Overlapping arch tear-out

[Michael White]

All,

I'm trying to cut overlapping arches using a router with a 1/2" two-spiral, upward-spiral bit and a template in a piece of 1x4 red oak. I'm cutting counter-clockwise, but I keep getting tear-out as the bit exits the wood. I'm only cutting a depth of 1/16" at a time, which seems to do better than

1/8" at a time (tried that earlier). I've even taken to screwing down the piece that's being cut out to prevent it from breaking off too quickly, but that didn't seem to noticeably help.

Any suggestions?

Thanks in advance.

[hard_way]

Are you using a template follower, with the router mouted in a table, or are you hand routing from above? If you are hand routing from above, go clockwise on exterior cuts, and counter clockwise on pockets and interior holes, this is will cause the cuting edge to rotate into the material. Going the opposite direction will cause the cutting edge to lift material out of the cut, thus causing tear-out. You may also notice that the router tries to move away from the template, I usually make serveral passes to insure that I have routed flush to the template. Long grain woods like oak are notorious for tear out so keep at it, and you will get their with practice.

[bluemax1811-newsgroups]

Is there a way to clamp a sacrificial piece of wood next to where the cut exits? Using a backer block can eliminate a lot of tear out.