Author Topic: making a cutter for rifling  (Read 36159 times)

Offline David Veith

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making a cutter for rifling
« on: August 30, 2011, 03:06:12 AM »
One of the members of the group came up with a neat way to make the teeth on a cutter. First he makes the cutter blank. Then mills a slot for it to sit in a bolt then runs a die over the blank.  In this case it was a 3/8 16? bolt Remove a few teeth harden sharpen it and away we go. Work fairly good barrel steel as I remember was of the 81-- I think.
David
David Veith

Offline greybeard

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Re: making a cutter for rifling
« Reply #1 on: August 30, 2011, 03:38:11 AM »
well what won't they think of next???   Bob

Offline Metalshaper

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Re: making a cutter for rifling
« Reply #2 on: August 30, 2011, 05:04:43 AM »
industrial power-band hacksaw blades, make really decent rifling cutters!! :D

works well enough in the "Junkyard Sine bar" my buddy made!

Respect Always
Metalshaper/Jonathan

Rasch Chronicles

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Re: making a cutter for rifling
« Reply #3 on: August 30, 2011, 05:24:25 AM »
Metalshaper,

Your buddy didn't happen to document his Sine Bar build did he?

Here is some more info on freshening a barrel

Best regards,
Albert “Afghanus” Rasch
Charged! Hog Hunting at its Best!
ΜOΛΩΝ ΛΑΒΕ!

Offline Metalshaper

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Re: making a cutter for rifling
« Reply #4 on: August 31, 2011, 01:00:21 AM »
<<<< Your buddy didn't happen to document his Sine Bar build did he?>>>

Albert,

 No, not hardly! :D  When I say it's the "Junk Yard Sine Bar" that's an accurate description!!

Made with the steering rack from an Olds. ( I think that's right? ) two sizes of aluminum channel.  an indexing head that I helped make for him. plus a few this-an-that's to get it done. Next time I'm in his shop, I'll try to remember to get some pics.

Respect Always
Metalshaper/Jonathan

Offline Ben I. Voss

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Re: making a cutter for rifling
« Reply #5 on: August 31, 2011, 03:37:03 AM »
That's a neat trick. I've seen them made by grinding off the sides of a piece of a tap and just leaving 3 or 4 teeth sticking up to do the cutting.

Offline James Wilson Everett

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Re: making a cutter for rifling
« Reply #6 on: November 01, 2011, 01:56:49 AM »
Guys,

Here is a design of a rifling cuter that has served well over the past 35 years.  The rod is 3/8 mild steel and the cutter is carbon steel, 1095.  I cut the shoe recess, 1-3/8 inch long about 1/2 way through the rod.  Then I cut a slot about 0.1 x 0.6 x 0.1 deep. at the center of the slot I drill through to the shoe recess, 0.1 diameter.  The cutter is shaped like a wide and squat "t" to fit into the slot with the center vertical of the "t" passing through the hole.  I then peen/rivet the cutter in place leaving a block of steel above the rod surface.  I then shape the round topped cutter teeth as shown - 4 teeth seems to work best.  Then I harden the whole end of the rod (1500 F followed by brine quench).  The cutter hardens while the mild steel rod does not.

The shoe is fully hardened steel, I have tried several materials here but hard steel is the best as it never wears or galls and actually burnishes the bore land during cutting.  Occasionally I sharpen the teeth with a thin India stone.













This cutter will cut a 7 groove barrel with round bottom grooves.  I shim in between the rod and the shoe to deepen the cut, a 0.001 shim will take about 4 or 5 cuts before adding another.  All in all, it takes about 700 pulls to fully groove a barrel, about 6 hours or so.  (I have never done it straight through  -  really tedious).

The 4 tooth cutter helps when rifling a forged wrought iron barrel as it tends to not be too disturbed when passing over a slag string of a weld flaw.  Sometimes when the slag string causes an irregularity to the smoothness of the rifling twist, I remove the cutter and replace it with a section of fine cut round file.  The file will help to correct the irregularity.

Jim Everett

Offline KNeilson

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Re: making a cutter for rifling
« Reply #7 on: November 01, 2011, 02:35:56 AM »
Jim, thx for the very informative post...      Kerry

Offline tim crowe

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Re: making a cutter for rifling
« Reply #8 on: November 01, 2011, 06:20:31 AM »
James
The cutter is peened in so the shims between the shoe and the cutter, raise and lower the height of cutting.
I guess I missed it; how does the shoe stay attached when it comes out of the barrel on either end, or for adding papers?
Tim

Offline James Wilson Everett

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Re: making a cutter for rifling
« Reply #9 on: November 01, 2011, 01:27:29 PM »
Tim,

You comment on the shoe dropping from the rod at the end of the cut is really astute.  Clearly you have a great understanding of the process.  I really like to answer such intellegent questions.

Certainly you do not want the shoe and shims to drop out since they will fall into the puddle of oil and metal chips on the machine bed.  This would really make a mess and slow everything down as you now have to gather and clean everything.  A metal chip stuck between shims will cause the cutter to jam on the next cut since it acts like an extra large shim.

