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lazlo
07-02-2011, 11:35 AM
I'm into week 5 of the Austin Community College power hammer class, and last week we forged blacksmith hammers. Thought some of you might be interested...

This is what we were shooting for: one of Will's finished hammers:

http://i164.photobucket.com/albums/u15/rtgeorge_album/Blacksmithing/WillsHammer2s.png

We started off with 2" rounds of 1045 (excellent toughness). Blacksmiths tend to like a hammer around a kilogram (2.2 lbs). So you figure out how heavy a hammer you want, and calculate the weight of the round bar with a materials calculator, and add 5 - 10% for oxidation loss from the fire scale.

The forge is definitely not conducive to taking pictures -- it's hot, there are 4 power hammers running with various dies and fixtures, and 6 students running around with hot forgings.

After you squared-up the round bar into the rough hammer shape and broken the edges comes the fun part: drifting the eye hole. You start by carefully marking-out the drift slot on the centerline, with what will be the hammer face 1/8" forward of what will be the peen. If you're off at all on the layout, the hammer face won't be centered on the shaft. It happens.

Then you get the hammer blank hot, and slit a hole through the block on the power hammer. It's a lot of work, and you need to slit from both sides to keep the hole centered.

The whole time you're doing this, the block is @ 1800 - 2,000°F, and if you don't hit it true, you turn your hammer head into a rhombus, which is a PITA to fix:

http://zonalandeducation.com/mmts/geometrySection/commonShapes/rhombus/rhmbs2.gif

Will with a hammer he just slit. He's holding the big drift that we're about to pound into the hammers with 12 lb sledges. Notice the black section through the middle of the hammer head: that's where the metal cool from the slitting chisel driving through the forging:

http://i164.photobucket.com/albums/u15/rtgeorge_album/Blacksmithing/Willforgings.png

This is one of the six hammer blanks slitted. I don't know who's it was, but notice the slit isn't straight -- oops!

http://i164.photobucket.com/albums/u15/rtgeorge_album/Forging%20a%20hammer/IMG_0226.jpg

lazlo
07-02-2011, 11:39 AM
Now for the the Old World blacksmithing: each person re-heats their hammer blank, picks a drift (you want to use the same drift each time), and puts the hot hammer blank on a drifting stand. The owner of the blank holds the drift, and 3 others strike with sledges, driving the drift into the hammer body. This is exactly like the black and white videos of the blacksmiths forging ship's anchors and chains.

People have asked if you can forge tool steel. High carbon steel is a lot stiffer under the hammer than mild steel. I've been forging tool steel blanks for katanas, and 52100, W2 et al is much stiffer than high carbon steel...

http://i164.photobucket.com/albums/u15/rtgeorge_album/Blacksmithing/WillStriking.png

It gets pretty crazy with three people striking and a fourth person holding the stake, but after 5 weeks you get into a rhythm...

Each time, you get the drift a little further into the hot hammer, then you run over to the power hammer and holding the hammer with the eye drift, you start forming the cheeks:

http://i164.photobucket.com/albums/u15/rtgeorge_album/Blacksmithing/WillPowerHammer.png

After each trip to the drifting stand, it's back into the fire. Rinse, repeat. Many times...

http://i164.photobucket.com/albums/u15/rtgeorge_album/Forging%20a%20hammer/IMG_0233.jpg

By the time you've gotten the eye drift through on both sides, and shaped the cheeks on each heat, your blank looks something like this. I've fullered the hammer head at this point. That's partly decorative, but it also isolates the mass of the hammer face from the body, so it's easier to shape:

http://i164.photobucket.com/albums/u15/rtgeorge_album/Forging%20a%20hammer/IMG_0230.jpg

lazlo
07-02-2011, 12:02 PM
The next step is to forge the peen, which was the most difficult part, in my experience. Will's hammers have a beautiful fishtail peen -- it flares-out on the sides. That's not only decorative, but you dress the points of the fishtail so you have a rounding face when you hold the peen diagonally.

