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T39 - finally hatched - weighing in at 42lbs ( 18.5kg )
Posted: Sat Sep 29, 2012 1:52 am
by Harley
Well, they finally got finished today
and came in at 18.5Kg each ( 42 lbs )
20" Wide, T39, 3012LF, Cut bottom for wheels, 9mm ( 3/8" ) Italian Poplar construction, 3 1/8" internal braces except for mouth. 1 hand-hold in bottom panel - 1 hand hold at back of top/top of back.
Here are the shots from a previous post;
Here're the finished articles;
Super light and going through their sound check tomorrow.
One thing I will never do again, even if the customer demands it, and that's cut the bottom back to fit wheels. In fact even leaving the back straight and putting inset wheels in - no no no no.
They rattle like buggery and the time taken to cut, trim, fit, line up, make sure everything is even - forget it, I am just past them. I'll buy the customer a collapsible hand truck instead.
These things are so light, they are an easy pick-up anyhow.
I learned that the thin Poplar needs a lot of control when assembling I ended up with one slightly curved top ( out by 4mm - gnat's tit over 1/8" ) on one and a curved bottom ( 3mm out ) on the other. I know what to do next time - use straight bars and clamp at each step which will fix that 100%
Other than that I am a happy camper so far.
If you need more pics, pay me!
The proof of the pudding is tomorrow, so long as the weather holds out.
Re: T39 - finally hatched - weighing in at 42lbs ( 18.5kg )
Posted: Sat Sep 29, 2012 2:04 am
by Radian
Harley wrote:Super light
42 lb. I'll say!! That's just a tad heavier than one of my Auto Tubas.

They look great!! 1/8" is nuthin' to sweat considering the flex you had to work around.
Harley wrote:One thing I will never do again, even if the customer demands it, and that's cut the bottom back to fit wheels. In fact even leaving the back straight and putting inset wheels in - no no no no.
Thanks for the tip.
Harley wrote: I'll buy the customer a collapsible hand truck instead.
+1
Re: T39 - finally hatched - weighing in at 42lbs ( 18.5kg )
Posted: Sat Sep 29, 2012 2:40 am
by Dan30
Great work Harley! Have you done a drop test?
Re: T39 - finally hatched - weighing in at 42lbs ( 18.5kg )
Posted: Sat Sep 29, 2012 2:44 am
by Bas Gooiker
Nice Harley,
Any chance you can give them a war volume review? Guess with 3 sets of braces all should be rattle free, but still...
Re: T39 - finally hatched - weighing in at 42lbs ( 18.5kg )
Posted: Sat Sep 29, 2012 4:13 am
by Grant Bunter
Noice!
Even got kitty interested...
Re: T39 - finally hatched - weighing in at 42lbs ( 18.5kg )
Posted: Sat Sep 29, 2012 7:12 am
by LelandCrooks
Sweet. Had to be hard with 1/4..
Re: T39 - finally hatched - weighing in at 42lbs ( 18.5kg )
Posted: Sat Sep 29, 2012 8:31 am
by Scott Brochu
Is that Palmer's cat?
Do you think the paint will crack around the horn mouth due to the flexibility?
If it is a success on the sound side of it, this will be awesome for shipping weights.
Re: T39 - finally hatched - weighing in at 42lbs ( 18.5kg )
Posted: Sat Sep 29, 2012 10:51 am
by Ryan A
If there was a contest for bass/weight ratio I bet this would take the marbles!
Re: T39 - finally hatched - weighing in at 42lbs ( 18.5kg )
Posted: Sat Sep 29, 2012 11:09 am
by Frederic Gelinas
I've used rollerblade style corner wheels and they don't rattle. With my clamp-on jig I made, it takes about 5 minutes to cut the hole with a router. With built-in wheels, I can bring 2 at a time: I push one and pull the other.
Re: T39 - finally hatched - weighing in at 42lbs ( 18.5kg )
Posted: Sat Sep 29, 2012 1:18 pm
by Harley
LelandCrooks wrote:Sweet. Had to be hard with 1/4..
It was 3/8" Leland, but yeah - hard enough.
1/4" wouldn't work, I don't think.
Scott Brochu wrote:Is that Palmer's cat?.
WTF is Palmer ?
Scott Brochu wrote:Do you think the paint will crack around the horn mouth due to the flexibility?
.
I have no friggin' idea at this stage.

Re: T39 - finally hatched - weighing in at 42lbs ( 18.5kg )
Posted: Sat Sep 29, 2012 1:19 pm
by DaveK
I use Leland's corner wheels. Since they are also the back feet of the cab they always have weight on them and don't rattle.
Re: T39 - finally hatched - weighing in at 42lbs ( 18.5kg )
Posted: Sat Sep 29, 2012 1:21 pm
by Harley
DaveK wrote:I use Leland's corner wheels. Since they are also the back feet of the cab they always have weight on them and don't rattle.
Of course they don't rattle standing up, but I don't stand the T39s up at a gig, I stack them laid on their side, one on top of the other as per the placement recommendations.
I also observed that no matter how well you level the wheels and the front buffers up, because the weight of the driver is off centre at the front when they stand up,
if the floor is not perfectly level, one of the back wheels will lift off the ground and there will be no pressure to prevent rattle.
Dan30 wrote:..Have you done a drop test?
As you can see they don't have corner prices on them yet, they are made from 3/8" Italian poplar and they are brand new - so I see no reason to do that at this stage.
Knowing how they felt during construction, I doubt they'd smash if dropped but I am not brave enough to try and prove it.
Also, the 3012LF drivers cost a fortune here and I'm not risking them just to prove my cab build strength skills are up to scratch.
Re: T39 - finally hatched - weighing in at 42lbs ( 18.5kg )
Posted: Sat Sep 29, 2012 1:38 pm
by Harley
Bas Gooiker wrote:
Any chance you can give them a war volume review? Guess with 3 sets of braces all should be rattle free, but still...
As mentioned, if the weather holds today, I will know. Sure, it's a risk, but one I was willing to take to prove I could build a decent sized T39 under 20kg ( 45 lb ) for my customers. Going by how it felt during construction, it will hold up I reckon, but there may be some things happen because of the 3/8" ( 9mm ) Italian Poplar that make it sound like shit...who knows at this stage

Re: T39 - finally hatched - weighing in at 42lbs ( 18.5kg )
Posted: Sat Sep 29, 2012 1:48 pm
by Harley
Frederic Gelinas wrote:I've used rollerblade style corner wheels and they don't rattle. With my clamp-on jig I made, it takes about 5 minutes to cut the hole with a router. With built-in wheels, I can bring 2 at a time: I push one and pull the other.
With 3/8" Italian Poplar you have to add extra bracing out of a much harder ply ( see my last photo ), whether you are using non-rattle corner wheels, heavy duty supposed 'no rattle' straight wheels like I used, or whatever wheels. That's not a 5 minute exercise when you need a solid bolting/screw solution that looks good for a commercial cab for a customer.
I have built in wheels on my other T39s that I gig with and yes, I agree, you can push one, pull one at the same time However, I banned the other guys in the band doing that because no matter how careful they were, they still managed to crash into brick walls, stone barriers - you name it - handling two at a time. It was mush easier doing one at a time with a hand truck and having much better control.
Re: T39 - finally hatched - weighing in at 42lbs ( 18.5kg )
Posted: Sat Sep 29, 2012 2:02 pm
by Scott Brochu
Harley wrote:
Scott Brochu wrote:Is that Palmer's cat?.
WTF is Palmer ?
http://billfitzmaurice.info/forum/viewt ... =7&t=18646