Slitter Geometry

[Charlotte]

Thank you very much for the work and patience you have shown here and else where.

In your demonstration you revealed to me the secret of an event that had often puzzled me.

The hardest blow that I've ever seen struck with a hand hammer was by a retired farrier doing a demonstration of forging horse shoes from scratch.

He drew out the toe clip on with one blow. It was not until I followed through you hammer demonstration and the accompanying explanation that I realized how a 70 year old man with 50 years of hammering behind him could still be hitting harder than I could at 30. He simply knew how to hold the hammer and how to strike with the confidence of a man that knew exactly what he was doing.

Bob Patrick, demonstrated at a conference I attended several years ago.
He remarked after doing a "green coal" tutorial that "Most of you don't know how to hammer"

I believe that you have helped my greatly and that after all these years I'm finally learning how to hammer.

[Hofi]

ON 1997 when I was first teaching at the ''ozark school'' Bob Patric was my student and he took two classes with me
Hofi

[Archie Zietman]

Hello.
I've read the thread through, though I'm still a bit confused on one thing: You drive the cold-chiseled punch through the metal from one side, and then use a flat punch of the same cross section to knock out the slug from the other side? Or do you use the chisel-punch to cut through from both ends and drift it to the final shape?

Thanks,
Archie

[brianbrazealblacksmith]

Hello.
I've read the thread through, though I'm still a bit confused on one thing: You drive the cold-chiseled punch through the metal from one side, and then use a flat punch of the same cross section to knock out the slug from the other side? Or do you use the chisel-punch to cut through from both ends and drift it to the final shape?

Thanks,
Archie

I drive the "cold-chiseled punch" through from one side, almost all the way to the anvil, then punch the plug out with the same punch from the other side. I do the same for the other punches also, [notice the shape of the plugs that come out]. I only use flat bottom punches on occasions where I want a counter sunk hole.

[irnsrgn]

I start with a hand held slitter made of oil well sucker rod with a rounded chisel sharpened end.



then switch to the rodded one on the right also made of sucker rod.



after using it on both sides of the eye,



I use the one on the left shown here for small eyes,



and the one in the middle of the second picture for larger eyes, made of 1045 PTO shaft.

[irnsrgn]

If you look closely you can see various slitters in my rack.

[Jura T]

Brian, a couple of questions if you don't mind. When punching thin stock, what is the colour of the plug when you flip the piece over and start removing it from the other side?

On the horse head bottle opener, do you use a drift the get the ring to final size and how do you make the cross section round? Are you using some kind of a bottom tool as the inside of the ring looks so clean?

[Hofi]

60 PERS OF TONGS PARTS SHISELED/SLITTED AND DRIFTED READY FOR THE NEXT AND LAST STAGE OF FORGING FOR GERMANY ''EYE'' nd ''woop 35mm'' tongs

[brianbrazealblacksmith]

Brian, a couple of questions if you don't mind. When punching thin stock, what is the colour of the plug when you flip the piece over and start removing it from the other side?

On the horse head bottle opener, do you use a drift the get the ring to final size and how do you make the cross section round? Are you using some kind of a bottom tool as the inside of the ring looks so clean?

The plug is darker than the rest because of the contact with the anvil and punch but quickly becomes the same color as the rest because of the heat being transferred back into the thinner material. I go by the shiny impression from the anvil contact and take my time to make sure I am lined up correctly with a lite mark before I deliver a sharp blow to punch the plug out.
On the bottle opener, I slit and drift both holes. [one is 5/8", the other is 3/4"] No special bottom tools are used, just an appropriate hole on the bottom. The bottle opener is hammered to size on the horn.

[Sam Salvati]

Dang Brian, that is a cool bottle opener well done! I gotta talk to the Northeast Blacksmith's Association head guys and see if we can get you out here for a demo one year!

