Bolsters on tapered tangs and fitup

[Jason Fry]

Working on a couple of knives with tapered tangs and either dovetailed bolsters or slotted guards. I envision the taper ending at the bolsters, so that the bolsters are on the flat and the scales are on the taper. On the slotted guard, I envision the taper running up to the joint of the guard and blade. I ran some trigonometry, and it looks like the angles will be off by .015 degrees, which translates into a .004 gap at the glue line between the bolsters/guard and the scales, assuming that the scales and bolsters are both at 90 degree angles relative to the part of the tang they sit on. I could see setting the table and doing the dovetails on the bolsters, then adjusting the table a *tiny* bit to do the dovetails on the scales. Or, do them the same and hand sand a *tiny* bit off of the scales to get the fitup flush.

Am I going nuts? Should I even be worried about it? How would you set up your dovetails to get the fitup right?

Parameters for my calculations were a 1/16 taper over a 4 inch handle, with 1/4 inch thick handle material.

 

[james terrio]

You may save some headaches by putting away the slide-rule and firing up the ol' calibrated eyeball.

 

[J. Doyle]

It would be easier to run the taper to include the bolsters. Then make your bolsters and scales the same angle and superglue them together and fit them to the tapered tang as if they were one solid scale. No gaps. No headaches.

Just my method. Others may be different.

 

[G. Shahan]

I taper my tangs all the way to the plunges. That way bolsters and scales are on the same flat area.

 

[Travis Fry]

Mssrs. Countryboy and Shahan have it right, or at least we do it the same way. Taper all the way to the plunge and don't worry about it. This also makes the widest part even with the bolster front, which, if you have a nice even distal taper, makes for a nice symmetry.

 

[Salem Straub]

I've had good success with tapering just to the dovetail area at the back of the bolsters- if your bolsters have a very curved or otherwise non-perpendicular face, there's no little glue gap at the front of them (due to the end of the tang taper) if you do it that way.

As stated above, treating the scale and bolster as being basically one piece on the same plane can be a good way to go, too.

For a slotted guard, it's easy. I measure the thickness of the tang at the guard, and at the butt. Take the difference and halve it. This will be the appx. thickness you can shim the front of the scale up off of the table (set to 90 degrees) to grind the face to fit to the guard with no glue gap. You can use the same trick for drilling your fastener holes in the tang/scales or for the slight difference in your dovetail angle due to tang taper.

Or even more easily, you can just give the table/workrest a little tap to barely change the angle, grind a bit, try fit, repeat/adjust as necessary. Leave the outline of your scales a bit large so you have room for adjustment.