647jc

647jc

Well Known Member
I recently bought several pieces of 6061 aluminum angle stock from ACS of different sizes, ??, 1?, 1 ?? and 2? all 1/8? thick. I had cut a 7? piece from the 1 ?? stock and was in the process of ripping one flange down to 1 1/8? on my band saw. I had already ripped the other flange down to 1? with no problems. While ripping the other flange to 1 1/8?, about 1? from the end of the piece the band saw just stopped cutting, even with quite a bit of pressure it would not cut anymore. I removed the aluminum angle and tried to cut another piece of aluminum and same thing, the blade was completely dulled. So, I replaced the blade and tried cutting a different piece of aluminum and it cut fine. I then went back to the piece of angle I was trying to rip and was able to cut about 1/8? further and then the blade was completely dulled again, ruined!

It appears there is a ?hard spot? in the aluminum angle that instantly dulls my band saw blade whenever I try to cut through the area. I?ve never had this happen before but after searching a bit on the internet I found documentation of this happening on different cast aluminum products. Apparently some manufactures mix some scrap aluminum in with their new melt and if there are any iron borings in the scrap, it can cause these hard spots in the casting. So, apparently the 6061aluminum angle I just got from ACS has some scrap aluminum with iron borings in it. This is all kind of interesting but unfortunately I?ve now destroyed 2 good band saw blades. Hopefully I won?t be running into any more of these ?hard spots?.
 
Your first blade got dull, overheated the 6061 aluminum and hardened it in that area most likely. Use a BM blade and not a flex back. I always lube the blade while its running with a Boelube solid stick on both sides of the blade and then the cutting edge, re-dressing it every so often while I am cutting.
 
I experienced this exact same scenario a couple months ago. After the blade dulled, I assumed it was some sort of steel inclusion in the aluminum and finished the cut with a hacksaw. Sure enough, the area where my bandsaw had stopped cutting would attract a magnet. Threw that entire piece of extrusion in the recycle pile and bought a new one and a new blade.
 
Interesting, but doesn't make sense. Let's assume a ferrous inclusion is possible. Why would it dull a blade? A lot of us cut steel on a regular basis. As for "hardened" aluminum, the hard alloys cut and machine easier than the soft ones.

Are you running a high blade speed? Was the extrusion getting hot? If so, examine the teeth on one of the "dull" blades with a 10X magnifier. You may find a tiny bit of aluminum deposited under the tip of each tooth.
 
Aluminum will often "fill" the teeth on bandsaw blades, which will quickly over heat them. I suggest going to a coarser blade or using a file card to clean the blade when it slows.
 
DanH said:
Interesting, but doesn't make sense. Let's assume a ferrous inclusion is possible. Why would it dull a blade? A lot of us cut steel on a regular basis. As for "hardened" aluminum, the hard alloys cut and machine easier than the soft ones.

Are you running a high blade speed? Was the extrusion getting hot? If so, examine the teeth on one of the "dull" blades with a 10X magnifier. You may find a tiny bit of aluminum deposited under the tip of each tooth.
Click to expand...

Dan,
He maybe using a standard wood blade on his bandsaw. Shiver, but I do. I just advance the work at the rate it works, and would not cut ferrous on it at all. It is not the "engineering" thing to do, but it works just fine. There are other issues with chip embedding in the drive tire, but not relevant to this thread.

OP: Spruce should be contacted and this piece sent to them if it truly contains iron material. I am with Dan, hard aluminum would cut the same way as the soft, only easier with better chip formation. I suspect this is a continuous cast and then roll formed piece then batch heat treated. I would be very surprised, as would Spruce, at find Fe in the mix. But that is the reason to tell them.
 
I was using a Craftsman 14 tpi non-ferous metal cutting blade. I've used this type of blade for quite a few years cutting aluminum and they work great however, if you cut or try to cut steel with them they will dull almost immediately.

Additional information: I just checked and the second blade I installed was NOT a metal cutting blade so that explains why it dulled immediately... my bad.

I plan to pick up some new metal cutting blades later today and will see how they do however I don't think I will try cutting the same piece of aluminum that dulled the first blade. A friend has offered to take that aluminum piece to his friend at Iowa State University who is a metallurgist and maybe he/she can identify what may be the problem.

I was cutting at a fairly high blade speed (adjustable) but I've done that many times before and I had just ripped another piece with no problems, the blade and saw usually cuts through aluminum very easily. I suppose at the higher speed I could have over heated the blade. Also, after I finally got the piece cut, I was cleaning the edge on my Scotchbrite wheel and noticed a few sparks coming off the wheel which shouldn't happen with aluminum. I stopped grinding when I noticed the sparks since grinding steel and aluminum on the same wheel can be very dangerous and create a Thermite reaction.
 
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