Making curves 'jigs"

[Ed Gibbons]

I am building a bench where the seat is rounded at the ends. Any jig ideas?

Thanks,
Ed

[Rod Sheridan]

Hi Ed, I don't understand the question.

Are you asking how to cut a radius on the end of a board?

More information will probably result in someone replying to your question.

regards, Rod.

[Marcus Ward]

You got a picture of what you're trying to do?

My best advice on curves is usually "Draw it on there and freehand it".

[Ed Gibbons]

I am looking to put a curve at the end of a bench seat.

[Bill Huber]

I am looking to put a curve at the end of a bench seat.

If this is what you are talking about.....

I would just measure back the radius of the circle and use a string compass and draw the half circle, then cut it with a jig saw, clean it up with a sander.
There are also circle cutting attachments for most jig saws.

Or you could, if you have a band saw cut a circle on it out of MDF with the same radius and then double back tape it to the bench top and use the bandsaw to cut it. Then with a trim bit in the router clean it up.

Of if you have a router with a circle cutting attachment you could also use a straight bit with a few passes and do it that way.

A lot depends on what tools you have and how many you are making. What you are making it out of would also help.

Looking down on the top of the bench.

102465

[Vince Shriver]

Ed, do you mean you want the ends of the board to simply be rounded? Or do you mean you want the board to be curved up on both ends which would look like an enlongated "U"?

[Prashun Patel]

I made a circle cutting jig for my router's plunge base. Basically, I chucked it with a 1/2" spiral upcut bit (you can use a staight bit, but it'll be cleaner with a spiral upcut), and plunged through a piece of 1/4 hardboard connected to the base to make a big ol' trammel arm. Screw the trammel arm onto the bottom of yr bench at the proper spot and you'll cut a smooth arc.

One tip: You'll risk tear out when the bit exits the arc. To minimize, either:
1-cut in very shallow passes
2-clamp blocks to the infeed and outfeed side of the cut (flush with the workpiece so the trammel can slide freely
3-cut yr bench wider than desired, then route the arcs, then rip the bench to the proper width.

[Vince Shriver]

I made a circle cutting jig for my router's plunge base. Basically, I chucked it with a 1/2" spiral upcut bit (you can use a staight bit, but it'll be cleaner with a spiral upcut), and plunged through a piece of 1/4 hardboard connected to the base to make a big ol' trammel arm. Screw the trammel arm onto the bottom of yr bench at the proper spot and you'll cut a smooth arc.

One tip: You'll risk tear out when the bit exits the arc. To minimize, either:
1-cut in very shallow passes
2-clamp blocks to the infeed and outfeed side of the cut (flush with the workpiece so the trammel can slide freely
3-cut yr bench wider than desired, then route the arcs, then rip the bench to the proper width.

or:

4-make a very small climb cut at the exit side of the board before you cut the arc.

[Joe Chritz]

I cheat and draw it in cad and go use a CNC router. Without that I would free hand the arc on MDF, jigsaw it, clean it up with a rasp/sanding and template route the piece, ALA David Marks.

I just did one where the arc is bigger than the width of the piece (the piece is 12" wide the arc is 16" diameter) and it would look good on the end of a bench. Mine is for a saddle stand for a Christmas gift.

Joe

[John Thompson]

Ditto Joe on template with MDF and overhead pattern bit on router even though that method has been around a lot longer than David Marks. I was told about it and started using it in the late 70's but we used ply as MDF was not available then.

1/2" MDF is much easier to shape than the ply which results in quicker. If you do use this method.. save the template as you never know when you might duplicate.

Good luck...

Sarge..