Farm Forestry New ZealandLarge diameter eucalypt milling, Woodmizer
The woodmizer portable bandsaw mill is not able to cut through the pith of large logs. Eucalypt logs have been known to jam against the head of the mill when halving because the top half will move upwards as the cut is made.
One option is to quarter the log with a chainsaw or chainsaw mill. In this example a large log has been quartered "freestyle" for subsequent easy handling. Each quarter is then placed on the mill for quartersawing. An accurate and straight cut with the chainsaw will dramatically improve recoveries. Other options are to use a headrig or large circular saw to quarter the logs. Quarters can then be quartersawn on the woodmizer into slabbed and then edged either on the woodmizer bandmill or edger. A breastbench can also be used for edging.
Faces are sawn before edges to release the tension in the log. Then edges can be sawn straight. However, keep in mind that although stresses are at an equilibrium, ripping slabs and boards through the middle can disrupt that equilibrium and cause crook.
Medium-large logs
Taking two or three perpendicular edges off the log ("squaring it up") might allow the woodmizer to then cut through the pith and halve the log. Care must be taken to ensure that as the halving cut is made and the top half moves upward it will not jam up against the head.
Note this log has had two edges cut off to allow the first cut through the pith to be made. The log is then turned 90º and a third surface cut made to be able to quarter the log.
At this point the sawyer decided to remove one top quarter because the band was not sharp enough to slab two quarters together. The quarter was stabilised with two fillets under it at each end (each end was levered up with a spade and the fillet placed under the quarter. The weight of the quarter holds it in place and it can be slabbed in position. Then the remaining three quarters are slabbed before then edging.
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