Planing a concave surface?

[Jamie Buxton]

Did you ever have an idea which makes perfect sense to you, but when you tell the rest of the world about it, they look at you like you have completely lost your mind? Well, I’ve got one of those today.

I’m designing a piece of furniture which includes a coopered panel. When a coopered panel comes out of glue-up, the faces aren’t smooth, they’re faceted. I’m used to smoothing the convex face with a standard handplane. It takes only a few minutes to fair it to a nice smooth curve. The issue in this piece of furniture is that both the convex and concave faces of the panel will be visible. No problem, I thought. I’ll just go get a different plane to clean up the convex side. I was expecting to find planes whose sole is curved. The curve would be such that if you put the plane down on a flat surface, it rocks side-to-side, but not front-to-back. This made sense to me, but when I starting looking around, I didn’t find anything like this in the usual plane catalogs. The closest I could find was a FWW article by a Krenov disciple who described how to build a wood-bodied one. I’ll build one if I must, but the dearth of information out there makes me suspect I’m barking up the wrong tree. Is there some better way to do what I want to do?

[Larry Cooke]

Jamie,

Have you looked/searched for circular planes? They're made for convex or concave planing. I'm no expert so if I'm off base be easy on me.

Larry

[Dennis McDonaugh]

Jamie, you need a spokeshave with a convex blade. I've see many for sale on ebay over the years.

[Jamie Buxton]

Jamie, you need a spokeshave with a convex blade. I've see many for sale on ebay over the years.

Why a spokeshave instead of a plane?

[Steve Schoene]

I've got a Stanley 100 1/2 model makers plane. It is small but fits the description of what you are looking for. And, I am sure coopers have a full collection of such items.

Seems to me handles would still get in the way.

A compass plane with adjustable radius runs the "wrong way" for your example, and would require cross grain planing.

[M. A. Espinoza]

Depending on your radius, spokeshave handles might get in your way. A travisher would work but they are spendy.

Look at what people use to do chair scoops and you'll get a good overview.

If its a one-off you might consider just using a sanding disc with a flexible pad on a grinder.

A compass plane might work as well, but also spendy. Maybe a scorp?

Kind of confused whether this is a compound curve or just a partial cylinder, sorry I couldn't be more help.

[Jamie Buxton]

Here's a sketch of the kind of panel I'm trying to get to. It is coopered from straight boards. The faces are is simple curves, not compound. Getting the concave face to be a smooth curve is what I'm chewing on.

Yes, it is possible to do this with a sander. I've done it this way in the past. However, it is a little tricky to control, and eats lots of sandpaper. That's what set me to thinking about a plane. I use a plane to shape the convex face. Why not the concave one?

[Jim Knauss]

How about investing in an old wood plane and reshaping the body and then the blade to match?

Jim

[Mike Wenzloff]

Hi Jamie,

Jim's advice of reshaping a woodie is a good, viable solution that won't cost a lot and works great.

A more expensive, though more extensible method is to try and find some pattern maker's planes. These have interchangable soles with different radii. I have two, one a short, 6 1/2" one made by Preston, and one a 12" one made by a pattern maker.

http://www.wenzloffandsons.com/temp/preston_pat_0001.jpg

http://www.wenzloffandsons.com/temp/pat_0001.jpg

I use these on coopered doors and moldings. iirc, they cost about $75-$100 each when I bought them.

Take care, Mike

[Cliff Rohrabacher]

You can build that plane very quickly. You can use standard cutters and modify them to have the radius you want.

If you don't want to build it google "Steve Knight" or "Knight Tookworks" he makes hand planes of all sorts and will custom make yours one off if you want. He's likely a great source of information too.

[Dennis McDonaugh]

Why a spokeshave instead of a plane?


Jamie, because I've seen plenty of convex spokeshaves, but never seen a plane like you describe.

[Dennis McDonaugh]

I've got a Stanley 100 1/2 model makers plane. It is small but fits the description of what you are looking for. And, I am sure coopers have a full collection of such items.

Seems to me handles would still get in the way.

A compass plane with adjustable radius runs the "wrong way" for your example, and would require cross grain planing.

Steve, that plane is radiused front to back and side to side. Jamie is looking for one that is only radiused side to side.

[Steve Schoene]

Duh. But the other alternative is readily available too. Chose your radius among a set of hollows and rounds, though the largest round is likely to have a radius of about 2" in a typical set. (The radius cut typically equals the width.) But this would be pretty simple to modify I would think. Or pay Williams and Clark to make a molding plane in precisely the curvature you want.

