Here is a rudimentary photo series offering some views of a problem - a luthier has used the point of a knife to roughly hollow bridge feet, offering the appearance of a fit to the belly at the edges of the feet - and a solution.

In this case it's a bit of a cluttered bridge, with a pickup having been mounted into it by Fishman. So I've had to tape the pickup jack and cord up out of the way to work on the feet, which were actually showing some gaps around their outer parts as well, in spite of this installer's lacklustre efforts in hollowing them out. The pratice of foot hollowing is probably as old as that of fitting bridges; it gets the job done, to all outward appearances, and so satisfies the short term need of cash in hand for the luthier, perhaps saving a few minutes' labour besides. Not a worthwhile shortcut however, as it leads to a) damaged varnish, and eventually damaged spruce, due to increased pressure around the sharp outer edges of the feet, b) reduced contact with the belly meaning reduced acoustical vibratory throughput, and c), degradation of the relationship between musician and luthier when the musician, inevitably, finds out about it from another luthier, or on their own while changing bridges. In case c) this ought to be horrifying to the luthier, as the potential lost income over the following years or decades amounts to many, many times any tiny advantage in the short term. A waste all 'round.

So, on with the show. Here are shots of the cello's feet prior to any work being done besides cleaning off some substantial amount of powdered rosin, apparently rubbed on to prevent the bridge feet from slipping.

hollow bridge foot treble side

hollow bridge foot bass side

And these are a couple showing how the bridge is bolted into a jig I made, similar to commercial types, but of plexiglas so that I can see through it to what's happening beneath. It is important to firm up one leg, with the bridge at about 89 degrees (it'll level out to 90 in a few minutes), then to stretch the other leg just a little to emulate string pressures on the top while in play. This is usually about 1mm with cellos but varies depending upon the sort of arching and the slipperiness of the varnish. Experience counts a lot here. For a bass, this ranges from about 1mm to 3mm, again, depending.

bridge in jig

bridge in jig2

And here's the 'secret' which I learned from a friend many years ago - a brand new piece of the highest quality sandpaper, the backing paper having been thoroughly wiped free of any abrasive particles, then held very firmly against the belly between thumb and fingers, stretching it a bit.

holding sandpaper

The other hand then comes in and, again pressing firmly on the jig and the bridge with very even pressure on both feet and the little finger pressing near to the wheel of the jig to prevent tipping. I couldn't really photograph this step, lacking a third hand... so on to the next step, which is to say almost done. The bridge pressed onto the belly should show no gaps at all around any edges. I refine the grooves of the 180grit Norton brand 'World's Best Sandpaper' (it really is great stuff, clearing of dust very easily) by very lightly and with carefully even pressure, filing across the feet with a Nicholson 'Tungsten' file. This file is the model used for adjusting spark plugs. It's about 1mm thick, 8mm wide, and has about 60mm of working area plus a small handle as part of the same hard metal. Great little files, with rounded edges so there's no tendency to dig in, and extremely fine patterning in the cut. It's always been one of my favourite files. Leaves only the finest trace of a pattern on the wood when used carefully, and of course this is pressed smooth on stringing up the instrument.

foot after fitting

foot after fitting

And of course lastly the feet of the bridge, exposed to the same Northern light shining across the feet to bring up any shadows, which now there are none.

foot after fitting

foot after fitting

And that's it. Of course the rest of the bridge was cut rather heavily up near the top, and there's some refinement to be done in the top curve, but the bridge now fits the cello and will undoubtedly provide better sound, with less abuse to the instrument itself. There are all sorts of deeper explanations and cautions I could bring in, but this page is not intended to be a thorough lesson in bridge fitting. It's just a word to the wise, a note pointing out one of the most common crimes amongst, sadly, the majority of luthiers whose work has later come across my workbench. There is no excuse for shoddy work, it's just laziness. I expect it from the cheapest of Chinese factory basses, but unfortunately see it on all fiddles from little kids' violins all the way up to doublebasses. Not a lofty example, and yet more Canadian luthiers seem to copy it than not.


gerard@luthier.ca