What I do is position a "precision" stick at the foot of the rifling machine that prevents the cut pull from finishing the stroke.  The stick is about finger size so the machine stroke is 48 inches minus one finger.  At this point the cutter teeth have exited the muzzle end but the shoe and shims are still held in place.  I pull out the "precision" stick while holding the shoe and am able to recover the shoe and shims cleanly.  Every once in a while I drop them and then have to wipe and inspect each shim to be sure that there is not a matal chip hiding there to cause me trouble.

When I mount the barrel onto the machine I position it so the at full stroke the shoe will just clear the muzzle by about 1/8 inch but the end of the rod stays in.

Jim Everett

Offline tim crowe

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Re: making a cutter for rifling
« Reply #10 on: November 01, 2011, 02:46:30 PM »
James
That clears it up. It really is a simple arrangement that is easily made with hand tools. Thank you for taking time to post your work. Do your have any more pictures of your forged barrels?

Tim

Offline James Wilson Everett

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Re: making a cutter for rifling
« Reply #11 on: November 01, 2011, 03:03:16 PM »
Tim,

Here is a photo of an all iron mounted pistol.  The barrel is forged from a buggy wheel rim.  This rim was narrow and thick so I was able to forge it octagon quite easily.  The bore was drilled out so this barrel is not welded.  The barrel is 10.5 inches long, 0.458 bore, swamped octagon shape, smoothbore.  When I make a barrel I never try to end up with a specific size bore.  I use a square reamer until the bore is smooth and shiney, then I measure it later.

Jim Everett









Offline bob in the woods

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Re: making a cutter for rifling
« Reply #12 on: November 01, 2011, 03:15:19 PM »
That is a real work of art !

Offline Paul Hamler

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Re: making a cutter for rifling
« Reply #13 on: November 01, 2011, 04:30:33 PM »
The attached photos show the style cutter I made for my .187 bore barrels,it's usually referred to as a "hook cutter". There is a similar design that has a skewed cutter that is called the  scraper cutter however they are a little more difficult to sharpen.
I made my hook cutter from a section of  a high carbide slitting saw blade that was the thickness of the required rifling groove. This design with a fine pitch adjustment screw (left end) gives accurate control for increasing the cut.
As the adjusting screw is tightened it pushes the inclined ramp under the cutter which raises the height of the cutter.






Paul

Offline Dave B

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Re: making a cutter for rifling
« Reply #14 on: November 02, 2011, 04:43:16 AM »
Here are three typed of single tooth cutters that are for my sign bar rifling machine.


Dave Blaisdell

Offline tim crowe

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Re: making a cutter for rifling
« Reply #15 on: November 03, 2011, 07:05:04 AM »
Jim
The shoe that rides on the bottom,have you found the closer it is to matching the interior radius of the bore it works better ?

The hand made pistol is very nice.

Offline James Wilson Everett

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Re: making a cutter for rifling
« Reply #16 on: November 03, 2011, 03:19:20 PM »
Tim,

Yes, of course, the radius of the shoe should match the bore radius.  Your observation is correct and it is obvious that you have a clear understanding of the rifling process.  This particular rod & cutter I use for bores from about 0.42 through 0.55.  Currently I am rifling a 0.467 bore wrought iron barrel for a crowd show-n-tell at 18th c trades fairs.  I use the same shoe for all bores within this range so the radius is close enough for all the bores.  The really important thing here is to use the traditional 7 groove bore so the shoe will be riding on a land as the cutter bit is in a groove.

Jim Everett

Offline James Wilson Everett

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Re: making a cutter for rifling
« Reply #17 on: November 30, 2011, 03:44:38 PM »
Guys,

I see several single tooth rifling cutters posted on this thread.  I have used a single tooth cutter with good success when rifling a muzzle loader barrel that is made from modern steel.  The cuttter works great because the modern stuff is very uniform throughout the entire length of the barrel.

However, when I tried the single tooth cutter on a wrought iron barrel the results were rather dissapointing.  With wrought iron the cutter will be passing over the tiny strings of slag that are present in the wrought iron.  When the single tooth passes over the slag string its motion is significantly disturbed and the result is a wobble or kink in the rifle groove.  It even gets worse when rifling a wrought iron barrel that has been forge welded.  Perhaps it is that my weld is not perfect, but it is the best I can do.

A multiple tooth cutter will tend to keep on track when passing over the slag string as the teeth that are not contacting the slag string will keep the other teeth from "misbehaving".  I hope this makes sense to you.

Jim Everett

Offline James Wilson Everett

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Re: making a cutter for rifling
« Reply #18 on: January 03, 2012, 06:26:29 AM »
Guys,

In the discussion under shooting "rifles vs smoothbores" there is a period quotation where a gunsmith rifled the barrel from an existing smoothbore in a "couple of hours".  For me it would be a "couple of days", but maybe the old timer was a lot quicker than I, but I think that it is a slight stretching of the truth.  We never do that , do we? 