[brianbrazealblacksmith]

ApprenticeMan, I'd love to come to New York. I'll be in Virginia in November at Yesteryear Forge doing a class on forge welding and hammer making, while I'm out that way, it would be a good time to do something in New York. Karen has put together some slide shows on my space that you may want your people to look at. Brazeal Brothers (Brian Brazeal) | MySpace.com

[primtechsmith]

Brian will be teaching those two classes and doing a demo for us in November. All are welcome!!!

[jimbob]

can you give a hint at to where in Va are you?

[primtechsmith]

The school/host location is in Crewe Virginia.
Here is a google link on the location:
Yesteryear School of Blacksmithing - Google Maps
From there you can zoom out and see what is going on....we are about an hour and a half or so south of Richmond.

Peyton

[jimbob]

thanks going to try and make it

[primtechsmith]

Cool!
I am really looking forward to the Hammer Making Class. There will be a lot to learn from Brian on everything from tooling to striking, and most importantly reasoning behind the actions and process in hammer making.

Peyton

[ofafeather]

Just found this thread over a year later but it's such a great one I thought I'd give it a bump.

[David E.]

Just found this thread over a year later but it's such a great one I thought I'd give it a bump.

Thanks for doing that,I read it at the time but after rereading it all,a lot more has stuck.
Thanks to Hofi,Brian et al for such good info.

[ofafeather]

Okay, here's a feeble attempt to make a 1/4" punch. It started life as a larger flat bottom punch. I shaped it on the grinder giving it a slight point, trying to copy Brian's. I tried to make a straight shaft and then have it taper after a bit. I tried it out and encountered some trouble. I was punching thin stock and it really didn't work out that well. Guess I need a bolster. Tried it with some thicker stock (1/4" I think) and it worked better but I could get the plug to drop out. It just kind of hung on. I poked it an pulled it off with pliers.

I have questions about this:

1) Does the shape of the punch make sense? It's not the best grind but it's my first attempt.

2) Can I quench this punch? I don't know what kind of steel it is, obviously tool steel of some kind. You can see in the pick that there was some color running from using the punch

3) What can I use for lube? I use a gas forge so don't have coal dust. Can I used regular copper anti seize compound?

I think that's it for now. Make think of some more.

Thanks.

Eric

[pkrankow]

Easy lube options:

charcoal, even briquettes that are pulverized are good for this!

Salt lube take a 1pint container, add 2 tablespoon dish soap, hot water, and table salt to saturate the water (about 1/2 cup), dip your tools and let dry. Makes 1 pint. (thanks for the recipe Mr.Hofi) They dry quick in dragon breath and after the tool is warm from use. Caution this solution can act like superquench and cause good steel to crack if the metal is too hot.

Those are what I have used with good success.

Phil

[ofafeather]

Easy lube options:

charcoal, even briquettes that are pulverized are good for this!

Salt lube take a 1pint container, add 2 tablespoon dish soap, hot water, and table salt to saturate the water (about 1/2 cup), dip your tools and let dry. Makes 1 pint. (thanks for the recipe Mr.Hofi) They dry quick in dragon breath and after the tool is warm from use. Caution this solution can act like superquench and cause good steel to crack if the metal is too hot.

Those are what I have used with good success.

Phil

Phil, thanks. Will try that. Any idea if I can should quench this punch or not? With the limited punching that I've done so far I've just let it air cool.

[John B]

Okay, here's a feeble attempt to make a 1/4" punch. It started life as a larger flat bottom punch. I shaped it on the grinder giving it a slight point, trying to copy Brian's. I tried to make a straight shaft and then have it taper after a bit. I tried it out and encountered some trouble. I was punching thin stock and it really didn't work out that well. Guess I need a bolster. Tried it with some thicker stock (1/4" I think) and it worked better but I could get the plug to drop out. It just kind of hung on. I poked it an pulled it off with pliers.

I have questions about this:

1) Does the shape of the punch make sense? It's not the best grind but it's my first attempt.

