Which Plane?

[Pete Staehling]

I build stringed musical instruments to supplement my retirement. Most have convex sides and ~0.090" thick sound boards (tops and backs). Something like this:

326572
The bottom is already trimmed in this picture, the top is not.

I am looking for the best way to trim the 0.090" faces flush to the convex sides. In the past I have used a router, used a bandsaw followed by a block plane and then a sanding block, even hogging it off with a bench top belt sander, and also tried a spoke shave followed by a sanding block. It seems to me as if some kind of plane must be ideally suited for this task. It needs to be able to cut the edge of the faces flush without marring the sides.

If the sides were straight I was thinking a bull nosed plane might be the answer, but with the convex curve I doubt it. I own a few planes, but currently no specialty ones. I already asked Santa for a router plane and a combination bull nose/shoulder plane for other tasks, but I could add another to the list if one would be ideal for this task.

BTW, my preference is always low to moderately priced solutions that get the job done without breaking the bank. Also I am not opposed to shop built solutions where they make sense.

[Brian Holcombe]

I'm not an instrument maker.

However, I do cut similar situations with a plane, normally I just stop when it is cutting flush. Have you tried something like a #4 plane and just run a piece of tape down the center of the plane so it can only cut until the piece of tape is touching the sides?

[Jim Koepke]

I'm not an instrument maker.

Same here. My only suggestion would be what are called violin maker's planes. There are many different types and makers, here is one from Lie-Nielsen:

https://www.lie-nielsen.com/product/violin-makers-plane

Maybe someone like George Wilson who has actually made instruments will chime in.

jtk

[Bill Houghton]

Block plane and care.

[Pete Staehling]

Thanks guys.


My only suggestion would be what are called violin maker's planes.
I'll look into that thanks.


Have you tried something like a #4 plane and just run a piece of tape down the center of the plane so it can only cut until the piece of tape is touching the sides?
No I have not tried using tape either on the plane or on the work. I may experiment with that.


Block plane and care.
Yeah that does work and has probably been my best practice so far. I have nicked a side a little now and then, but never bad enough to not sand out OK.

[John Sanford]

It would seem that a shop made "wide body" plane (1-2") with a narrow blade, 1/2" or less, would be the ticket. Lots of registration, leetle eety beety cutting surface. You could accomplish nearly the same thing by crazy skewing a block plane so only a minimal amount of the blade is actually on the work. This has the advantage of being a no cost solution. Just glue up out of scrap a bunch of pseudo necks (or whatever it is in your pic) to practice on until you've got the technique down cold.

[John Vernier]

I think skewing the block plane is what I would do here too, but if I were doing a lot of this sort of work it would be worth the trouble to put a fair amount of camber on the block plane's blade, just to make certain that the blade's corners are well out of the way, and the cutting edge is restricted to a narrow bit at the center of the plane's mouth.

[Pete Staehling]

It would seem that a shop made "wide body" plane (1-2") with a narrow blade, 1/2" or less, would be the ticket. Lots of registration, leetle eety beety cutting surface. You could accomplish nearly the same thing by crazy skewing a block plane so only a minimal amount of the blade is actually on the work. This has the advantage of being a no cost solution. Just glue up out of scrap a bunch of pseudo necks (or whatever it is in your pic) to practice on until you've got the technique down cold.

but if I were doing a lot of this sort of work it would be worth the trouble to put a fair amount of camber on the block plane's blade, just to make certain that the blade's corners are well out of the way, and the cutting edge is restricted to a narrow bit at the center of the plane's mouth.

I like the idea of either using a block plane with a lot of camber or a shop built plane. I don't mind dedicating a plane to this as it is a very frequent operation in my shop.

[steven c newman]

I might have to put on the flame-proof suit, but here goes

At harbor Freight, there is a 3 pc set of mini block planes. Brass and wood infill style. Very good reviews for them, too. less then $15 for the set. Might be worth a look?

[Patrick Chase]

I am looking for the best way to trim the 0.090" faces flush to the convex sides. In the past I have used a router, used a bandsaw followed by a block plane and then a sanding block, even hogging it off with a bench top belt sander, and also tried a spoke shave followed by a sanding block. It seems to me as if some kind of plane must be ideally suited for this task. It needs to be able to cut the edge of the faces flush without marring the sides.

I would only use a plane for rough take down if at all, and then switch to a card scraper to bring the side panel level with the top/bottom. I'd probably tune it with a fairly subtle hook to minimize the chance of gouging. You gain a lot more control of the cutting edge that way (assuming your technique is good), and you can actually see what you're doing.

What you're trying to do here has a lot in common with taking inlays down to the surrounding surface, and scrapers are widely used there. The fact that the tops/bottoms are curved means that you'll have to be careful about grain direction if you use a plane.