Scratch: Electrics cavity depth question

I am building a scratch SG from Queensland Mahogany and have been very slack not putting in a build dirary. I have the photos so will get around to it soon.

I am about to cut the electrics cavity and seeking advice on how thick I should leave the top of the guitar.

The pots I purchased have a 3/8" (9.5mm) bushing and by the time I have the washers etc. on it it looks like there is only about 5mm left for the thickness of the top (cap)

I have never measured the thickness of the cap on the kits I have built and searching the web gives me all sorts of answers around 1/4" (6.3mm).

It would be appreciated if someone who has built a scratch guitar can give me some clues and maybe anyone currently building a kit could measure the depth of a pot hole for reference.

Greg

Hi Greg,
I just finished an AG-2 kit. The body thickness is 37 mm and the electronics cavity is 32 mm deep.

Regards

4-5mm is a pretty standard depth for the top of a control cavity. It's certainly the depth you'd have if you had a ply-topped guitar. With long-shaft pots you can go deeper if you want, but 5mm will suit medium-shaft pots. Short-shaft pots are really only for direct scratchplate mounting.

If you're worried about strength, some makers countersink the pots slightly into the 'underside' of the top of the control cavity (it would be nice if there was a single word to describe it) so that it's a bit thicker everywhere else.

Thanks Trevor
It's interesting that the AG-2 is 37mm. The standard SG is supposed to be about 35mm. My lump of Qld Mahogany was pretty rough but I managed to dress it to 34mm.
Looks like 5mm of the mahogany in the cavity will be fine. The Qld Mahogany has a similar close grain to the PitBull kit mahogany so I will go ahead as planned.
This is my first scratch build so small careful steps for mankind, as you can imagine.
Greg

Edit - Trevor I just saw your guitar on GOTM. Hope I can get mine as good as that. Good Luck

Thanks Simon.
I purchased an Allparts SG wiring kit which came with the large pots so recessing them might be a bigger job. I will assess how things are going as I carefully route out the cavity.
My measurements today indicated that the 3/8" shaft is just long enough. Anyway I can get longer shaft ones if necessary.
5mm of this heavy Qld mahogany would me much stronger than ply.
Thanks again for your advice.

What is Queensland mahogany?
Google is not very clear, it suggests red or white mahogany and yellow or white stringy bark.

It's not a real mahogany, it's a eucalyptus variant that looks rather like mahogany.. There seem to be red and white variants, so as it matches the kit mahogany, then it's probably the red type, as the white type looks rather more maple-like to me.

True mahogany is of the Swietenia genus, then you get related wood types, also often given a 'mahogany' title such as those of the Khaya and Meliaceae genus. The eucalyptus 'mahoganies' just look quite similar, and the 'mahogany' title is really a sales/marketing, rather than a scientific term.

https://www.wood-database.com/wood-a...s-the-lowdown/

Hi Cliff
The Queensland Mahogany is Eucalyptus Resinfera.
They say it makes a great construction timber and good for wharfs. Guitars????
It is about the same weight as mahogany and maybe bit harder.
I got it cheap to make a table decided a guitar might be worth a try being a rank amateur.
It has a nice light red colour
I will put my build in a diary shortly. Been slack.

Arh, red messmate, hard and heavy. :o

Cliff
Is messmate a local term? Guitars ??
My wood came from Gove

https://en.wikipedia.org/wiki/Eucalyptus_resinifera

https://www.business.qld.gov.au/indu...s/red-mahogany

Looks like it would make a good neck wood. Considerably harder than Mahogany (Honduran). Heavy in a body, but SG's are relatively thin. It'll be indestructible I bet.

Cliff and Fender
Thanks for your interest. I had missed the reference to Red Messmate in my earlier research.

I guess it will be pointless trying to smash this guitar against the wall when I keep missing those chords then. hihi.
At this stage I have shied away from building a neck. I purchased one from ebay for this build. If I get brave it could easily be replaced.

While on the subject, I have had a fleeting thought about building a Telecaster with the Red Messmate But I can only get a thickness of about 35mm from the plank. A Tele is thicker 35 to 45mm is appears. Raises the question is the "resonance" caused by the volume or the density.
I could add a cap of course. Build up the old muscles.

I wouldn't be too concerned about 'resonance'. 35mm is going to be rather on the thin side though. My 'Emicaster' Tele with a mahogany body made by a friend was originally about 45mm thick. Being mahogany it weighed a ton. So when I re-finished it I sanded it down on the top of bottom to reduce the thickness and weight. I then ended up taking a bit more off in order to get the surface level, and it ended up at 38mm thick, and much, much lighter. It looks fine on its own, but when I compare it to my two Fender Teles, which are both 42mm thick, it looks quite anorexic. 35mm would really be pushing it, and you'd probably have issues with control cavity depths with a very thin section of wood left at the bottom of it.

You would certainly need to think about what controls you want to fit. Both CRL and Oak Grigsby selector switches are 34mm deep, so ideally for those you want a cavity that's 35mm deep, and at least 36mm it you want to copper shield it and leave a decent gap to avoid electrical shorts. The import switches are slightly less deep, but obviously the quality generally isn't so good. I managed to source a decent 27mm deep switch for the Emicaster, but it was still a very tight fit once the wire and solder depth was added on.

So 35mm really is too thin to be practical. I'd be looking at between an 5mm and 8mm cap. 8mm would be ideal as it allows for some sanding flat of both pieces to get to the fairly standard 42mm thickness for a Tele.

Thanks for the detail Simon.
The Tele will probably be next years project as this SG is taking a lot of time. I take a lot to time trying to build up the courage to get out the drill or router for each stage. About to cut the electrics cavity now I have been bolstered by all the support in this post.
Then the neck pocket (uh oh)