Astrowood

I am using a straight cutting bit with these patterns to cut the final shape with this 3/4" plywood. In the secound picture you can see the burn marks on the wood. Will a spiral cutting bit work better ? Or is the Baltic Birch the problem?

Thanks for any advice Roy

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harrysin

Roy, burn marks are caused by a blunt cutter/moving the work-piece too slowly past the cutter. For important work like this, use only high quality cutters, price is usually a fair guide.

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Harry

Mike

For the best results cutting plywood you need a compression cutter. An up cut spiral bit pulls the sawdust towards the router motor, this cleans out the cut as it is lifting the debris. This can cause the top layers of a laminate to lift and tear. A down cut spiral bit pushes the debris away from the motor or into the cut. This in effect prevents the laminate from lifting on a partial cut. With a through cut in plywood you want to push down on the top, and pull up on the bottom to prevent separation, and this is exactly what a compression cutter does. Woodcraft is clearing out CMT bits so you should be able to find one at 30% off. Other than a great sale price I would go with Whiteside. Whiteside bits are always top rated in comparison testing.

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Mike
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Astrowood

Harry & Mike

Thanks for the replies - great advice ! I am looking on line now for a new bit, thanks again.

Roy

bobj3

Hi Roy

The Compression bits are bit hard to find,here's just one spot to get one
Just a note*** they break easy and are not cheap, note the tip of the bit they will work on 7/8" thick plywood but that's about it...I will say they will burn the stock if you stop in the pass...like most router bits, the key is to remove all the stock you can with a band saw or what every to get that nice clean look..

One more small note *** they are not saw blades so if you are asking them to do that job it will fail..

Compression Up/Down Spiral Router Bit
http://www.mlcswoodworking.com/shops..._updown_anchor


This 2 flute solid carbide bit is needed to get clean, chip-free and splinter-free cuts in composite sheet goods such as Melamine or 2-sided Formica/Laminates and veneered plywood.
The Up-shear/Down-shear design of the bit cuts toward the center of the sheet from both sides at once, saving time and eliminating waste.

The bit I would recommend would be the

Shear Angle Straight Router Bits with or without bearing.
http://www.mlcswoodworking.com/shops...r_angle_anchor

2 flute, carbide tipped. The shear angle cutting flutes produces a smoother cut than traditional straight fluted bits. Instead of chopping at the wood fibers at a 90º angle, the shear angle design allows for smoother shear angle, slicing cuts. Use this bit to eliminate tear-out problems from routing end or cross grain on very hard woods.


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karateed

Hi Roy,

Another tip I read and have tried is that the final cut should be very small. This will help remove any burns that exist and leave no burn marks on the project. This does require a bit of forethought so one doesn't end up taking more wood off than they originally wanted to.

Ed......:-)