[skip coyne]

I just did a search on ebay and it looks like compass planes are bringing around 100

I would consider buying one , doing the project and reselling it on ebay

might evan make a few dollars on the deal

[M. A. Espinoza]

Remember a compass plane has the radius along the long axis. I'm not sure that would work for the cooper panel.

Try Japan Woodworker, I know they have a few options. I was researching this a couple years ago, needed something to work on seat scoops.

I ended up building my own. It works well, I was concerned about the particular radii that I wanted. For a cooper panel I think I would just buy a wooden plane and modify.

It will be a very gentle radius by the looks of things so matching the blade to the body radius shouldn't be too difficult.

And making shavings is so much better than dust, isn't it?

[Dennis McDonaugh]

I think Mike has the best idea. You should be able to find a coffin smoother or larger wooden plane pretty cheap and modify it.

[Doug Shepard]

I was actually asking myself the same questions pretty recently. Fortunately the inside of my coopered panels wont show so I decided to skip it. I do still have to thin out the 1/4" or so on the ends so they fit into curved dados but that's not quite so bad. The only thing I could think of when contemplating rounding out the inside were some of the real small Ibex violin makers planes to get as close as I could. Then making up a card scraper to the exact radius to finish things up. That's all I could think of at the time Dont know how wide your pieces are but mine are pretty narrow. The whole plane body would have had to have been narrow enough that it didn't bottom out on the adjacent pieces. Like I said, I decided to skip it. No one will see the inside of mine, but it will haunt me anyway.

[Jamie Buxton]

Ron Hock sells blades designed for Krenov-style planes with curved bottoms. Perhaps that's way to go -- build one. But it sure seems weird that there are zillions of planes to make wood flat or convex, and darn near none which make wood concave.


BTW, I've learned a name for this kind of plane: gutter plane. That seems particularly descriptive. If you were making a wooden gutter by muscle power, this shape of plane is exactly what you'd use.

[Mike Wenzloff]

Hi Jamie,

A gutter plane has a steeper radius than you may desire. The curve extends up the sides a bit more than is useful for controlling the cut--except when making wooden gutters of course <g>.

In the past, before I had the pattern maker's plane, I made one with a radius from side to side like you need from a Stanley transitional. I forget the #, but is was about 12" long.

A transitional is often an inexpensive plane, they are found even where I live often enough, and being that they are wood-soled yet have a Bailey-type frog and adjusting mechanism are quite easy to use. And it is an easy task to modify the sole to the curve you need. The iron is easy enough. Just set the chip breaker back far enough that the corners nearly meet the beginning of the radius of the iron. Set for a light cut.

I would be surprised if it took more than 30 minutes to be planing by using a transitional as the donor plane.

Take care, Mike

[Kyle Stiefel]

Here's a sketch of the kind of panel I'm trying to get to. It is coopered from straight boards. The faces are is simple curves, not compound. Getting the concave face to be a smooth curve is what I'm chewing on.

Yes, it is possible to do this with a sander. I've done it this way in the past. However, it is a little tricky to control, and eats lots of sandpaper. That's what set me to thinking about a plane. I use a plane to shape the convex face. Why not the concave one?

Jamie,

I know this off the plane idea. I made a chair with a coopered top. Following the glue I did the main clean up on the band saw for both the front and back following the desired curve I drew on it. This is probably using a bit more stock then you would like to get rid of thought. After that the sanding goes pretty quickly because the majority of your form is there.


Kyle

[Jamie Buxton]

Jamie,

I know this off the plane idea. I made a chair with a coopered top. Following the glue I did the main clean up on the band saw for both the front and back following the desired curve I drew on it. This is probably using a bit more stock then you would like to get rid of thought. After that the sanding goes pretty quickly because the majority of your form is there.


Kyle

Kyle -- The bandsaw is a good idea, but for this piece I'd need one with a resaw capacity of 30" or so.:eek:

[Jesse Cloud]

I just finished a table with coopered legs. I used a combination of block plane, compass plane, and convex/concave scrapers. Worked pretty well.
Pic is attached. You can find compass planes on ebay pretty often. Lie Nielson makes a small plane with a curved sole, but somehow I just can't get the hang of it.

[Mark Singer]

Check this post:
http://www.sawmillcreek.org/showthread.php?t=14045&highlight=coopered+cabinet