Tapered Tangs

[Marko3]

I posted up on another forum about this I will try here.

I have been trying my hand at tapered tangs when I forge. But the problem is I have only been getting a 50/50 return on them because for one reason or another they start drifting one way or another to the point that I cant equal them up and I bin them. Last night was the last straw. I had a really nice blade that I was able to finish up. I noticed it was leaning a little so I tried to compensate and now the knife is in the trash.

Basically I had three knives I had been working on that all ended up in the trash. I am not going to continue doing them unless I can get it down 100%.

Currently I will forge in a distal taper and a tapered tang. I feel like I have them all nice and even off the anvil and I always hope for a easy clean up and be done with it. To the naked eye they seem lined up.

At this point should I scribe in a line and just use that as my gauge to how even they are. Or laying it on a piece of granite and put a feeler gauge under it and go with that... Or would it be best to scrap hammering in the taper and just hammer to shape and grind to dead flat and start with a scribed line.

The sanders I work with are a variable disc grinder and 2x72 with a glass platen. I put this disc grinder together specifically to help me with this. I have had some success but some heartbreak doing it my way.. I have no way to know because I am self taught.

So I just need some solid advice on how to best approach this right from the start and I am confident I can make it happen after a little help.

Thanks for any help

 

[Fred.Rowe]

Have you tried a Bubble Jig?

I make all forged blades with hidden tangs I grind the entire blade using the BJ. I start at the ricasso by looking down the sides from the rear or butt of the blade. I want to access which side of the forged ricasso looks true with the spine and the tang generally. After picking a side I flatten it on my disc grinder or the 2 x 72 belt. When I have the one side of the ricasso trued I set the bubble on the BJ with the flat platen surface. I can then set the magnet against the ground side of the ricasso, placing the raw side against the moving belt; holding the bubble centered the ricasso will be trued and aligned with the blade. To make the tang match the ricasso, place the BJ on the surfaced ricasso and use the bubble to grind the tang to match the ricasso. Shift the BJ to the opposite side of the ricasso and grind the other side of the tapered tang. Now you have a blade where the ricasso is centered with matching sides and the tang matches the ricasso.
Now you can use the Bubble Jig to grind the bevels; they will match the ricasso and the matching tang.
You can also use the BJ to grind the tapers forward and towards the butt end of the knife. They will match as well. These days I use the BJ to grind the complete blade; in this way the entire blade will match. The blade below was ground in this manner, every surface matches no matter which way you look at it. This blade is 13 1/2 long from tip to plunge, I have not thrown a blade away in 5 years.
Fred

 

[jawilder]

I've only done a few tapered tangs but to me it sounds like you are forging them too thin and not leaving yourself enough metal to grind off. Unless you are amazing with a hammer there will be plenty of steel to take off with the grinder, hence the term "Forge it thick and grind it thin".

Oh, and those trashed blades are nothing more than hidden tangs waiting to happen

 

[Marko3]

I forgot to add that I was trying to leave forged finish flats so I think this is part of the problem. Not truing up the ricasso is the real culprit then. I will scrap the forged finish look I was going for. I want things to be symmetrical. I want to take my work to a higher level.

Good idea about the hidden tangs with the rejects.

Fred..I do have a Bubble Jig ! I use it often and I think its a great grinding aid. I never even considered using it in the manner you described. Thanks.

 

[javand]

It's all about the Ricasso Mark. You've got to create (or utilize a pre-existing) truly parallel foundation for which to gauge the center.


Also, planishing needs to be done after rough forging, and ideally, finish with flattening (using a flatter), which I usually manipulate to straighten also. Which is the final operation. It's very important when flattening and straightening, to use appropriate heat, i.e. lower heat for planishing, and even lower for most straightening. I usually straighten with dull color at low light. If you try to planish and flatten in high red or orange heat, you're likely forging more than equalizing, unless you've got a very steady hand.


As knifemakers we tend to forge in very linear fashions, but if you look at the real pro forgers (talking mostly blacksmiths here), you'll notice a progressive approach, depending on the heat and the operation. Roughing at high heat, planishing as the heat gets lower, for example. Truly efficient forging, is like watching a master play chess though, and can only be achieved (IMHO) by a non-linear approach.


Here's some food for thought: http://www.youtube.com/watch?v=5BoFD-qv2OM Notice how he intentionally encourages the work to bend off the anvil to avoid heat loss, and how there are multiple stages of refinement as the heat gets lower.

 

[i4Marc]

Marko3,

Wanting to take your work to a higher level is good. We all do. Asking for advice is good. Vowing to discontinue what you are doing until you can get it down 100%, not so good. You can't get to 100% unless you keep on doing it. Our mistakes teach us more than our successes. Don't be so hard on yourself. This stuff is not easy. The rest of us are where you are or have been where you are. You'll get there. Don't think about forging in a finish. Think about forging the blade as straight as you can. When you clean it up on the grinder you can decide what parts get sanded and what parts are left "anvil fresh". And Jason is right. Never throw away a blade that can be revised.

 

[Marko3]

Thanks

I will apply this advice to my next forged blade .

 

[Tom Lewis]

Get "How to make Knives" by Loveless and Barney. Bob Loveless has a good section on tapering tangs. He uses the stock removal method, but I have also applied his method to forged blades with success. With a glass platen on a 2x72" grinder, and a 36 grit belt, it's really pretty easy.