Birch Bark Strip Cutter

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Birch bark is easy enough to harvest from a fallen tree. I never take from a healthy tree, though it certainly can be done without irreparably harming the tree – there's just enough available from fallen trees or firewood trees that there's no reason to deface a beautiful and elegant tree that's left standing. To harvest, just take a sharp knife and make a longitudinal cut through the bark. The only tricky bit is getting the first inch or so up from the cut. After that, I can usually peel the piece of bark from the entire circumference of the log. I just need that first inch to have something to hang onto.

The difficulty actually comes after the bark is off. Most birch bark crafts require cutting the bark. Stout scissors work fine, but are imprecise. Knives are excellent, but slow. If you want a lot of uniform strips for something like basket weaving, you need a way to slice up the bark uniformly.

My wife recently took a class at the local Folk School, where she got to see the birch bark cutter they had specially made by a machinist. It has two circular blades and can be set to give uniform strips of several different widths. I'm not a machinist and I don't pretend to be one, but I am pretty good at figuring things out when I have a goal in mind. So, I wanted to see if I could make a birch bark cutter that would make uniform 1/2” strips. That's a size that I think will be useful for woven sheaths (tuohituppi in Finnish) and also small woven baskets.

My starting point. A piece of oak I had in my scrap wood for enough years that I can't recall when or where I got it. A 45mm rotary cutting blade available wherever cloth cutting tools are sold. And a 5/16” bolt, two washers, and a nut. Also a few wood screws.

I cut a base 4” by 6”. Another 4”x6” piece yields the blade holder and what I'm calling the fence.

For the circular blade to fit through the blade holder, I needed a slot not much wider than the thickness of the blade.  I bought these miniature saw blades several years ago for a project I never made.  This is the first time I've ever taken them out of their package.

I forgot to take a picture before I started, but you can see an excellent slot in the blade holder.  I had to cut through from both sides, but careful work made it possible.  

Here, I'm cutting the groove for the blade to fit into in the base.  Notice that bar clamp holding it in place. This is pretty important, as I needed both hands on the drill to steady it.  And I don't like the idea of my fingers coming anywhere near that rotating little saw.  I even unplugged my drill when I changed the bit because the idea of that saw blade hitting my hand just gave me the willies.

I drilled pilot holes for the wood screws and a larger one for the bolt that will hold the blade.  Oak needs pilot holes because it won't compress like soft pine will.  The pilot holes also mean nothing is going to shift right as I drive the screws in.   

I also countersunk the holes so the screw heads will be flush with the surface of the wood.

With the blade holder screwed to the fence, I used the hole in the blade holder to guide the bit through the fence.  That bolt needs to go all the way through.

I screwed the fence onto the base and it is essentially complete.  Note the gap between the blade holder and the base.  My thought was that a close fit like this will make sure the bark doesn't bunch up in the cutter.  I learned later that a bigger gap would be better.

Here you can see the screws that hold the blade holder in place and the hole between them for the bolt.

Four screws on the base, all nice and flush.

Because the blade is essentially a circular razor blade, I needed both hands to carefully assemble the contraption.  But it should be pretty obvious what's going on.  I plan to make some sort of blade guard.  That slicer is up where careless fingers could be cut all too easily.

And here it is in use.  I used two bar clamps to hold it to my work bench because with one, it would shift and rotate a little bit.  I want the cutter to be steady.

And that's a nice, 1/2" strip of bark coming out!

However, not pictured is what happened next. I got the bark most of the way through, but there was a thick bit (the black knobby part of birch bark) and it was about 3/16” thick, being forced through a 5/32” gap. I got it in far enough to jam in place and had to take the fence off the base to get it loose. Doing this over, I'll plan for 1/4” gap. In this case, I don't think the tight gap is actually important to the function of the tool.

There you have it. Not a professional machinist-made instrument, but a functional birch bark cutter that does the job.

 If you improve on this, please let me know.