Pein profile

[rockstar.esq]

On Saturday I was forging hammer heads into tomahawks using my cross pein to spread out the blade area. I'm fairly new to blacksmithing and I felt like my progress was slow. After two hours of forging, I still don't have the head area spread enough. My cross pein comes to about a 1/8" radius. It's a fairly typical 3lb cross pein hammer like you'd find at a hardware store.

I've noticed that several cross peins available at Centuar Forge have much wider pein's. The hofi style pein seems to be nearly flat for 1/4" with a small radius on each side.

I know that everybody has their own take on things but I'm curious if the flatter pein has an advantage?

Thanks,

[Rich Hale]

Metal moves under the force you provide, in this case with a hand hammer. And it really comes down to how much force you can apply and that could be measured in psi or pounds per square inch. Think about lady in a high heal with a little tiny heal foot print stepping on the top of your barefoot. That would hurt. Now if the same lady wore a foot with a bottom surface larger than the top of your foot it would directly change the psi applied to youir foot.
Hammer faces are all about psi applied. A portion of the hammer that makes contact with the metal that is really small will apply more psi than one with a larger contact surface. A contact surface of hammer face that has a one eighth inch radius will apply more psi than one with a larger contact surface if each of them weigh the same and is traveling the same speed and the surface the piece being struck is the same on each instance.
For how you are using the hammer you will make dents deeper into the hot metal with your pein than you will with one with a larger radius or one with a flatter radius. Get with other smiths in groups and watch how they forge and see how they move metal. Lots of other things enter into this whole thing. Are you getting the metal to forging heat? is the metal a steel known to take more force than other metals? Is your anvil up to wot you are asking of it? Are your forging skills up to this task? Don;t be offended by these questions. They all are part of this. I would use a small radius pein to move metal fast then a flatter face to remove all of the texture I have done to it if I want it smooth. ( I do not know a short answer that would be of value)

[David Gaddis]

impossible to explain it any better

[rockstar.esq]

Rich,

I understand the PSI example you gave. To answer your questions, the metal is a hammer head so it's an unknown high-carbon steel. I'm using a coal forge and working the metal when it's bright orange in daylight (my smithy is outside). My anvil is a new NC Tool 70lb Short Sugar, it's been great for everything thus far. It's mounted on a firm stump and it doesn't move under the hammer.

It's entirely possible that these hammer heads are red-hard. I've successfully drawn out hawks before with less difficulty. I am however, eager to learn as I've little experience compared to others.

So if the wider peins are applying less pressure and are hence moving metal more slowly, What advantages does this offer? Blacksmiths seem to always have a good reason behind every aspect of their tools. What does a wider pein do better?

[bigfootnampa]

The wider peens are indeed more commonly favored. Because they will thin and spread the metal adequately. A too thin peen (which is normal on hardware store hammers) tends to make sharp grooves in the metal and take a lot of flattening work to get smoothed again. You will almost certainly be happier with your peens reshaped/dressed to slightly wider radii... because almost all smiths like that shape better... proof that it works better for them. I don't know just how to explain it but the sharper peens might seem as if they would move thick, tough steel better and theory seems to support that... experience says differently... the blunter peens are faster as well doing a cleaner neater job. It seems to me that the narrow peens allow the metal to escape the hammer forces by squeezing out to the sides... while the slightly wider peens capture enough metal to thin and widen the work instead of just grooving it.

[bigfootnampa]

BTW VERY few hammer heads are high carbon steels... most are a medium carbon steel around 1045 or so. High carbon steels are usually considered to be around 1090 and up.

[John B]

1/8 radius is fine for texturing. What you are trying to do is spread the metal, so you need a "fullering" process, this can be done using the bick of the anvil, or a top fuller with the work on the anvil face, or a top and bottom fuller, or a hammer with a wider pein

Basically when you are forging on the anvil face with the flat face of the hammer you are trying to compress the workpiece and by the nature of it being solid it will spread to escape this compressive force and become thinner.
To spread metal we "fuller" it, if you refer to the Blacksmiths Tools explained in the tools section there are some fullers and "cheese" fullers illustrated.

By using the radius on a fuller (or bick or straight pein), as you apply pressure to the metal between the flat face and the curved face, the material is squeezed outwards as well as being thinned in the centre, if you do this at intervals, producing a corrugated effect, you can then flatten the peaks of the corrugations to return the material to a smooth finish.

