Attaching Scales

[Chasper]

I'm working on a something new and I need to know more about how knife makers attach scales. I'm putting handles on kitchen utensils, not knives

I want to use poly resin to pour the scales. What I have in mind is to make a master scale mold and cast various colors and embedded materials. I think it will be important to attach the scales with very little or no scratches on the casting (I will have to hand sand and buff out the scratches). I know there are various types of rivets, bolts, and pins used to hold the scales in place, but it seems that the usual practice is to grind the ends off the pins/bolts after tightening them down.

I need to hear from someone who knows a lot more than I do about how to do this before I go any further.

 

[jskeen]

There are a couple of types of compression rivets or screw together nuts but as far as I know, all of them require grinding them flush before finishing. The possible exception might be the smaller cutlery rivets. They are smooth faced and shallow enough that you might be able to countersink them slightly and press them together for a final finished fit. Depends on the radius of the curve and how it looks on the final product. In any case, I always used either acraglass or jb weld to seal the slab to tang watertight and if I could get away with it, I would use a dremel to cut some random grooves in both to give the epoxy a little extra place to grip. The last thing is to make sure you don't get the tang hot enough make the glue release after you get it all assembled.

 

[paps]

As JSKEEN stated there are several types of bolts or rivets you could use to attach the scales but most of them would require grinding down after tightening. That is gonna cause heat and would need to be done very slowly to keep the glue and the PR from getting too hot. One thing you might consider is to use hollow tubing instead of bolts. That way you have less to grind off and less heat produced. You can get tubing in stainless as well as brass.
If your tang is soft enough, another option is to drill holes in the tang and thread them. Then you could use screws to attach the scales and the screw heads could be countersunk. Hope this helps.

 

[gallianp]

All of this scale talk sounds kind of fishy to me!

 

[jskeen]

I hadn't really thought of that, but lots of high end knives nowdays use screws to hold scales on, and there are some pretty nice looking polished stainless head hex screws available. Again, I don't know what you are planning to make, but I suspect that you may have a hard time making a casting fit precisely enough onto a preshaped tang. Most traditional handles are glued on oversize and ground down to final shape taking off a bit of the tang as well, to give a perfectly flush fit. Some newer "Tactical" knives have gone to scales slightly smaller than the tang screwed on, and the edges of the tang rounded and polished, but it's not a look I've tried to reproduce yet, although I do have a gerber folder on my desk I have been "working" on for a while in that style.

 

[Chasper]

Thanks for the suggestions, I'm going to try a couple options and see what works out. What I'm trying to do is to cast scales in resin, not cast a block of resin and tool it down into a scale. I'm trying to make a mold of a scale with the holes already in place. Then I plan to make castings in various colors that can be taken directly from the mold to assembly.