Black Magic paint.

[pwdrive]

Hi,

Thanks Lawrence. no you didn't misunderstand my tyre question I did mean the tyre around the band wheel rims. On my Startrite these are rubber and I was curious about the saws you used with red diesel to prevent resin build up on the band; I hadn't realized the wide band saws ran the band metal to metal so to speak; although the band wheels are crowned was there any provision to prevent the teeth coming into contact with the band wheels as this would quickly remove the set of the band on the side with contact on the band wheel?

I too noticed the one dog used and thought it looked quite dangerous and the saw operator appeared to be throwing the sawn timber around randomly rather than stacking it neatly? The large pressure rollers look to be very efficient but as you say they only apply freewheeling pressure unlike power feed rollers.

I imagine if a band suddenly breaks it would be highly dangerous to anyone in close proximity to it; I've had bands break on my own saws and it doesn't half make me jump. Now with lots of practice I can tell when a band is on the way out by the sound of it.

Not a bad job in summer but being so exposed to the elements won't be a joy mid winter?

I've just returned from taking a full car load of conifer branches to the tip. These are the branches damaged by last winter's snow fall so I've removed them as it would have been a big job to try to realign and tie them in position.

Kind regards, Col.

Yes the bands run metal to metal, the tracking has to be set correct, almost every band will have a different setting, the tracking is altered by tilting the top bandwheel relative to the bottom band wheel, the bottom wheel is fixed once any preset setting up installation adjustments are made to it.
Obviously the teeth must not come into contact with the bandwheels, the tracking is first set by hand, the new band is slipped on and part tensioned, the wheels are then turned by hand and the blade will find a settling point, the tracking is then adjusted to tilt the top bandwheel, this will start to throw out the teeth on the band over the edge of the bandwheel, it is adjusted until the bottom of the gullett overhangs the bandwheel by approx 3 mm, the tension is then set to full and the saw is then blipped up for a couple of secs, re adjusting the tracking as required, then it's a full run to see how the band sits, an odd tweek or two on the tracking is then normally all that's required and off yer go, if it's a new band it will need re adjusting every so often.
Yes, large bands can break, the experienced sawyer will recognize the tell tale signs, these are normally when the band starts to oscillate in a lateral direction, if it's not resin on the band or the bandwheels then almost certainly the band has started the first main crack, normally at this stage the crack will extend from the bottom of the gullett to about 8 mm or so into the width of the band, an experienced sawyer will at that stage change the band and send it off for welding and resharpening.
If the situation is allowed to continue then the depth of the first crack will extend rapidly, once this has happened then smaller cracks will start to appear either side of the main crack and so on, at this point it can if not carefull get dangerous especially if the bandwheels have a lot of resin on them as the band can suddenly break.
If it breaks and all the guards are fitted and the sawdust extractor is working properly then normally not to much of a problem, a bit of a shock maybe.
But trouble can arise if the bottom of the bottom bandwheel (the driven one) is packed with sawdust between the blade and the ground (or the bottom of the sawdust pit)
Because the band is now trapped between the packed sawdust and the driven bandwheel the rotating bandwheel will grip the snapped blade and throw it out like a snake, that's when it can get hairy, that's not good, only ever seen it happen that way once and that was enough.

Lawrence.