So, I saw this Japanese carpenter on a video using a long T-type square, and I thought I would like one of those. Thinking about it I figured I would need a steel rule that is 40-60,000th's (3/64-1/16th+/-) range. I found a rule that was 45,000th's figured 12 bucks ....ok. I ordered it. Not satisfied being in Hawaii and would have to wait 3-5 days to get it; I decided to take one of the office steel rules we had and make a prototype to work out the bugs. Anyway this is it. I broke one of the screws, but at least I figured how to do it.
I used East Indian Ebony, I had 1"x1/8 brass bar and brass screws, the ruler and a SS 1/4 x 1" bolt this is what I had so that is what I used.
The tools used were a table saw, a dove tail saw, a chisel and a file. I cut a slot to receive the brass bar .125 deep. and then cut a perpendicular slot just deep enough to receive the ruler. Once completed, I sanded it with 240 and oiled it. I did check with my machinist square and it is square. The one thing I discovered was this ruler I used was about 1-1.5 thousandths wider on each end which, prevented it from sliding in to the slot I made for it. So I had to file the 1st 4"or so on each end to get it "trued-up".
Now, when the real ruler I want to use comes, I know exactly how I will do this. I think I will change the design to turn the brass 90° and cut a shoulder to carry it above the ruler guideway. Use a wider brass bar and possibly bury a piece of a coping saw blade on each side of the ruler guideway to prevent the ruler grooving the wood.
Also, that red line in one of the pixs is the camera light highlighting the wood imperfection.
I used East Indian Ebony, I had 1"x1/8 brass bar and brass screws, the ruler and a SS 1/4 x 1" bolt this is what I had so that is what I used.
The tools used were a table saw, a dove tail saw, a chisel and a file. I cut a slot to receive the brass bar .125 deep. and then cut a perpendicular slot just deep enough to receive the ruler. Once completed, I sanded it with 240 and oiled it. I did check with my machinist square and it is square. The one thing I discovered was this ruler I used was about 1-1.5 thousandths wider on each end which, prevented it from sliding in to the slot I made for it. So I had to file the 1st 4"or so on each end to get it "trued-up".
Now, when the real ruler I want to use comes, I know exactly how I will do this. I think I will change the design to turn the brass 90° and cut a shoulder to carry it above the ruler guideway. Use a wider brass bar and possibly bury a piece of a coping saw blade on each side of the ruler guideway to prevent the ruler grooving the wood.
Also, that red line in one of the pixs is the camera light highlighting the wood imperfection.
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