To get the fishtail, you need to use flat dies on the power hammer, and step down from the body to the tip of the peen. If you use accidentally use drawing dies (curved dies) like I did here, you'll pull out a straight tapered peen with no fishtail flare :)

http://i164.photobucket.com/albums/u15/rtgeorge_album/Forging%20a%20hammer/IMG_0228.jpg

So I got to class early on Wednesday, and upset the peen. That involved getting the peen hot (and not the body), clamping the glowing hammer head in a leg vise, peen up, and hammering the thin edge of the peen to mushroom it. That flares it in both directions (makes the peen fat), so another trip to the power hammer with flat dies this time, and I ended up with this:

http://i164.photobucket.com/albums/u15/rtgeorge_album/Forging%20a%20hammer/IMG_0231.jpg

At that point, you heat the head up one final time, drive the eye drift on softly (just as a handle), and dress the hammer face and peen.

For a blacksmith hammer, you want a large radius curve on the face. The peen is radiused in two axis': long-wise and front to back. If you forge these shapes, you don't have to grind off material from the hammer, which throws off your weight calculation.

This is after dressing and some cleanup on the belt grinder:

http://i164.photobucket.com/albums/u15/rtgeorge_album/Forging%20a%20hammer/IMG_0232.jpg

lazlo
07-02-2011, 12:05 PM
Finally, the fun part -- differentially heat treating the hammer. This is a blacksmith shop, so the heat treat is amazingly simple and effective: you gradually heat the hammer to non-magnetic. That means putting the hammer on the hearth of the forge, then slowly moving it into the forge over a period of about 10 minutes. You want to reach austentizing temperature (around 1500°F), but you don't want to ruin the grain size by overheating it. The forge is 2,000° F, so you have to carefully watch it, and keep pulling the hammer out and checking against a magnet. When it hits the Curie point (non-magnetic), you quench it into a bucket of water at 115°F.

At that point, the hammer is glass hard. If you drop it onto the concrete floor, it will likely shatter. Checking the hammer face with a fresh file, it just skidded across. One of the students described it as "hard ice."

This is what I thought was the really neat part: differentially tempering the hammer. You take the hammer to the belt grinder, and grind/polish clean faces on the face, peen, and the cheek bevels. Then you take an acetylene torch, and carefully heat the center of the hammer. This "fire cleans" the hammer: the high temperature of the torch flame blows the scale off, and slowly builds-up the temperature of the body. The body turns purple, and soon afterward the face and peen turn a very light silver-straw color. At that point, you quench the hammer again (since the core of the hammer is still hot), and if you did everything right, you end up with a hammer face and peen around 50 HRc, and a main body around mid 40's for maximum toughness.

Here's the final product. The handle is Osage Orange -- very hard and dense, doesn't rot, and doesn't transmit shock up the handle like oak does. We're going to handle the hammer and stain on Wednesday -- the Osage Orange turns that beautiful redish-brown in the first picture. It's hard to see the violet color I left on the main body -- need to take another picture:

http://i164.photobucket.com/albums/u15/rtgeorge_album/Forging%20a%20hammer/IMG_4181s.jpg

PeteF
07-02-2011, 01:58 PM
If you wanted a hammer why didn't you just go down to Harbor Freight?

:p

Nice job BTW, thanks for posting. Didn't you do some work on I Katana I'm very keen to see you post on that.

Pete

DATo
07-02-2011, 02:27 PM
Thanks for the instructional tour. I've been a machinist a long time but I've never done any forging in my life. I found your pictures and text explanations fascinating. Very nice work too by the way !

rollin45
07-02-2011, 03:08 PM
Very cool!!
Thanks for that.

rollin'

Sonnet
07-02-2011, 03:26 PM
Neat project:) Looks fun and challenging. Lots of good education as well. Nice job!

wierdscience
07-02-2011, 06:00 PM
Looks good,Osage Orange handles,must be a Texas thing:)

You gonna leave the head rough,or polish it out all the way?

doctor demo
07-02-2011, 06:13 PM
After reading the text and looking at the pictures I have a new respect for hammers.
But now I can't use one of My favorite phrases any more:(
"That boy is dumber than a bag of hammers."

Nice work!

Steve

sasquatch
07-02-2011, 07:15 PM
Thanks for posting that great gallery of pictures, very educational!!

