Barrel Making

[brooktrout]

I have seen vid clips of Colonial Williamsburg's gun makers in the process of making a barrel.  It's all pretty clear but I still am in a fog about how they "rifled" the bore.  The one original gun I have has a 7-sided barrel (outside" and 7 inside barrel "walls" but I cannot tell if there is a twist in the interior or not.  How did they do the 7 sided insides?  There are "groves" between the sides (interior) which almost seem as if that is what would be rifling? Not a builder and probably never will be but I KNOW you guys have the answers!!

[David R. Pennington]

Once the barrel is successfully welded and rough forged to octagon shape it is straightened and drilled then reamed to get a smooth uniform bore. Then it is put in the rifling machine and the wooden guide which has spirals cut in it pulls the rifling cutter through the barrel one pass at a time moving the indexing to cut each individual groove. Shims are added behind the cutter to deepen the grooves. Hundreds of passes might be required to cut the desired number of grooves to the proper depth.
This is a simplified version of the process. There are lots of videos and books available on the subject. I'm sure a search on this site will turn up lots of info.

[Acer Saccharum]

A very short video on youtube:

It leads to other videos, if you're interested.

Tom

[brooktrout]

So then it would be similar to what I'll term "shaving" down the inside. First they would bore it to "round" then shave the rifling in.  I think I get it.

[Acer Saccharum]

What you term 'shaving' is correct, it's a rotary tool called a reamer, which trues the hole to round, and makes it a consistent diameter, and very smooth.

The spiral grooves, or 'rifles', are a second operation, separate from reaming.  Rifles are scraped with a cutter that is pulled through the round bore.

If the tool went from one end to the other without any spiral motion at all, the rifles would be straight grooves.

[rtadams]

7-7-14

Brooktrout,

Go back and count the number of sides or flats on the exterior of your barrel. I believe you will find that you have an eight sided or flats barrel, often called a octagon barrel.

Best Regards,

Robert

[brooktrout]

Gee, y'd think at my age I would be able to at least count to 8!  Yes, eight on the outside but 7 on the inside.

[Bob Roller]

Straight grooves are called splines and are common to motor vehicles.
They come in a wide variety of patterns including irregular and involute.
They are both internal and externally applied as needed.

Bob Roller

[JBlk]

Brooktrout, if you go to your library and checkout foxfire book , I believe #5 the have pictures of both rifling machines and descriptions of how it was used.The book also  describes how the smith made the guide for the rifling tool to follow.The machine is actually a hand  a hand operated broach made by craftsmen for a defined job.

[Acer Saccharum]

Bob, just to talk about grooves a bit, I understood, and maybe incorrectly, that the groove itself is a 'rifle'.
There are examples of German fowlers with straight grooves. Maybe to load easier?

Rifling: History
The inventor of a rifled barrel is alleged to be one of two inventors, both of them German-speaking. According to The Gun and its Development, one was Gaspard Kollner of Vienna, sometime in the 15th century, others allege that his grooves were straight in nature and the first spiral grooves came from Augustus Kotter of Nuremberg in 1520. Regardless, a lot of the early rifling development came from German speaking areas. The Germans already had a history of manufacturing crossbows that would spin their bolts in flight (either by shaping the arrow head, arranging the feathers of the arrow slightly off center, or by passing the arrow through a tube with grooves in it to impart spin), so they were aware of the basics of rifling and its benefits, even before they started manufacturing firearms. So while the British military took until the 1850s to start issuing rifles to their forces (British troops used the venerable Brown Bess smoothbore musket for a very long time), the forces of the Landgraf of Hesse were already using rifled weapons by 1631 and Maximilian I, Elector of Bavaria, had several troops using rifled arquebuses by 1640. In the early days, most infantry commanders of other countries did not like rifling because it was harder to clean gunpowder recidue which got into the grooves.

from: http://firearmshistory.blogspot.com/2010/05/rifling-history.html

[Daryl]

At one time - in Europe, Husqvarna, for instance, straight rifled guns to meet the law requiring rifles to be used for moose hunting.  Thus one barrel of a SXS would be rifled straight and the other smooth - meeting the 1900's law that stated only rifles could be used for moose, yet still shooting well with shot.

At another time, deep spiral grooves were cut to 'collect' the "DIRT" from firing for the rifle would/could give accuracy over a longer period of time. This, of course was a short lived venture as the accuracy from such a piece was always poorer than intended.

Perhaps the straight rifling in muzzleloaders observed in some Euro (& US) guns of the 18th and 19th centuries was intended for the purpose of holding fouling and/or easing loading of a 'fouled' bore'?

 Peter Mauser's deep rifling that held fouling-buildup idea and Husqvarna's straight rifling were not their original ideas, but 'collected' from previous lessons in History.

[whetrock]

Trout,
The traditional technology for this is a bit different from some of the modern technology sometimes used in making modern production barrels. So if you just search reaming or rifling on this site, you may be left with some confusion about what they are describing.

The traditional reamer for polishing the bore is long cutter, a few inches in length, that is usually square in cross section and slightly tapered. It is pushed or pulled through the bore and is rotated as it passes through. The cutting edge is along the length of the reamer, and it scrapes the bore as it rotates—that is to say it cuts on a rotating stroke.

