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Upward - Downword and Compression bits

1914 Views 6 Replies 4 Participants Last post by  EdC
Can someone please tell me what a compression bit does?

Thanks - Ed
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What is a compression bit?
A compression bit is the combination of both upcut and downcut spirals. Typically, a compression spiral has an upcut single, double or triple flute at the tip of the cutter, approximately one third of the cutting length. The remaining two thirds is ground to give a downcutting shear.
By combining both geometries, you achieve a win/win situation. The bottom of the material is pulled upwards while the top of the material is pushed downwards thus eliminating the risk of damaging the laminated surfaces. When run at full depth, the bit leaves a sharp, clean edge on both sides of your workpiece.
Blue Bumper Wood Gas Automotive exterior
Blue Bumper Wood Gas Automotive exterior
Tire Automotive tire Wood Bicycle part Fastener

A compression bit can be a little more expensive than standard router bits, we recommend them as an essential tool when processing double laminate wood materials.
Thanks John - I have a possible special use for this kind of bit. I have an old skill planer that I cannot find a bit for and wondering if the bit would work in my router?
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I would add to what John said in that it works really great on plywood. I cut 1/2" BB full depth with a 1/4" compression bit nearly every day for Longworth chucks and these bits are fantastic for that.

Thank you David for your additional direction! - Ed
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Thank you David for your additional direction! - Ed
Here is an excellent video that compares down/up spiral and compression bits. Bits
Thank you Bob - Really informative!! - Ed
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