- Joined
- Oct 20, 2008
- Messages
- 5,547
Well, I had a nice 10" integral chef forged out and ground the other day- and warped it in the quench, then ultimately cracked the edge. I had ground it too thin prior to HT. So, I had to re forge the blade for the customer. I thought this time I'd document the process with pics.
When I first started using my Little Giant, I noticed that there is not a wealth of information on the web about the specifics of using them in blade smithing. This is me trying to contribute. Ive forged a good few of these with no mechanical help, and the hammer is a godsend for integrals, especially with some basic tooling.
Here's the first blade. It's been soft back drawn, prior to the last straightening attempt.
Here's the edge. You can see that bad ripple warp caused by an edge too thin for austenization. I'm now just using the blade for a rough template for the new one. Later I'll probably cut the crack out of the edge and re-shape it into a knife for my wife's cafe.
First, I select a 2 roller bearing out of my stash. Then, I cut a handle out of some #4 rebar, about 24" long. I do prefer a somewhat heavier handle, but I just had this on hand. I bevel the end of the rebar, to get full penetration with the weld.
I set a firebrick on the anvil for a welding table, and clip the bearing into the ground lead from my AC arc welder. I set up the torch on my anvil torch stand, light it, and use the cutting head as a small rosebud to preheat the bearing. You get better penetration with your weld into the bearing metal this way, and the weld takes like butter without a cold start. I don't preheat the rebar end, as I find this leads to undercutting and a weakened handle.
Using 6013 at about 120 amps, I weld it up. Ugly but strong.
I had the forge preheating while prepping the bearing. Into the forge with it. I use my big blown forge for this work.
With the bearing probably an even 1800 degrees, I throw it on the power hammer. The first heat blocks it out roughly solid.
The second heat brings it down to about 1-1/4" square.
The third heat brings it to the target dimension of 1" square, and finishes by truing and flattening the sides, parallel to the dies.
Next I begin to draw out and taper the end of the bar. I forge it thinner toward the tip, thicker toward the planned heel as I need that steel there to draw out the width; on this particular knife the heel needs to be 2-3/8 wide, which presents a challenge to efficiently forge right next to the 3/4 tall bolster.
Using light blows with the hammer, feathering the clutch, I forge a point into the tip. It's much easier to start this early, as a point is much harder to forge on tall, thin stock. The trick here is to hammer lightly while smoothly drawing the stock backwards. Stopping the motion at any point can lead to shoulders you dont want in the profile.
The bottom die is a very mild drawing shape, and the top die, while slightly more aggressive, is a mild drawing shape as well. This is a good combination for general forging; there are no abrupt corners to form cold shuts or nicks in your blade. It is a bit more forgiving when using hand held tooling as well, tending not to knock the tools around sharply if they are held slightly misaligned.
I take an educated guess at roughly where the heel of the blade will drop from the bolster. I use a large spring fuller to forge in a double shoulder here. I only go down to about 1/2" thickness, saving the rest for the more accurate and correctly shaped guillotine fuller.
Using the guillotine fuller, which fits into the hardy hoe of the anvil and can be seen in the background, I finish fullering the shoulder at the front of the bolster down to about 1/4" finished thickness. I built this guillotine myself, with heavy angle iron, square stock, and plate steel. It has dies made from leaf spring, and a mild steel striking surface welded to the top die.
Going back to the power hammer, I use a fairly aggressive top fuller to selectively spread the steel wider at and near the heel. This saves a lot of cross peen work by hand.
As a close-up shows, this is a rough process and tends to force the metal equally to each side. This needs to be corrected. I use another hammer tool for this- essentially its a short block of 1.5 square steel welded to a handle, with the corners softened a little. I use it as a top hammer to set the bolster down at the heel, bringing the spine and the top of the bolster more or less in line. This is repeated as necessary during forging.
I spend a heat forging parallel to the dies, widening the main body of the blade. The top fuller is not necessary here.
Back to the heel area with the top fuller again.
Back to setting the bolster in line with the spine again.
Heres a shot of the profile as formed on the hammer. Pretty rough yet, but most of the steel has been pushed where it needs to go, and the rest can be done by hand in a couple of heats.
I do some tuning and flattening near the heel.
I hang the heel over the anvil edge, and use a half-face blow on the spine and bolster to even up the spine and get rid of that hump near the bolster.
I use a set hammer on the bottom of the bolster, with the blade edge up, to further set the bolster correctly in line with the blade.
