Making a Wooden Plane
The "Chipbreaker"
The chipbreaker is considered by many to be the last significant development in plane technology. Other than metallurgical improvments, it's really the only thing that separates our simple plane from those used by the Greeks and Romans 2000 years ago. Nonetheless, it's an important separation.
The chip breaker is a fairly thin piece of bent metal that is attached to the blade, and serves at least two functions. It helps to bolster the relatively thin blades of modern planes, and keep them under tension, thus reducing chatter. It's main function, however, is implied in it's name. The breaker radically changes the path of the freshly cut wood fibers coming off of the blade edge, thus "breaking" them and limiting their tendancy to tear. This is difficult to describe, but can be easily seen through experimentation.
The breaker is a piece of metal roughly the same width as the blade, thick enough to tap and accept a small screw, and bent so that it's raised ~1/16" off the iron ~1/2" in back of the edge. The breaker should meet the edge of the blade at roughly the same angle as the blade (ie. 25 to 30 degrees). I happen to use 1/8" mild steel, but 1/16" will also work. Use what you have available to you. Making one requires a fair amount of grinding and filing, so be prepared for this.
Chip breakers for metal planes are long, and bent more drastically than we need, although they'll work if you spend some time working on them. I'd suggest that you at least tap a new hole that is lower down on the breaker. The really crucial thing about the chip breaker is that the point of contact along the edge of the blade be flat, and smooth. File or grind it flat, and then take the time to really work it smooth on one of your medium, then fine sharpening stones. If the iron/breaker surfaces don't meet perfectly, fibers will jam between them, causing the plane to stop cutting entirely! I can't emphasize this enough! When you attach it to your blade, set it back no more than 1/32 of an inch, and try to keep it as close as possible to the edge for your fine work. A 1/64, or less, is all you should really need for your smoothing plane. This will produce your finest cuts, and it will also quickly point out any inaccuracy in the fit with the iron.
There is probably a lot more that can be said about these 2 small metal parts of your plane. The edge of the blade should be dead flat for jointing, but can be slightly convex for general work. The blade can have the slightest rounding at the edges to avoid digging in at the corners. Other things you will discover on your own. You don't have to follow my advice verbatim, but rather find what works for you, and continue to experiment.
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Steve Spodaryk
Medford, MA
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article
12.10.2008
- Making a Wooden Plane
Introduction
Tools
The Iron
The Chipbreaker
Wood
Marking Out the Blank 1
Marking Out the Blank 2
Forming the Plane Bed
Drilling the Pin Holes
Making the Pin
Test Fit
Glue Up
Post Glue Cleanup
Adjusting the Mouth
Making the Wedge
Test Run
Shaping the Plane Body
Troubleshooting
Advanced Topics
- Making a Wooden Plane
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