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This may be the stupidest DIY question ever, but I want to make sure before I return it: is this non-ferrous metals saw blade faulty?

In the picture, see where one of the titanium carbide teeth seems to be too large and to extend into the expansion slot. BTW, I had made 4 cuts of 9-15" or so, in 3/16 aluminum plate, before I noticed this; it cuts OK and seems like it could have been smoother, but I've never cut aluminum with a power saw before, so I don't really know what to expect.

Here is the blade:

https://www.amazon.com/gp/product/B00LFCMI34/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

... and the picture of mine:

Enter image description here

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  • it may have stuck to that particular tooth due to the temperature difference near the J relief cut
    – Mark Schultheiss
    Commented Mar 19, 2019 at 16:32
  • Be careful! That's the nest for the spider whose web you can see on the adjacent teeth. Don't let it bite you!
    – Hot Licks
    Commented Mar 19, 2019 at 22:45
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    Evidently NOT the stupidest DIY question ever :-) . Thanks all for the helpful advice; wish I'd known this stuff before I did all the cuts I've already done.
    – RustyShackleford
    Commented Mar 19, 2019 at 23:28
  • Did you end up returning it? Or did lubrication work? WD 40 - wax?
    – Joe Fala
    Commented Mar 27, 2019 at 6:43
  • Sorry, yes, I put as a comment on the "answer" I checked (first one below). I was able to pull it off with needle-nose pliers. Am done cutting, but will certainly try WD-40 next time.
    – RustyShackleford
    Commented Mar 28, 2019 at 16:47

4 Answers 4

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The filling is melted aluminum that galled/melted and filled the gullet and is covering one of the Tungsten Carbide teeth. You can pull it off with a pliers.

The negative rake angle of the blade is fine for cutting aluminum, it will push your workpiece away instead of tending to grab onto it. It will generate more heat and be more likely to melt the aluminum. You can feed the work harder to generate a thicker chip to carry the heat instead of rubbing/melting it off.

A little spray of WD40 on your path can help immensely.

The J Shape is supposed to be there.

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  • 3
    Yep, pulled it off with needle-nose pliers (tried that before, but didn't try hard enough).
    – RustyShackleford
    Commented Mar 19, 2019 at 0:19
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    So you're saying I should've pushed the saw harder (maybe can't tell from the scale, it's a 7-1/4" circular saw, not a table or miter saw) ? In fact, sometimes when I pushed harder, it seemed the aluminum provided less resistance. One lives and one learns.
    – RustyShackleford
    Commented Mar 19, 2019 at 0:20
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    I can see some chips galled to the teeth in front of the plugged gullet-- so it was being pushed hard enough to form those, which is a good sign (as opposed to melting). How hard you can push it depends on what type of aluminum alloy, the thickness, system stiffness, chip evacuation, and lubricant... best judged by feel, as you mention, especially with a hand tool. WD40 will help keep the chips moving out of the gullet and from sticking to the cutting edges, this is pretty critical with a circular saw. I think you will have good results with some lube and steady feed. Good luck, safe cutting!
    – Tyler Swenson
    Commented Mar 19, 2019 at 1:20
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    Because of the negative hook angle of that blade, all the force to push it through the material comes from you. It will not bite or self feed without you pushing the saw. It wants to back out of the material rather than dig in.
    – JPhi1618
    Commented Mar 19, 2019 at 19:29
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Yes the J shape is supposed to be there for expansion. If you look at a Diablo blade it has the J relief cuts at the edges and also d-shaped relief cuts within the body of the blade. The large tooth looks like it may be build up of aluminum on the carbide tooth. It definitely doesn't look like carbide. If it is Aluminum it should be easy to pull off with a pair of needle-nose pliers. Aluminum is really good at gumming up blades. I'm pretty sure they actually make blades that are specific to aluminum to avoid the gumming up issue.

Here's an example of an aluminum blade enter image description here www.diablotools.com

From the website

Diablo's next generation Aluminum saw blades are optimized for cutting thin (up to 1/8”), medium (3/32”-1/4”) and thick (3/16”-7/16”) aluminum metals. Featuring the new, specially formulated Diablo TiCo™ Super-Density Micro-Grain Carbide, these radical blades withstand impact, reduce wear, provide clog free cuts and last longer than standard carbide in metal cutting applications. The specially formulated metal cutting carbide teeth feature a Triple Chip Grind (TCG) Tooth Design for clean, burr-free finishes, virtually eliminating any type of rework. Tri-Metal Shock Resistant Brazing allows these Aluminum blades to slice through metal materials while withstanding extreme impact for maximum durability. Diablo's Aluminum saw blade series is ideal for corded and cordless saws when on-the-job cutting non-ferrous metals such as aluminum extrusions, copper pipe, brass plate, etc.

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    Could be aluminum build up on a bad tooth - good point. I assumed it was slag build up from the laser cut operation that made the J or brazing the tooth on the blade.
    – JPhi1618
    Commented Mar 18, 2019 at 19:31
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I agree that the blade seems fine. Next time you are cutting, try using wax to lubricate the blade. You can use regular candle wax, but there is special wax formulated for this purpose and formed to make it easy to apply. I often stop mid cut and add more wax to the blade and kerf.

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I don't understand why are you not using a cutting wheel to do this is so much easier , whit this type of blade you are using creates so much vibration . I will use a metal cutting wheel, much smother less waste, faster work. Just a thought .

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  • An abrasive blade ? I have one of those on an angle grinder, and have cut some aluminum angle with it, and it seems to leave a (I'm not sure what to call it) flange of thin possibly-melted metal; very un-clean. Maybe it's the wrong blade though, I believe I bought it to do a one-time cut of a brick. Anyhow, I'm done cutting the 3/16" plate, but wonder specifically what blade you'd recommend for the angle grinder for cutting angle ?
    – RustyShackleford
    Commented Mar 20, 2019 at 23:22
  • Hey my friend if you really want a cut with no ruff edges is kind of difficult using the regular methods that we use it will always be something there , I must use piece of sand paper or a metal file and smooth it out nice and easy .
    – Luis
    Commented Mar 20, 2019 at 23:42
  • You need to go to the hardware store and get a cutting wheel do not use the grind wheel to cut the specific metal it will tear it apart if too thick for it to be a smooth cut. Don't get me wrong , you can cut with the grinder wheel but if you want a better cut then use the proper wheel.
    – Luis
    Commented Mar 20, 2019 at 23:44

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