I correct the resultant bulges in the spine, flattening the blade again. I use a mild cross peen to further widen the blade right at the heel.
The profile now being smooth and correctly sized, I adjust the overall shape of the profile by shwocking (a term I believe Wayne Goddard coined) the blade on a stump with a hollowed top. This allows me to bend things and change the profile of the blade without making any hammer marks in the spine or edge. Im using a dead blow hammer here.
The profile is good for now. Its time to cut it off the bar, and draw the tang.
I get the steel nice and hot, then cut it off of the bar with firm blows over the cutoff hardy, using a 6 lb. hammer. A heavy hammer and heavy, deliberate blows help a lot here.
With the stock nicked almost through all around, I bend it apart with a pair of tongs. Hmm, not much of a stub there, seemingly.
I heat the tang/bolster stub and insert it into the guillotine fuller. This is another area where a 6 lb. hammer and some slow, heavy blows will help. The guillotine fuller works much better than a spring or godzilla type fuller, for most tasks.
The resulting shouldered tang stub.
I bring the heated tang end over the power hammer, and draw it out. It takes me two heats to do a nice job.
I finish forging the tang true by hand.
Heres the finished profile, from the forge. Everything has been left significantly thicker than the finished knife will be, both to assure decarb removal in grinding and to give plenty of leeway to remove an accurately ground blade from the surrounding steel.
I normalize the blank...
And after normalizing, I do three sub critical anneals, heating to 1350 or so, air cooling to 1000 or so, a black heat in shadow, then quenching each time. The last time I dry the blade off and set it aside for grinding tomorrow. These thermal cycles approximate a rough spheroidizing of the forged blank, making grinding and drilling much easier and less wasteful of belts; especially with 52100, it works a lot better than wood ash, vermiculite, or leaving it to cool in the forge.
Here is a detail shot of the three main tools used to form this blade on the Little Giant 50. The top fuller is on the left. Its made of a small roller bearing welded to a mild steel bar.
The square top hammer is in the middle; its just mild steel 1.5 stock welded to a handle, then reheated and quenched to add a little toughness. It holds up very well if only used on hot stock.
On the right is a spring fuller. The fuller ends are 1 mild steel round stock, quenched after welding. They are welded to 3/8 x 1 mild flat bar for the spring. Using flat bar for the spring helps the dies not slop sideways under the hammer, and the two cheek plates welded to the spring are guides to further keep the fullers in line.
Stay tuned, grinding shots will be posted soon.
When I first started using my Little Giant, I noticed that there is not a wealth of information on the web about the specifics of using them in blade smithing. This is me trying to contribute. Ive forged a good few of these with no mechanical help, and the hammer is a godsend for integrals, especially with some basic tooling.
Here's the first blade. It's been soft back drawn, prior to the last straightening attempt.
Here's the edge. You can see that bad ripple warp caused by an edge too thin for austenization. I'm now just using the blade for a rough template for the new one. Later I'll probably cut the crack out of the edge and re-shape it into a knife for my wife's cafe.
First, I select a 2 roller bearing out of my stash. Then, I cut a handle out of some #4 rebar, about 24" long. I do prefer a somewhat heavier handle, but I just had this on hand. I bevel the end of the rebar, to get full penetration with the weld.
I set a firebrick on the anvil for a welding table, and clip the bearing into the ground lead from my AC arc welder. I set up the torch on my anvil torch stand, light it, and use the cutting head as a small rosebud to preheat the bearing. You get better penetration with your weld into the bearing metal this way, and the weld takes like butter without a cold start. I don't preheat the rebar end, as I find this leads to undercutting and a weakened handle.
Using 6013 at about 120 amps, I weld it up. Ugly but strong.
I had the forge preheating while prepping the bearing. Into the forge with it. I use my big blown forge for this work.
With the bearing probably an even 1800 degrees, I throw it on the power hammer. The first heat blocks it out roughly solid.
The second heat brings it down to about 1-1/4" square.
The third heat brings it to the target dimension of 1" square, and finishes by truing and flattening the sides, parallel to the dies.
Next I begin to draw out and taper the end of the bar. I forge it thinner toward the tip, thicker toward the planned heel as I need that steel there to draw out the width; on this particular knife the heel needs to be 2-3/8 wide, which presents a challenge to efficiently forge right next to the 3/4 tall bolster.
Using light blows with the hammer, feathering the clutch, I forge a point into the tip. It's much easier to start this early, as a point is much harder to forge on tall, thin stock. The trick here is to hammer lightly while smoothly drawing the stock backwards. Stopping the motion at any point can lead to shoulders you dont want in the profile.
