Bigger Convex Curve than #18 Hollow Moulding Plane - How to?

[Stewie Simpson]

Paul; view the attached video; https://www.youtube.com/watch?v=ijUDrOsHW54

[Tom M King]

That sounds like a pain. Why didn't you just run the piece through at an angle to cut the cove in just a few pass? Just curious.

I thought we were talking about a convex shape. It was for a short, missing piece on a mantle. It had a couple of quirks, but they weren't very deep. There wasn't much of a cove. It was on a strange, early 19th Century mantle. I don't know what the part of the frame looks like that this thread started about, but the question was about a convex shape. I never heard a question about a cove. It would take a LONG time to cut a cove with any hollow plane.

[Tom M King]

It seems like some people are confusing the difference between a hollow plane, and a round plane, not to mention convex, and concave.

Here is a picture of a Hollow plane. The sole of a round plane curves the other way.

[Mike Lemon]

I think the original question is throwing people (it is me). It says convex but reads like concave is meant. Convex is easy- grab any plane and go. I don't even try and I get convex when I plane.

[Jim Koepke]

I'm awaiting the arrival of the largest hollow plane #18, which I believe, produces a 1.5 inch wide convex curve [edited] Is there a reason that hollow and rounds stop at this width?

They do become harder to push the bigger they get.

My understanding is the numbering system for hollows & rounds would have the #18 being 1-1/8". A 1-1/2" plane would be a #24 which is also the largest hollow plane in my accumulation. It doesn't have an accompanying round. Hollows and rounds are a 1/6 section of a circle. By working sections side by side you may be able to create the profile you are trying to match.

It will be easy to see if the plane will match the profile. Retract the blade and set the plane on the molding. If the plane sole contacts fully, it should be fairly easy. If the sole meets in the center but not the edges, it is still doable. If the edges touch but the center doesn't, oh well.

jtk

[Keith Mathewson]

It takes a little time but you can hit a larger curve.

[Matt Bickford]

Hollows and rounds don't stop at 1.5" radius. Larger sizes are not as common but they are out there. There's a good chance that the 18 you have coming creates a larger arc, in fact.(note: the physical size of the plane tends to remain the same with these larger radii. They just create less than 60 degrees of an arc.)

If you really want to use this method then make the round of the planes you have coming to the profile you want and then use it to change the hollow.

I have made a hollow/round pair that cuts an 8" radius, for instance.

[Paul Carson]

Really informative and helpful. I think I'll wait and see how well the #18 on the way conforms to the curve I need to make, and assess what kind of adjustment would be necessary as Matt has suggested.

If the adjustment is too drastic I may try bench planes + a curved scraper, and if I end up having to make much more of the same profile then I'll look at the possibility of converting a wooden jack or similar.

Thanks again