Wednesday, December 30, 2015

Precision

As I dial in each part of the printmaking process, it reveals other parts that need work. Now that I've created a system for registering my blocks, I can see that the blocks themselves aren't always square. It's my own fault. To save on time, I used the table saw to cut them. For the next batch I'll try the radial arm saw which is a better tool for the job.

For now I'll just turn the blocks until I find a square corner and make sure that I carve it in that direction.


[Off square at this corner]


[Square corner]

While doing this, I realized that my old jig was set up to require blocks to have two square corners, one in the lower left and one in the lower right. For now, that's a lot to ask so I made a new jig with the square corner in the lower left, which is also the origin (0,0,0) in the computer model.


[New jig that honors 0,0,0]

Clamping the piece to the cutting table is tricky and vital. Thankfully, there is a beautiful grid on the surface of the table. I made extra sure that the cutter rails were perfectly square and matched the grid when I built it.

See that tiny x? I set up the "Red Berries" files to think that the block is 1/8" smaller on the horizontal edges to make it easier to register the cutter.


[The lines are square to the cutting rails]

To make sure that the cutting tool is exactly where the computer thinks it is, I zero out the three axes separately.


[Setting X]


[Setting Y]

There is a trick to zeroing the Z axis. I learned this when doing 3D printing. I use a sheet of paper and move the tool tip up and down until I feel the "right amount" of tension when I slide the paper.


[Setting Z]

And that's it! The tip of the tool is exactly at the origin so the computer can move and always know exactly where it is in physical space. Time to carve it!

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