Recommendation? pins with flexible blade

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danmc91

Joined
Aug 10, 2006
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I'm planning on making some kitchen knives and also a flexible blade spatula for one of my kids. I have some apple wood from a tree she planted from seed when she was about 4 and now she's grown and we moved but I kept a bunch of wood from it. My plan is to have it stabilized. For the knives I'm planning on a couple of paring knives and a chefs knife using O1 blades from Hock tools (I haven't taken the blade making step yet) and stainless steel mosaic pins with an apple design. My real question though comes on the spatula/pancake turner end. The blade there will be fairly thin (maybe 0.030" or so) 304 stainless. Do I need to worry about just treating that like a full tang knife and gluing the scales + pins with gflex? On the knives, the steel is pretty sturdy so I'm not worried about any flexing but of course the spatula will be quite flexible. Should I consider drilling some extra holes in the tang area so I'm directly gluing the scales to each other in a few spots? Any thoughts/comments/suggestions would be greatly appreciated.

-Dan
 
Stacy E. Apelt - Bladesmith said:
My suggestion is using two Corby bolts at each end and the mosaic rivet in the center. That is what I do on some kitchen knives I want my custom "A" rivet on.
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Do you find that the heads on the Corby bolts collect gunk when used in a kitchen? The mechanical connection is attractive. Thanks for the suggestion!
 
Ken H> said:
Normal use of Corby bolts is the screwdriver slot is ground away when finishing the handle leaving a smooth surface looking like a rivet.
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that would make sense wouldn't it. I'm glad I asked. Should some sort of thread lock adhesive be used?
 
No, the epoxy locks the bolts in place (not that there is much of any chance they could unscrew anyway.

I saw the excess off on the bandsaw after the epoxy cures and grind the bolts flush in the handle shaping and finishing.
 
I made a handle for a flexible spatula out of linen Micarta. I used JB Weld (the slow cure stuff) and Corby bolts. No problems after 15 years plus. It has endured many hours soaking in the sink with other dirty dishes. I did put JB Weld on the corby bolt threads and ground them flush.
 
One tip on Corby Bolts - DO NOT put epoxy in the female bolt hole. It is OK to put epoxy on the male threads. If you put resin in the female hole it will not screw in because there is no escape for the resin. Personally, I don't put any resin on the M/F parts. I just put resin on the sides or the bolt heads and let it seal the holes in the scales. It will make the bolts impossible to back out.

Now, all you folks with your minds in the gutter please refrain from comments!
 
If you're worried about the scales popping off could you modify the design to isolate the flex to the front part?
First option that occurs is add a metal front part and do it as a hidden tang. If you solder or weld the metal detail that should hold it
The other thing that occurred to me was to make it thicker just in front of the handle, optional tapered tang after that. That should keep most of the flex in the spatula bit

Might not be practical with your equipment though
 
Alex brings up the answer to most of these issues - a thicker tang at the ricasso. The purpose of the ricasso on blades is a thicker part just at the handle. The blade can taper to as thin as needed from there and all flex will be forward of the handle.
 
Alex Topfer said:
If you're worried about the scales popping off could you modify the design to isolate the flex to the front part?
First option that occurs is add a metal front part and do it as a hidden tang. If you solder or weld the metal detail that should hold it
The other thing that occurred to me was to make it thicker just in front of the handle, optional tapered tang after that. That should keep most of the flex in the spatula bit

Might not be practical with your equipment though
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I have limited equipment and metal skills. My plan on the spatula had been to start with a piece of 304 stainless sheet metal so that my metal work is cutting it out, sanding edges smooth, drill some holes, and make 2 bends with a small brake I have access to and then add scales. I don't currently have access to welding equipment.
 
With that type of spatula, I don't think you have any worry about the scales popping. I think most flexing will be at the two bends, not the handle/blade junction.
Use peened pins if you can't get Corby bolts and use good epoxy.

I have hibachi spatulas that are super thin and never had a problem. Still can't twirl them worth a darn, but the work fine. The front and left edge are knife sharp single beveled.
 
danmc91 said:
I have limited equipment and metal skills. My plan on the spatula had been to start with a piece of 304 stainless sheet metal so that my metal work is cutting it out, sanding edges smooth, drill some holes, and make 2 bends with a small brake I have access to and then add scales. I don't currently have access to welding equipment.
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It sounds like you will be fine. I was just trying to think through the problem, and how to address it in different ways
You can solder to stainless if you're feeling like a challenge, but maybe not a first project
 
Soldering stainless is not a problem.
File/sand/grind to bright metal, flux with Stay Clean flux, and use Stay Brite (or other 4% silver bearing solder.) Heat until solder flows-and don't overheat
 
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