AmericanLongRifles Forums
General discussion => Gun Building => Topic started by: Nate McKenzie on September 02, 2013, 09:28:30 PM
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I bought a set of these stamps and am having trouble getting a good print. Anyone having better results and willing to share the secrets? Whats better- one hard blow or several lighter ones. What weight hammer? How do you hold the stamps steady so you don't kill your fingers? How many strikes as you rock the wider stamps on a round barrel, etc? Thanks for any advice.
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Usually 3 strikes to roll a stamp over a rounded surface that won't allow it to imprint in one wack, or doing a large imprint stamp onto a flat surface .
The style of cut of the stamp makes some much harder to use than others. Some imprint the background into the metal, leaving the figure standing. Those are particularly difficult to hand stamp as a tremendous amount of metal has to be displaced. They are easier to make as the figure is simply cut out instead of relief cut, but much harder for the user to punch into place. I've seen some of the English stamps made this way
Use a large hammer, one that you can confortable handle. You don't want to have to raise it much higher than the back of your head and then come down squarely on the stamp. If you need to raise it farther back to get more force,,the hammer is too light. The farther you have to raise it, the more off the mark your hammer strike can be. If the hammer is too heavy to lift, you'll have the same accuracy problem when trying to strike the stamp.
I usually put a piece of tape on the surface where I want the stamp to be. That'll be the bottom edge of the imprint. Not as important in proof marks and the like but it gives you something to work off of if you're like me and has to get in close to see correctly.
Place the stamp down (oriented top/bottom correctly of course!) on the surface and pull the bottom edge up against the edge of the masking tape you laid down.
Now roll one the stamp up one one edge,,either right or left,,does make a difference.
Stamp that edge into the metal. You should have approx 1/3 of the image in place and a nice depth at that.
Replace very carefully the stamp into the imprint at the same angle it was struck. You must make sure it is correctly seated again.
Now roll it back to the upright position and strike it again. That imprints the 2nd 1/3 of the print on a rounded surface,,it will imprint the entire image on a flat surface (but not very deeply).
Roll over to the other side and complete the last 1/3.
After you do a bunch of these, you can do them w/o ever lifting the stamp from the metal. A quick 1,2,3 as you roll the stamp over from one side to the other on the rounded surface.
Vibration or 'give' in your set-up is your worst enemy. The part must be dead solid when struck. Bounce-back is commonly seen in hand stamp markings. That double image thing. It can be from the impact of the stamp,,the part recoiling and bouncing back and restriking the stamp again. Or too light a hammer bouncing off the stamp after punching it and restriking it a second time.
Careful w/barrels. It's easy to imprint the metal and have it show on the inside. Many M/Loader bbls are softer steels. Muskets can be thin. It's easy to 'make your mark' on the inside,,not that it's going to be seen too easily. It's just something you don't want to do.
(I will always remember the imported O/U shotguns in one custom shop I worked in in the 70's that were refused because everyone had their bbl marking so heavily imprinted they could be seen inside the bores.)
Filling the bore with Cerro-Safe helps with deadening the strike & any vibration for a nicer imprint, but it does not lessen the chance of a signiture of your work on the inside of the bore if you get carried away.
Wear safety glasses... stamps are file hard. They can chip and chatter, I've had them escape and fly away right out of my gnarly digits too when struck. I'm still missing a 7.
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I hand stamp serial and heat numbers on parts I make at work. I never use hard hits, just a ball pean hammer in excess of 28 oz and several light strikes while carefully rocking the stamp. I even use this method when applying replica barrel markings and they come out as they should.
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I agree on the technique of starting the stamp on one edge, and tapping it in a bit at a time. Much easier on the nerves and bore, much less likely to get a double strike.
I think this stamp was done while the barrel was hot. It's very deep. it's about 5/16 square.
I would think that the bore would have been upset, so this would have been stamped before reaming. Just taking a guess.
(https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Fi12.photobucket.com%2Falbums%2Fa246%2FTom45-70%2FOriginal%2520gun%2520photos%2FDSC_2219.jpg&hash=1d6db0565588fbd3530e1551f8e9b436d0a4e68c) (http://s12.photobucket.com/user/Tom45-70/media/Original%20gun%20photos/DSC_2219.jpg.html)
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Nate,
I also wrap a piece of leather around the shank of the stamp an hold onto it with a short/small pair of Vise-grip pliers.
