Plywood drilling

[paul60]

i do alot of drilling in 3/4 pine plywood
i have tried both down sprial and up sprial bits
1/4 and 3/8. using a router.
my problem is the amount of tearout i am getting
any idear how to get over this problem?
thanks paul

[erik_f]

you could try using a compression bit

[Gary Campbell]

Paul..
You dont mention how deep you are drilling or if your tearout is on the face or back of the material.

I drill 10mm holes for cabinet leveler legs (1/2" deep) best setup: 10mm carbide tipped boring machine bit, 2500-2800 rpm

5mm to 9/32" shelf, hinge, slide holes (1/2" or less deep): appropriate sized cabide boring machine bit, 5000 rpm

3/32 to 1/8" thru holes for assembly screws: solid carbide step drill with countersink at 5000 - 8000 rpm. There is a small amount of tearout on the back with these bits, but they are located in dados and covered by bottom or stretcher pieces. Hope this helps.
Gary

[myxpykalix]

call fred at www.centuriontools.com (http://www.centuriontools.com) he has a nice bit designed to reduce/eliminate tearout on both the in point and out point of cutting holes.

Usually you have that nasty blowout at the bottom of a thru hole but i seem to have eliminated that. Granted i don't drill hundreds of holes but it seems to work way better than what i used before.

[paul60]

the problem is with tearout at the bottom
of a thru hole.
these are on cabinet parts. holes for conformat screws.
and bolt for connection holes.

[Gary Campbell]

Paul..
As I said earlier, I have tested many combinations and the boring machine bits seem to work the best when power fed. They make a special bit that is for thru drilling thru veneered material. I have a couple but my machine is down for maintenence.

5082
Gary