Dunavin’s T39 build

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J_Dunavin
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Dunavin’s T39 build

#1 Post by J_Dunavin »

After drawing the lines on layout diagram one and two, do the half inch lines go on the inside or outside of the points drawn?
2 - OTop8
2 - T39
8 - DR200
2 - DR250
9 - T24
6 - T45
1 - Auto Tuba

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Bill Fitzmaurice
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Re: Dunavin’s T39 build

#2 Post by Bill Fitzmaurice »

To the outside. To double check it take measurements on the side in the Sketchup model.

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J_Dunavin
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Re: Dunavin’s T39 build

#3 Post by J_Dunavin »

thank you!
Another one.. At 20" width, singe 12" driver, is this considered a wide cab? Trying to determine if i need panel 7.

EDIT: read the plans .... "A narrow cab is one made at the minimum width, wide is anything wider"
2 - OTop8
2 - T39
8 - DR200
2 - DR250
9 - T24
6 - T45
1 - Auto Tuba

Bruce Weldy
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Location: New Braunfels, TX

Re: Dunavin’s T39 build

#4 Post by Bruce Weldy »

J_Dunavin wrote: Sat Apr 16, 2022 5:41 pm thank you!
Another one.. At 20" width, singe 12" driver, is this considered a wide cab? Trying to determine if i need panel 7.

EDIT: read the plans .... "A narrow cab is one made at the minimum width, wide is anything wider"
Researching your question in the plans just further confirmed my belief that the old T39 plan was easier to build. Of course, if you use the Lab, you have to use the new plan.....too bad that the Neo drivers went sky-high back then and necessitated the new plan.

The old ones are purtier too..... :mrgreen:

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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J_Dunavin
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Re: Dunavin’s T39 build

#5 Post by J_Dunavin »

Lucky for me we have a really good group to answer questions 😄
2 - OTop8
2 - T39
8 - DR200
2 - DR250
9 - T24
6 - T45
1 - Auto Tuba

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J_Dunavin
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Re: Dunavin’s T39 build

#6 Post by J_Dunavin »

Cut the sides, all internal panels to width, and baffles.
CF82FB4D-DF95-4BB6-96BD-D66BEDF70886.jpeg
B77CDAF6-BB32-4C4E-858A-4FCA69BE2EDC.jpeg
2 - OTop8
2 - T39
8 - DR200
2 - DR250
9 - T24
6 - T45
1 - Auto Tuba

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J_Dunavin
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Re: Dunavin’s T39 build

#7 Post by J_Dunavin »

I think I made a mistake
Looking in this thread the driver is sitting down in panel 2. I made panel 2 and the backing plate the same dia.
Do I need to take a router so the 3012 sits down on the backing plate?

Bill, maybe you could tell me what the implications are if this does not sit down a half inch? Will the brace on the door interfere with the driver? Or does it mess up the displacement at all?

Example from this thread:
viewtopic.php?f=30&t=25327
FC282FBE-ADD4-48EE-8F85-B0ADE8455511.jpeg
2 - OTop8
2 - T39
8 - DR200
2 - DR250
9 - T24
6 - T45
1 - Auto Tuba

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J_Dunavin
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Re: Dunavin’s T39 build

#8 Post by J_Dunavin »

What we’ve got currently…
Is this wrong?
6612EE9C-6085-4008-8E39-18A599AC17F7.jpeg
2 - OTop8
2 - T39
8 - DR200
2 - DR250
9 - T24
6 - T45
1 - Auto Tuba

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Tom Smit
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Re: Dunavin’s T39 build

#9 Post by Tom Smit »

Sorry, but, yes, it is wrong. A fix would be to do the router trick that you were thinking of. Perhaps, you could put a support plate under the backing plate and pin a couple of layers on it to raise the level and thus give the router something to rest on.
All the best to you, in regards to the recovery.
TomS

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Bill Fitzmaurice
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Re: Dunavin’s T39 build

#10 Post by Bill Fitzmaurice »

Yes, the driver should be inset into Panel 2. The main effect will be to reduce how wide the brace on the access cover can be made. I wouldn't say it's a critical error, but fixing it would be best, which would require a deft hand with a router.

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J_Dunavin
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Re: Dunavin’s T39 build

#11 Post by J_Dunavin »

Thank you Bill for the quick response.
I’m going to give it a go, of which most I can do with the router on the face, except for the top 1/3 of the arc.
Tom you have a good idea there. I’ll have to cut and clamp a board the same height as panel 1. I did check, my handheld router will just have enough depth.
This is going to have to be surgical precision.

Some further progress tonight….
A98A68BE-ED5B-4C36-A070-B9938ABEA076.jpeg
6CE9DF05-EC9B-435F-8175-AD368E774CF8.jpeg
2 - OTop8
2 - T39
8 - DR200
2 - DR250
9 - T24
6 - T45
1 - Auto Tuba

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J_Dunavin
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Re: Dunavin’s T39 build

#12 Post by J_Dunavin »

I still need the mouth brace but got the rest put together
A shot before I closed up the side.
BB39E9F6-65AF-4554-B288-ACF3A2560F61.jpeg
2 - OTop8
2 - T39
8 - DR200
2 - DR250
9 - T24
6 - T45
1 - Auto Tuba

Bruce Weldy
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Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Dunavin’s T39 build

#13 Post by Bruce Weldy »

Yeah, it's almost a shame to have to close 'em up.....nobody can see all the work that went on inside. I feel the same way about duratex......I love that pretty sanded wood, but ya gotta' cover it up.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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J_Dunavin
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Re: Dunavin’s T39 build

#14 Post by J_Dunavin »

Speaking of the pretty wood, I should emphasize how much nicer it is to work with Birch. Most of my previous builds have utilized ACX plywood from menards.
Birch is so much more stable, consistent, cuts nicer, and takes Brads from the nailer better.
2 - OTop8
2 - T39
8 - DR200
2 - DR250
9 - T24
6 - T45
1 - Auto Tuba

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Tom Smit
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Re: Dunavin’s T39 build

#15 Post by Tom Smit »

J_Dunavin wrote: Fri Apr 22, 2022 11:40 am Speaking of the pretty wood, I should emphasize how much nicer it is to work with Baltic Birch. Most of my previous builds have utilized ACX plywood from menards.
Baltic Birch is so much more stable, consistent, cuts nicer, and takes Brads from the nailer better.
Fixed it for ya. :)
TomS

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