2) Can I quench this punch? I don't know what kind of steel it is, obviously tool steel of some kind. You can see in the pick that there was some color running from using the punch

3) What can I use for lube? I use a gas forge so don't have coal dust. Can I used regular copper anti seize compound?

I think that's it for now. Make think of some more.

Thanks.

Eric

Hi Eric, First off small holes in thin stock, are not the easiest thing to practice on, especially as a learning curve, By the time you get in position the tip of the punch sucks heat from the piece and then makes the punch prone to mushrooming or deforming in the punched socket before you get all the way through.

If the slug is hanging on, you have not got the two points of entry exactly in line, as the slug should drop out cleanly, the bolster plate only supports the area surrounding the punched hole to prevent the bar bending or deforming an possibly trapping the punch.

"Does the shape of the punch make sense? It's not the best grind but it's my first attempt."
Pictures are better than words, but can still be open to misinterpretation, and I personally do not favour this type of punch/slitter point. However if it is a slitter you are making, it wants to be tapered all the way as opposed to parallel, and would be better forged then finally poilished as opposed to grinding to size. In the pic it looks more like a centrepunch than a hole punch/slitter, that may be due to camera angle and small size.

"Can I quench this punch? I don't know what kind of steel it is, obviously tool steel of some kind."
Personally I would forge it to shape, allow it to cool (normalise it) and then use as is, cooling the business end during and after use, but not letting the end get to a red heat when on the workpiece, well before that point in fact, keep your workpiece hot, and the business end of your cutting tool cool.

As for lube, I cool in tallow or water and don't use lube as such, so bow to the more experienced in those techniques.

[ofafeather]

Okay. I'll make another pass trying to forge the punch. I'll start with the same piece of steel. Let's say I would like to forge a round punch in the 1/4 - 3/16 range. If I make the shaft long enough to hand hold comfortably will it still be rigid enough to do the job? What would a good length be? Should I try something different first?

[John B]

Okay. I'll make another pass trying to forge the punch. I'll start with the same piece of steel. Let's say I would like to forge a round punch in the 1/4 - 3/16 range. If I make the shaft long enough to hand hold comfortably will it still be rigid enough to do the job? What would a good length be? Should I try something different first?

Guessing the sizes by looking at your pictures I would say that will work

Good length is what you are comfortable with 6" overall plus will work, or you could hold the punch in suitable tongs.

Forge your end to the required diameter, remember forge the square to size you are making, forge off corners to octagon shape, then forge off all corners until you reach round, it can be slightly tapered, and my preference is for a flat end at the cutting face with a sharp corner which helps shear off the metal as you pierce into the metal. Keep the end cool by dipping the tool into water after two or three blows,

You may find it easier to practice on material 3/16" plus

There are other end configurations and angles that can be used, but I find the square cornered flat end works well for me

[bigfootnampa]

Okay. I'll make another pass trying to forge the punch. I'll start with the same piece of steel. Let's say I would like to forge a round punch in the 1/4 - 3/16 range. If I make the shaft long enough to hand hold comfortably will it still be rigid enough to do the job? What would a good length be? Should I try something different first?

You wouldn't use a slitter for a 1/4" hole. Your shape is not too bad but taper it on a long angle. Do NOT grind it parallel at the tip. The continuous taper strengthens the tip... make it 3/16" if you are aiming for a 1/4" hole. If you need it straight sided, drift or drill after punching. The center punch shape is fine and will help you get started in the right place... the small point will also limit contact with the hot metal until you make your first hit. Make sure that you have a cutting saddle in place though, so that you don't mar your anvil. I like longer punches in the 8" to 10" range (even longer in the larger sizes) and that metal will get too thin if you draw it that much... so compromise on this one. I would probably quench that punch in oil and then flame it off a few times (about 5X) to temper. I would only heat the tip but quench most of the punch (well up past the hot tip). The quenching is not too critical though as a small punch like that gets exposed to lots of heating and cooling cycles... your original HT is unlikely to have a long term effect. I'd likely re heat treat it after every half dozen holes or so.