Making a hollow round plane *LINK*

step saving alternative  *LINK*

John Truxell-Svenson (jvs)

>


hollow/round pair

what's the catch?

Jack Guzman from Maine

>Why so cheap? Anyone tried those? Are they functional in hardwood?---Jack

Re: what's the catch?

Alan Hamilton

>Jack,

I have the pair. The irons aren't very good; still the planes are serviceable. They work pretty well--but they're hardly a delight to use. I have to be careful about grain direction and keep the irons sharp. That's about the highest praise I can honestly give them right now.

However, the bodies look very good, so I'm going to spend some more time on them and see if they can't do better. I may even give Ron Hock a call. I'd like to see someone else's experience with them. Perhaps there's a trick or two that will get more out of them.

Alan

Re: I wouldn't do it!

William Duffield on the Cohansey

>I don't know anything about that particular plane, but there is a serious pitfall you should be aware of, when considering whether to make such a modification.

First, we need to discuss the confusing nomenclature of molding planes. Usually a molding plane's name describes the shape of the molding made from it, not the shape of the blade and the sole of the plane. For simple hollows and rounds, however, this is not the case. If the sole is concave, it is a Hollow. If the sole is convex, it is a Round. So, a hollow round plane is an oxymoron, unless your desire is to create one with an ogee profile, that is both :^)

The shape of the mouth opening is important in molding planes used by cabinetmakers, if one wants to minimize tearout. (If tearout is not important, just get a rustbucket #45 :^) For good performance, the shape of the back edge of the mouth should conform to the edge of the cutter. The intersection of the front surface of the throat and the sole determines the geometry of the mouth opening. To create a consistent opening all the way across the mouth, this front surface of the throat of a hollow is round (convex), while the front surface of the throat of a round is hollow (concave). If this is as clear as mud, don't feel like the Lone Ranger. It helps a lot to have one of each in hand while you are trying to visualize the geometry. Remember that the top surface (the back) of the cutter is flat.

If you want to convert a rabbet plane into a Round, then you have to remove more stock from the outer edges of the sole. Since the front surface of the throat on a rabbet plane is flat, this opens the mouth towards the outside edges of the blade, resulting in increased tearout at the outside of the concave molding. OTOH, If you want to convert a rabbet into a Hollow, you remove stock from the center of the sole. This opens the mouth at the center of the cut, at the center of the convex molding you are trying to create.