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Ah. OK. Thanks.
Thought T-nuts would be better than screws.
May replace them with threaded inserts or epoxy some nylock nuts into baffle blocks for use with M6 Allen bolts.

Screws are better than any style of nut and bolt as screws don't loosen. You can secure bolts and nuts with Loctite, but then they're difficult to remove should it ever be necessary.

Many thank for the tips Bill.
Will use Loctite or similar on bolts.

LankyJohn wrote: ↑Wed Apr 17, 2024 10:05 am Many thank for the tips Bill.
Will use Loctite or similar on bolts.

May I suggest a Loctite that is easily undo-able? I've used the red stuff, and one needs heat/torch to free up the bolt. Blue isn't as bad. Yellow is okay. If it were me, I would just put a small dab of silicone on the last 3 bolt threads.

Tom Smit wrote: ↑Wed Apr 17, 2024 10:30 pm

LankyJohn wrote: ↑Wed Apr 17, 2024 10:05 am Many thank for the tips Bill.
Will use Loctite or similar on bolts.

May I suggest a Loctite that is easily undo-able? I've used the red stuff, and one needs heat/torch to free up the bolt. Blue isn't as bad. Yellow is okay. If it were me, I would just put a small dab of silicone on the last 3 bolt threads.

Thanks Tom,

Yes, I'm definitely not going to use the red Loctite.
I have blue Loctite, which one drop on a clean nut & bolt will hold against vibrations and be undoable with hand tools.

LankyJohn wrote: ↑Thu Apr 18, 2024 1:45 pm

Tom Smit wrote: ↑Wed Apr 17, 2024 10:30 pm

LankyJohn wrote: ↑Wed Apr 17, 2024 10:05 am Many thank for the tips Bill.
Will use Loctite or similar on bolts.

May I suggest a Loctite that is easily undo-able? I've used the red stuff, and one needs heat/torch to free up the bolt. Blue isn't as bad. Yellow is okay. If it were me, I would just put a small dab of silicone on the last 3 bolt threads.

Thanks Tom,

Yes, I'm definitely not going to use the red Loctite.
I have blue Loctite, which one drop on a clean nut & bolt will hold against vibrations and be undoable with hand tools.

Uh-huh. My question is: if you need to pull the driver, will the wood be sufficient in holding the T-nut in place? I don't want you to have regrets.

That's one reason why I stopped using them, having spun more than one nut and then having to cut the bolt. It's not too late to fix this, add eight more retention blocks and use screws.

Bill Fitzmaurice wrote: ↑Fri Apr 19, 2024 6:58 am That's one reason why I stopped using them, having spun more than one nut and then having to cut the bolt. It's not too late to fix this, add eight more retention blocks and use screws.

Thanks again Bill: I will heed your advice and add new retention blocks for depth and use woodscrews to hold the driver in.
Don't want the hassle of cutting bolts.

Tom Smit wrote: ↑Thu Apr 18, 2024 9:22 pm

LankyJohn wrote: ↑Thu Apr 18, 2024 1:45 pm

Tom Smit wrote: ↑Wed Apr 17, 2024 10:30 pm

May I suggest a Loctite that is easily undo-able? I've used the red stuff, and one needs heat/torch to free up the bolt. Blue isn't as bad. Yellow is okay. If it were me, I would just put a small dab of silicone on the last 3 bolt threads.

Thanks Tom,

Yes, I'm definitely not going to use the red Loctite.
I have blue Loctite, which one drop on a clean nut & bolt will hold against vibrations and be undoable with hand tools.

Uh-huh. My question is: if you need to pull the driver, will the wood be sufficient in holding the T-nut in place? I don't want you to have regrets.

Thanks again: I will heed your advice and add new retention blocks for depth and use woodscrews to hold the driver in.
Don't want the hassle of cutting bolts.

Some more pictures of the build process.
Better plywood (WISA birch) from Fall Timber in North Yorkshire, UK.

Fitted ports & braces.
Glued nail holes.
Replaced retention blocks for mounting driver with screws instead of bolts.

Setting out for routing the hole/rebate for the pre-assembled jack plate (from Blue Aran U.K.) containing 2 x 4-pole speakon connectors.

Completion of the second Simplex 12

Glued back to cabinet. Can you have too many clamps?
Un-routed edges - side
Un-routed edges - back
Finished edges flush with back & sides using half-inch flush-trim bit
Routed edges - front showing squared edges
Routed edges - all done - squared & rounded
Woodwork finished - all edges except inside front baffle rounded over with 9.3mm radius router bit
Ready for the "Funky Purple" TuffCab paint - takes about 20 minutes per coat to apply, dries within 5-6 hours (even at 9 Celsius).
Starting with the bottom of the cab.
After painting the bottom, put 6mm x 50mm wood-screws wrapped in a little masking tape into the bolt holes to act as feet while painting the rest of the cab.
Finished cabinet with first of three coats of TuffCab "Funky Purple" paint

Lessons learned:

Read the plans. Read the plans. Read the plans again.

Heed advice from experts on this forum (Bill & others).

Buy the best plywood you can afford - the difference between the WISA baltic birch and the eucalyptus ply is well worth the extra £££ ($$$)

Sawing ply one quarter inch oversize then routing to finished size produced much better edges than hand planing sawn edges and more precise component parts.

Gluing one side to the top & the other side to the base before gluing the pair around the baffle (see thread above) made for a better glued joint between the baffle edges and the cabinet, with less mess & stress trying to fit the glued edge inside the box top & sides.

Have now learned how to saw and route plywood sheets accurately using clamping guide bar(s) - from Rutlands in the UK.

Making the top and one side, then using them as templates (with a flush-trim bit) to make the matching base and other side ensures the cabinet fits perfectly.

Clamping corners with quick-grip clamps and plywood triangles, as suggested by Bruce Weldy - thanks again, works a treat when gluing the first pieces together.

Making 14 stand-off grille spacers was a bit of a chore. Used old cycle inner-tube between spacers (15mm copper pipe with wood core turned on lathe) and grille. Will replace inner-tube with ciircular black rubber tap (faucet) washers.

Use wood-screws and support blocks to mount the handle and driver to the cab.

Using a ready-made jack-plate (from Blue Aran, UK) with two parallel speakon connectors fixed to a PCB is quicker and less prone to dry joints than making a similar thing from its component parts.

Bill is always keen to provide help & constructive critique despite being incredibly busy - thanks again.

Users of this forum are very helpful.


These are the first speaker cabs I have ever made. They sound better, and are cheaper, than commercial cabs.
I've enjoyed making them & improved my woodworking skills in the process.

Don't expect our band with get big enough to need any more bass cabs, but if P.A. cabs, foldback monitors etc. are needed I will buy Bill's plans & build them with confidence of making a quality product for very reasonable outlay.

This cab & its twin must be ready for rehearsals & gigs starting next week: will post more pictures of them in use.

Looking like another great build there, John. Well done sir. Well done.

Fine looking cab.