bandmill blade questions

[chainsaw_louie]

Running the back of the blades to close to the guide roller flange is the biggest blade breaker when sawing hard,  You need 1/4"  between the blade and flange.  Soon as the blade hits the flange its going the crack the gullets  Steve

The WM manual is quite specific that the inner flange-to-blade gap should be 1/16" and the outer 1/8" .

Wouldn't a 1/4" gap allow the band to be pushed back onto the wheels and the teeth start to ride on the drive wheels ?

[Stephen1]

Running the back of the blades to close to the guide roller flange is the biggest blade breaker when sawing hard,  You need 1/4"  between the blade and flange.  Soon as the blade hits the flange its going the crack the gullets  Steve

The WM manual is quite specific that the inner flange-to-blade gap should be 1/16" and the outer 1/8" .

Wouldn't a 1/4" gap allow the band to be pushed back onto the wheels and the teeth start to ride on the drive wheels ?

No it would allow more room for the blade to run with out hitting the flange. 
Running a dull blade will result in pushing the head harder into the log, resulting in the blade running up against the flange. Thus resulting in a broken blade. 

[Magicman]

The blade guide flange is doing it't job when it stops rearward movement, but remember that the duller the blade, the more rearward movement you have.  Properly adjusted Horizontal Tilt pulls the blade into the blade guide when the blade contacts the flange.  This does put some stress on the blade but the rearward bending of the blade probably causes more.  If your bandwheel tracking is correct, even with 1/4" rearward movement, the blade teeth should not contact the bandwheel.

Dull blades are the principal cause of blade stress.

[ladylake]

Running the back of the blades to close to the guide roller flange is the biggest blade breaker when sawing hard,  You need 1/4"  between the blade and flange.  Soon as the blade hits the flange its going the crack the gullets  Steve

The WM manual is quite specific that the inner flange-to-blade gap should be 1/16" and the outer 1/8" .

Wouldn't a 1/4" gap allow the band to be pushed back onto the wheels and the teeth start to ride on the drive wheels ?

The 1/16 and 1/8 gap is way outdated.  Back when we ran 10 hp mills and higher hook angles the blade wouldn't push back much, now with higher hp mills and lower hook angles sawing way faster the blade pushes back a lot more.  Steve

[barbender]

I'd agree with Ladylake on this one, I put my top two out there kind of taking for granted that everything is properly setup. Touching those guide flanges breaks blades really quickly. I adjust mine just short of 1/4" back. 

When the blade is flexing back, it is spread out over a wide area of the blade. When they touch the roller flange, it concentrates the stress in that small area. I wouldn't think it was a big deal if I hadn't experienced it a few times. 

The things I watch to see how how dull a blade is, first the obvious if it isn't sawing straight. But then I watch how the sawdust stream is exiting, if it is spilling and making kind of a cloud instead of a nice compact stream, and then at the exit of the cut watch and see if your blade jumps ahead. Its a good visual of how far the blade is flexing back.

Yellowhammer made an excellent video on blade sharpness and things to watch for on his Hobby Hardwoods Alabama YouTube channel.

[chainsaw_louie]

Well, that's two voices of experience saying 1/4" gap works better than whats in the book, I'll check what mine is set at and make adjustments because I have broken a few blades lately.  Granted these are used blades but what you're saying makes sense.

Also, I did get the value of 1/16 & 1/8" from the current , online WMzr LT40 manual that covers the year my mill was made (2013).   They could easily update that value and should if 1/4" is better.  OTOH , they do sell blades 

[barbender]

I could live with 3/16 and 1/8".