Friday, December 17, 2010

Good Fences Make Good Jointers

A reader who owns the Jet 10” jointer-planer kindly wrote to tell me how he handles the issue of not being able to tighten the adjustment on the fence. I had written that the handle doesn’t turn all the way because it hits the fence and couldn’t figure out how to tighten it. He took out the screw that connects the handle and uses the handle as sort of a wrench to tighten it down. Thanks for offering that very nice solution. I’ll try it out tonight.

That got me thinking about the fence on the jointer being kind of flimsy and not flat. I'm thinking of how I could make my own fence. The design of this fence really seems to emphasize the flexibility of being able to tilt it for beveling. While that is a nice feature that I'm sure some people will like and use, I think this is one of those cases where Jet compromised the major function of the fence (90 degree edge jointing) for the occasionally (rarely) employed function of beveling. If they had built the fence only for 90 degree edge jointing and not had to worry about hinges and locking devices, they could have made it much sturdier.

Since I don't anticipate wanting to tilt the fence to do bevels, I am thinking of designs that would only serve for 90 degree edge jointing. My first idea was to bolt a fence to the side. The fence would be made of a piece of steel or a piece of granite or a torsion box made of plywood. The downsides to that would be the difficulty of making it square – you’d have to shim it somehow because you would be depending on the side of the table being perfectly perpendicular to the top, which probably isn’t the case. You’d also have to drill your own holes down the side, which could well weaken the table. Also, that would mean the fence was set at one location, which would mean the blades would get dull in that location faster than everywhere else. This is already one of the criticisms of this machine – that the fence isn’t adjustable front to back across the table.

So my new idea is a strip of ¾” plywood (or two strips for rigidity) attached to a back piece that could be clamped to the table. Here’s a little diagram.

You would only be able to clamp it to the outfeed table because the infeed table needs to be free for adjusting up and down. To make sure the fence was square to the table, I would probably attach the fence to the backing while the backing is already clamped to the table, adjusting it with pressure from the screws. I’ll play around with it at some point, but I think this would work.