Yes, this is a bit of a joke, but it's a joke that plays and sounds pretty good!

I got my tennis racquet for 50 cents at the local Salvation Army.

Because I could only fit one tuning gears at the "peghead" end, I mounted the 
other two at the opposite end, just behind the bridge. I took care not to drill
through any part of the banjo rim where the drill bit might hit/sever any of the
racquet's string-grid.
The "fingerboard" was created by simply sanding flat one side of the racquet's 
handle -- as seen in the illustration. 

I used a piece of clear mylar (this can be obtained from nearly any commercial
printer. They throw out lots). Broken mylar drum heads will work fine too.
Mylar is attached very solidly using a line of super-glue and staples spaced 
about every inch or inch & a half or so.

Strings are 60 pound (.028") and 80 pound (.037") monofilament weed-whip line 
(WalMart, K-Mart, Ace etc.)

"Tailpiece" = three #6 x 1/2" screws - two screws at the end of the racquet's 
handle the other one at the opposite end.

Bridge & nut = made from ANY wood in a minute or two.

"5th" string -- a couple of small brads (see my article on making a gourd banjo
                for more details)

All construction details can be seen in this photo:

HERE for a short YouTube video showing this instrument being played

Dennis Havlena - W8MI  
Mackinac Straits, northern Michigan

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