Hand Tools

Cap iron picture for steve D *PIC*

David Weaver
Here are three cap irons that I've used - that's an important thing, because it's one thing to look at them and ponder what they could be like, and another thing to use them in planing.

All of these are wood plane irons, but the cap iron style is shared with infills with parallel irons.

The fattest and most sprung is butcher. The initial junction of all of these is around 50-60 degrees (I don't do steep on try planes - they need to limit tearout to prevent shaving's being discontinuous and to be at levels less than what the smoother will remove in regular finish smoothing).

The middle one is an old ibbotson cap iron on a plane from around 1830 or so, but I don't know that it's original (suspect it may not be)..

and the thinnest and least sprung version is attached to a ward iron and the name of the cap iron maker is obscured.

Of these three, the lowest profile is physically easier to use - easily noticeably - for the same level of tearout control (even though it doesn't look like the last little bit is steeper, it is - how much? Not sure a 32nd? What's really notable here is that it's also in the steepest pitch of these three planes, about 4 degrees steeper than the plane that the butcher cap iron is in.

If I were going to manufacture cap irons, I would make them like the thinnest one here. The plane adjusts wonderfully and is the easiest to use physically. It also has a better feed profile without steepening the wear because there's not much there behind the initial junction (this issue doesn't exist in a stanley plane).

I may be on the spectrum - I often feel things other people don't notice until I point them out, but that's neither here nor there. Everyone on this board would feel the difference in effort for the same work with these planes, even though the cap irons are all prepared identically and the planes are all around 8 pounds with the same width iron.

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