Hello. I am well into the process of doing the 6505+ 112 to head mod that a lot of people have done. However, I don't have the tools readily available so I am buying things as I need them. Sorry if it's a simple and dumb question, but I didn't want to revive mega-old threads about the combo to head mod.

My question is, which roundover bit for my router would be the closest match to the contoured edges done by the factory?

I have seen recommendations for a 3/8" roundover bit but I just want to make sure!

Main Rig
Korg Pitchblack > Digitech Bad Monkey
Peavey 6505+ 112 w/ 2x12 (Celestion Vintage 30 and WGS Veteran 30)
[Effects Loop] Boss GE-7 > Boss CE-5 > TC Electronic Flashback
I think I used a 10mm router bit when I did my head conversion which is approximately 3/8.

If in doubt, take one of the metal corners off the old cabinet with you on the way to the hardware store (the inside of it is radiused to the size you want) and ask a member of staff to help you find a bit with a guide bearing that matches that radius.
Quote by Axelfox
Some care, here. If you're going to add a covering to the equation, assume that you're going to add to the radius of the curve by doing so. I changed the covering on one of my amps from faux tweed tolex to real tweed, which is much thicker. Made for some interesting adjustments regarding stock hardware.

Note that it's also possible to use coatings like Duratex (a textured, rubberized coating that can be applied with a special roller to look like tolex) or LineX (a sprayed-on-hot two part coating usually used on pickup beds), and if you use either of these, you may want to make adjustments in your round-over.
dspellman I used Marshall Tolex for covering my head case and I didn't have the problem you're describing. Everything managed to fit just fine.
Quote by Axelfox