About Shims (a.k.a. pad washers)

We take flute shims seriously and because of this we have become the largest maker of these delicate washers. We supply technicians, manufacturers, and distributors around the globe with our shims. Chances are you’ve used ours even if you didn’t buy them directly from us.

A Little History:
I made our first set of punches for making shims. These were crude tools, but they made pretty parts. The set of steel punches (that I hardened myself) was a two-hit wonder. The outer diameter was cut first with the “host” tool and while the paper discs remained housed in that tool, a second tool was inserted into the first to punch the center hole. The force being applied with a blow from a hammer. We began by punching pages from a telephone book.

We’ve gotten much more sophisticated over the years. We transitioned to a manually operated precision press with a gang of three punches for each diameter size. While we kept that in use for certain materials, we graduated most paper shims to a custom-built machine that would punch one shim at a time but would work unsupervised. It placed 100 shims into each of the many cups rotating on a carousel.

We now use CNC controlled machinery to run our flute shims. And the tooling is awesome! There are times where we get a request for a small quantity of an unusual size, and we do use the manually operated precision press for these.

Regardless how we have made the shims, the determination to build a gorgeous part has always been there.

On Paper:
We make shims of both plastic and paper. Paper can conform to the dipped shape of the cup over time, and this can be of benefit when padding with traditional felt pads who also conform to the cup shape to a degree.

Our paper is selected from mills that offer us material within a tight tolerance specified. We find that mills don’t produce the same paper endlessly-they do runs (what we call batches). It is because of this that the corresponding color to a certain thickness may change over time.

Besides being in tolerance for thickness, we aim for paper which is moisture resistant (not fully waterproof) that will glue up nicely.

Plastic:
Plastic shims are made with precision thickness color-coded materials.
.012mm (.0005”) Silver
.025mm (.001”) Amber
.050mm (.002”) Red
.076mm (.003”) Green
.101mm (.004”) Brown
.190mm (.0075”) Translucent

Why plastic? Plastic is not affected by moisture, and this becomes a chief ingredient in the success of some shimming over time. Consider that some pads do not hug the inner diameter of its cup and therefore don’t create a vapor barrier to the shim. This is seen particularly with Straubinger and S2 hard backing style pads. Wrapped felt pads will usually hug the wall of the cup sheltering underlying shims from moisture.

Plastic shims work best on a flat service; a cup with a machined flat interior or a stamped cup with a plastic or metal stabilizer installed.

Without a flat backing, a plastic shim may distort behind the pad when you begin to apply downward pressure from the installed pad. This distortion can cause “springiness” which will cause issues (including you might lose your mind).

Specs:
Shims are available for the full range of instruments. The larger sizes for alto and bass flutes are usually made to order. We also make paper piccolo shims for those who prefer not to float the pads.

Diameters are signified as 17.0mm, 17.5mm and so on. We actually cut these .003” shy of the diameter specified so that the shim doesn’t need to be tucked tightly into the cup. This in turn makes certain that the shim will not distort in the cup.

We have begun to offer 17.25 and other quarter step sizes to technicians.

Our standard center hole is 9.5mm and we can produce custom sizes for large users.

Jeff