T39 20"

[whines]

I've already built a pair of slim T39's and am very happy with them, but I have the itch to build some more stuff and like the idea of lowering the HPF on the group to 40hz. So two more T39's it is! This will be the first time I've built a pair of cabinets in parallel and I want to be sure to take my time and get more things right this go-around.

Initially I'm ordering just a single 3012 driver, the speakon jacks and a pair of casters so I can get the cutouts right. I'll order the rest of the hardware later in the build process when it's relevant. Maybe I'll be less tempted to rush when I don't have boxes of pretty parts just begging to be installed when I SHOULD be sanding and painting.

I'm going a little wider this time...playing with Cutlist makes 20" look like an efficient size to cut out of 5x5 sheets of BB. I had the lumberyard pre-cut the sheets like this:

Sheets 1&2: 19" -- 19" -- 19.5"
Sheets 3&4: 19" -- 19" -- 20"

The 19.5 is for the starting side and the 20 is for the finishing side, slightly oversize so I can trim it to fit if I'm a little off.

So far I've picked up the wood--it fits MUCH better in my partner's small SUV cut down--and cut the starting sides to the right length and marked them up.

[Chris_Allen]

Sounds like a nice sensible approach to a build to me.

Assuming your sheets are already square, you should have enough to play with for those cuts. Table saw or circular?

Were the slims 10" or 12" driver?

[whines]

I just have a circular saw. The slims are 3012 loaded, 15" wide.

All stacked together that'll be 36ish inches, not too excessive...possibly fewer people sitting on them though!

[whines]

Went over the plans and model VERY carefully to get the handholds in panel 1 cut right, since apparently that's easy to mess up.

I didn't cut handholds in my first pair of t39's and have regretted it ever since...I put a nice flip-out handle on the back of them about 30" up. Looks really sharp, and if I was about four feet tall it would be ergonomic. Sadly I am not and it isn't. :/ There isn't enough room to add a corner-mount handle, even, because the speakon jacks are in the way. (I'll be putting strap handles on the upper edge as a last resort)

...so anyways, yeah, don't skip the handle cutouts like I did.

I did cut handles in to this one, using the pin nailer to hold the template down while I routed them out. The little pins don't have any holding power but they do a great job of keeping things from sliding around, and can be pulled out with pliers when you pull the template/whatever off.

[whines]

Friday night I cut panels 2-4. Lots of angles, but since I needed two of each I could flip the source board over and re-use cut edges, nice! Made sure to make the guide board with the slight angles on them.

I ordered some pre-cut driver spaces from speakerhardware, hoping to save myself the pain of cutting out the hole for the driver, but they were too small for the 3012 so I went ahead and did it by hand with a jigsaw. I'm learning to take this really slow, and it came out pretty well, not needing much trimming. Rough cut the other baffle, used the pin nailer to attach them and then used the router to make a copy.

Since this weekend was the hottest so far this year in Austin (104, feh) I decided to do assembly on the dining room table.

Wrapped the guide boards in saran wrap, tacked them down with the pin nailer, and 2-3-4 went together nicely. Here scraps from the handles are used as guides. I used two screws each to pull them tight to the sides.

Sides are nice and even! I've had trouble with this in the past,

Added panel 5 and called it a night before starting on the braces.

[whines]

Got the 3/5 braces in and then added panel 6. There was a 1/4 gap on one cabinet between where the end of panel 5 was and where it should have been where it meets up with 6....I didn't check it again after putting the screws in, so apparently they missed the holes drilled for them in the panel and pulled it out of place. It was still flush to the guide board, though, just shifted along its length a little, so I PL'ed a wood strip to close up the gap and didn't worry about the extra 1/4" in the end hanging out in free space.

Getting braces in was messy and it's hard to reach my fat hands in there to add PL to areas where it got scraped off, but I put a disposable glove on and smeared it in there.

Panel 6 wasn't hard to attach but where the upper corner should be eluded me. Initially I was measuring it from the baffle, but while thinking about it on a trip to Home Depot to pick up more PL and brads it occurred to me that I could be multiplying errors by doing that. I used the square and yeah, it was nearly an inch off from where it should have been at the end opposite where it attached to the starting side. Fortunately it wasn't too late to re-position the temporary braces to hold it where it should be.

My difficulty getting the 4/6 in should have given me a clue that something was off. On the bright side the other cabinet was fine.

