Tuba 30 CNC build

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tactix
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Tuba 30 CNC build

#1 Post by tactix »

Hi folks,
Thank you all again for your help in getting me to the point where I'm ready to build my first Tuba!

I'm going to try to build this by pre-cutting all my pieces on a CNC mill and assemble them offsite. As such, while I haven't yet started to physically build the unit yet I have done a bunch of digital work as well some test with the router so I thought I should start a build thread now to fully convey the process and my thinking.
I do have a couple of questions I'm asking myself at this point so perhaps you'll have some insights there.

The basics:
Model: Tuba 30
Size: 24"
Material: 1/2" Baltic birch
Driver: Eminence Kappalite 3012LF

For my own sanity and to be clear about what I'm doing I decided to make a model of the 24" Tuba 30 using Rhino 3D. It may have been possible to try to program cuts directly in CAM software but the modeling approach allows me to make adjustments and ensure that, at least in model, everything fits together. Working from the plans with the existing sketch-up models as reference I essentially recreated the model Bill provides but with tighter tolerances. At first I tried working with the original model but quickly found that it didn't match the plans exactly so I ditched that idea. I followed the plan dimensions as much as I could but did have to deviate from them slightly because modelings requires a higher degree of precision than the layout instructions provide or could possibly be followed when working by hand. I decided to use dado joints on one side of the cabinet to help with alignment. I might try milling a second side with dados as well to see if I can get it to fit but with warping and build errors it seemed like a recipe for disaster. My first past a modeling assumed 1/2" thick material and 1/8" dado. More on that in a bit.

Here are some views of the Rhino model.
Image
Image
Image

I've only put one set of braces in but at 24" it seems like it could use a second set - thoughts?
A side benefit of this is I could more easily place a centered connector plate on the back (panel 10). This panel is also going to hold my casters.
You'll also noticed I put a ton of handholds - overkill?
I've also decided to leave panel 7 long, to be cut later as per the plans, to give me a little wiggle room with fitting. Maybe on later cabinets I'll cut this to fit from the get-go as well.

So to get all my tool paths down, sort out my dado joints, test the accuracy and quality of the milling, as well as figure out how to do the opposite facing angled cuts on panel 6 I've begun doing some small test.

Image

As you can see the first attempt at this (the one behind) was using the wrong bit so things got kinda mashed up. It also had too loose a step over on the plunging operation which left a strip of leftover wood inside the dados. What I'm really testing here is how thick I should assume the sheets of ply are while modeling.

Image
Image

The panels will fit in the dados at .485" but .49" is a better fit - I can get them in there without a mallet. .5 if fine but they're a little loose and can easily tip from their groove. Obviously there will be some variation across sheets of ply and even within a single sheet but I'm considering remodeling the Tuba using .49 sheets to get this snug fit. Another question is the depth of the dados. They work at 1/8th but I think they would hold the sheet better at 3/16th so if I do remodel I'll probably shift these depths. The dados have rounded corners as I used a 1/4" bit to cut them. I could drill these out but I worry about leaks so I'm going to apply a second finishing pass with an 1/8" bit. I even have a 1/16th but that seems silly. We'll see how it goes.

Anyhow that is where I'm at! With hope I can find the time to remodel tomorrow and cut a sheet to start gluing over the weekend. :hyper:

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Tom Smit
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Re: Tuba 30 CNC build

#2 Post by Tom Smit »

As you have found out, the material isn't an exact 0.500" thick. I'm glad you found that out first rather than after all the milling. :clap:

If you are going with the 24" width, you will need 2 sets of braces per panel where the plans tell you to.

I would do two hand-holds per corner, if only for better control. Some assistants (and there likely will be some) might not be able to handle/control the cab motion while transporting.
TomS

CoronaOperator
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Location: Medicine Hat, Alberta, Canada

Re: Tuba 30 CNC build

#3 Post by CoronaOperator »

tactix wrote: The panels will fit in the dados at .485" but .49" is a better fit - I can get them in there without a mallet. .5 if fine but they're a little loose and can easily tip from their groove. Obviously there will be some variation across sheets of ply and even within a single sheet but I'm considering remodeling the Tuba using .49 sheets to get this snug fit.
Remember you need to leave some room for the adhesive. If the fit is too tight it will wipe the adhesive clean off the sides when you assemble.
Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
2 x DR250 2510/asd1001
For best results, point the loud end of the array towards the audience

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Bill Fitzmaurice
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Re: Tuba 30 CNC build

#4 Post by Bill Fitzmaurice »

Your sketchup model contains a 24" wide cab, showing exactly what you need for braces.

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tactix
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Re: Tuba 30 CNC build

#5 Post by tactix »

Tom Smit wrote:As you have found out, the material isn't an exact 0.500" thick. I'm glad you found that out first rather than after all the milling. :clap:

If you are going with the 24" width, you will need 2 sets of braces per panel where the plans tell you to.