Mike Burdick
07-02-2011, 07:31 PM
I've enjoyed blacksmithing for over 50 years and have made many forging tools. For hammer blanks I go to stores like Goodwill and find old "made in the USA" sledge or ball peen hammers and reforge them into any shape I need. Cost is minimal! I see "tools" in all kinds of junk.:o Now you will too!:)

.

Mcgyver
07-02-2011, 07:32 PM
Nice Robert, thanks for sharing it

Black_Moons
07-02-2011, 08:13 PM
After reading the text and looking at the pictures I have a new respect for hammers.
But now I can't use one of My favorite phrases any more:(
"That boy is dumber than a bag of hammers."
Nice work!
Steve

Sure you can. Anyone who would put such artworks into a bag where they would smash and dent into eachother is pertty dumb. :)

I don't know who's it was, but notice the slit isn't straight -- oops!

Just call it an ergonomic hammer, Nobody will question it.

sasquatch
07-02-2011, 08:18 PM
May be a silly question here but somewhat on topic,, i've read Alex Wagers books a few times about smithing, if anyone hasn,t seen them, they're not a bad read at all, an interesting guy.

( I posted this in response to the above post about "Seeing" tools in scrap, as Wagers often did,, and i suppose many who forge and work metal also do.)

S_J_H
07-02-2011, 08:49 PM

Steve

07-02-2011, 09:09 PM
I never realized there was so much to making a good hammer....:D

JCHannum
07-02-2011, 09:40 PM
Good thread Robert, thanks for the write up. I didn't realize osage orange had a use beyond fence posts. It is a miserable wood to work with.

http://i164.photobucket.com/albums/u15/rtgeorge_album/Blacksmithing/WillStriking.png

Obligatory caption; "When I nod my head, you hit it."

RussZHC
07-02-2011, 11:12 PM
Thanks for the pics and informative words.

Does my heart good to see something I would love to do still being done (esp after F*&^%\$# around with wiring for hours)

boslab
07-02-2011, 11:18 PM
thanks for a well written, well described 'lesson', i'm learning slowly, but things came back to me from when i was a kid, my dad had a forge, one of the things he kept drilling me with was not to 'burn' the forging, i was young with no metallurgical knowledge of grain size so it went over my head, i now see the significance, i've made loads of chisels and the like, some better than others, i can see the failures were in fact overcrystalised or burnt and thats why they broke, one even displayed a shrinkage crack along its length, overquenched overheated, those pritty colours shure do mean a lot.
I have no one to teach me now mores the pitty but some things come back to me
Adding a handfull of lime to the water quench bath, i still dont know why but i tried it, theres somthing in it i'm shure, the old man insisted that on no account was the water quench to be changed, just topped up with rainwater from the butt outside, not tap water, and a handfull of lime to sweeten it up.
all these things seemed weird to me, but the addition of lime seems to stop algie growing in the bath and just alter the boiling point a touch to ease the boil bubble layer that can insulate the item during quench.
Keep it moving boy! was the other thing that came back, its no bloody good just sticking it in! [there was a rather crude inference to sex at that point which as a kid was quite embarrasing but i was on a farm!], this would seem to also help with the removal of the bubbles that surround the article being quenched,
Another thing that it lead to was remembering how to tighten somthing up, say when a hole was just a little too big, heat it up, quench and repeat, there was a permanent shrinkage, particularly noticable with wrought iron, i have since found this to be a fact from some controlled experiments.
We had lots of quench 'baths' usually tin buckets!, oil [old engine, handy for blackening too, just dip burn it off with a torch, repeat till black enough, looked nice ] water with a touch of lime and the most vicious of them all seawater from the tidal river, he used that on scyth and scycle blades, folk were still hand cutting in the 60s, especially the grass verges at the sides of roads, a free source of hay for the winter if you had limited land which we did as it was not a very big farm, more smallholding really. I can remember my mother using a dutch scyth iuside the local oil refinery and cutting about 1/2 an acre of grass a day, mind she was a big strong woman, not to be messed with.
I still have some fullers and punches but alas no hammers, other than the ones i have bought, need a power hammer really if your on your own, another item to add to the list!
thanks for the article, really good
regards
mark

lazlo
07-03-2011, 02:02 PM
If you wanted a hammer why didn't you just go down to Harbor Freight? :p

Why buy a tool at HF when I can spend 10 hours in a hot forge making it? Dumber than a bag of hammers! :)

Nice job BTW, thanks for posting. Didn't you do some work on I Katana I'm very keen to see you post on that.

