Producing a larger sweep curve in moulding than #18 Hollow

[paulc]

Hello,

I'm interested in trying to reproduce some picture frame moulding which incorporates a wide (2.5 - 3 inches / 60-80mm) shallow to middling sweep convex curve. I'm awaiting the arrival of the largest hollow plane #18, which I believe, produces a 1.5 inch wide convex curve but this is about half the size I require. And I haven't seen any individual moulding planes with this type of profile.

Can anyone recommend a hand tool process to produce this kind of curve on moulding?

Is there a reason that hollow and rounds stop at this width?

Many thanks, Paul

 

[StraightOffTheArk]

The biggest size of standard moulding plane that I've come across was a 22 on ebay - I was sorely tempted, but I haven't really got enough space for the tools I do use, so after a stern word with myself, avoided the buy it now button. Pattern makers planes come up with a set of soles/irons to various concave/convex curves - something like that might have the right sort of radius, if you're lucky. If I wanted to make a one off size, I'd convert a cheap wooden smoother or jack. Otherwise, I'd mark the curve on the ends and take the waste out with a rebate plane, getting rid of the last flats with a curved scraper/sandpaper.

Tara a bit,

SOTA

 

[Sheffield Tony]

You might just have found a contemporary use for a pattern maker's plane ?

Edited to add: Hah, beaten to it. I have a pattern maker's plane - being from a steelworking family I was drawn to it, but have never found need for such gentle curves. It has IIRC 4 or 5 different convex soles with matching irons.

 

[Racers]

You can make your own plaine using an old wooden jack plane by shaping the sole and blade.
I think their are several videos on line.

Pete

 

[David C]

Pete,

I did this as a result of a suggestion in Alan Peters book.

Described in my book, (one or two)

David

 

[AndyT]

It would be useful to see a sketch of the profile you are planning in case I have misunderstood it.
But the wider and more gradual your convex curve is, the easier it is to produce it with ordinary flat bottomed bench planes. You aim for a succession of ever smaller facets and then blend them into a curve with sandpaper. (You might want to make a shaped backing block for this.)
If your convex curved section is defined by beads or something else similar, you won't be able to use a smoothing plane as it won't cut right to the edge, but a rebate or shoulder plane will.

 

[Cheshirechappie]

Stock selection might help in getting a good result. Mild, straight-grained timber will mould more easily than wilder-grained stuff.

James Krenov used to make his own planes, including curved-soled ones. His method of construction was very simple; a back block cut to the required bedding angle, and a front block with a relief for the waste cut from the same piece a little wider than his selected plane iron, and two side pieces about 1/4" thick. All glued up, with a bridge inserted between the side pieces for the blade wedge to bear against. Any sole curvature could be made thus.

Thinking about blade bedding angles might be worth it. Most moulding planes were made for architectural work in softwoods, and were bedded at about 47 to 50 degrees, but some were made for cabinet use in harder, wilder, tearout-prone timbers, and bedded higher - up to 60 degrees ('full pitch' or 'cabinet pitch').

A home-made plane (either Krenov style, or like a modified wooden rebate plane if the blade needs to get right into the corner) bedded at 60 degrees should produce a nice, smooth finish, needing very little scraping or sanding. It might be a little harder to push than one bedded lower, but on a one-off job, that's not really such a big problem - more but shallower cuts. Using a plane with a reasonable sole length should give nice, straight mouldings free of any humps and bumps, too, and quicker than by scraping to shape.

 

[AndyT]

A few thoughts on why standard hollows and rounds stop at around no 18:

Most ordinary domestic joinery doesn't need anything bigger. Even if you are building a big hotel or bank, broad mouldings are likely to made up of several smaller elements.

Bigger curves are less likely to be sections of circles, except in very specific work such as pattern making, so it's harder to make a standard item in advance and have it be just what is actually needed.

Wide planes need bigger, rarer billets of beech.

A wide plane is much harder to push - and probably too hard to get consistent, smooth work.

A broad concave curve can be made with successive cuts from a large round, blended in to each other.

A broad convex curve can be made with successive cuts from a flat plane, blended in to each other.

If a special size was really needed, it could be made to order.

 

[Racers]

You could but a Stanley 57 core box plane, if you are feeling flush.

http://www.supertool.com/StanleyBG/stan8.htm#num57

Pete

 

[AndyT]

The OP said he wants to make a convex curve, as produced by a hollow plane.
I think he was choosing his words carefully but a sketch would help!

 

[StraightOffTheArk]

Thanks for posting the link Pete - I really enjoyed re-reading the amusing blurb on the 55 just above your link, especially the ending -

"If you're dying to own one of these beasts, it's a better buy to get one complete and in the original box. You'll eventually grow to hate it, and it's easier to recoup your investment, when you go to sell it, with the tool complete and in its original box. "

Wise words - I did own a 55 for a while, and while I really admired the thing, it's just easier to use proper moulding planes.

Tara a bit,

SOTA

 

[Racers]

The OP said he wants to make a convex curve, as produced by a hollow plane.
I think he was choosing his words carefully but a sketch would help!

Errr I was suggesting he use the 57 to shape the sole of a jack, yes that’s what I was suggesting

Pete

 

[paulc]

Really informative replies, I'll check out Dave C's books. Krenov's techniques and any videos I can find online. No time to upload a sketch right now AndyT, but yours / everyone's interpretation of my meaning is spot on. I'll most likely experiment with bench plane / shaped scraper or sanding block first and if required then move on to making/ modifying a wooden jack plane to suit.

Cheers, Paul