It saves the fingers and, the stamps don't fly nearly as far!
Cheers,
Smoketown
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I agree on the technique of starting the stamp on one edge, and tapping it in a bit at a time. Much easier on the nerves and bore, much less likely to get a double strike.
I think this stamp was done while the barrel was hot. It's very deep. it's about 5/16 square.
I would think that the bore would have been upset, so this would have been stamped before reaming. Just taking a guess.
(https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Fi12.photobucket.com%2Falbums%2Fa246%2FTom45-70%2FOriginal%2520gun%2520photos%2FDSC_2219.jpg&hash=1d6db0565588fbd3530e1551f8e9b436d0a4e68c) (http://s12.photobucket.com/user/Tom45-70/media/Original%20gun%20photos/DSC_2219.jpg.html)
Any possibility that a mandrel was used in conjunction with the stamp on a hot barrel? Would that tend to lessen upsetting?
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vice grips to hold the stamp. Usually about 4 accurate strikes with a 4lb hammer.
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I would think a mandrel would have to be in the bore, hot or not. A stamping that deep would squish the tube oval.
(https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Fi12.photobucket.com%2Falbums%2Fa246%2FTom45-70%2FOriginal%2520gun%2520photos%2FIMG_4314.jpg&hash=0ba37f21820c5e02c475ba8490733a6ab6b3185f) (http://s12.photobucket.com/user/Tom45-70/media/Original%20gun%20photos/IMG_4314.jpg.html)
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Actually, where that stamp is, it doesn't matter whether the bore is deformed or not. Only the charge sits in that area and it couldn't care less about the shape of the bore.
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Some of the extemely large and/or deep impressions on bbls I'd just guess have had to be done with the bbl in the rough state for them not to show on the inside. Perhaps also done while the steel was at red heat during work yet.
Not knowing what muzzle loaders look like inside with these large marks on them, but I do know what cartridge guns do,,and the heavy deep stamp does not show inside. No deformation of the surfaces. Not even on a reletively thin shotgun bbl breech and shotgun bbls dent almost as easy as looking at them..
The Jos Whitworth Trade Mark stamp on some shotgun tubes is good example. Impaled just ahead of the bbl flats on the bottom, it is extremely deep. The 'Wheat Sheaves' portion of the mark is wide and displaces more metal that a simple hand stamp can do.
(This one small thing that can be spotted in a fake upgrade in some shotguns especially high grade Parkers.)
The stamping must have been done when the tubes were in the rough yet, perhaps aided by punching while hot also.
Other makers marks on imported tubes are found especially on Damascus bbls and many of those are the same extreme heavy deep punched mark. No damage to the inside.
Fox stamped the bbl weight in the same location on each tube (1-4) w/a large single number punch while the bbls were in the rough state. They all started out the same size/diameter.
Finish & final boring removed any mark on the inside.
Bringing the rough tubes down to finished weight & contour still leaves the numeral in the bbl though the #1 (heaviest) is seen deeper than the #4 (the lightweight) because of the amount of metal filed away. They are really punched deeply into the metal.
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Some stamps could have been done when the barrel was red hot but not many, certainly not the proof marks. However, some marks could have been made while the barrel was rough bored, these would not show evidence of the exterior stamping in the bore.
I can only speak of military barrels but I can give an example of a British Sea Service pistol barrel with a perfect bore that showed distinct protrusions in the bore where the view and proof marks were stamped on the exterior. We need to keep in mind that these antique barrels were made from relatively soft wrought iron, not the harder steel that modern barrels are made from.
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If you ever tried to straighten a modern barrel, you'll appreciate how resistant they are to being distorted! It would be easier to bow a barrel than to dimple the bore on a medium/heavy walled barrel.
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Thanks for the input and advice.
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I also had a pair of antique Dragoon barrels I stocked into pistols. The proof marks on both barrels were a visible dent inside the bore. My Carolina guns will have slight dents inside the bore from the English proof stamps I use. Makes no difference in safety or how the gun shoots.
Basically, dents from proofs stamps inside the bore is historically accurate. ;)