Yes, the katana was extremely challenging, a lot of work, and a lot of fun! I wanted to wait to post it when I was finished, but the problem is that we used high vanadium tool steel for the blade, and I'm finding that it's a bitch to finish profile/polish. It literally strips the grit off high-quality sandpaper.

I tried to take a machinist short-cut of setting it up on the surface grinder -- if I can get the Shinogi-Ji flat (the flat ridge along the back 1/3rd of the blade), the rest of the polishing is pretty straightforward. But the blade has a distal taper. I tried to shim the taper on the magnetic chuck, but the heat treated steel is very springy, and it just sucks down around the shims.

I've been slowly polishing it on traditional waterstones, but it's very time consuming, and the tool steel eats the stones like crazy.

I'm going to try setting the blade up on a sine plate -- that would fully support the blade and save me about 40 hours of work...

In the mean time, I have a Photobucket folder with a bunch of pictures and videos:

http://s164.photobucket.com/albums/u15/rtgeorge_album/Katana/

This was one of my favorites:

http://i164.photobucket.com/albums/u15/rtgeorge_album/Katana/IMG_0612.jpg

lazlo
07-03-2011, 07:30 PM
Looks good,Osage Orange handles,must be a Texas thing:)

I'd never heard of it before, but from discussing with several Texas natives, including John (TexasTurnado) it's more commonly known as "Bodark" (a TexArkana contraction of "Bois D'Arc").

From Wikipedia:

"The heavy, close-grained yellow-orange wood is very dense and is prized for tool handles, treenails, fence posts, electrical insulators, and other applications requiring a strong dimensionally stable wood that withstands rot. Straight-grained osage timber (most is knotty and twisted) makes very good bows. In Arkansas, in the early 19th century, a good Osage bow was worth a horse and a blanket"

If you forge with an oak-handled hammer, you get tennis elbow pretty quickly -- it feels very stiff. Ash and hickory work well. Will didn't have enough osage orange to go around, the other hammers were handled with Ipe, which to me feels like teak. Seems stiffer than osage, but I haven't used it a lot.

You gonna leave the head rough,or polish it out all the way?

Dunno, I'm torn about that. Machinists like things to be flat and shiny. 'Smiths like to leave "texture" on the stuff they make. I think I may polish the top and bottom and leave the sides textured :p

PeteF
07-03-2011, 07:35 PM
I think a good Japanese blade must surely be the pinacle of blacksmithing. I have absolutely zero experience in this myself, but have been exposed in a roundabout sort of way from ... err a "user's" perspective ;)

Thanks very much for posting that Robert, I now have even more respect for your work and look forward to the end result. From the little I know about the process, it looks like you've taken a traditional approach to making it, right down to the hardening process. I think you're pretty keen to be hand sharpening using Japanese waterstones however :eek:

Pete

dp
07-03-2011, 07:51 PM
I see!
http://metalworkingathome.com/images/splittingHammer.png

Do you suppose that is something you can make with a BFH or is a power hammer needed?

fciron
07-03-2011, 08:05 PM
Good looking hammer. Nice write up of the process.

My favorite pick-up tongs for the last 15 or so years are a pair that Will gave me when we worked in Memphis. He's a great teacher, glad to see that program going strong.

Bois D'Arc? Here we've bastardized it all the way to 'burdock'. It is supposed to make a very nice handle.

dp, you can do it with a BFH and a lot of enthusiasm, but this way is a lot easier.

Lewis

lazlo
07-03-2011, 08:21 PM
I see!

Thanks Dennis -- iPhone, no flash :)

Do you suppose that is something you can make with a BFH or is a power hammer needed?

You could do it with a striker (a partner with a sledgehammer), but it would take you forever with a hand hammer. Starting with square stock would save a lot of time.

The katana I drew out from bar stock on the power hammer, but that's just a time-saver. Something as thin as a sunobe (katana forging) is very doable by hand. Believe it or not, the Japanese "national treasure" Mastersmiths use power hammers for the same thing -- forge welding/folding the tamahagane and drawing out the sunobe. The one modern amenity they allow themselves.

