Homemade tension hoop

If you have been following my all English banjo build, you may remember that I have been planning to make the majority of the metal hardware components required.

First of all I had to find a way to accurately bend the 1/8″ brass flat bar into a circular tension hoop. There are commercially available ring rollers available to do this but not having access to one, I decided to make my own form to bend the brass around.

The jig consisted of a 11″ diameter piece of mdf which then had a dowel glued into its centre to act as a pivot point for an arm that would do the actual bending. The say a picture says a thousand words so here goes.

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Banjo tension hoop bender

The brass flat bar is then attached to the form and by rotating the arm around the form the brass should then be bent to shape. I also used several clamps to hold the brass in place and reduce the risk of it springing back and causing an injury.

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Clamped up tension hoop

 

Unfortunately I had not considered how much spring back there would be and when I removed the brass from the former it was nowhere near the required circle.

I therefore made another form this time with a diameter of 9″ and repeated the process. Now while things were starting to resemble more of a ring, there was still a way to go. So a third form was made, this time with a 7″ diameter. The brass almost looped the form twice but once it was released from the form it was much more promising with only a small amount of spring back remaining.

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Tension hoop nearly circular

The two ends of the ring were secured with a bracket made from 1.5 mm brass with 4 drilled and taped holes through both the rim and the fixing plate and hold the lot together with machine screws.

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Tension hoop fixing bracket

Next the hook notches needed to be cut into the ring, this was done with a hacksaw and finished of with files to create 14 inward sloping notches evenly spaced around the hoop.

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Tone ring with notches