Est. 1998 — 27 years of woodworking knowledge
Mouth Size On Wooden Planes
Reds
>I am starting to flatten the soles of my wooden planes and I was wondering how much space should be between the front part of the mouth and the iron in the cutting position. I am working with three plane styles; fore plane (22" long and 1/8" gap), jack plane (16" and 1/4" gap) and coffin smoothing plane (8 3/8' and 5/32" gap;7 7/8" and 9/32" gap).
Reds
Re: Mouth Size On Wooden Planes
Paul in NJ
>The thickest shavings will be done with the fore (jack) plane, so maybe a 1/16 opening but it is not that critical. You should have a heavily cambered (curved) blade for this plane. The try plane should have a tighter mouth, smaller than a 1/32, and less cambered blade. The smooth plane should have the tightest mouth, smaller than 1/64, and very little camber on the blade. I find it is easier to put a mouth patch in than re-sole the whole bottom. Make the patch thicker and plane it down level with the sole after the glue has dried. Also make the mouth tighter than necessary and pare/trim to final fit with a sharp chisel.
Paul Dzioba
Re: Mouth Size On Wooden Planes
woodburnbob
>I agree with what Paul in NJ says. But whether it matters depends on what your belief is about what the front lip is doing. The rationale for tight mouths in metal planes on the order of 0.005" is that downward force at the front lip prevents fibers from splitting ahead of the blade edge and thus tends to minimize tearout. That is meaningful if you are planing into grain and you believe that the idea is true.
In other words, I hope after flattening the soles and tuning the planes you have a chance to use them for awhile and get a sense of how much they suffer from having "relatively" large mouths.
Re: Mouth Size On Wooden Planes
paul womack
>In other words, I hope after flattening the soles and tuning the planes you have a chance to use them for awhile and get a sense of how much they suffer from having "relatively" large mouths.
Heartily agreed.
In fact, it's not really a big decision. If you did choose to re-sole, or patch the mouth, you'd want to flatten the sole as a preliminary stage anyway.
So flatten, use - and then decide. It's a no-loss course.
BugBear