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Timbuck
08-24-2018, 11:46 PM
Im upgrading my Foxy type bender ..I'm making a new soprano side bending former ..It looks a bit odd shaped co's I'm trying this time to compensate for the spring back I get with mahogany.
111468

leonel_elguti@hotmail.com
08-25-2018, 07:28 AM
It looks like it'll work fine. Probably it'll even improve the waist radius to get an even smoother joint of the three radius and the
fluidity of curves at the transitions while changing from one radius to another (I don't know if that makes sense in english...).
Anyway! It'll work surely, Mr. Timbuck. Aloha!

sequoia
08-25-2018, 07:51 AM
Im upgrading my Foxy type bender ..I'm making a new soprano side bending former ..It looks a bit odd shaped co's I'm trying this time to compensate for the spring back I get with mahogany.
111468

I've always wanted to make a compensated bender but never get around to it... Interestingly, when the Wright brothers were making their first airplane wing they encountered problems with springback too. It puzzled them. We are not alone.

Timbuck
08-25-2018, 08:27 AM
Coming along nicely...20 10mm rods to hold the heat, the old one had only 14..I recon this will cost me about 70 quid when it's done but it will be worth it if I can reduce the hand bending.....The hardest bit is done now "drilling and reaming the holes so that they are just flush with the rim" :)
https://farm2.staticflickr.com/1883/30395284778_e473d38984_b.jpg (https://flic.kr/p/NiVMd7)IMG_1017 (https://flic.kr/p/NiVMd7) by Ken Timms (https://www.flickr.com/photos/150702140@N02/), on Flickr

sequoia
08-25-2018, 05:49 PM
You really do like working with metal Ken. Beautiful.

Timbuck
08-25-2018, 08:21 PM
Working with wood is just the same as working with metal..only you make more progress with wood..My Dad told me that :)

*EDIT* Anyone who is considering making one of these bender formers..remember to make the profile to the inside measurments of the uke (not the outside) plus the thickness of the steel slatt that goes under the sides while bending .. if using a heater blanket under the side piece allow for the thicknes of that as well..I know it's common sense but ?? :)

mikeyb2
08-26-2018, 12:26 AM
Keep the pictures coming Ken, it'll be interesting to see how this develops.

Timbuck
08-26-2018, 08:35 AM
Keep the pictures coming Ken, it'll be interesting to see how this develops.

I started a thread a couple of years back showing how i did this on a concert size bender .. it can be seen from page 6 onwards...only Photobucket killed all the pics with their ransom demands..but there is a fix you can download so that you can view them all again..The thread is here https://forum.ukuleleunderground.com/showthread.php?121329-I-m-going-to-make-some-concert-size-Ukes&highlight=concerts

mikeyb2
08-26-2018, 10:36 AM
Thanks Ken, I'll check that out.

Timbuck
08-26-2018, 10:35 PM
with this former being a different shape to the old one i had to make another waist caul to suit ..Here it is being glued together at the side of the original caul.111503

Beau Hannam Ukuleles
08-27-2018, 04:15 AM
Nice Ken!
Is there a way you calculate how much tighter to make the mold for the spring back or do you just give it 1"tighter curve if it springs back 1"??

leonel_elguti@hotmail.com
08-27-2018, 04:16 AM
We all have to trust the new one will be even more accurate onto the vintage Martin waist and radius than the older one. In Ken we trust (? Hahaha... Anyway it's a fact that I (and I dare to say we all) think there's a positive reason for you to upgrade the device. Hope this will result in the same good quality (or better) Soprano uke!

Timbuck
08-27-2018, 05:29 AM
Nice Ken!
Is there a way you calculate how much tighter to make the mold for the spring back or do you just give it 1"tighter curve if it springs back 1"??

