I spend many hours a day sitting alone pulling handles and have had time to reflect on many things. After 35 000 hours or so driving single grip harvesters in a myriad of different conditions I feel compelled to record some of my experiences here.
About three years ago I bought a Logmax 6000b and hung it on my Valmet 921 wheeled harvester, the 370 head that came with it having reached the end of its useful life (it was stuffed).

Firstly I would like to say I am a fan of using the right machine for the job and this combo is best suited to first thinnings, second thinnings and immature unthinned clearfall under 45 cm, in that order.
The carrier is big enough to handle the head easily with plenty of oil without pulling the head apart.
After 2000 hours the head is still in great order with little wear in pins and bushes, although we have had some pistons fall off rams and a rotator self destruct – the latter being a mystery crash as I have similar rotators with 20 000 hours on them and others that didn’t make 3000.
I like this head, it is reliable and pulls well, feeds fast and delimbs well in the right size range. The saw does its job but doesn’t saw like the Valmet 370 it replaced, the manual saw tensioner works well and is low maintenance.
Which brings us to measuring.
At present there is a lot of %$@! flying around about Logmax measuring, my experience is the logmax 6000b measures like a treat with the following cautions.
The measuring wheel hides in a nifty little cubbyhole that can fill up with limbs or bark that can stop the wheel dead or make it spin in fits and starts, even preventing it from coming out.
When cutting larger trees the rough butt bark will jam the wheel sure as… and the log will run long.
The Logmax system relies on pulsing open the knives to modulate knife position via a sensor on the top knife, the right combination of knife position and pulses is critical for good measurement.

We came up with a few little mods that have proved helpful.
Firstly I welded a guard on the link to protect the banjos into the rotator (rotator valve on head model). I made this guard robust enough to give the top knife a tap when it is stuck back (happens ).
Next we found after around 1000 hours that the hoses down to the saw were failing due to the saw chain hitting them when it flicked off .There was a tin guard there but it wasn’t a complete success so we built a little block in the mill – fixed.
I like to fall left to right hence process right to left (best visibility in a 921). When processing this way the little Logmax likes to cover the windscreen with sawdust so I welded a little deflector on the sawbox.
After 1000 hours or two the manual saw tensioner will get worn in one spot and annoy you; just use a punch to stipple the flat surface lightly to get things going again while you contemplate buying new parts- worked for me 500 hours and counting.

Summing up I really like this head, it doesn’t react as fast as some certainly doesn’t saw like some of the mad fast heads out there and some days I think the engineers put stuff in my way just to make it hard to fix but it produces good product reliably every day.

– Pat Brennan