Three-lobed handwheels are a special case that only requires one compass setting to lay out. First, set your compass to the desired radius (3" in this case) and draw the circumference.
Next, strike off six sectors without changing the compass setting. Note pi is not involved since you are striking chords, not arcs.
From any adjacent pair, strike two arcs that intersect outward and from that intersection, swing an arc inward..
Repeat twice more.
After bandsawing, outline sanding, roundover, final sanding and a coat of BLO.
Next, strike off six sectors without changing the compass setting. Note pi is not involved since you are striking chords, not arcs.
From any adjacent pair, strike two arcs that intersect outward and from that intersection, swing an arc inward..
Repeat twice more.
After bandsawing, outline sanding, roundover, final sanding and a coat of BLO.