The bottom die is a very mild drawing shape, and the top die, while slightly more aggressive, is a mild drawing shape as well. This is a good combination for general forging; there are no abrupt corners to form cold shuts or nicks in your blade. It is a bit more forgiving when using hand held tooling as well, tending not to knock the tools around sharply if they are held slightly misaligned.
I take an educated guess at roughly where the heel of the blade will drop from the bolster. I use a large spring fuller to forge in a double shoulder here. I only go down to about 1/2" thickness, saving the rest for the more accurate and correctly shaped guillotine fuller.
Using the guillotine fuller, which fits into the hardy hoe of the anvil and can be seen in the background, I finish fullering the shoulder at the front of the bolster down to about 1/4" finished thickness. I built this guillotine myself, with heavy angle iron, square stock, and plate steel. It has dies made from leaf spring, and a mild steel striking surface welded to the top die.
Going back to the power hammer, I use a fairly aggressive top fuller to selectively spread the steel wider at and near the heel. This saves a lot of cross peen work by hand.
As a close-up shows, this is a rough process and tends to force the metal equally to each side. This needs to be corrected. I use another hammer tool for this- essentially its a short block of 1.5 square steel welded to a handle, with the corners softened a little. I use it as a top hammer to set the bolster down at the heel, bringing the spine and the top of the bolster more or less in line. This is repeated as necessary during forging.
I spend a heat forging parallel to the dies, widening the main body of the blade. The top fuller is not necessary here.
Back to the heel area with the top fuller again.
Back to setting the bolster in line with the spine again.
Heres a shot of the profile as formed on the hammer. Pretty rough yet, but most of the steel has been pushed where it needs to go, and the rest can be done by hand in a couple of heats.
I do some tuning and flattening near the heel.
I hang the heel over the anvil edge, and use a half-face blow on the spine and bolster to even up the spine and get rid of that hump near the bolster.
I use a set hammer on the bottom of the bolster, with the blade edge up, to further set the bolster correctly in line with the blade.
I correct the resultant bulges in the spine, flattening the blade again. I use a mild cross peen to further widen the blade right at the heel.
The profile now being smooth and correctly sized, I adjust the overall shape of the profile by shwocking (a term I believe Wayne Goddard coined) the blade on a stump with a hollowed top. This allows me to bend things and change the profile of the blade without making any hammer marks in the spine or edge. Im using a dead blow hammer here.
The profile is good for now. Its time to cut it off the bar, and draw the tang.
I get the steel nice and hot, then cut it off of the bar with firm blows over the cutoff hardy, using a 6 lb. hammer. A heavy hammer and heavy, deliberate blows help a lot here.
With the stock nicked almost through all around, I bend it apart with a pair of tongs. Hmm, not much of a stub there, seemingly.
I heat the tang/bolster stub and insert it into the guillotine fuller. This is another area where a 6 lb. hammer and some slow, heavy blows will help. The guillotine fuller works much better than a spring or godzilla type fuller, for most tasks.
The resulting shouldered tang stub.
I bring the heated tang end over the power hammer, and draw it out. It takes me two heats to do a nice job.
I finish forging the tang true by hand.
Heres the finished profile, from the forge. Everything has been left significantly thicker than the finished knife will be, both to assure decarb removal in grinding and to give plenty of leeway to remove an accurately ground blade from the surrounding steel.
I normalize the blank...
And after normalizing, I do three sub critical anneals, heating to 1350 or so, air cooling to 1000 or so, a black heat in shadow, then quenching each time. The last time I dry the blade off and set it aside for grinding tomorrow. These thermal cycles approximate a rough spheroidizing of the forged blank, making grinding and drilling much easier and less wasteful of belts; especially with 52100, it works a lot better than wood ash, vermiculite, or leaving it to cool in the forge.
Here is a detail shot of the three main tools used to form this blade on the Little Giant 50. The top fuller is on the left. Its made of a small roller bearing welded to a mild steel bar.
The square top hammer is in the middle; its just mild steel 1.5 stock welded to a handle, then reheated and quenched to add a little toughness. It holds up very well if only used on hot stock.
On the right is a spring fuller. The fuller ends are 1 mild steel round stock, quenched after welding. They are welded to 3/8 x 1 mild flat bar for the spring. Using flat bar for the spring helps the dies not slop sideways under the hammer, and the two cheek plates welded to the spring are guides to further keep the fullers in line.
Stay tuned, grinding shots will be posted soon.
