The Flexter, created by Jim Poe, measures cane hardness and flexibility. This is an overview of using the Flexter along with some handy calculations to infer the performance quality of the reed cane before further processing.
TORQUE & HARDNESS
The Flexter uses a lever arm to apply an axial load tangent to the circumference of the gouged bassoon reed cane. The axial load applies a shear stress across the reed cane, the deformation of the material is measured in degrees of deflection. Within this system, we can calculate the torsional resilience of the reed cane as torque. We can then sort the reed cane using this measurement to assess the toughness, or resistance to deformation and strain, of the cane during the reed making processes and during active performance.
Since the gouge thickness, gouge eccentricity, density, and other factors of the sample are perhaps unknown; it is imperative to calculate the torsional strength when using this apparatus, the deflection angle alone will tell you very little. Also, a starting test group for such experimentation needs a minimum of 50 pieces of cane. The apparent density of the cane should be calculated as well so a comparative analysis can be conducted. You can learn how to calculate the Apparent Density of the cane here.
If the dimensions of the gouge, including the radius of the tube cane, are consistent and the cane is pre-sorted based on relative density (using the normal distribution of the sample set based on mass), then the comparison of the deflection angle can be used in the sorting process.
- Clean workspace
- Scientific Balance
- Bullseye Surface Level
- Dry Gouged Bassoon Cane
- Computer with Microsoft Excel
- Pencil, HB art pencil is preferred, but a soft #2 pencil will suffice.
- Clear a workspace and gather your materials.
- Check that the table or workspace is level using the bullseye surface level. To have the most accurate measurements, it is critical that the scientific scale and Flexter are on a level surface.
- Using a pencil, label each piece of cane on the inside, or pith, in consecutive numerical order.
- Next, use the digital scientific scale to measure and record the mass, in grams, of the weight that came with the Flexter.
- Then, use the scale to measure the mass of each piece of dry gouged bassoon cane and record the measurement in the excel spreadsheet.
- Repeat this step for the number of pieces you are going to test.
- Calculate the apparent Density of the cane; you will need to calculate the average volume of the sample set.
- Find more information on calculating the density of your cane here.
- Next, use the Flexter to measure the deflection angle of gouged reed cane.
- Attach the reed cane to the fixed arm of the Flexter, then attach the other side of the cane to the Gauge Arm.
- Turn the Digital Angle Finder on and zero the gauge.
- Apply the axial load and let the system sit under load for 3 to 5 seconds.
- Record the deflection angle and remove the weight from the system.
- Remove the piece of cane from the apparatus.
- Repeat step 8 for each piece of gouged bassoon cane.
Personally, I use the Flexter to judge batches of cane that do not meet the quality control standards I have set for CB Reeds & Tools. A lot of times I need to adjust the gouge thickness and reed profile of the batch to meet the consistency in performance I would like, this is just my personal preference. I would rather change the proportional dimensions of the reed to meet the needs of the player, instrument, or finished reed than discard a large quantity of cane. Each piece of reed cane is unique, and we need to adjust for its material properties- at least until my process is being used by the entire industry, then we won’t have any reed problems.
When using Flexter I generally, grade the cane using the chart below. The number corresponds to the plastic storage bin label and subsequent flexibility, where theta is the deflection angle. I also calculate the apparent density, stiffness, and resiliency of the cane before gouging using a different method- the Flexter is just an end check to see if I need to adjust the gouge further, especially during seasonal shifts in humidity and pressure, or when processing cane and making reeds for those players who are at altitude.
The Flexter has a range of 0 to 50 degrees, and the ranges of flexibility here are based on the performance characteristics of specific gouge dimensions so, these parameters may not necessarily work for your setup, playing style, or instrument. However, the methodology here is consistent in leading me to the identify certain characteristics of the cane and the correct adjustments needed to process the cane on my machinery.