Pretty sure I read about this idea somewhere, long ago, but don't remember when or where. I searched before posting this and found a few posts discussing a guide pin that can be purchased and installed on the upper blade guides or something like that. That might work well, but this worked *really* well for me. Since I don't think it is discussed often, I thought I would share.
I'm making a crib and my design calls for some broad concave and convex curves on a few pieces. I am not the best at freehanding these sorts of gentle curves- easier to do straight lines or tighter curves IMO. So I thought I'd try this idea out.
A simple template guide for a bandsaw made out of scrap plywood screwed together and clamped to the table:
bandsaw template guide.jpg
The plywood part jutting out towards the blade has a rounded end (radius of a WD-40 can) with a notch cut for the 1/4" blade to fit into. All of the parts were just cut by eyeball on the bandsaw and chopsaw, and screwed together. There is no real precision in it. The blade sits in the notch, and you can adjust how closely the blade cuts to the template by bumping the jig forwards and aft. In the picture it is set *very* close, leaving maybe 0.010" extra. Not much more than most flush trim router bits would leave.
You can see I cut a rabbet on the bottom of the notched part; that isn't strictly necessary but I wanted it to contact the template near the top only, in case my spokeshaved template edge wasn't perfectly square.
Here's it in action, cutting 7/8" thick white oak:
bandsaw template in action.jpg
And the result:
bandsaw template result.jpg
A really nice thing about this method is that you can take the part straight over to the router table on the same fixture and finish it off, one setup for two tools. Because the bandsaw cut so closely to the line, I was able to (carefully) climb cut with the flush trim bit (the mass and size of the template fixture helps with climb cutting too).
router cleanup.jpg
Didn't take long to do all of the legs:
final results.jpg
I also did a few parts with broad convex curves, with equally good results. This method might struggle with much tighter radii, or require some kind of modification. Most curves I have ever done are like in these pictures, so this should be a very useful technique going forward.
-Robert
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