Leaving a cylinder unfluted does not increase its strength. It is also correct that the thinnest cross section on any Colt style cylinder is the section between the outside of the cylinder and the bolt locking slot. A cylinder will fail at the thinnest point of the metal. Adding metal somewhere else does not make the cylinder stronger, it will still fail at the thinnest point.

 

Here is a photo showing views of the front and rear of a 2nd Gen Colt cylinder. The rear view of the cylinder is not perfectly in focus, but I can tell you that the thinnest section between chambers on this cylinder is only about .043 thick. The cross section between the chambers and the outside of the cylinder is about .055 thick, or about .012 thicker than the space between chambers. Looking at the front view, there is a whopping .120 of metal at the thinnest section between the chambers and the flutes. Even allowing for the slightly smaller diameter of the chamber throats, there is still far more metal at the flutes than there is at either of the other two locations. Leaving the steel in the flute area will not strengthen the cylinder at all.

 

cylinder

 

The bolt locking slot has been cut about .030 deep into the cylinder, and one edge of the slot is within .010 of the centerline of the chambers. Doing the math that tells us that there is only about .025 of steel between the deepest part of the bolt locking slot and the chamber wall. Ruger did indeed shift the location of the bolt locking slot on their cylinders away from dead center on the chambers, in order to help strengthen the cylinder.

 

When a cylinder fails, that thin cross section at the bolt locking slot acts as a stress riser. It lets go first. A few years ago, Rusty Marlin, who was a line engineer at Ruger at the time, put an ‘original model’ Vaquero to the test, putting higher and higher pressure loads through it until the cylinder did indeed blow up. He filmed the destructive test with high speed video. Playing the video back in slow motion he clearly saw the cylinder fail first at the bolt locking slot. The crack then propagated both forward and back along the center line of the chamber. Rusty’s comment to me at the time was it was just like watching a zipper open up. Once the crack reached the front and back of the cylinder, the thin sections of the cylinder between the chambers on either side began to fold until they too failed. Once those walls failed the remaining steel separating the two chambers from the outside of the cylinder failed.

 

That is why when a cylinder fails, the outsides of three chambers are usually ruptured. First, the overstressed chamber fails at its center, starting at the bolt locking slot. Next the two adjoining chambers are ruptured, and finally, two big chunks of steel go flying.

 

When Ruger first started developing a revolver for the then new 44 Magnum cartridge, the first prototype revolvers used cylinders having the same standard dimensions as their then current 357 Magnum revolvers. They quickly realized they would need a more massive cylinder, so they made up cylinders .053 larger in diameter and 1/8” longer. This meant the frames needed to be larger than the standard Blackhawk frames, to house the larger cylinder. They also made the decision at that time not to cut flutes in the chambers. But this decision was not to make the cylinder stronger, it was to add a little bit of weight, to make the gun slightly heavier because of the massive recoil of the new cartridge. The new gun also had a steel grip frame, instead of the aluminum grip frame used previously on the Blackhawks, also to add weight.

 

Deleting the flutes on the Super Blackhawk also added to the mystique of the new revolver, harkening back to the appearance of the Colt Dragoon with its square backed trigger guard.

 

When Ruger chambered the Vaquero for 44 Magnum, despite the fact that the cylinder was the same size as the Super Blackhawk, they added flutes to the cylinder. The cylinders were just as strong as the unfluted Super Blackhawk cylinders.

 

 

 

Howdy Red

 

What became known as the Bessemer process was discovered in 1851 and Henry Bessemer patented it in 1855. However, Colt was still using malleable iron for their frames and cylinders well into SAA production. Colt did not begin using low/medium carbon type steels until approx SN 96,000, which would have been sometime in 1883. Flutes were standard on the early SAA malleable iron cylinders.

 

 

Rusty never told how much pressure it took to blow up the gun, but he did tell that under their normal proof testing (which is far beyond SAAMI max loads for the round), there was enough pressure that in the 1000 frames per second film you could see the top strap flex, the cylinder sides bulge, and the hammer jump a bit, but NOTHING was hurt. The same round woulda turned a SAA Colt into a jigsaw puzzle.

[Chicken Coop SASS 5791 L]

I am not going to discuss cylinder fluting. It is basically a weight saving issue.

 

However, rifle barrel fluting is about heat dissipation, barrel "stiffness", and damping harmonic vibrations. The fluting "ribs" will give a certain amount of directional stiffness (harmonic dampening) to a precision rifle barrel. Nonetheless, there was a considerable discussion many years ago about longitudinal barrel fluting versus axial barrel fluting. Can you say "Acme Threads"? One example of a prototype axial fluted rifle barrel was this smallbore rimfire "work of art". I believe it was a collaboration between K. Kenyon and the late (good friend) George Stidworthy, a world champion High Power and Smallbore shooter.

 

Check this out:

 

http://i626.photobucket.com/albums/tt342/crcooper1943/Cooper%20Firearms/kenyon-full.jpg

 

Chicken Coop