All the shaping is done by hand, of course.

The Japanese bladesmiths use what the English members would recognize as a "cutler's hammer" -- a longer/thinner hammer (same weight as a Western hammer) with the handle at the end. Much simpler design -- I'm going to try to squeeze one of these in between sessions this week.

This is from Brent Finnigan on the Bladesmith Forum:

http://i63.photobucket.com/albums/h151/BrentFinnigan/Custom%20tooling%20I%20build/IMG_0180.jpg

wierdscience
07-04-2011, 11:14 AM
I'd never heard of it before, but from discussing with several Texas natives, including John (TexasTurnado) it's more commonly known as "Bodark" (a TexArkana contraction of "Bois D'Arc").

Well familiar with Osage aka Bodarc,good material for boat propellar strut bearings,never used it for handles though.Probably the best is Hickory sapwood,much more shock resistant than the heart wood.

lazlo
07-04-2011, 11:24 AM
Probably the best is Hickory sapwood,much more shock resistant than the heart wood.

Thanks Darin -- I'll see if I can find some sapwood hickory. I'm getting pretty good at re-handling hammers :)
For some reason store-bought hammers come with long, skinny handles, so the first thing I do is drill them out and re-shaft with a thicker, 13" handle.

I got a couple of PM's asking about storebought blacksmith hammers. There's a Chinese 2 1/2 lb German pattern blacksmith hammer that's branded as Sears, Plumb, and Vaughn (probably a dozen others). It's forged, and pretty decent:

http://www.amazon.com/Vaughan-2-Pound-SuperSteel-Blacksmith-Treated/dp/B0002IGHCK/ref=sr_1_1?ie=UTF8&s=hi&qid=1309793384&sr=1-1

Same long, skinny hickory handle, and you'll need to dress the face and peen, but I've been using it for awhile and I like it.

wierdscience
07-04-2011, 07:47 PM
Same problem here,baseball glove hands tiny little hammer handles.

I get my replacements at the local farm supply,they have a barrel full of sledge handles that are sold as seconds.They may have a knot or a split but for \$3 ea and a sharp draw knife I can usually get three hammer handles out of one.

boslab
07-05-2011, 02:06 AM
if you have a woodturning lathe, is there a way to do handles that are oval not round or is it not worth the effort?
martk

DFMiller
07-05-2011, 09:06 AM
Thanks for the pictures and the narrative. I find this stuff so fascinating. I remember when I was a scout we had several days with a blacksmith. Made a couple of punches. Every time we go to a historic site like Louisburg I can spent hours watching. So cool. Thanks again. Dave

lynnl
07-05-2011, 11:46 AM
Where I grew up we called Osage Orange, aka Bois d'arc, aka Bodarc, "hedge apple." From the big lumpy fruits it bears.

Never knew of its use as handles, but it excels at any application out in the weather, as JCH alluded to in his fence post comment.
After weathering it takes on an appearance much like teak, to a little coarser.

Far and away my preferred handle shape is octagonal. Just seems to provide a more comfortable, user friendly feel.

Rustybolt
07-05-2011, 12:59 PM
Bois d'arc,

Literally - wood of the bow

The Osage Indians used the tree for their bows. Very powerful bows. The plains indians used it for their bows. It was not uncommon for a mounted warrior to shoot an arrow completely through a running buffalo.

J. Randall
07-05-2011, 11:06 PM
Where I grew up we called Osage Orange, aka Bois d'arc, aka Bodarc, "hedge apple." From the big lumpy fruits it bears.

Never knew of its use as handles, but it excels at any application out in the weather, as JCH alluded to in his fence post comment.
After weathering it takes on an appearance much like teak, to a little coarser.

Far and away my preferred handle shape is octagonal. Just seems to provide a more comfortable, user friendly feel.

We have lot of it here, I think most was planted in shelterbelts after the dust bowl days, I have heard it called all of those names here, but the most common use is Bodarc, with hedge apple coming in second.
James

lynnl
07-06-2011, 10:26 AM
Where I grew up we called Osage Orange, aka Bois d'arc, aka Bodarc, "hedge apple." From the big lumpy fruits it bears.

