THT low profile build.

[But it Hertz]

Hello again... Happy New Year and all that.

Been at it making sawdust over the holiday period. Really enjoyed this build. I relaxed into it much more and this build has been the smoothest so far. I made a couple of silly mistakes but nothing show stopping.

First task was figuring out a way to handle 8 x 4 sheets accurately and safely. My cheapo table saw doesn't really cut the mustard when it comes to long rips and I end up with banana shaped strips.

I realized the fence was not parallel and had a little step in it so I screwed some plywood onto it to fix that. Then I Macgyvered a fence extension and got some pretty good results.

Next I got some pedestal roller stands to support the sheet and put some weights on the bottom of the table saw to stop it moving all over the place. It sucks chasing your table saw across the room while juggling an 8 x 4 sheet!

After this lot I was able to accurately, and more importantly safely cut up the sheets.

[But it Hertz]

I decided on the 15 inch Dayton RSS-390HF-4 subwoofer. I chose it purely because it has the highest power rating of any of the recommended drivers.

For width I decided to go with 24.5 inches for minimum waste and decent compromise over performance.

First job was to mark the layout.



Turns out I don’t much enjoy spending hours and hours filling and sanding and hate seeing screws. I was going to use dado slots but I saw a pair of David’s built using pocket screws so I decided to give them a go instead. I didn't need to use 2 screws.... over kill.

Pocket screws allow about 1/16th inch wriggle room so you can really massage each joint untill you get it just so.



Pocket screws turned out to be awesome and it allowed me to build pretty much the whole cab dry. I'm not sure I would build dry again as it adds (perhaps) unnesessary steps. It certainly isn't the way to go if you are getting paid by the job!!









I'm going to fill the pockets with PL in the end.



Panel 5 was a challenge. It took me a couple of attempts to get the 52 degree angle right! Here is a little jig I made. I used pocket screws to attach it to the sled.





Success!

[But it Hertz]

Weird double post!

[But it Hertz]

The Baffle was up next. I wasted a lot of wood here. At first I was going to go double width because the driver is sooooo heavy and Bill mentions you can have double width in the plans. After a couple of false starts I put the idea of double width baffle in the “too hard basket” and set about making a single width baffle.

The challenge as I see it is to make a perfect gasket surface while allowing enough material for the t-nuts to bite into.

IMHO the magic formula for the RSS390 turned out to be a 13 13/16” hole.





Then use a 5/8” + 1/2” bevel trim with bearing to make the angle right.







2/6 braces installed.



T-Nut test fitting.





The finished baffle.







Then break in the driver per the plans.

[But it Hertz]

The 1/8 brace was next. I used a jigsaw and chisel.



Test fit.



I got these cheap clamps from Harbor Freight. They are excellent for jobs like this.



Put loads of glue on to make sure it penetrated the joints. I later cleaned it up.

[bitSmasher]

quality

[But it Hertz]

It was at this point I decided to take everything apart and glue it.



I broke from the recommended order of installation a little because I had various braces attached.

















Ready for the side to go on!











No going back now!!





Squeeze out.

[But it Hertz]

Didn’t realise how tall this thing is!! This pic was taken at standing eye height!!



I have been dreading this bit.



It actually went OK but there is a slight bow in panel 8 if you look closely.



Next up the chamber braces.









This is where I am right now. Tomorrow I’ll do some clean up and make the chamber cover sit right…. Figure out where I'm going to put the binding post.... Then I can fire the old girl up and see what she’s got.

Woooooo!

[brendan_alw]

Looks awesome!
Keen to see more progress.

[Bas Gooiker]

Beautifully done... very clean looking build.

Loving the pocket screws... i'll buy a kit like that after work.

[Harley]

Nice and clean workshop you have there

[LelandCrooks]

Wait, I was under the impression pocket screw joinery was not very useful in 1/2 ply. Did you have any trouble?

[Bill Fitzmaurice]

I broke from the recommended order of installation a little because I had various braces attached.

Doing so is why this occurred:

It actually went OK but there is a slight bow in panel 8 if you look closely.

If you put the braces in first you can't adjust their position to remove any warp.
An excellent build otherwise.

[shawn_g]

Looks great! Very clean build.

[Radian]

Didn’t realise how tall this thing is!!

Wait until you hear it!

Sweet looking cab and excellent job documenting your build!