How do I make this cutting board curved joint?

[Alan Lightstone]

This maybe a complete stupid suggestion, but this is the internet...could you overlay the boards and cut the curve on both at the same time with a band saw?

You can, but you get a rough cut, albeit both pieces matching well. Hard to get a smooth curve.

That's easier with the same species of wood. A little tougher this way.

[Bob Falk]

This maybe a complete stupid suggestion, but this is the internet...could you overlay the boards and cut the curve on both at the same time with a band saw?

That was my question. My father used to make cutting boards with curved elements (e.g.,wine bottle outlines) that way and they had tight joints.

[Bob Cooper]

I’ve built something like what Glenn shows where you take a single board and dado out say 1/4” or 1/2” of it. Then you use a bandsaw to cut down the moddle of the dado so that you have two pieces. Then use a straight bit with a collar to remove the left over part that was not cut out by the dado. Yes pictures would help. Now you cannot glue these two pieces directly together for the reason that Glenn shows but you can fill
it in with 1/4” or 1/2” of other material like he shows. This was a FWW article.

But for your case you could use one of those two pieces as a template for your other wood

You would need to keep the filler material between your two big pieces but it would solve your snug fit issue.

otherwise you need to do the router offset template idea

BTW the one issue I really struggled with was clamping. I found it very challenging to be able to apply pressure and not have the curves cause the pieces to shift as I applied pressure

[Bob Cooper]

Ok here’s a few pictures. Really only the first picture is important but figured the other might give you some ideas if you wanted to add some other woods

[Ed Mitchell]

https://www.youtube.com/watch?v=3mqrIGp-PQ8

[Malcolm McLeod]

I’ve built something like what Glenn shows where you take a single board and dado out say 1/4” or 1/2” of it. Then you use a bandsaw to cut down the moddle of the dado so that you have two pieces. Then use a straight bit with a collar to remove the left over part that was not cut out by the dado. Yes pictures would help. Now you cannot glue these two pieces directly together for the reason that Glenn shows but you can fill
it in with 1/4” or 1/2” of other material like he shows. This was a FWW article.

But for your case you could use one of those two pieces as a template for your other wood

You would need to keep the filler material between your two big pieces but it would solve your snug fit issue.

otherwise you need to do the router offset template idea

BTW the one issue I really struggled with was clamping. I found it very challenging to be able to apply pressure and not have the curves cause the pieces to shift as I applied pressure

If a pattern for each side is needed, then you could follow Mr. Bradley's and Mr. Cooper's process - just don't glue one side: Take the single board 'pattern', cut the (1/4") dado through it, bandsaw into two pattern pieces, flush trim the 2 sides, fill with proper (1/4") strip - only glued to one side of the patterns, and clamp them back together. ...With proper caution for clamping alignment, as per Mr. Cooper.

Now in theory at least, you have 2 properly sized (mating) compound curves in the resulting 2 piece pattern.

I think I would use as thin a dado & fill strip as reasonable? If you keep it thin, it might save steam bending, laminating, or at least the wrestling match of trying to get the filler strip glued/clamped in place.

[Jim Becker]

Can't you cut through both boards at the same time to get a tighter joint?

Straight, yes...but with curves, the "kerf" of the tooling you are using to cutting means the two sides will not match. That's why I indicated that two templates are required to get a perfect match; one for "each side of the line".

[Kevin Jenness]

You can make matching templates with a router by accounting for the bit diameter and offsetting the cut as shown in Chistopher Giles' post. Here is a similar technique with sturdier bits.

Make a template for one side of the joint by sawing and sanding. Clamp the initial template on blocks above the bench. Clamp another piece of template material roughly cut to mate with the first one, offset from the first less than 1/2" horizontally and 1/2" lower. Run a 1/2" diameter top bearing trim bit against the initial template, producing an offset cut 1/2" different in radius from the first. Now clamp the second template above a third piece and trace it with a 1/2" shank, 3/8"diameter bit with a 1 3/8" bearing. The third piece should match the first.

[Thomas Canfield]

This maybe a complete stupid suggestion, but this is the internet...could you overlay the boards and cut the curve on both at the same time with a band saw?

That will work and adding a thin strip in the joint helps to minimize any mismatch since the strip is the eye catcher.

[Bruce Wrenn]

Best I can remember, Bill Hylton's book "Router Magic" covers this. Been a few years (1996) since I bought it at American Wood Worker show in King of Prussia PA. Actually wife bought it for me as a birthday present.

[Wes Grass]

Patterns, a mating pair. And they have to be really good. Even milling these from a plate, they warp and have to be 'spring clamped' and given a finish pass.

I wound up doing 3 different patterns for this guy, and Lexan templates for the last 2. I did it 'cheap' for the experience ... but you'd have to be thinking real production to justify what it would cost in the real world.

template.JPG

[Mark Hennebury]

I used to make a lot of complimentary curve items.
You need one template and router template guides that move the router bit from one side of the cut line to the other.

538284_1.jpgcrop_1343.jpg

[Rich Engelhardt]

So I taped the boards next to each other, with filler pieces underneath with a gap and used a handheld router with a bushing and a 3/8" spiral downcut bit.


This went great until the middle of the board on the big curve when the grain changed on the board. The router jumped, and ruined the board.

It wasn't the change in grain that caused it. It's the fact that one side of that trench is being made by a climb cut. Secure the work - switch to an upcut bit that pulls debris out of the trench and take much shallower passes.
If you look carefully at the above post you can see how the template is shifted so it avoids using a climb cut.

[Alan Lightstone]

It wasn't the change in grain that caused it. It's the fact that one side of that trench is being made by a climb cut. Secure the work - switch to an upcut bit that pulls debris out of the trench and take much shallower passes.
If you look carefully at the above post you can see how the template is shifted so it avoids using a climb cut.

It's actually shifted here too. You just don't see it in the photo. The work is actually secured also. I should have taken a better picture.

[Rich Engelhardt]

Alan,
It's my fault - I know what I'm trying to get across but I can't seem to find the way to put it on paper (so to speak).

Anyhow,, Stumpy Nubs has a Youtube about it:
https://www.youtube.com/watch?v=fZmIMmdCTYA