Laying out your subs accurately

[Tim A]

Here's a tip for laying out subs or anything else that requires two mirror image sides. It's a small investment in time that will pay off like crazy, even if you're only doing one sub. If you're good about storing things, it'll last forever. Never throw out a template!

Start with some posterboard. Nice and cheap. Cut it/splice it to end up with the size you need. Masking tape works fine for the splices, tape both sides. You want to end up with the exact dimensions of the panel you're laying out. Once it's to size, do a dead-accurate layout on one side of the template, then use a razor or utility knife to cut out just the ends of each run. Make sure the cuts are accurate! Mark the template as sides 1 and 2, or right and left, or some way to remind yourself. This is a T39:




Once all the ends are cut lay the template on the panel, exactly flush with all sides. Tape it in place if you wish. Now, trace out all the cuts in the template to the panel:



When that's done, remove the template and play a game of connect the dots with your straight edge:



IMPORTANT! After you've completed this step, repeat it on the second side panel with the template flipped over! (Side 1 and side 2)

When you're done, you'll have two perfectly identical sides in mirror image, ready for drilling and assembly!

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[SoundInMotionDJ]

+1

Awesome!

I have built a T48, and this was one of the first things I thought of to make the building process go easier.

My plan was to make the template with hardboard, or something similar. I'm planning to build 4-6 T39's, so durability of the template is a consideration.

In addition to marking the "inside" of both edges, I was planning to mark the "outside" of both pieces - to give me a better aiming guide for the brad nailer.

--Stan Graves

[bgavin]

I find that even being anal with my square, I cannot hit perfect plumb between two sides across a 26" span. If I predrill the holes in the second side, I find they are not perfectly to my liking.

I have to manually mark the second side to account for the slight alignment drift of the horn plates.

BTW, I really like the template idea. I was puzzling over something similar, but did not think outside the box, and come up with the connect-the-dots thing. Great idea, and thanks for the tip!

[Harley]

It's a small investment in time that will pay off like crazy, even if you're only doing one sub. If you're good about storing things, it'll last forever. Never throw out a template!

Good idea Tim and cheap and easy to do.

I build my layout emplates out of 24g galv, drill 2mm dia holes at the intersecting points and use a metal scriber ( Awl ) to poke through the holes onto the sheet and do the connect the dots like you do.

I did some out of thin hardboard but it didn't tale much to damage them. with the humidity we have here, over wonter poster board would curl up so you'd have to store it well.

But your idea is superb - I like it.

Harley

[Tim A]

I'd thought about using 1/4" masonite or even 1/8" birch for the template, but as long as you're careful about storage (I have a 'flat file', basically two pieces of ply with my templates sandwiched between) it should last for a 1/2 dozen cabinets or more. If the need arrises, I'll make a better one.

This is actually a time saver. Even if you're doing one cabinet, the time it takes to lay out 2 sides individually is more than the time it takes to make the template and trace it to the wood. The biggest advantage, of course, is accuracy.

I don't recommend using a better material if you're making anywhere from 1-6 cabs and that's all you'll ever do. Just the need for power tools instead of a razor knife to cut it out will double the time you spend on the template, and as stated above, as long as you're careful it'd be a waste of material.

[sddj]

Like Mr. Gavin above, even after being very anal about drilling through both sides clamped together in the very first step... I still find that the slight horn panel drifts can make a difference when using 1/2" internal horn plates, by the time you get to the final side panel of the cab. Answer??

When placing the final side on the cab, I take a small finish nail and tap it into each pre-drilled hole, while the side is clamped in proper position. I remove the side, and then align into the center of the 1/2" birch, each individual position where the screw should be placed. This way I assure that each screw when drilled/recessed, after glueing, is centered on each piece of the horn panels.

I too like the above template idea. Wish I had though of it before I started building the T30s... I am on number 6, with two more to go!

[fender3x]

I found once I was ready to attach the 2nd side to a T39, I could could actually draw on the inside of the panel exactly where the inner panels made contact... This seems easier than using paper to me, particulary if things shift a bit during construction.

(1) Mount the 2nd panel using screws and clamps but NO GLUE. The idea is to pull everything into place as if the last panel were about to be glued on, but not to glue it.

(2) Trace the outside edges of panels 6, 7 and 9. You need to reach inside with a pencil to do this, but there is enough room. Should be even more room on a T48

(3) Reach through the access panel and trace the inside edges of panels 2, 4 and 3.

(4) Remove the panel and measure 1/4" in the appropriate direction from the traced line to mark where the pilot holes go.

I mounted and removed my 2nd side twice without glue just to make sure everything lined up consisently. I traced the first time with a pencil and the second side with a highlighter pen just to make sure that everything was lining up the same way both times. It worked for me, anyway...