adorshki
Reverential Member
The thinner edges allow more movement, allow the mass of the rest of the top to move. Note 'guards rarely extend to the edge of the top, and those that do look like amateur hacks. So they're not restricting motion in the critical area, they're just along for the ride on prt of the top that barely moves anyway.In interviews, I've listened to Bruce Van Wart, Richard Hoover and Dana Bourgeois discuss graduating the outer edges of their guitar tops by hand. I'd also swear, but am not 100% sure that I've heard Ren Ferguson discuss it as well, or a similar process, but I sure could be wrong about that. What they are doing is simply thinning the top at the outer edges after planing and sanding to get more "response" or "excitability", whatever you wish to call it, out of that top. To me, in my laymen's terms, that simply mean to enable that top to achieve more vibration. From there it would seem that to glue a piece of plastic to that then "tuned" top might inhibit that vibration to some degree. To glue two pieces of plastic to a top? Well. I do know that some makers choose to use very thin material for pickguards for that reason.
Guild's "floating X" bracing, reserved for the highest level tops, also aid that edge flexibility by not extending the braces all the way to the edge of the top. In fact they even said in one of the later Guild Galleries they didn't use it on 17" tops because it would allow too much movement, tops that big didn't need the additional edge flexibility and it was counter-productive.