We are starting to run maple mouldings along with our oak mouldings. Everything I have read says that they should mould the same. They both need similar hook angles, and knife cuts per inch. My problem is that I am getting a great amount of tearout on the maple. I can run oak pieces right behind the maple and they turn out fine. I have also checked the moisture content of the wood, and it is very close for both species. The oak is at 8% and the maple is about 8.75%. Why am I getting so much more tearout on the maple?
(Solid Wood Machining Forum)
This worked for me. Grind your knives at 23 degrees. One angle - just 23 degrees. I don't know why, but it got rid of tear out and chip out on our maple.
Hard maple is tougher to machine than soft maple. Hard maple varies dramatically depending on where it was harvested.
The moisture content is important. Dry maple will tear out more. If you are running maple at 6% or so then a 10 degree or 5 degree hook head will help. If the maple is 8% or a little higher then a normal 12 degree hook head should work. If the wood was dried too fast and not conditioned, then a hook angle change may be necessary. The direction that the wood is fed into the moulder, grain direction, can cause more problems.
The thing I have found works the very best is to use a shear cut corrugated cutter head. We have used them for years doing both straight and profile knives. It requires a different style of tool rest for the grinder is all. The shear action greatly reduces the tearing of the wood and reduces the extra horse power requirements that are seen with non-shear heads.
Dave Rankin, forum technical advisor