Attaching mokume/damascus bolsters

R

rscoffey

Joined
Sep 12, 2006
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I have been wondering if anyone remembers seeing either a WIP or tutorial on attaching patterned metal bolsters to a blade. Obviously, the most common way is with screws, which brings up the issue of tapping one direction on one side and the opposite direction on the other. If the screws go all the way through, you could put nuts on the opposite side. The photos I have seen seem to have screw heads on both sides which would seem to indicate that the maker is tapping in from both sides. Probably using shallow screws, which brings up the thicknes of the blade stock being used.

I hope this doesn't sound like your basic "duh" type question. That's why a tutorial would be helpful.

Thanks,

Bob
 
I´m not really an expert allthough I´ve attached bolsters with screws a couple of times. If I use screws, the blade is tapped and the bolsters are drilled for clearance and counterbored for the screwheads. You are not, however, tapping in two directions as you suggest. Just tap the blade all the way trough. My blades are typically 3,5-4mm thick (.138-.157 inch) and as such, each screw has only about .07 inch "hold" which I have found to be sufficient.
Another option of course are to drill and tap the one bolster with blind holes, and clearance drill both the other bolster and the blade.
I do however also like damaskus bolsters that are attached with peened pins of a contrasting material, such as stainless or gold.

Hope this helps,

Brian
 
You could use a 2 part fixing like corby bolts or something similar to a pivot for a folding knife. No tapping required then. Just holes straight through then a counter sunk hole for the head.
 
Tiiiiiiiim said:
You could use a 2 part fixing like corby bolts or something similar to a pivot for a folding knife. No tapping required then. Just holes straight through then a counter sunk hole for the head.
Click to expand...

That is another option but since Corbys are quite big, I personally feel they take too much space in a beautiful damascus bolster. If one wants to avoid tapping the blade, one could however use a 3 part assembly, like a folder barrel pivot, but with smaller screws.
Personally, I´d just tap the blade since its a very easy and fast operation.

Brian
 
Gody said:
That is another option but since Corbys are quite big, I personally feel they take too much space in a beautiful damascus bolster. If one wants to avoid tapping the blade, one could however use a 3 part assembly, like a folder barrel pivot, but with smaller screws.
Personally, I´d just tap the blade since its a very easy and fast operation.

Brian
Click to expand...

You can get a .120" corby. Thats pretty small. What about just pinning them?
 
That I did not know. A .120" Corby would be an option, but like you say, so would just pinning them.

Brian
 
The problem the OP is trying to get around is the fact that a pin or bolt will show up clearly on a patterned metal surface, like mokume or damascus. Screws are the answer in most cases. Here are a couple ways to use the screws:

Use two screws, both screwed into the tang - Clamp the bolsters in place and drill the pilot holes. Re-drill the tang with the tap drill size, and the bolsters with the body drill. Counterbore or countersink the bolsters for the heads. Tap the tang. Carefully adjust the screw lengths to get a snug fit. This works good with 56-80 pitch screws.

Use one bonding screw and one dummy screw - Start the drilling as above, but drill the tang and one bolster with the body drill and the other bolster with the tap drill. Counterbore/countresink the head seats on the bolsters. Tap the one bolster and use a long screw from one side and a very short "dummy" screw on the tapped bolster. This works well for 40-56 pitch screws.

Use an insert - Pilot drill the assembly. Drill the tang to accept a threaded insert, and screw the bolsters to it. This is done just like it is on a handle.You will have to drill the bolsters to fit the tube, and counterbore the outside for the screw heads. This works well for 32-40 pitch screws. This is essentially the same as installing a pivot.



Alternative solutions:
On mokume, use a brass or copper rivet to match the main metal color. Carefully peening and sanding can make this not show much at all. If possible, make the hole in a swirl or raindrop.

You can make damascus rivets to do damascus bolsters......but it is a lot of effort. Occasionally you find them for sale.

Use mosaic rivets/pins - Pilot drill the bolsters and tang a standard bolt size that is smaller than the mosaic pins. Put temporary stainless steel bolts through the assembly to clamp tightly in place, and solder on the bolsters. Re-drill the holes for a snug fit to the pins. Epoxy the pins in place. Make sure you "clock" the mosaics. The one thing I spot on 90% of knives using mosaic rivets in the handles is that people don't align the mosaic pattern exactly the same on all rivets. This sticks out visually like a red headed girl in a group of blonds.
 
What about a combination of hidden pins, epoxy and perhaps a reverse dovetail? Where the pined scales provide support for bolsters... no visible pins to ruin the pattern
 
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