Thread: Tungsten tipped metal cutting blade dead by third cut.

I bought a 12" TCT metal cutting blade. Cost me Aud $90. I used it to cut a structural steel channel, 50mm x 100 mm with 6 mm walls. I do not know the grade, but I am guessing not mild steel. So 255, 355 grade etc.

My saw runs at 3800 RPM and the TCT blade is able to handle that....or should.

The first cut was wonderful. Seconds to go through the channel. Clean cut. Dead accurate. Best metal cut I have ever experienced.

Second cut was throwing splinters of the work piece all over the place. Really had to push hard. Blade was riding up on the face of the channel and left a shard on the bottom of the cut, for all my pushing. Took about 3 times as long as the first cut.

Third cut was a washout. The blade will now burn a 2X1 piece of pine.

Have I done something wrong, or is this a crap blade? The first cut was like a hot knife through butter, the second like a wooden razor, to quote a couple of phrases.

Appreciate any help or advice on this. I want to go back to the vendor with some knowledge.

Most of those cheap metal cuttings blades are only good long term for soft metals like Al and Brass. They will cut mild steel but not for long and anything slightly harder will be just as you experienced. Some product will say this in their fine print. Check before going back to the vendor. BTW I reckon 3800 rpm is WAAAY too fast for even mild steel.

Originally Posted by BobL

Most of those cheap metal cuttings blades are only good long term for soft metals like Al and Brass. They will cut mild steel but not for long and anything slightly harder will be just as you experienced. Some product will say this in their fine print. Check before going back to the vendor. BTW I reckon 3800 rpm is WAAAY too fast for even mild steel.

Thank you for your candid reply.

Ok so I hazz been had.

So basically it's not just the blade, but I need the right saw.

For my level of usage, I will probably go back to abrasive. Pity. That first cut was so sweet.

I will be simply going back to the vendor, fine print or not. Grrr. Even if it's just to let them know they are an ....

They did claim it could cut "U-channel"

You might be better off with a 6X4 bandsaw, very quiet, no fire risk, no sparks.
Kryn

I agree, the RPMs are too high, by a factor of 4 or more. These dry cutting saws also appreciate some cutting oil even though they don't officially need it.

In defence of the seller, as a consumer we should be very familiar with cutting speeds of different metals. With this diameter and rpm the cutting speed is near 1200 m/min. We would expect the same results with that cutting speed on a lathe or mill.

Rusty

As Bob said, 3850 is far too fast, the surface speed is well above that recommended for TCT.
My Makita metal cutting TCT saw runs at 1300 rpm unloaded and slower when cutting, so less than a third of what you were running.

Hi Nick,

I agree with previous posters, way way too fast for steel ! In addition you might find that the grind on the teeth was not correct or suitable for cutting steel.

Originally Posted by REALOldNick

They did claim it could cut "U-channel"

Probably 1mm thick U-channel.

Did you keep the packaging - it would be interesting to see what the fine print says.

I agree with Kryn, bandsaw is the way to go. It's slower but you can walk away and go do something else while it completes the cut by itself and turns itself off.

hmmm...my metal working these days is casual. Bandsaws start at around $500. Bit much for me to justify.

Well the blade has 3800 rpm written on it. shrug. There is no fine print in the packaging. I do not have a 1300 rpm saw. Guess I may as well get it resharpened and use it for wood.

I have both a bandsaw AND an abrasive metal cuttoff saw. I prefer the BS but alot of the time it's actually quicker and easier to fire up the cutoff saw. Hey BTW, you can get bandsaws cheaper than $500. Keep an eye out S/H. In the meantime, just use the abrasive cutoff saw, as noisy and sparky as it is, at least it works!

Simon

Originally Posted by REALOldNick

Well the blade has 3800 rpm written on it. shrug. There is no fine print in the packaging. I do not have a 1300 rpm saw. Guess I may as well get it resharpened and use it for wood.

Its almost certainly a negative raked toothed blade - if so it will be slow as treacle in wood - but keep it to cut ally/brass and plastic.

Another thing we forget about abrasive wheels and grinders is the amount of dust they generate. Not just metal dust, but dust from the wheel from both the abrasive, filler (often fibreglass) and the binder. My dust particle counter goes off the scale whenever I use any abrasive wheel without dust extraction. The docs suspect the Sarcoidosis I have could come from exposure to metal dust.

[QUOTE]hmmm...my metal working these days is casual. Bandsaws start at around $500. Bit much for me to justify.[/QUOTE]

Keep you eyes open for a second hand one - I picked up mine for $100.

That's a pity, must of been exposed over an extremely long time.
Might be an option to go your employer unless self induced.

Can you give us a little more information about the make of your blade? A picture would be even better.
I suspect you may have an aluminium cutting blade, which is a very different beast to a blade meant for ferrous metals. The speed rating is a bit of a give away.
Any 300mm blade retailing for $90 is on the suspect quality side of life and most true metal cutting blades of that size would add almost $100 to that figure.