Diving in the cut

[charles mann]

Possibly been answered, and i tried the search function, more than likely im not putting in the correct search word/s. 
I was cutting a 26" pine that was pretty soft about 6-8" towards the heart. I had made already made 6 cuts, not counting the squaring cuts. Had a lil sap build up on the top of the blade, but not much so i increased the water/pinesol (might have been using the wrong mixture (water and dishsoap) and had a mix of 4:1 water pinesol) flow 3 cuts before the blade dove, then climbed back to its set cut height (1"). The dive happened about 18-20" in the cut, no knots, no metal, no engine bog, wasnt pulling the blade through any faster than the preceding cuts. The adjustable guide was at its furthest inner position as well. 

I did one more cut with the blade to clean up the fouled up cut and it cut just fine, minus being a lil wavy bc the blade made contact with the adjustable guide roller lower bracket. At that time, i changed blades and of course cut quality and speed was a big improvement. 

Im guessing dull or getting very close to needing to be changed and i am not sure the hook angle, since it was the blade that came with the mill in a box, not marked. 

[doc henderson]

I would say a combo of all the above.  Sap, build up, dulling blade.  you should be able to measure the cut angle, and after sharpening they may not be as the original stamp indicates (may no longer be accurate).

[OlJarhead]

Hard to say but Doc is probably spot on.

As for mix, I use about a half cup of PineSol in 5 gallons of water with a healthy squirt of dish liquid.   Unless it's below freezing or will be then I use windshield washer fluid rather than water or a mix of it and water if not too cold.

[Southside]

i changed blades and of course cut quality and speed was a big improvement. 

Sap build up will cause a band to dive, but what you said right there tells the story.  The band was beyond dull and letting you know.  It's best to change them before they loose performance, IE slow down, basically you want it to still be sharp, not dull, when you pull it off.  Dull bands create heat which causes metal fatigue, and band failure.  Pulling a sharp band off will result it more total BF out of that band when it is all said and done.  

Watch your sawdust, it should be corse, not fine powder coming off the saw and should be like a firehose as the band exits the cut before it hits the roller, not a spray pattern. 

[charles mann]

I would say a combo of all the above.  Sap, build up, dulling blade.  you should be able to measure the cut angle, and after sharpening they may not be as the original stamp indicates (may no longer be accurate).

Wasnt stamped that i could see anywhere on it to begin with. It was just loose blade in a box in a garbage bag taped to the pallet. Didnt have any idea what was in the box till after i had my unit assembled. Ill look at it and compare to the turbo 7s and 4° i ordered with my mill. 
I just found it weird that it dove and come back to where it was initially cutting and cut the remaining 9' of log with no more diving or any other tom foolery and zero indication before or after the cause or anything in the wood. I honestly thought i found a hard knot or metal, but nothing. 

[charles mann]

SS, i changed it bc i hit metal on the mill. Plus i had a LOT of hardened sap on the idle wheel, very little on the drive. It took a bit of scrapping to get it off. The drive side, lite pressure wire brushing took it off with ease. 

Now that i see how much i can cut with one blade, i'll be ordering another 15 T7s for all the pine and small hardwoods and leave my 4s for the wide hardwoods. 

[Southside]

Weird grain will cause a band to deflect if it is experiencing other issues, build up, tension loss, dull.

Try diesel in your lube tank, especially with pine. Use the absolute minimum amount you can, just a drop every few seconds, not enough to smell or see it, and you won't have build up again. 

[charles mann]

I was hopping not to use diesel, but seeing how much i used to mill that pine and a fresh sawn red oak 35" 10' long, i will at least change to diesel for pine. 

I'll hit it again in a couple wks when i get off work and back hm. Iv got a min of 6 40+" pines to fell, haul and mill.