Over the past few months I have been taking a lot of notice of the main areas that i'm getting the spring back, mainly the waist and the area where the butt joints are ..The butt ends came out flat co's that was the shape of the former , the new former is now rounded at the ends..but the waist was springing back approx 1/4" so I increased the waist shape by an extra 1/4" deeper which should come out OK ..Thats if the sides don't break :uhoh: also there is a flat spot just a bit south of the waist on the lower bout so I added a bit on in that area ...Most likely I will still have to adjust a bit by hand on the hot pipe , but not as much as i have been doing :)
Here is the old one showing the areas that I needed to adjust.
https://farm2.staticflickr.com/1861/42495943020_bea01b6925_b.jpg (https://flic.kr/p/27KdPjL)IMG_1034 (https://flic.kr/p/27KdPjL) by Ken Timms (https://www.flickr.com/photos/150702140@N02/), on Flickr

mikeyb2
08-27-2018, 06:10 AM
If anyone hasn't seen this video, it might be of interest regarding springback. https://www.youtube.com/watch?v=1qrQn84kVIk

Pete Howlett
08-27-2018, 11:27 AM
Matthias Wandel in his much mocked (here) how to build a ukulele series shows how he calculated springback using math.... I don't get springback...

sequoia
08-27-2018, 07:07 PM
I don't get springback...

Never? Not even a little bit?

Timbuck
08-30-2018, 08:42 AM
I got the mods finished today and before I quit for the day I thought I'd give it a test...switched on the Foxy to heat up..then got a pair of dodgy looking sides, I've been saving these co's they are very highly figured sapele ,you could say curly..and looked as if they would be very dificult to bend, so ideal for this first test...If these turn out ok anything will.

I wetted them wrapped them in aluminium foil and as the Foxy temperature reached almost "too well done" on the kitchen Meat thermometre I put them in...As I wound down the top caul and started the bending of the waist something went bump ??:uhoh: I immediately thought "they have broke..so disheartened i disided to carry on and see how the rest of the bending had gone and switched off the power at about 300 C...After about 15 minutes it had cooled down enough to get the sides out..first thing I noticed before I removed the foil was how tight the waist bend was and when the foil was removed,to my great amazement the waist wasnt cracked or broken at all, but when I put the sides in the mould it was slightly overbent (now I need springback in that spot) :) That I can easilly fix... all the rest of the bends were spot on and I'm now a happy bunny... I'll supply some pics tomorrow as i'm now relaxing :cheers:

Timbuck
08-30-2018, 09:16 PM
Here are some pic's
The new former alongside the old
https://farm2.staticflickr.com/1855/29443004037_d2509d8216_b.jpg (https://flic.kr/p/LRM6jD)IMG_1128 (https://flic.kr/p/LRM6jD) by
In the bender cooking the sides
[url=https://flic.kr/p/27RQuA5]https://farm2.staticflickr.com/1898/42570803000_1a67018715_b.jpg (https://www.flickr.com/photos/150702140@N02/)IMG_1138 (https://flic.kr/p/27RQuA5) by
And the result
[url=https://flic.kr/p/27RQvxf]https://farm2.staticflickr.com/1886/42570806200_8cd003d32f_b.jpg (https://www.flickr.com/photos/150702140@N02/)IMG_1144 (https://flic.kr/p/27RQvxf) by [url=https://www.flickr.com/photos/150702140@N02/]

leonel_elguti@hotmail.com
08-31-2018, 12:44 AM
Wow! It looks like it will work perfectly. The wood used for the sides looks pretty! Regards!

Timbuck
08-31-2018, 02:45 AM
Bent another set today..and put them together ..This is much better now, they are trimmed and glued to the end blocks straight from the bender with no further heat adjustment needed...So that's taken a lot of mental stress out of the build.:D
https://farm2.staticflickr.com/1900/30516150028_f76a8ec948_b.jpg (https://flic.kr/p/NuBfeJ)IMG_1164 (https://flic.kr/p/NuBfeJ) by [url=https://www.flickr.com/photos/150702140@N02/]