There are many examples of this if you look at vids of power hammers and forging presses working, as they come down on the sow block / bottom die (which are usually a radius/curved profile) you can see the squeezing effect lengthening the workpiece.

Different applications need different size fullers, so a radius on a hammers' pein is a compromise, and one that is most useful for the size of work the smith regularly works on, consequently many smiths have more than one hammer shape.

Hope this clarifies the situation somewhat

[John B]

Double post, sorry

Edited August 6, 2012 by John B

[rockstar.esq]

Bigfootnampa. John B, it sounds like the main reason for the wider pein is to reduce the sharp indentations that take so much work to remove. As I think about it, I can draw out stock much faster using the rounded edge of my anvil as a bottom fuller than I can with the pein. Making tomahawks has focused my attention on the pein since I'm spreading the metal across the bar rather than along the bar. I'll redress my pein wider and see if that helps things.

Bigfootnampa, you may be correct about the hammer being medium carbon. I can say that it hardens in water and it sparks like HC on a grinder. I'm not knowledgable enough to determine the difference between high and medium carbon. For the purposes of a throwing hawk, it doesn't make much difference since I temper them fairly soft to avoid chipping/spalling when they accidentally hit something hard.

Thank you all for your replies.

[Larry H]

are you sure of the type of hammer you have ?

[peacock]

A hot cut is pretty sharp but it is nearly impossible to draw stock out with it. Too sharp a pien lets the hammer penetrate but the taper binds and stops it. Half of the job of a properly shaped pien is to create ridges to concentrate the force of the hammer blow on a smaller area the next pass whitch moves the metal faster. Watch the hammer meet the work when Brian B forges, fuller, flatten, fuller, flatten, very efficient. Not deep narrow grooves but as mentoned earlier a wavy surface.

[JNewman]

Too sharp a pien can create grooves with sides too steep, the next blow beside it can cause the edge to fold over. The folding is a cold shut which can cause cracking.

[rockstar.esq]

Larry H, I'm not sure I understand your question but my hammer is a 3lb cross pein no-name brand I've had for a decade or so. The stock is a harbor freight el-cheapo ball pein that I'm forging into a tomahawk. Peacock, good analogy with the hot cut. I didn't really consider that it would be such a hinderance. J Newman, I've never had it give me a cold shut, but I can see how it could happen.

Thanks all for your help.

[Ramsberg]

A very good experiment in regards to pein shapes is to take a rasp or belt sander to some bits of wood and produce different pein profiles on them.

Then take some clay, playdough will do, and force the wooden peins into the clay. Then take another bit of wood with the same general profile as your "flat" hammer head and push down the bumps made by the peins.

This exercise will show rather clearly where what profile of pein will move the metal too. It will also show, to a degree, which shapes will make cold shuts.

Then after all of this is done, grind the hammers pein into the shape of the best wooden pein.

Caleb Ramsby

[Frank Turley]

I saw Peter Ross a few years ago, and he talked about his hammer peen that was neither half round nor sharp cornered. After inspecting his hammer, I tried to emulate the same style peen on my hammers. Peter was asked why he dressed his peens relatively "flat," and he said, "Less cleanup." As shown, my peen lengths are crowned. The peen thickness on both hammers is 7/16". I was using pretty much half round peens, before I dressed them all. I still get quite a bit of spread compared to the half round style, and there is "less cleanup."

The "red" hammer is my 2.5 pound Channellock, and is my most used hand hammer. It is high carbon steel. The larger hammer I forged from an 18 wheeler truck axle, and it weighs 4.5 pounds. The old truck axle was SAE 1045.

0.60% carbon through 1.3% carbon is considered high carbon.

[Finnr]

Most of the hammers I have made have a peen radius about equal to a nickel and slightly flattened like Frank's hammers. I got lazy on the first and didn't fully round it like I had planned and ended up liking it that way. I have some lighter ones with sharper peens for special uses .

[Francis Trez Cole]

divide and conquer that is what I do. Divide the sections you want to spread and work one section at a time as Rich said mass (hammer weight) x acceleration (speed of your swing = force. Using the horn of the anvil will help.

[rockstar.esq]

Frank, now that you mention it, I recall seeing Peter Ross on a "Woodrwights Shop" program and his cross pein was pretty flat like yours. It just goes to show that blacksmiths always have a reason for what they do. Thank you all for your responses, it's been educational for sure!