shaper knife hook angle

[Tom Gardner]

I'm shaping Beech pieces 20"L x 2"W x 7/8"T with a 3" radius along the 20" side and getting a 30% attrition due to break-out and tearing. I'm using a

5hp Powermatic with a 3 blade 3" dia. shaper collar having 45 degree hook angle on 1/4" thick by 1.5" wide lock-edge knife stock. I've tried climb-feed, opposing-feed, faster and slower table speed. I suspect the hook-angle is too acute, but before I make new cutters, I want some advise. What is the worst of what I am doing wrong? The 30% bad is killing me!

[Tom Plamann]

I make my own tooling and would go 10-15 degrees for wood such as beech. You will need to reduce your feed rate with the decreased angle.

Tom Plamann

[Tom Watson]

It's good to see you 'round these here parts, Tom.

Are you still in the midst of that huge project and will you ever be able to post pictures of it?

Hope everything is going well out your way.

Regards, Tom Thomas J. Watson-Cabinetmaker Gulph Mills, Pennsylvania

[*Casey*]

Maybe several passes would do it? Close-fitted fence inserts (zero clearance) ? The blades are well-ground, balanced and set identical? BTW, how does one measure the angle on these blades, other than 45*? Does a

15* angle mean as in a scraping chisel (wood turning), or a very low angle like in a fine paring chisel? IOW, do we mean angle from flat or from 90? Casey

[Tom Plamann]

Hey Tom

Yeah, I am still on my "project". They started the house 20 months ago and have yet to sheet rock. I am looking at finishing the woodworking part by next summer. It is very much a dream job for a woodworker. It will have provided me and my helper with a year and a half of work plus I was able to design the interior. Basically I am doing whatever I can think up that looks cool. It's almost embarrassing. I wish I had time to do the cabinets in this house. I will post pics on 'abpw' when possible.

Take care

Tom Plamann

[Tom Plamann]

Casey

Yes, the knife needs to be a low angle scraping type for hard and fibery wood. If the angle is too much, the arc of the cut pulls the wood up and pops it apart. In other words, you don't want the edge of the knife to get under the grain.

Tom Plamann