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General Category => General Scroll Saw Talk => Topic started by: EIEIO on May 29, 2013, 12:20:05 pm

Title: Banjo
Post by: EIEIO on May 29, 2013, 12:20:05 pm
I've been asked to scroll cut a banjo for someone. They want the ring (the round part that the skin sits on) from Black Walnut and the neck from Maple.

I have a piece of 2" thick x 8" wide black walnut, but the ring needs to be 12" diameter. So I can join boards to get to the width, but then scroll cutting will pass through the joint. I was concerned about the strength of the joint. I will need to stack 2 rings to get the desired depth.

Does anyone have a good suggestion for the side-by-side joint? Maybe finger joints, biskets in the circumference, angle cut the joint at 45 degrees, etc. Or is just a square glued joint strong enough? Should the boards be opposite in grain to minimize warping? How about the stack - should they line up grain-wise, or one be rotated 90 degrees before gluing?

Any thoughts will be appreciated.
Title: Re: Banjo
Post by: daveo on May 29, 2013, 01:41:40 pm
Hi
O had to do this with some oak the other week and found that a simple butt joint using a resin based glue was enough, biscuits are a good idea as long as you can plan them to be away from the cuts
Dave
Title: Re: Banjo
Post by: Gary Morris on May 29, 2013, 02:35:16 pm
you could put a couple of dowels in, I did that with some oak, a bit like Dave's, but if the peice won't be handled a lot glue on it's own should be ok.

Gary
Title: Re: Banjo
Post by: Rapid Roger on May 29, 2013, 06:32:17 pm
I think that glue would be strong enough but, if you want to take the time and effort to do a tongue and groove joint on the boards before gluing it would add a little interest to the joint.
I think on stacking the two rings, that lining up the grain parallel would look best but, stager the glue joint so that it doesn't align exactly and if you do use the tongue and groove splice, and anyone ever notices it would be even more interesting and a real "head scratcher" for most folks.  :D :D

Rog   
Title: Re: Banjo
Post by: dgman on May 29, 2013, 08:38:13 pm
The but joint will be strong enough providing you have good jointed edges. When I glue up boards for wider blanks I run the edges through the jointer, but a good ripping or combination blade on your table saw will do a good job too. Once you apply glue to the edges, you need to clamp the boards together with clamps. Use a good woodworking glue like titlebond. If done properly, the glue joint will be stronger then the wood itself. Using biscuits or dowels will not make the joint any stronger but will aid in aligning the boards but as Roger said, you have to position them so they will not be visible after you cut. Let the glue dry overnight and you should be good to go!