Sawmill Design

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Overview[edit]

Sawmill Sawmill Design

Design[edit]

Z Height Leveling

  • Turnbuckle attached to upper z adjustment peg

Evenness of Z Height Raising Along 4 Posts

  • Build 4 inch winch drum - each revolution winds 1' of wire

Log Taper Adjustment

  • Disconnect mechanism for connecting rod between front and rear z-risers to create a height differential between the two ends of the log

Edger

  • Adjustable from 1-3 blades in standard version, up to 6 for 6 2x2 lumbers in one pass
  • In 3-blade configuration, top edger blade is controlled by a crank that can be adjusted while sawmill is running

Gantry

  • Box truss design

Carriage'

  • Clearance of 1/8" around gantry

Hydraulic Hoses

  • 4 Hoses
  • Mast at either end

Trailer Hitch

  • Telescoping piece of tubing in frame
  • Hitch retracts for sawmill operation

General

  • Counterweight for hydraulic motor on one side of gantry - balancing
  • Saw and collar - typically from same manufacturer

Vertical Motion

  • One crank with a worm gear controls one side, connected to second side via connecting rod
  • Vertical adjustment - 4 worm gear sets - [1]
  • Bronze bushings - for vertical adjustments

Horizontal Motion - Crosswise

  • Crank with indicator
  • Sprocket with chain to another sprocket with pinion, riding on rack
  • Rack faces down
  • Sprocket and pinion sheltered from dust
  • Connecting rod connects to other end
  • Link rod contains a telescoping slip joint with pin, to retain of modularity of track lengths

Horizontal Motion - Lengthwise

  • Festooned hydraulic hose
  • Hydraulic motor rides under the gantry
  • Engine moves carriage via a spool over which a wire is wrapped

Horizontal Dimension

  • Set by guides that are rolled out with a single crank

Automatic Feed

  • Separate hydraulic motor - with a riding bidirectional valve that trips its lever to other dimesion upon reaching end of track
  • Wire drives carriage
  • Have a safety trip in case of running into metal objects in wood

Dust Ejector

  • On top of blade guard

Set Works

  • Set relationship of saw to the log to make the next cut
  • Dimensional sawmill needs setting in 2 dimensions

Log Holding

  • 2-stage dogs - one for staring the log (high center of gravity), and second for low center of gravity
  • May want to flip log if it's difficult to hold towards the end

Outstanding Design Issues[edit]

  • Hydraulic hose cabling guide
  • Multiple edger blades in future
  • Crank edger adjuster

Action Points

  • Saw collar

Design[edit]

CAD[edit]

Materials Sourcing[edit]

  • [10] 3/4" bearings for rollers on top of gantry- [2]
  • Cam followers - 4x the cost - [3]
  • [4] V-groove bearing for x (transverse) direction motion on inverted angle- [4]
  • [4] 2-bolt, 1/2" flange bearing for y (lengthwise) motion - for pinion gear shaft
  • Rack - 8' - [5]
  • [2] Main shaft pillow block bearings, 1-7/8" - [6]
  • [2] Secondary blade pillow block bearings - [7]

Fabrication[edit]

Blade

  • Anneal blade to machine
  • Harden blade by heating and quenching
  • Surface grind to flatness

Dogs

  • 1.25" square bar, sharpened to a 45 deg angle

Log Handling

  • CAT 966 was industry standard for large sawmills; largest logs are 14000 lb
  • John Deere 450 bulldozer - entry level, handy tool
  • Yale lift

Documentation[edit]

  • Z raising mechanism: worm gear for 4 posts, with adjustable wire tension
  • Y axis - transverse motion - gear rack with chain linkage

See Also[edit]