Sawmill - Design Rationale

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Things the sawmill must be able to do. See Sawmill Analysis for calculations based on these requirements.

  • Must adhere to OSE Specifications. (Open documentation. Low cost and easy to manufacture/replicate. Design for life, disassembly, repair. Robust, multipurpose.)
  • Must be able to cut about 2400-3000 linear feet of dimensional lumber per day.
  • Must handle up to 3000 lb logs.
  • Must cut 4x4s and flat 2x of large width.
  • saw wobble specification 1/16"


Motor Rationale[edit]

  • Power is about 40 hp - available from 55 hp Deutz, at .72 system efficiency.
  • Hydraulic motors utilize 24 gpm at up to 3600 PSI. Each motor is 40 hp, around 700 RPM.
  • 2 Cushion valves are used for stopping in bidirectional configuration.
  • 2 spool control valve needs to handle the full fluid flow (24 gpm) to each motor.
  • To use power effectively, one should be able to control the amount of flow to each of the two

motors, from full power in one to full power in the other.

  • Main blade RPM - 1500 RPM.
  • Edger blades - 3500 RPM.
  • Simple pulley system, with single pulley of 3x for main blade.
  • Double pulley for edger blades, about 2.5 ratio for each.

Platform Function Rationale[edit]

  • Needs a platform that will be able to hold the weight of the motors, pulley system, blades, and frame.
  • The weight of the platform will be about 25 lb. per motor, etc for a total of about 200 lbs.
  • The platform must be stable enough to make straight cuts.
  • The platform should be able to roll in the x axis.
  • The platform must move precisely and hold securely in the y and z axes.
  • The y and z axis movements must be about 3-4 feet for large logs.


Function List[edit]

  • blades with insert teeth would be best to use, but maybe expensive
  • 2 edger blades on same axle
  • 2 edger blades are adjustable
  • Move onto hydraulic log handling later
  • Move on to automatic sawmill operation with remote control, for ease of cutting.
  • Allow for log turning in addition to taking slices out of the wood
  • Safety cage around blades
  • Blade cooling soapy water?
  • Logs loaded with tractor loader
  • Mechanism to secure log to track
  • use bearings to ride on a flat track?

Log Holding and Blade Direction[edit]

  • The blade must spin into the product and into the table or stops or whatever is holding the substrate being worked. Otherwise we make missiles.