I would do two hand-holds per corner, if only for better control. Some assistants (and there likely will be some) might not be able to handle/control the cab motion while transporting.
It's no sweat adding the extra hand holds when you're milling so I can do that. Re-read the plans: "Use two sets for 17 to 25
inch panels". Got it. Thanks!

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tactix
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Re: Tuba 30 CNC build

#6 Post by tactix »

Bill Fitzmaurice wrote:Your sketchup model contains a 24" wide cab, showing exactly what you need for braces.
Got it now. I didn't pay close attention of that model because it was a double loaded cab but I'm clear now that it's the width that matters.

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tactix
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Re: Tuba 30 CNC build

#7 Post by tactix »

CoronaOperator wrote:
tactix wrote: The panels will fit in the dados at .485" but .49" is a better fit - I can get them in there without a mallet. .5 if fine but they're a little loose and can easily tip from their groove. Obviously there will be some variation across sheets of ply and even within a single sheet but I'm considering remodeling the Tuba using .49 sheets to get this snug fit.
Remember you need to leave some room for the adhesive. If the fit is too tight it will wipe the adhesive clean off the sides when you assemble.
Yeah I wondered about that. I have some of proper adhesive now to test with so I'll find out what works shortly.

jimbo7
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Location: St. Louis

Re: Tuba 30 CNC build

#8 Post by jimbo7 »

I like reading all the builds, but aren't the CAD pics in violation? The outside dimensions are on the sales page obviously, but couldn't someone figure out the rest of the dimensions from the iso views? Mr. F., what is your decision on the matter?

Don't get me wrong. This build looks interesting, but I'm selfish and wanna keep the BFM secret as long as possible. Carry on.
BFM builds:
XF212
T24 BP102 24"
2x SLA's 6-5" mids, 9- gt-302's
2x AT 14" MCM 55-2421
TrT 5" MCM 55-2421
AT 18" JBL GTO804
2x OT12 flat array
2x SLA Pro 2-Alpha 6's 2-Goldwoods
2x T39 24" 3012lf
Simplex 10 BP102

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tactix
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Re: Tuba 30 CNC build

#9 Post by tactix »

[
jimbo7 wrote:I like reading all the builds, but aren't the CAD pics in violation? The outside dimensions are on the sales page obviously, but couldn't someone figure out the rest of the dimensions from the iso views? Mr. F., what is your decision on the matter?

Don't get me wrong. This build looks interesting, but I'm selfish and wanna keep the BFM secret as long as possible. Carry on.
The only relevant dimensions I provided were overall which seemed kosher as it's on the main website. I did not post any orthographic images of the interior - just the perspectives which seemed like the same thing showing any build photo.

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Bill Fitzmaurice
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Re: Tuba 30 CNC build

#10 Post by Bill Fitzmaurice »

It's no more of an issue than build pictures.

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Padde298
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Re: Tuba 30 CNC build

#11 Post by Padde298 »

Looking damn nice!!! :cowboy:
Just added a CNC mill on my wish list for Christmas this year..! :noob:
More bass, more bass! :chainsaw: :chainsaw:

2 x TAT

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tactix
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Re: Tuba 30 CNC build

#12 Post by tactix »

So I've remodeled the Tuba with .49" board thickness, added the second set of braces I missed and doubled the handholds.

Image
Image

One of the things I noticed on the Sketchup models is that Bill seems to prefer to put the connectors outside of the horn path. Because I'm using a plate to hold connectors it seemed tight to stuff them up in the corners so I'm planning to put it in the middle of panel 10 between the braces. I assume this is fine but if anybody has objections to this approach I'd appreciate hearing about them.

More soon!

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Tom Smit
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Re: Tuba 30 CNC build

#13 Post by Tom Smit »

You can put the connectors anywhere that you would like but just make sure that they are air-tight.

Having extra connectors on Panel 7 allows you to hook them up when using a V-plate and facing away from the audience and, thus, giving a cleaner look at the venue.
TomS

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tactix
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Re: Tuba 30 CNC build

#14 Post by tactix »

Tom Smit wrote:You can put the connectors anywhere that you would like but just make sure that they are air-tight.

Having extra connectors on Panel 7 allows you to hook them up when using a V-plate and facing away from the audience and, thus, giving a cleaner look at the venue.
So you wire two sets of connectors? I was already going to throw casters on the back of 10 (not modeled yet) so I'm not sure how much of difference it will have aesthetically but I understand what you're getting at. For me it begs the question why not put the casters on 12 and always lay the unit on its side, vplate or not? Does anybody run them like that?

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Bill Fitzmaurice
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Re: Tuba 30 CNC build

#15 Post by Bill Fitzmaurice »

If someone is given the opportunity to step on a cable, potentially breaking the connectors, they will. Consider all of the ways that you might set up the cabs, then install as many connection points as needed to take that possibility off the table. Better to spend a few bucks on connectors than risk catastrophe at a gig.

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