Pointers on tapered tangs

Sean Jones

Well-Known Member
I've done several tapered tangs now. However I always seem to end up with the same problem. One side of my tang will be almost completely flat even before I hand sand it on my granite table; which is good.

However the other side, almost always the right side, I end up spending hours chasing flatness. The butt end is always a bit low. In the case of my KITH Bowie there was about half an inch in length gap at the butt end. The gap when I first noticed it was approximately 1/64 in width maybe a bit less.

This really slowed me down on my KITH Bowie. I spent several days getting one side flat. I eventually got it with a lot of hand sanding but it was extremely tedious and time consuming

So any ideas what I might be doing wrong? I've looked at several tutorials on tapering tangs and I think I'm doing it correctly.
 

Kevin Zito

KNIFE MAKER
Put a hollow grind down the center of the handle on both sides. Then you have much less surface to flatten.
 

Sean Jones

Well-Known Member
Put a hollow grind down the center of the handle on both sides. Then you have much less surface to flatten.
I've been doing that. I've been using the 2" idler wheels on my flat platen. I don't have any other wheels. It doesn't make the nice deep and wide groove that I see on most other tapered tangs. But it's working? Would a three inch wheel work better?

I've been wanting to get a set of small wheels for some time now. Perhaps that's the trick
 

Casey Brown

Well-Known Member
I almost always have to finish with some hand sanding on a surface plate to finish it off. If you don't have a surface plate, it's a necessity.
 

Sean Jones

Well-Known Member
I almost always have to finish with some hand sanding on a surface plate to finish it off. If you don't have a surface plate, it's a necessity.
I have a small granite surface plate. I've been using that. It just taking me a very long time. Maybe my method on the surface plate is wrong.
 

Sean Jones

Well-Known Member
How are you inducing the taper?
I use Dykem on the edge. Mark my center and then scribe on the butt end the width I want the end of the tang to be. I'm then using a welders magnet to hold the knife. I then start grinding vertically from the end towards the Ricasso. I apply more pressure on the tang end and let up as I approach the Ricasso. It is partly by feel I suppose, so there could some inconsistencies there . Which I've been cleaning up on my surface plate.

And the surface plate is where I find these big gaps that take forever to clean up. One side of the blade will be almost perfect and the other side will usually have a 1/16 gap or greater at the end of the tang. Which takes a long time to clean up.

I should mention, which I haven't (oops) this is on steel that has already been heat treated. AEB-L.
 

EdCaffreyMS

"The Montana Bladesmith"
I've been reading what you wrote, and am not completely sure that I understand the issue(s). Are you seeking to make hidden tang knives with a single flat plane throughout it's length, from blade to the end of the tang? OR, are you designing/grinding the blades to an elongated diamond (as viewed from the spine)?
 

Sean Jones

Well-Known Member
I've been reading what you wrote, and am not completely sure that I understand the issue(s). Are you seeking to make hidden tang knives with a single flat plane throughout it's length, from blade to the end of the tang? OR, are you designing/grinding the blades to an elongated diamond (as viewed from the spine)?
Ed, not a hidden tang. It's a full tang. Attempting to grind the elongated diamond.
 

oldknife

Well-Known Member
Sean, I do things same as you to the point of grinding the flat taper, and I do this before heat treat, use a new 50 grit, hold the knife by hand, tip up grind from the but up to where I want to stop the taper, I never hand lap them, allways finish on the platen, if you have a mill you can do them in it also. Forgot I also use a push stick. Deane
 
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tkroenlein

Well-Known Member
Ok. If your platen is dead flat, like a glass platen, make sure your magnet is too. A strong magnet will suck down an uneven surface flat, then you grind the opposite side "flat," then you take it off the magnet and neither is flat. Make sense?
 

Sean Jones

Well-Known Member
Are you grinding one side done (or mostly done) then doing the other side?
I had to think about this, but I believe so. While I've always been careful to grind my bevels evenly I may be derelict with the tang. I'll have to watch and make sure next time.
 

Sean Jones

Well-Known Member
Ok. If your platen is dead flat, like a glass platen, make sure your magnet is too. A strong magnet will suck down an uneven surface flat, then you grind the opposite side "flat," then you take it off the magnet and neither is flat. Make sense?
That does. The magnet is a Harbor Freight 30 lb welders magnet. I'll check it and make sure it's level
 

Sean Jones

Well-Known Member
Sean, I do things same as you to the point of grinding the flat taper, and I do this before heat treat, use a new 50 grit, hold the knife by hand, tip up grind from the but up to where I want to stop the taper, I never hand lap them, allways finish on the platen, if you have a mill you can do them in it also. Forgot I also use a push stick. Deane
On 1084 I've been grinding my taper pre-heat treat. The problems seems to crop up the most on bigger knives, especially the two I've done in AEB-L
 

Sean Jones

Well-Known Member
Based on responses so far, and thanks to all who responded. It looks like there's a couple things I need to do to improve this.
1. As John Doyle suggested, or at least implied, I need to treat the tang the same way I do the knife bevels and grind each side a bit at a time.
2. I need to check and make sure my magnet is level.
3. I think I might invest in a 3" wheel for the hollow grind for the taper. The 2" wheel on the flat platen doesn't seem to be all that consistent. I could use a 3" wheel for making razors at some point and other small hollow grind items so it wouldn't be a one purpose.

Make sense? I really like tapered tangs but they are a bear when I spend hours cleaning them up.
 

Sean Jones

Well-Known Member
You could be getting warp from building up heat from massive hogging of steel on only one side.
I wondered about that after your first post. Also when I use the magnet to hold the blade I don't feel the heat build up and have to remind myself to dip it in my water bucket.
 

Casey Brown

Well-Known Member
One last thing with the surface plate. Coat your tang with blue dykem and scribe a center line with a height gauge on the surface plate. Use your ricasso as your reference. Do this on both sides of the tang.

I gave up on grinding with a magnet. It's just too easy to roll one way or the other and not get a flat grind. Use your thumb to apply more pressure to keep your grinds even.
 

Sean Jones

Well-Known Member
One last thing with the surface plate. Coat your tang with blue dykem and scribe a center line with a height gauge on the surface plate. Use your ricasso as your reference. Do this on both sides of the tang.

I gave up on grinding with a magnet. It's just too easy to roll one way or the other and not get a flat grind. Use your thumb to apply more pressure to keep your grinds even.
Thanks for the tip Casey. I believe I did so.
The magnet is convenient. Perhaps too convenient. I'll have to think about that one.
 
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