Successfully dovetailing baltic birch plywood. March 20, 2001
I'm dovetailing Baltic birch plywood and experiencing a lot of tearout. I am using a Porter Cable Ominjig 24" with a 1 1/2 horsepower Porter Cable Router. I am using a 1/2" 12 degree dovetail bit, brand new.
Do I need a bit with a smaller angle? Do I need to score the plywood before each cut?
A shallow preliminary cut across the face of the work-piece is usually a good idea when using this type of jig. It quickly scores the surface fibers and prevents tearout when exiting the material each time a pin/tail is cut. Make this cut after getting work pieces aligned and ready to go, then start cutting dovetails.
I dovetail wider stock than I need and rip it to width afterward, because the bit usually blows out the last (unbacked) pin.
When you score, be sure to use a climb cut. Be careful when traveling in the opposite direction with your router.
From the original questioner:
The initial scoring cut barely hits the ply. It actually does not make a cut through the first plywood layer. I am using a 12 degree bit. Should I use a larger degree bit to achieve the depth? I cannot adjust the depth of cut on the jig, because the sides of the drawer (pins) will plunge too deep into the drawer fronts (tails).
Try to use a 1/2" shank bit. Maybe cut a little deeper. Also, remember that the first signs of wear on a dovetail bit will be the points--they're inherently the weak spot. A good way to quickly check a carbide bit for wear is to look at the edge from the cutting side--if it's shiny, it's worn.
The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).
Comment from contributor A:
If you are having trouble with the last pin blowing out or tearing badly, do what I do and add a small piece of same thickness material to the side of the one you are cutting the tails into. This adds a backing to the final pin, and all but eliminates its blowout.
Would you like to add information to this article?
Interested in writing or submitting an article?
Have a question about this article?
Have you reviewed the related Knowledge Base areas below?
KnowledgeBase: Cabinetmaking: Custom Cabinet Construction
KnowledgeBase: Cabinetmaking: General
KnowledgeBase: Lumber and Plywood
KnowledgeBase: Primary Processing: General
KnowledgeBase: Woodworking Miscellaneous
KnowledgeBase: Woodworking Miscellaneous: Accessories
KnowledgeBase: Knowledge Base
All rights reserved. No part of this publication may be reproduced in
any manner without permission of the Editor.
Review WOODWEB's Copyright Policy.
The editors, writers, and staff at WOODWEB try to promote safe practices.
What is safe for one woodworker under certain conditions may not be safe
for others in different circumstances. Readers should undertake the use
of materials and methods discussed at WOODWEB after considerate evaluation,
and at their own risk.
335 Bedell Road
Montrose, PA 18801
Copyright © 1996-2018 - WOODWEB ® Inc.