I'm currently in the process of building the TubaHT.
I have a question regarding the mounting of the subwoofer to the panel (panel 4). Initially I was going to screw the subwoofer to the panel using woodscrews, all the way into the retention blocks. However seeing as the subwoofer is supposed to be removeable, I feel like wood screws are not the best option to screw in / out, as I'm expecting them to loosen their grip after just a single unscrew / rescrew.
So I thought I should get some machine bolts (M5 metric bolts) and some metal threaded inserts, threading these inserts only into the panel 4 and leaving the retention untouched and just use them to keep the newly created socket airtight.
What is the recommended way of mountain the subwoofer to panel 4? Is my threaded insert and machine bolts a bad idea?
Why would you want to remove the driver? The only reason you'd do so is if you blow it, which is highly unlikely. We use screws because they don't loosen. Bolts do.
Yup, back in the day, we all used to use t-nuts and bolts to secure drivers. Just seemed like it was the superior solution at the time. However, after switching to screws on Bill's recommendation a good handful of years ago, I'll never go back to bolts.
I've had driver screws in and out several times due to driver testing changes and other reasons and haven't had any issues with screws "losing their grip". Although, supposing that was a real issue, or I inadvertently stripped one out, it would be simple enough to rotate the driver a smidge and put the screws into fresh material. Or, put a little wood glue on a toothpick/wooden skewer, tap it in, and cut flush with a razor blade to fix a stripped hole. In the absolute worst case scenario imaginable, drill out the stripped hole and glue in a plug. I don't think anyone will likely need to resort to that. Screws have been working really really well for a good while now, is the premium solution, and is the recommended method in the plans.
I'm the kind of guy that always wants to make things my own by "improving on the plans". Being DIY, it's certainly allowed and generally encouraged. However, Bill has done a really good job in thinking everything through thoroughly. I'd venture to say there's not much room in the plans for improvement, so much as there's room for personalized customization.
Many people move forward with their "improvements" on the plans recommendations without asking and find out after the fact that they could have saved time, money, additional build complexity, AND had a better overall finished cab quality if they'd have just followed the plans. By "many people", I mean me. I wish I had the wisdom to stop and ask more often than I do. You did the right thing.
It's your cab. Use inserts if you like. Screws are recommended.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded
