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Comment by David Beede on May 31, 2011 at 8:05am

Hey Rand,

Sure, feel free to kick off the discussion. As I mentioned, I borrowed this technique from the boat building community where it's used to make hollow tapering masts. There is a good article on Duckworks magazine that addresses more sides and even has an on screen calculator that tells you the angles to use for the "mouth."

http://www.duckworksmagazine.com/04/s/articles/birdsmouth/index.cfm...

The up side of the octagon is that you only need to set a blade to 45 degrees - as the number of sides increases you need to know two diff. angles.

I used this system to make an urn for a friends ashes once. I can't seem to find the pics at the moment, but it showed me how easy it would be to glue up a multi sided tube, say 2 or 3 feet long, then slice off your box frames on a table saw.

    Keep me posted...

David

Comment by Rand Moore on May 26, 2011 at 7:24pm

Hi David Beede,

I really like the simplicity of you "birds mouth" method for making an octagonal drum (or sound box) for your "home depot banjo". Can you use this method to make sound boxes with other numbers of sides, or will it only work with octagons? Please let me know. I have a discussion group on CBN which specializes in making sound boxes for those that want to build something beyond a cigar box guitar (or those who don't have access to cigar boxes, like me).  The group is called "Home Made Resonator Boxes 101". I think your method warrants a discussion of its own within my group. Can I use your photo and start the discussion? Please let me know.

-Rand.

Comment by David Beede on April 24, 2009 at 8:40am

Hey Roger - I did figure out your link... it's .org... I loved the pictures of your banjos.

http://www.banjohangout.org/myhangout/photos.asp?id=24829

Comment by David Beede on April 24, 2009 at 8:31am

Hey Roger,
Thanks for writing.
Yes that's a pretty straight forward way to make a banjo pot.
Is that the Stanley Hicks style pot like the Foxfire books featured in the 70s? The link you mentioned didn't work & I couldn't hit on the right variation to get it to go through. Here's a pic of what I think you're speaking of?

At first glance we tend to think an octagonal box involves "tricky angles" and if made the usual way they do use 22 degree angles on both ends of all the parts. But the cleverness of this method is that you are using 90 degree angles... you know like Cigar BOXs have a bunch of. Yes to cut one I set my saw blade to 45 degrees, but that's not what I would call a "tricky angle." The other thing not immediately obvious is that when you wrap a cord or strap around this geometry, it "locks" into shape and it would be hard to force it to be anything but an octagon.

You didn't say how long your 12" poplar board was, but I'm guessing 4 ft, since you're cutting 4 circles from it. With this technique, I could make twelve approx. 2" deep pots from the same board.
Please post a working link to your banjo site as I'd love to see what you do.

Comment by Roger Martin on April 24, 2009 at 4:45am

I build my banjos a bit simpler.The way I do it is to buy a 12 inch wide plank ( poplar) from Lowes,then draw 3 or 4 11 inch circles on the plank, cut it out and then go back and cut out the INSIDE circle. Glue it all up and I have my rim.It has worked for me every time.I'm far too lazy to do all the measuring involved with all the tricky angles as you did.
What you did makes a nice looking rim but its too much work for a lazy guy.
Check out my banjos on the www.banjo hangout.com site and you can see how my way works out.

Comment by Old Lowe on April 24, 2009 at 4:44am

That's pretty darn cool.

Comment by David Beede on April 24, 2009 at 2:01am

The 90 degree notches can be made in many ways. A table saw with the blade set to 45 degrees. A 90 degree bit in a router. A band saw or hand saw would be trickier, but possible. The sides could be thinner and the top could be covered with wood or thin ply.