Thread: closed in cap irons

Hi Chemfish, the cap iron should stay straight on any plane that doesn't have a non-flat sole, no matter what you do with the iron.

If you use a plane with a heavily cambered iron for rough work, sometimes you still have to set it close to dimension really nasty wood reliably, but there is no camber on those irons, either - the cap iron does its job straight across.

Conceptually, if you think about it, the iron takes a heavy cut in the middle of a cambered iron. The heavier the cut, the farther the cap should be from the edge. Leaving the cap straight and camber on the iron is a self-solving issue. The outsides of the cut away from the middle cut a thinner shaving and the cap is closer to the edge there. You potentially would make that part of the cap less effective if you cambered it off.

If you ever buy a profiled plane with a double iron (a moulding plane with a curved bottom or a gutter plane), then you would want to profile the cap. Those types of planes are rarely used by us, though.

So the basic rule is match the cap iron to the shape of the bottom of the plane.

Originally Posted by D.W.

Conceptually, if you think about it, the iron takes a heavy cut in the middle of a cambered iron. The heavier the cut, the farther the cap should be from the edge. Leaving the cap straight and camber on the iron is a self-solving issue. The outsides of the cut away from the middle cut a thinner shaving and the cap is closer to the edge there. You potentially would make that part of the cap less effective if you cambered it off.

If you ever buy a profiled plane with a double iron (a moulding plane with a curved bottom or a gutter plane), then you would want to profile the cap. Those types of planes are rarely used by us, though.

So the basic rule is match the cap iron to the shape of the bottom of the plane.

That's an interesting point of view. As I get more and more familiar with this capiron effect, I can see what you mean but it's a new way of looking at it for me.

Have a good day,
Normand

I should clarify part of that.
* Gutter Planes are rarely used by us
* double iron moulding planes are rarely used by us

Moulding planes themselves (with single irons) certainly aren't rarely used by us!!

Yeah, I think it works . I've cambered the cap iron to match my blade on one plane maybe two ? I've thought of the same question many times starring at that curved sharp edge when setting up . I've got a few working no 3 an 4 size planes with different camber on each .
Ive never seen a mouldings plane with a cap iron ?

Originally Posted by auscab

Yeah, I think it works . I've cambered the cap iron to match my blade on one plane maybe two ? I've thought of the same question many times starring at that curved sharp edge when setting up . I've got a few working no 3 an 4 size planes with different camber on each .
Ive never seen a mouldings plane with a cap iron ?

There are two-iron type japanese planes where the moulding planes have a separate cap that is crisply profiled to match the cutting iron. I don't know how they use them, though. In western work, the hollow and round plane arrives late in the game after something else does most of the work, so the speed of being able to take a thick shaving without tearout is really of no advantage.

there are western style flat bottom wooden rabbet planes with double irons, too (ECE makes one - it's expensive for what it is, though. I found one used for a very low price and it works a treat, but I wouldn't pay $200 for one when vintage rabbet planes can be found for $10 or $20.

Like this?

Japanese iron.jpg

That style, but rounded irons. I'll see if I can track one down.

here is one:

Japanese style moulding plane | Other planes | Wood working tool, Japanese wood working tool shop

Notice they are expensive.

(not intended for Rob, nor necessarily for the OP) I've noticed that this question gets asked often. I often answer it, people radius their cap irons anyway. It's probably the last time I'll answer it because I find that really annoying.

Nice looking Japanese moulding planes there. Hows the thickness of the cutter !

Rob

Originally Posted by auscab

Nice looking Japanese moulding planes there. Hows the thickness of the cutter !

Rob

I'm sure the thickness has something to do with the long span of unsupported iron, same with the cap (vs. a western plane where the wedge is down closer to the cut).

Never seen one used.

Someone years ago gave me a double iron set like those (but a straight iron) in those pictures, but no plane body. No clue what to do with them, but they look nice.