Hollows and Rounds –
I have not had much shop time over the last couple of weeks. Actually I have had no shop time … I’ve been down with the flu! I traveled to Maryland two weeks ago and must have pick up the bug at the airport. I’m thankful I got a flu shot at the end of last year … no telling where I’d be had I not. But at any rate … I’m now back amongst the living!
As I mentioned earlier, the horizontal frame members of Lynnsay’s Prie Dieu will receive a bit of sticking. To achieve the sticking, I’ve pulled out a No. 8 round, a No. 10 hollow, a rebate plane, by shop made rebate saw, and just in case, a coffin smoother.
Hollows and rounds are rather straight forward planes, they have a concave or convex sole and cut either a hollow or round profile. Unlike almost every other plane, hollows and rounds are named by the shape of the plane’s sole, not the profile it creates. So with that said, a hollow has a concave sole, a round has a convex sole. Don’t ask me why. Some hollows and rounds have skewed irons to help with difficult wood and working cross-grain. Picture skewing your bench plane when you tackle a tough board and you’ll see what I mean. British planes are commonly found with skewed irons, American planes less so. Most hollows and rounds cut a 60 degree arc of a circle. The most common numbering scheme for moulding planes is to assign the plane a number based on the radius of the arc it cuts in 16ths of an inch. So using this convention, my No. 8 round cuts an arc with a 1/2 inch radius, and my No. 10 hollow cuts an arc with a 5/8 inch radius.
Contrary to popular belief, you don’t really need a lot of moulding planes. You are only limited by your imagination when it comes to the profiles you can create with just one hollow and one round.
For this particular project I’m trying to reproduce the profiles found on the original desk on frame. For the horizontal frame members I’ll just be using a hollow to produce something like this …
... for the lid to the desk, I’ll be using both a hollow and a round …
Sharpening the irons of these planes is nothing like sharpening other plane irons. Given that the blades were hand made, with the steel being laminated by a blacksmith, the back of the iron is not perfectly flat. So there is no need obsessing about flattening the backs as with other plane irons. I usually just strop the cutting edge of the hollow with a leather wrapped dowel charged with chromium oxide …
and the cutting edge of the round with a flat leather strop.
I sharpen the rebate plane iron as I would a chisel or any other plane iron.
With highly polished cutting edges …
.. I made a dry run of the horizontal frame member profile.
Guess what I’ll be doing for the next several days!
Next up … the completed frame! Thanks for looking … all comments and/or questions welcomed … more to come!
Lynnsay's Prie Dieu #1: Getting the Jump on Lent
Lynnsay's Prie Dieu #2: Replication in a Cold Dark Shop
Lynnsay's Prie Dieu #3: Rip Saw Tune-up and Frame Members
Lynnsay's Prie Dieu #4: Mortise and Tenon Joints
Lynnsay's Prie Dieu #5: Hollows and Rounds
Lynnsay's Prie Dieu #6: Slight Detour
-- Ron in Lilburn, Georgia. Knowing how to use a tool is more important than the tool in and of itself.