Saturday, January 10, 2009


I had noticed earlier that there was a little too much slop in the mini table router. The Y-axis was rotating, being insufficiently restrained by the Z-axis carriage.

So this afternoon I got around to doing something about it (or maybe it was just an excuse for some boring action.. :)

I decided to add another pair of linear bearings to the top of the Z carriage so that a moment about the Y-axis would be carried by the bearings on the same rail instead of working to seperate the rails. This should (with a little pre-load) be much stiffer.

And while I had the boring set out, I enlarged the motor mount opening. The top photo is the boring bar in action, on autofeed. I love the finish it leaves! This is using a carbine tipped bar in aluminium which isn't ideal, but it was the bar I had to hand.

Nest was making a bracket for the linear bearings. This is a simple piece with 2 x 22mm holes for the linear bearings, and 2 x 7mm holes for attaching it (and 1 x 6mm holes in the center for the threaded rod to pass through). The digital readout on the mill makes this a piece of cake: Just touch off the piece to find the corner, set it to (0,0) on the DRO, then just drill 6mm pilot holes for the 2 x 22mm, enlarge to 16mm using a roughing mill bit, then use the boring bar to enlarge 1mm at a time to 21.8mm, then enlarge 0.0.05mm at a time to get to 21.99 which leaves the linear bearings a press fit.

Last photo in the new bracket installed. It's the top bracket on the Z carriage (the carriage on the vertical rails). There's a little preload from the Y rails, so it's now nice and stiff. Well, not up to cutting metal stiff, but it should now be adequate for wood and plexiglass. (I'd previously just used it for XPP foam and wax).

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