Mike G
Petrified Pine
I've had a jig for thicknessing thin strips of wood by hand in my mind for many a long year. Now, I'm about to embark on a lot of Kumiko*, I thought it high time I got around to building it.
*Don't be ridiculous, of course I'm not. But I am going to be making some louvred doors.
I found a beautiful lump of old 4" x 3" PAR in my scrap pile:
I sawed off the end, where there was a knot and a small split:
The principle of this jig of mine is a pair of sliding wedges, where the top of a moving wedge stays parallel as it moves up or down the slope of a fixed wedge. They have to be absolutely spot on accurate, which means starting with accurately dimensioned stock:
Once I'd got a face and an edge, I ripped it down a little in width on the bandsaw, then planed it all round until it was perfect:
I set out the cut to make the pair of wedges. It's an ad hoc slope:
After ripping that by eye on the bandsaw as accurately as I could, I planed the 2 wedges smooth and square:
Turns out that my bigger planes vary in width by about 4mm:
I decided to make the jig a snug fit for the widest (my number 5-1/2). I found a couple of pieces of reclaimed rubberwood, made up of glued strips. I can't remember where it came from, but it seemed ideal for the job of making the sides. I ripped them to width on the bandsaw, then spent a long time getting the top edges perfectly straight and square, before clamping them onto the wedges to mark out for rebates:
Funny old stuff, rubberwood. Most of it planed beautifully, but 3 or 4 inches was horribly furry. Nonetheless, I ended up with 2 straight rebates:
Clamped onto the wedges, I tried the 5-1/2 in place:
The critical part of the whole construction (after the accuracy of the wedges) is to line the rebates up perfectly with the top of the top wedge. I started by drilling 6 or 7 screw holes in each side, so that if I messed up one screw location whilst setting the side in place I could use another. Then, I just proceeded very slowly and carefully, fixing first one side then the other:
After fixing the side boards, I had to take a shaving or two off the moving wedge (the top one) to free it up.
Finally, I worked out where I wanted a slot in the side to take a retaining screw (to lock it in place once adjusted). I couldn't think of a way of cutting a stopped slot using hand tools, so I rigged up a fence and got the router out:
I then drilled a hole in the moving wedge to take a 6mm threaded rod:
....and carefully Araldited it into place. Spilled Araldite at this stage could be a bit of a nuisance.
The finished jig gives me depth adjustable from zero to 26mm:
The pink line on the inside of the sides indicates the end of the fixed wedge, and thus the approximate length-limit for stock I am planing. Anything extending past that line would have a tendency to tip.
I used a slow setting Araldite (the only one I've got!), so it will be a couple of days before I can give this a test. I've only got a stop to add, which will take seconds.
*Don't be ridiculous, of course I'm not. But I am going to be making some louvred doors.
I found a beautiful lump of old 4" x 3" PAR in my scrap pile:
I sawed off the end, where there was a knot and a small split:
The principle of this jig of mine is a pair of sliding wedges, where the top of a moving wedge stays parallel as it moves up or down the slope of a fixed wedge. They have to be absolutely spot on accurate, which means starting with accurately dimensioned stock:
Once I'd got a face and an edge, I ripped it down a little in width on the bandsaw, then planed it all round until it was perfect:
I set out the cut to make the pair of wedges. It's an ad hoc slope:
After ripping that by eye on the bandsaw as accurately as I could, I planed the 2 wedges smooth and square:
Turns out that my bigger planes vary in width by about 4mm:
I decided to make the jig a snug fit for the widest (my number 5-1/2). I found a couple of pieces of reclaimed rubberwood, made up of glued strips. I can't remember where it came from, but it seemed ideal for the job of making the sides. I ripped them to width on the bandsaw, then spent a long time getting the top edges perfectly straight and square, before clamping them onto the wedges to mark out for rebates:
Funny old stuff, rubberwood. Most of it planed beautifully, but 3 or 4 inches was horribly furry. Nonetheless, I ended up with 2 straight rebates:
Clamped onto the wedges, I tried the 5-1/2 in place:
The critical part of the whole construction (after the accuracy of the wedges) is to line the rebates up perfectly with the top of the top wedge. I started by drilling 6 or 7 screw holes in each side, so that if I messed up one screw location whilst setting the side in place I could use another. Then, I just proceeded very slowly and carefully, fixing first one side then the other:
After fixing the side boards, I had to take a shaving or two off the moving wedge (the top one) to free it up.
Finally, I worked out where I wanted a slot in the side to take a retaining screw (to lock it in place once adjusted). I couldn't think of a way of cutting a stopped slot using hand tools, so I rigged up a fence and got the router out:
I then drilled a hole in the moving wedge to take a 6mm threaded rod:
....and carefully Araldited it into place. Spilled Araldite at this stage could be a bit of a nuisance.
The finished jig gives me depth adjustable from zero to 26mm:
The pink line on the inside of the sides indicates the end of the fixed wedge, and thus the approximate length-limit for stock I am planing. Anything extending past that line would have a tendency to tip.
I used a slow setting Araldite (the only one I've got!), so it will be a couple of days before I can give this a test. I've only got a stop to add, which will take seconds.
Last edited:
- Rob