Looking at the driver mounting screws, it seemed like they wouldn't be grabbing much wood...the gasket on the back of the 3012 is shallow and feels pretty compressible, and the screws seem to have a shaft with no threads for a half inch or so, way more than just the metal of the driver frame needs . Since I had the premade spacers I went ahead and glued them to the back of the other ones. Should be no harm in it.

[whines]

Didn't have much time last night but I got a lot of the fiddly bits installed around the access panel.

Without a table saw, I couldn't think of a clever way to do the 3 degree angle on the little 2" long braces so I just cut them square and then sanded them. Not having anything coarser than 150 grit on the power sander meant this took a long, long time. In retrospect I should have used the jigsaw to nibble it close before using sandpaper.

Just need to put the little braces behind the panel 6 extention now and add panels 7, then back to big satisfying slabs of wood.

[Titanium Hand]

Looking good whines!

I love my T39's, soo chest thumping loud from such a small cabinet. Instead of using jigsaw for speaker cutouts I just bodgy up a circle cutting jig from an off cut of ply. I mount the ply to the router base. Measure from outside edge of the bit with a rule to my desired radius, nail punch it, 3.5mm drill, line this hole up with desired hole centre mark on panel, drill through. using a screw I then screw the jig through panel and into my work bench. Plunging a wee bit at a time I have perfect holes cut in no time.

Your four pack is going to sound great

[Chris_Allen]

I'm looking forward to the colour scheme on this cab, maybe a full sized hyena?

[whines]

Hmm, that's an excellent idea Definitely room on the backs for it, and that's all you can see when it's V-plated anyways!

Panel 6 ext braces and panels 7 added. I got the panel 6-es flush with the front of the cabinet, but wasn't checking if it was parallel to the TOP, so...eheh, the panel 7 farther from the side had to be a half inch longer on one box. Embarrassing, but I can't immediately see how it will cause a problem other than aesthetically, so...we'll see.

[whines]

Back to big panels!

I cut two backs and got to work laying out all the stuff I wanted on them. 19" feels generous to me after a slim, but if you want corners and handholds AND a jack plate all behind panel 9 you run out of space fast.

I started laying stuff out and then remembered that I'd already cut handholds into the top, so placement was dictated so that they'd match up. 1" from the corners...so yeah, I'll be severely trimming the plastic corners. Oh well. At least the sides will be intact where they need to interlock with the ones under/over them when stacking, that's the important thing.

I laid out a symmetrical pair of handholds on the bottom, did rough cutting with the jigsaw...then remembered the casters. Gah. Recut a new side and this time gave it just one down there so there's space for the corners and casters.

Rough cut out the handholds with the jigsaw (again), pinned down the template to smooth them out, then roughed out the second side and pinned them together and used it as a template--that was fun and quick.

There was some 1/2" scrap with a 45 degree edge so I cut a little section of it to put the speakons in. Glue, pin, clamp....and that's a day. Test fit the panels, looking nice!

[whines]

Got the backs attached. While sliding one of the cabs around to get to the edge, the folding table I was using to work inside collapsed, dumping the one I'd just glued on the floor...erk. Amazingly some of the pins held...did have to re-glue it, but otherwise no harm done.

Squeeze out is scraped in the appropriate spots now. Still loving those handholds, once I roundover the outside edges they'll be really comfortable!

[whines]

Got almost all of the remaining panels cut this weekend, leaving only the access covers. Plenty of good sized scrap left so those will be easy.

Painted the 9 and 11 angle panels since those will be hard to reach later, two coats of primer with a light sand between. Installed the 9's, then reflected that drilling the hole for the wire is going to be a moderate challenge at a 45 degree angle. Oops.

Cut the slots for the corner-mount casters too deep on one bottom (not accounting for the fact that it was abutting the back), as I consistently do, but at least I only did it once! Easy patch with little strips of scrap glued in.

Back braces went in fine, although one of them is riding pretty high, evidence that things aren't square underneath. I'll cut that down once the PL dries, not that anyone will ever know.

Got the bottom on. Excited since this is all the exterior panels except for side 2!

I'll try putting the mouth braces in before adding side 2 this time, probably less messy that way, Braces are cut and notched but need the handholds added and rounding, so they'll probably take an evening on their own. The handholds there are very useful in the slims, so I gotta keep those.

[Chris_Allen]

Good going. You're certainly truckin' with this build.

[whines]

Thank you! Progress is faster than I thought, I'm trying to remind myself to take my time.

Went to an ACL taping for Nickel Creek last night and didn't get back until late, so I just used the router to round off the braces and the outer parts of the handholds with a 1/4" radius. Ready to glue those together next.