Mount the armband, measure accurately from the spindle and mark out hole centres.
Rule of thumb is measure twice, cut once.
Cut holes 1mm oversize, this will give you enough wriggle room to ensure accuracy.
Use nuts/washers on the underside of the armboard - this will be far more rigid than using inserts.
Personally I would not use wood, it is not rigid enough. Try aluminium or gunmetal.
There are plenty of small engineering shops with small scale manufacturing CNC machines. If you can provide an a drawing with accurate measurements, the cost of cutting an armboard is not huge.
Rule of thumb is measure twice, cut once.
Cut holes 1mm oversize, this will give you enough wriggle room to ensure accuracy.
Use nuts/washers on the underside of the armboard - this will be far more rigid than using inserts.
Personally I would not use wood, it is not rigid enough. Try aluminium or gunmetal.
There are plenty of small engineering shops with small scale manufacturing CNC machines. If you can provide an a drawing with accurate measurements, the cost of cutting an armboard is not huge.