Great Question to Consider
I have a question about chip breakers. I notice on Krenov style wooden planes and other kits out there employ the use of a chip breaker. Is this necessary? I see most traditional wood body planes do not use chip breakers. And it also seems they are primarily used for depth adjustment on metal planes. Hope you can shed some light on this for me. Also thank you so much for everything you do. You have truly changed my life as a wood worker and as a man. You are an inspiration!
This is the part of the bench planes where Americans erroneously name the cap iron a chip breaker; a part used in the planing machine known in the US as a planer and in the UK as a thicknesser or a thickness planer, nothing to do with bench plane parts. This started happening in the UK too, unfortunately. Oh well. This ‘chip-breaker’ is the cap made from plate steel locked beneath the wedge or the lever cap that flexes the two-component cutting assembly to reduce vibration by causing tension in the cutting iron and the cap iron and so prevent chatter. It neither causes the wood to chip nor prevents the wood from chipping. Actually, the reference you made about wooden planes having single irons is more incorrect than correct. Almost all bevel down planes developed and used over the past three centuries have been bevel-down, two-part assemblies with the blade and the cap iron locked together with a single setscrew. So, wooden bench planes from 1700’s used cap irons and retained them all the way through to today. Now when you go to wooden bodied planes with thick irons you can use them without cap irons as I do with home made special planes. Remember that wooden bodied planes do not flex and vibrate like metal planes do within the body itself. There is no conflict between the wooden bed and the iron as there is with all metal bodies. In actuality, wooden planes absorb vibration within the body of wood itself and this serves as a dampener if you will.
On then to the term chip breaker. I have thought about this before and put it down. If the cap iron were to be called anything other than a cap iron I would suggest tensioner or better still diverter. Semantics or not, the term chip breaker applies to a planing machine that is a long bar directly adjacent to the cutting blades that stops the wood being planed from lifting and splitting wood away from the cutter before the cutter cuts. Because of the power of a machine and the blade hitting the wood, there would be a tendency for any weaker area of grown or rising grain to surface fracture. The chip breaker applies pressure and holds the wood down as it passes into the cutter. The cap iron on the plane does no such thing.
Now then, one last thing. All bevel up planes are cap iron free for obvious reasons. So, on wooden bodied, usually low angle planes, you need no cap iron.
Thanks for the Question. I like these!