I bought a vintage Woolworth hollow body electric guitar from Craig’s List that needed a few parts. It had four of six strings and hadn’t been touched in years and was missing a tremolo lever, bridge cover and a truss rod cover. I ordered a replacement tremolo lever off eBay; a replacement bridge cover wasn’t to be found; I had two choices for the truss rod cover: buy one off eBay, being unsure if it would fit, or, as the guitar tech at a local music store suggested: make one from a spare pickguard.
I was on a budget and had an extra black pickguard, so I chose to make one. I started by making measurements, drawing up a template in AutoCAD, and then cutting out a paper template. Then I scored an outline into a wide spot on the pickguard and jigsawed it out. Next, I bevelled the sides with a file. Then I drilled holes using a counter-sunk specialty bit and attached the truss rod cover with some new stainless steel screws to the guitar.
It fit nice.
I chose a triangular shape with filleted corners at the top and sharp corners at the bottom to be consistent with the guitar’s vintage design.
If interested, here is a video showing how the guitar sounds: https://plus.google.com/
T.S.