# Pattern Bit for Red Oak



## rstermer (Apr 22, 2008)

I'm making a couple of safety catches for a folding workbench I invented. The material is red oak. I've made a pattern and am attempting to rout them out on the router table using a three cutter pattern bit I got from MLCS. The shape of the part is such that the cutter wants to dig in if I rout in the correct direction. Back routing seems to work a lot better, but I've still managed to break off pieces from each of the two parts I've worked on today. Any ideas as to a better bit? Would an upcut spiral pattern bit work better?

Thanks,
rstermer


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## Hamlin (Dec 25, 2005)

Could you post a pic?


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## BigJimAK (Mar 13, 2009)

Is your bit really sharp or are you feeding too fast, rstermer? Feeding too fast will cause the bit to chatter and can grab more wood than you want. My next question would be on the depth of cut. If you take shallow enough cuts it's pretty tough to break off pieces unless there was a lot of stress in the wood.

As mentioned above, without seeing pictures...


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## Drew Eckhardt (Aug 2, 2008)

rstermer said:


> I'm making a couple of safety catches for a folding workbench I invented. The material is red oak. I've made a pattern and am attempting to rout them out on the router table using a three cutter pattern bit I got from MLCS. The shape of the part is such that the cutter wants to dig in if I rout in the correct direction. Back routing seems to work a lot better, but I've still managed to break off pieces from each of the two parts I've worked on today. Any ideas as to a better bit? Would an upcut spiral pattern bit work better?
> 
> Thanks,
> rstermer


Routing into the grain like this ->\\\\ will break parts where -> is the direction your router is moving and \\\\ is the grain direction when the angle is in the wrong range (a certain amount of deviation towards that from along face and across end grain works fine) regardless of cutting to within 1/16" of the pattern using a saw, using a 1 1/8" pattern bit so the bit is entering at a shallower angle, getting a brand new bit, or changing router speed and feed rate in a variety of combinations which don't burn the wood.

See the attachment - the clamped side is likely to break. When I finally realized what was going on and flipped the symmetric parts for the second half everything was fine.

Assuming you're making a solid shape, flip the part over so the opposite face is against the table and you're routing like this ->//// in the correct direction. That means either attaching the template to the opposite side of your work or switching to a bottom bearing (flush trim) bit.

Most of the router bit companies make bits with bearings at both the top and bottom so you can just change the router height instead of re-attaching your pattern or changing bits.

Spiral bits and ones with shear angle produce less tear-out where there are grain reversals and should be better since the entire height of the cutting edge isn't contacting the work at the same time; although I didn't try that solution. Bearing guided bits with shear angle are much less expensive solid carbide spirals.


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