So I ordered a cheap 11" hand drum to make a full size banjo however when it arrived it's a 10" drum. So I've decided to bite the bullet and attempt to make my own pot.
My idea is to attach dowels at regular intervals to the outside of the 10" rim to match the inside diameter of an 11" rim, then use it as a jig for the laminations, building it up till I reach the outside diameter. I'm toying with the idea of using felxi ply (which is also cheap but bendy) but not knowing anything about rim construction I don't know if this will work.
What is the inside diameter of an 11" rim?
Of course if anyone knows a better way to construct a rim on the cheap I'd love to hear! I don't have a workshop or lathe so a block rim would be out of my scope.
Well if you used the 10 inch drum without any dowel additions you would have a 1/2 inch thick pot when you laminate it up to 11 inches. Any additions will make the rim thinner.
To answer your question - the inside diameter of an 11 inch pot is directly related to how thick the pot will be. 1/4 thick pot inside is 10 1/2. 1/2 thick pot inside is 10 inches. 3/4 inch pot inside is 9 1/2 inches.
If it was me I would probably just make the banjo using the 10 inch drum.
Thanks, that makes sense, 1/2" thick sounds about right, I've just coated the rim in aluminium tape (to avoid gluing it to the rim) all I need now is some veneer sheets, glue and clamps
You could just build up the 10" rim until you have reached an 11" outside diameter, and you would have a perfectly good, if fairly thick, 11" rim.
Many ways to do it—what tools do you have at your disposal?
Did think of building up the rim to 11" but it would look very thick, plus it would need more laminates than if I built it just from 10" to 11"
As far as tools go, I have the basic,
small desk vice
Nothing in the way of powered machinery, no band saws, pillar drills or belt sanders
There are some places that sell 1/16" veneer. If you can find that in a straight grain, in some wood like maple, you can bend strips without steaming.
You could cut strips to the exact length for each layer and stagger the joints—each successive layer stiffens the lamination and stops it from going out-of-round.
You would have to use web-clamps to clamp the layers around the inner 10" mandrel
eight 1/16" laminations would bring a 10" O.D. up to 11" and you would have an 11" rim, very similar to the 7-ply ones Vega made in the early 1900s, which were about 1/2" thick and among the best rims ever made
Here's a close-up of a 1020s Vega rim, and you can see two of the staggered joints, which were staggered all around the rim
Edited by - Ken LeVan on 05/17/2021 05:33:43
That's massively helpful thanks Ken, I was thinking maple but with a contrasting inner and outer layer. Bending without steaming will be much easier!!
1/16" veneer it is
There's no absolute RULE that a banjo MUST be a certain size.
You have a banjo body with a ten inch head.
Adding laminations will give you an eleven inch body, with a ten inch head.
Unless you're planning to replace the head.
I have made a nice sounding banjo from a ten inch drum, as may be seen in the accompanying video.
Edited by - mike gregory on 05/17/2021 05:59:47
Love it Mike
Here's my 10" attempt
"Help! I've come within 30 paces of a very loud salad bowl banjo, and I can't get up!"
'cordless pole saws' 2 hrs
'Fearless Leaders' 5 hrs
'Hide Head from Greg Boyd's' 11 hrs
'1967 gibson rb250' 11 hrs
'Hungarian Rhapsody #2' 14 hrs