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Make a wedge and pin a couple pairs of Popsicle sticks. Use a third stick as the blade.

They are very unforgiving, if you can pin them you will have it down, good enough to do real scales. Try...

Yea, you are overthinking this. Pins bend because of being hit too hard, the pin bend in the middle instead of mushrooming on the end.

Your holes, and pins, must be perpendicular with the blade,...