Replacement Blade for Metal Band Saw

[trlvn]

For my edification, is there a rule of thumb in metalworking as to how many teeth should be in the cut? In woodworking, if too many (small) teeth are in the cut, the gullets will fill up with sawdust...leading to various problems.

Could the aluminum chips be jamming up in the kerf and causing the blade to jump off? Would a coarser tooth blade work better?

Craig

 

[Dabbler]

In metalworking a minimum of 3 teeth (I use 4 personally) must touch the material at all times. Some guys use 2, but that can lead to excessive tooth pressure and sheared teeth.

I like to try for 5-6, with 3 as my absolute. That means cutting thin material (like .110 thick) on a 30 degree diagonal with a 16 pitch tooth blade.



I always cut my angle iron with the open face down, or, on a 45 degree angle. I get better and faster cuts.

 

[Tom Kitta]

If you ignore the 3 / 4 tooth rule you end up with either a broken blade or with many teeth missing.

The problem is that a blade with a lot of teeth will cut thick and thin material but the thick material will take forever. The blade with relatively few teeth will work sometimes as much as 20x or 30x faster on thicker stuff.

My super old saw when using blade with tiny teeth will lock itself often when trying to cut thick stuff even with little pressure. My blade with few teeth cuts thick stuff like a total champ. BUT cutting thin stuff is disaster waiting to happen.

 

[YYCHM]

This morning I tracked down and fixed the wobbly tensioning wheel. A hold down bolt on the tensioning guide was loose. I then remounted the blade and ran the saw for 30 minutes with no load. No evidence of blade creep was discerned, so I setup and sliced off a piece of 2"X2" hot rolled solid bar stock. No issues encountered and a nice square cut was achieved.

Soooo.... I setup and attempted to cut a slice off of a piece of 1 1/2" solid round aluminium and hey that made it through without incident. Only time will tell if the situation in rectified.

I did notice this however.



After cutting the aluminum the whole length of the blade had little pieces of swraf in the teeth as shown. Cutting the steel did not exhibit this phenomenon.

 

[PeterT]

I shoot WD40 into the kerf when cutting aluminum to help clear chips & from bonding to the blade. You might also consider choking up on your bearing support distance, the blade could be twisting.

Some generic info here.
https://www.lenoxtools.com/Guides/LENOX_20Guide_20to_20Band_20Sawing.pdf

 

[Tom Kitta]

Yeah WD40 or any generic coolant should help. I run out of coolant on my saw yesterday when cutting some plate and was a bit shocked how hot the plate got - I could not hold it without a glove on. Added coolant to make sure blade gets the lube which also washes off swarf. Some saws even have little brushes to clean the blade.

 

[CalgaryPT]

Ditto on the WD40 on AL. I think the new blade/sharp blade on AL could be contributing as it grabs until the blade dulls a bit; running it on steel for a few cuts would solve this part of the problem. Good catch on the tensioning wheel.

Glad you got it working. Thanks for the update.