Bending 1/4" thick banjo rim

[Steve Senseney]

Impressive work!

[Jon Whitney]

Bill, I'd really like to hear more about your process of clamping the compression strap to the wood. It seems to me you wouild have to put the strap and clamps on the wood before heating it, in order to have time to bend and remove clamps after you take it out of the water - is that right? What type of clamps do you use?

[Bill Rickard]

Jon:

I place the clamps on the ply and compression strap after the wood is boiled or removed from the steamer. Prior to steaming the wood I do a dry run and have the "C" clamps set in position and ready to go. I then steam or boil the ply and as soon as I remove the wood ply from the steamer I immediately clamp the ply to the compression strap in four places along the length. To help speed up the process I have a ledge that's bolted to my rolling machine that I lay the ply on as I clamp up the wood ply. This ledge also assures that the ply is feed into the rolls 100% in line with rollers. I then hit a foot switch which starts the rolling process plus activate a pneumatically activated set of pressure rollers. As soon as the first clamp comes in contact with the roller I lift my foot off the switch to stop the rollers rotating and quickly remove the 1st. "C" clamp. I complete this cycle until all four "C" clamps have been removed and the ply is fully rolled into a circle. All this probably takes less than 35 seconds to complete. As I said earlier you must move real fast once the wood is removed from the steamer or the wood looses it's flexibility. Everything has to be ready to go prior to removing the wood from the steamer. For this reason I've experimented with boiling the plies instead of steaming and I've found that the boiling process definitely gives me more time to get the job done after the wood is lifted out of the boiling pipe. It also really helps when I'm bending rosewood or cocobollo rims. I've witnesses rims being rolled without using the "C" clamps to hold the ply in the compression strap but have personally always used 4" "C" clamps to do the rolling. I'm also rolling some real thick ply rims that would not be possible without the addition of the "C" clamps. What you notice happen is that the extreme pressure created between the wood ply and compression strap actually forces the clamps to slide along the length as the ply is rolled regardless of how tight you tighten the clamps.

Prior to building the automated vertical rollers as shown in the previous photos I used a horizontal set-up as the picture below shows. I switched over to the vertical device as I thought it would work better as I'm working one armed from a wheelchair as mentioned earlier. I've since abandoned both of these machines and am now building up a fully automated rim rolling production line which will consist of five tables each supporting two roller heads with internal heat blankets to force dry the plies. When completed I'll share some photos of the completed set-up. Interesting thing is that I got into banjo building as a form of rehab after my accident, as I couldn't play anymore. It's now turned into a 7 day a week rehab obsession and a full time growing business! After my accident all the professionals told me I'd never go back to work again. Just goes to prove that you shouldn't take the professionals too seriously when they start to tell you what you can or can't do!

[Chuck Tweedy]

Good golly Bill, you really have something going on there. Those are some serious machines!

[Michael Lewis]

Bill, when you mention bending the plies, how many plies at a time? How many plies make the rim thickness? How thick are the plies?

[Jon Whitney]

What you notice happen is that the extreme pressure created between the wood ply and compression strap actually forces the clamps to slide along the length as the ply is rolled regardless of how tight you tighten the clamps.

That's what I thought must need to happen, based on my experience with a hard and fast stop on both ends of the compression strap. It simply doesn't work too well. You need a little slipping and sliding while still maintaining as much linear compression as possible.

It seems like you could use those vise grip wood clamps to clamp things up even quicker.

What about boiling the wood, strap, clamps, and all? Any reason that couldn't be done or wouldn't work?

[Steve Senseney]

I have used 1 inch steel strapping for backing.

I drilled a couple of holes in the steel, screwed on a wood "handle", and made another handle at the other end. Cut the board to the right length so it was tight between the two handles.