Anyways, when I rifle a barrel that is already threaded for the breech I first must make an insert to thread into the breech end with the exact gun bore hole and a funnel shaped lead in for the cutter.  I cannot start the cutter in the bore over a sharp or square end, it really needs a somewhat gradual taper (like a blunderbus muzzle) to get the cutter started.  I can not see any way of getting the cutter started when you have a half inch or so of breech threads to get the rifling cutter across before it gets to the gun bore.  To make this "lead-in" fitting would be a couple of hours by itself when using modern tools, and probably all day when using 18th c tools.

I forgot to tell that I always rifle with the cut going from the breech end to the muzzle, rather than the other way around.  I would be interested if anyone out there has any other way of rifing an existing smooth bore barrel.

Jim Everett

Offline kutter

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Re: making a cutter for rifling
« Reply #19 on: January 04, 2012, 06:59:37 AM »
....A multiple tooth cutter will tend to keep on track when passing over the slag string as the teeth that are not contacting the slag string will keep the other teeth from "misbehaving".  ....

Would the same apply when rifling a damascus construction barrel?
That being a multiple tooth cutter the better choice than a single hook cutter to do the work.

Offline James Wilson Everett

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Re: making a cutter for rifling
« Reply #20 on: January 04, 2012, 04:44:55 PM »
I assume that the multiple tooth cutter will do well in rifling a twist iron barrel.  I say "assume" because I have never rifled one.  I have lined one with a very good result - see the topic "rifle barrel liner".  I believe the reason that a single tooth cutter is so much disturbed by a wrought iron barrel is that the slag strings are parallel to the axis of the bore and so at only a very slight angle to the direction of the cutter, I use a 1-56 twist (the best of course).  As a single tooth cutter passes across the slag string, at about 1 degree angle or so, the slag string forces the cutter parallel to the bore axis for a little way until the increasing torque in the mechanism will again move the cutter back in line with the twist.  So you get a little "dogleg" as the cutter passes over the string.

With a twist iron barrel, the slag strings are at nearly right angles to the bore axis and probably would not disturb the cutter in such a way, at least that is my thought on it.

My advice is to use a mulitple tooth cutter simply because this was certainly the cutter design used in the 18th c.  These cutters were coarse toothed, just as the example, above.  The use of very fine cutter teeth, such as a section of a round file will tend to fill quickly with chips and does not make a good cutter design, although I do use this type to smooth out any visible "doglegs" that I do get.  I read somewhere on this site about a gunsmith rifling with a very fine tooth cutter and the number of pulls to rifle the barrel was rather high (like a bazillion pulls), the coarse multiple tooth cutter can finish rifle a barrel in 500 - 700 pulls.

Let me know how the twist iron barrek turns out.

Jim Everett

Offline kutter

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Re: making a cutter for rifling
« Reply #21 on: January 04, 2012, 10:24:48 PM »
The bbl I have is a damascus 15/16 oct, 50cal. It came from Ken Bresien's shop.
He had started to rifle it and ran into a problem I'd estimate perhaps 1/3 to 1/2 way through the rifling process.
A dog-leg or skip in one of the grooves is a good description I guess.
He shelved the bbl,,along with 2 others.
How long ago he worked on these I do not know.

A year or so ago when his health was bad, his shop was cleared of some excess inventory and sold. These bbls among them. I believe at least one of the 3 was rifled sucessfully, the other 2 (including the one I obtained) had problem areas in them.

The rifle bbl appears to be what I would call new/old/stock, not a resurrection of an old worn bbl.
Never breeched, no dovetails, slots, etc.

Bore is diamond bright as all Ken's work was.
From what I remember he used a single point cutter in the little work I saw him do for me.
Perhaps that caused a problem in the damascus bbl.
I remember once when I gave him a Winchester 73 bbl to rebore/rifle from 38wcf to 44wcf, he was very careful to know the ser# of the rifle to check bbl steel. He said the stuff they used early on would cause problems with hard & soft spots and 'snag' his cutter.

Perhaps the existing rifling he cut is deep enough to use as in 'refreshening' and deepen and straighten out the bad spot which is about 4 or 5 inches from one end.
Other than that, a step up in size and re-rifle.
Perhaps a liner,,to side step any possibility of a problem.


Thank you for your information..your posts are most helpful and interesting.

Offline James Wilson Everett

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Re: making a cutter for rifling
« Reply #22 on: January 05, 2012, 04:55:46 AM »
If the bad spot is near the breech end of the barrel, everything may turn out OK.  The reason I rifle from the breech end to the muzzle is that whenever I get those inevitable OOPS! they are at the breech end.  Often the first few inches of rifling at the breech end are not pretty.  If the rifling is in good shape at the muzzle the gun should shoot alright.  However, if the bad spot is 4 inches from the muzzle end, it is a problem and the barrel will probably not be a real "tack driver".

I would stay away from the single point cutters, they are for modern guns, like those that load from the back side.

Jim