In contrast, traditional rifling cutter is pulled. It does not cut on a rotating stroke, but rather on a pull stroke. Thus is it shaped like a very short, thick hacksaw blade, and the groove of the rifling is literally a saw kerf. If it were to be pulled straight through, then straight rifling would result. (A similar effect would result if you just passed a hacksaw blade through the barrel and sawed a straight groove into the inside of the barrel tube.)

If you put that short, thick hacksaw blade on the end of a long shaft and attach the shaft to a slowly spiraling machine, that machine will cause the cutter to spiral slowly as it is pulled through the bore. The result is a kerf that spirals, rather than being straight. To get seven such evenly spaced kerfs cut into the bore, the spiraling machine has seven corresponding positions into which it will lock. Each position corresponds to a different groove in the final product.

To move the cutter from one groove to another, the machine is just moved from one of its lock positions to another. The rifling machine is usually made of wood. The positions are defined by seven wooden teeth in a box that correspond to seven notches (grooves) in a long wooden spindle. To move from one position to another, the spindle is withdrawn from the box, rotated slightly, then repositioned in the box.

The cutter only cuts one groove at a time, and the same cutter is used for each groove. The height of the cutter is gradually adjusted by putting paper shims underneath it, so as to lift it up a few thousands of an inch at a time. So each groove is cut once at a particular height. The cutter is then raised the thickness of one shim, and then each groove is cut again at the new height. The eventual result is seven equally spaced grooves of equal depth.

The following links show images of these tools and processes.

Traditional, square barrel reamer:
http://americanlongrifles.org/forum/index.php?topic=30175.0

Traditional, hacksaw-like rifling cutter (and corresponding wooden rifling machine):
http://americanlongrifles.org/forum/index.php?topic=30643.0

[Bob Roller]

Somewhere I read that the grooves at first were to give fouling someplace to go.One thing is sure,whoever put a piece of cloth or leather around a ball probably fired the first accurate shot.The same article also stated that the German word at that time was "Rifeln"meaning to groove. The modern term I think is "Zuge"which can also mean a rail or tracks.I have done nothing with loading a patched round ball into a smooth bore so I can't comment on which is easier to load.About 99% of my shooting has been done with rifles and revolvers and I claim no knowledge of smooth bore muzzle loaders or loading them.

Bob Roller

[Acer Saccharum]

A straight rifle fowling gun is a rare bird in this country, in this century. I have no experience with the beast.

[James Wilson Everett]

Brooktrout,

One reason for the octagon barrel was the forging process.  When the smith would hammer the hot metal on the anvil surface the result was two opposite flats, top from the hammer and bottom from the anvil.  So, it is natural to make an even number of flats when forging the barrel, universally 8 flats.  Think of how difficult it would be to hammer forge a 7 sided barrel!

One reason for the 7 groove barrel rifling was the rifling process.  Very often the smith would use a rifling head that was designed with a cutter opposite to a shoe.  This head would give a groove opposite to a land, and so an odd number of grooves - very often 7 grooves.  If an even number of grooves were to be used, the shoe would ride on the opposite groove and perhaps damage the groove.  Although barrels with an even number of grooves are often encountered, the 7 groove barrels are more common.

Here is a photo of a rifle barrel muzzle, 8 sides to the barrel and 7 grooves to the rifling.  Also a photo of a rifling head showing the cutter opposite to the shoe, adjustment of the cutter depth is made by inerting thin shims between the shoe and the rifling rod.

 

[brooktrout]

All most interesting and informative and greatly appreciated.  As I said, I'll never be a maker but in conversation with a lot of visitors questions are asked and my ability to respond is either wrong OR just partly right.  Barrel making has been one of the most frequent topics people seem to want to discuss.  Mr. Everett:  That last photo of the cutter finally seems to bring it all together.  I viewed some other photos all of which helped my understanding but that one made the little light go off!

Thanks to all.  Have read and contemplated every word.

[sweed]

As for the number of rifles, there was also the ease of layout.  Seven rifles, six flats. The radius of a circle, layed out around the circumference gives you six equaly spaced points. That is also why early wagon wheels had six or twelve, even twenty four spokes! Old timers knew the KISS principal!   

[Steve Bookout]

And then Sweed, you have me.  I always rifle 5 grooves with a LEFT hand twist.  That's because I got tired of people telling me that I didn't rifle that barrel.  Then I'd have them examine the barrel a bit closer.  A left hand twist can throw some folks for a loop!

[Don Getz]

Bookie..........I always knew that you were different.    Five grooves, left hand twist??    I think such a twist would give you
a good shooting gun........if you lived south of the equator.   And to continue along the same lines, you might try coning the
barrel at the breech.   (this is all said in jest, hopefully no one will try it)........Don

[Mark Elliott]

Bookie..........I always knew that you were different.    Five grooves, left hand twist??    I think such a twist would give you
a good shooting gun........if you lived south of the equator.   And to continue along the same lines, you might try coning the
barrel at the breech.   (this is all said in jest, hopefully no one will try it)........Don

Don,  I actually think you are right about the southern hemisphere thing and a left hand twist.    I vaguely remember from college dynamics having to take the Coriolis Effect into account in certain ballistic type calculations.