Thursday, December 11, 2008

Squaring a large blank (in a small shop)

The large blank for pedestal 2 has to be squared up. Here I cut an edge on the table saw, then flipped it the to make the other side parallel. The blade doesn't reach even halfway thru, so it has to be cut from from both sides. Once it's flipped over onto the other face, tho, the table saw fence won't work anymore to index the next cut: the fence is too short, but more importantly, the surface I want to index from is closer to the blade than the fence is.

Another fancy jig - an offset fence. This will allow the blank to be indexed off that recessed, already-trued face.

Self-explanatory when you see it in action.

But since the blade can't reach even halfway, there's still an uncut section down the middle.

I'm not sure this qualifies as a jig, but putting two sticks of the same size along either side of the ridge gives the router a way to register to that flat face without encountering the ridge. It's pretty easy to set the cutting depth for the bit, too: just lower it until it touches a section that's been cut by the table saw.

Then that whole ridge is easy converted into a ludicrous amount of obnoxious, and I mean really, really, obnoxious MDF dust.

I had a little offset after routing, so I hit it with a hand plane. I checked the faces for square and lucked out.

To square the ends you use a cross-cut sled or miter gauge, but again you have the problem of the blade not reaching all the way thru. Here it's been cut, rotated 90 degrees, cut, rotated, etc. until you've reached in as far as the blade can from each face, leaving the center uncut. The big faces that have been cut are square to the blank provide a nice surface to register a chisel against. While it feels weird hand-tooling MDF, it works well enough.

All that produces a big, square block of MDF....

... which is then marked out with the template, and takes 4 trips thru the bandsaw...

.... twins!!

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