Shaping tapered tang bolsters questions

P J 234

Well-Known Member
I'm working on my first tapered tang knife which I've also decided to add dovetailed bolsters to. I've done 2 sets of bolsters before (one stainless and one micarta), but they were on flat tangs so I just pinned them together to shape them and finish the fronts before installing them (the same way I also do my scales on flat tangs without bolsters.)

I'm getting close to start shaping, dovetailing, and finishing the fronts of these bolsters, and when I pinned them together I realized that since the bolsters are not parallel to each other my 'normal' way of doing this is not going to work! Is there a trick to shaping and finishing tapered tang bolsters together so that they match each other?

Thanks in advance for any help!
 

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Paul.

Easiest way is to taper from the back of the bolster to the but end. This way your bolsters are parellel to each other and the holes will be square.

If you've already tapered the tang to the front edge of the bolsters then put pins in the bolsters and clamp with a small c-clamp. Use a shim in between to simulate the taper of the tang. It wont take much of a shim.

-Josh
 
What Josh said is the way I used to do it. Scribe lines on the tang where the rear of the bolsters will be, then taper on to the butt. When I did these, I was using a vulcanized fiber liner. That completely took up any off grind, as long as the taper grind was close to start with, and the liner looks good anyway.
 
Thanks for the help, guys. The tang is already tapered to forward of the bolsters (I thought this would be far easier than trying to get the angles right where the bolsters and scales meet if done the other way) and the bolsters are drilled perpendicular to the center axis of the knife.

I'll see if I can come up with a shim to put between the bolsters and fumble my way through getting them to match.
 
That's the same problem I had the first time I did a tapered tang - finishing the front of the bolsters...I now only taper to the back of the bolsters as well, makes things much easier and only a really trained eye can tell the difference when looking at two knives side my side.
 
If you round the front of the bolsters, you won't see any effect from the taper of the tang. If you just taper the tang to the back of the bolster and dovetail the bolsters, the dovetail angle will be different between the scale and bolster and there will be a gap between the bolster and scale.

You can see what I mean in the attached photo about rounding the front of the bolsters. This is the only knife I've ever done with bolsters and I only got this one photo of it before it found a new home so I can't show a top view.

100_0602.jpg

Hope that helps,
Carey
 
That's the same problem I had the first time I did a tapered tang - finishing the front of the bolsters...I now only taper to the back of the bolsters as well, makes things much easier and only a really trained eye can tell the difference when looking at two knives side my side.

I tapered all the way to the front of the bolsters, because I couldn't figure out how to get the angles to match between bolster and scale. How is that done?

If you round the front of the bolsters, you won't see any effect from the taper of the tang. If you just taper the tang to the back of the bolster and dovetail the bolsters, the dovetail angle will be different between the scale and bolster and there will be a gap between the bolster and scale.

You can see what I mean in the attached photo about rounding the front of the bolsters. This is the only knife I've ever done with bolsters and I only got this one photo of it before it found a new home so I can't show a top view.

View attachment 5666

Hope that helps,
Carey

I'm not sure I'm following you Carey (I'm a little dense sometimes!). What do you mean when you say by rounding the front of the bolsters, you won't see any effect from the tang taper?

Thanks for the input!
 
If you look closely at the picture I posted, you can see that the front of the bolsters have a radius or curve both vertically and horizontally. You can almost think of it as similar to the surface of a sphere.

Does that make sense?
Carey
 
If you look closely at the picture I posted, you can see that the front of the bolsters have a radius or curve both vertically and horizontally. You can almost think of it as similar to the surface of a sphere.

Does that make sense?
Carey

Yes, I think I understand what you are saying now. Thanks!
 
If I understand you angle question right> I first set up the platen on the grinder at an angle and use the work table and grind both teh scales and the bolster at this same angle. Ive got a mark on my tool arm and platen arm that I use to index that angle. Or you could just rough grind that angle on those two components at the same time using some other jig. I then use the try fit, re-grind, try-fit again method to get the angles to match. You just have to cut your scales a little oversize to allow for some adjustment grinding.
 
DLBrothers,

Yes, my question is if you taper to the front of the scales but the back of the bolsters, how do you get that angle to match at the bolster/scale mating surface (I suppose whether you dovetail or not.)

If I understand your reply, it sounds like you match them first as if they were on the same plane, then slightly change the angle gradually using trial and error afterwards until the angles match on the tang?

Thanks for your help!
 
I(f you taper the tang, you have to have the taper extend beyond the face of the bolsters. The bolsters and sclaes have to be on the same plane. The dovetail will match up then. This is how I do it and it works. Drill all your holes in the tang and the bolsters first before you taper the tang. First make sure the side of your boslters that contacts the tang is flat. Then, I clamp both my bolsters to the tang and drill all the way through at once. That way, they all line up. Drill at least three holes for the pins. Then shape the front of the bolsters and grind your dovetails and put them back on the knife to be sure you have it all lined up. Then take the bosters off and taper your tang, grind your blade, heat treat and temper, then finish your grind. Next slightly ream the holes on the bolsters with a tapered reamer. Now attach your bolsters and smash your pins with a 3lb hammer. This will draw everything together. The force of the strikes will slightly bend the pins and everything will come together. You have to hit it hard, not tap it. I've been doing it this way for a while and it works consistently.
-John
 
I(f you taper the tang, you have to have the taper extend beyond the face of the bolsters. The bolsters and sclaes have to be on the same plane. The dovetail will match up then. This is how I do it and it works. Drill all your holes in the tang and the bolsters first before you taper the tang. First make sure the side of your boslters that contacts the tang is flat. Then, I clamp both my bolsters to the tang and drill all the way through at once. That way, they all line up. Drill at least three holes for the pins. Then shape the front of the bolsters and grind your dovetails and put them back on the knife to be sure you have it all lined up. Then take the bosters off and taper your tang, grind your blade, heat treat and temper, then finish your grind. Next slightly ream the holes on the bolsters with a tapered reamer. Now attach your bolsters and smash your pins with a 3lb hammer. This will draw everything together. The force of the strikes will slightly bend the pins and everything will come together. You have to hit it hard, not tap it. I've been doing it this way for a while and it works consistently.
-John

Thanks for your response, John! So are you saying that you drill the bolsters before tapering the tang, then after tapering (when the holes will no longer line up in the bolsters), just smashing them good with a hammer will realign/flatten everything together? If I understand you correctly, that seems somewhat simpler than trying to drill and shape after tapering takes place, but I'm not sure I'm following you (and how that would actually work.)

Thanks again for all the tips!
 
The holes will all be aligned. The bolster surface and tang are not paralell to each other. The holes will be aligned because you drilled them all at once then you tapered the tang. Just try it exactly as I have detailed.
-John
 
Thanks again, John. I'm still not 100% sure if I'm following you as I'm having trouble understanding how that might work, so I may just give it a try to understand.
 
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