Never knew of its use as handles, but it excels at any application out in the weather, as JCH alluded to in his fence post comment.
After weathering it takes on an appearance much like teak, to a little coarser.

Far and away my preferred handle shape is octagonal. Just seems to provide a more comfortable, user friendly feel.

Correction on my comment about weathering: I now realize that I was thinking about black locust. Not really sure how bodarc weathers. I'd think it would be even coarser still, and maybe prone to splitting.

lazlo
07-06-2011, 11:39 AM
things came back to me from when i was a kid, my dad had a forge, one of the things he kept drilling me with was not to 'burn' the forging, i was young with no metallurgical knowledge of grain size so it went over my head, i now see the significance, i've made loads of chisels and the like, some better than others

When you're a machinist, you hear or read about grain growth when you're heat treating cutters, but I always just passed it off as a technical detail. But when you're blacksmithing, you run into it in a very big way. Sooner or later, you forget about an iron in the fire, and it burns. Mind you, the forge is 1800 -- 2,000°F, well below steel's melting point, but the steel burned, ruining the crystal structure, and you get giant grains, which show up as crystals all over the surface.

If you clean it up and attempt to forge it some more, the steel is very brittle, and will literally fracture under the hammer.

I've had limited success normalizing burned steel. I think once the grains grow beyond a point of no return, you're screwed.

i can see the failures were in fact overcrystalised or burnt and thats why they broke, one even displayed a shrinkage crack along its length, overquenched overheated, those pritty colours shure do mean a lot.

Like you say, I think this is why you end up with broken heat treated tools, like punches and chisels -- poor temperature control during heat treat. There's a lot to go wrong.

Far and away my preferred handle shape is octagonal. Just seems to provide a more comfortable, user friendly feel.

That's what I like as well. We start with a 1 x 2 x 13" blank, and knock the edges down on a belt grinder to make a hexagon. Then a lot of shaping to fit the eye hole and your hand.
You can also correct for an off-center eye hole with the shape of the handle eye.

I'm going to put some tung oil on the bodarc tonight. I'm curious to see how dark it turns...

PeteF
07-06-2011, 08:25 PM
When you're a machinist, you hear or read about grain growth when you're heat treating cutters, but I always just passed it off as a technical detail. But when you're blacksmithing, you run into it in a very big way. Sooner or later, you forget about an iron in the fire, and it burns. Mind you, the forge is 1800 -- 2,000°F, well below steel's melting point, but the steel burned, ruining the crystal structure, and you get giant grains, which show up as crystals all over the surface.

If you clean it up and attempt to forge it some more, the steel is very brittle, and will literally fracture under the hammer.

I've had limited success normalizing burned steel. I think once the grains grow beyond a point of no return, you're screwed.

So to recover this steel would you need to literally taken it back to its molten state?

Pete

lynnl
07-06-2011, 11:20 PM
So to recover this steel would you need to literally taken it back to its molten state?

Pete

To recover it back to the original state, I think you'd need all the assets and expertise of a steel mill, since many, maybe most, of the trace alloying elements and ratios are now irreversibly altered.

I once read that if chefs had to observe the same precision level in their recipes that metallurgists do in making steel, they would have to count out individual grains of salt, pepper, etc. In other words, it's a very exacting science. :D

PeteF
07-07-2011, 08:38 PM
To recover it back to the original state, I think you'd need all the assets and expertise of a steel mill, since many, maybe most, of the trace alloying elements and ratios are now irreversibly altered.

I once read that if chefs had to observe the same precision level in their recipes that metallurgists do in making steel, they would have to count out individual grains of salt, pepper, etc. In other words, it's a very exacting science. :D

Yes I've also heard strong comparisons between fine cooking and steel making. It's an art, it's a science. It's exact, it's imprecise. Every batch needs to be the same, every batch is slightly different (hence why they issue test certificates for each one).

One thing I don't understand (well actually I don't understand much at all about this area), is that I thought it was the structure of the material that had changed with various heating/cooling (or in this case overheating). In contrast to some blacksmithing processes where the basic makeup of the material is changed, I would have thought that if the material were simply overheated, the actual alloy components within the material would still be there intact and just the grain would be different?