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maddog

Chop Saw blade recommendation

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I seem to be getting only about 30 cuts out of my 14" chopsaw blades despite the fact that I wear them down to a 7" nub. I have not been cutting much heavy stuff. 1" angle iron, 1" pipe, 5/8" rebar and the like. It works out quite expensive. I'd appreciate some recommendations for a blade with a longer life.

Also, I am wondering about using the stubs in my angle grinder with an arbor adapter. I would think that since they are rated for the RPM I should be able to use them.

Thanks

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A number of possible causes come to mind.

First, is the material tightly clamped? If there's ANY chatter it'll eat blades fast and chatter can be the result of thin stock vibrating after the clamp. To avoid the second, use less feed pressure.

Are you buying good quality blades? The cheap ones will actually cost you more, up to maybe body parts and fluids. :blink:

Are you keeping a steady moderate feed pressure throughout the cut? Back off only at the very end so it isn't as likely to bind when the drop drops.

Shaped materials, pipe, angle, wideflange, channel, etc. can cause problems as they don't heat evenly during cutting so they tend to warp and this can bind the blade from the side, wearing them out fast. The thinner and more odd the shape the more important it is to feed slowly so the stock doesn't heat unevenly.

Less likely causes can be a bent motor arbor or loose blade, a lot less likely is a clamp that's come loose from the saw platten, ANY chatter will wear blades fast Fast FAST.

I would NOT recommend using hot saw blades in an angle grinder. They're designed to be held on a secure stable arbor and holding one by hand it's going to move sideways or tip. If the blade binds in the cut you WILL BE EATING HIGH SPEED SHRAPNEL!:o This is a BAD thing. Don't do it.

I rarely use my hot saw, usually only on very light stock. For the most I use my horizontal vertical metal bandsaw. It's the only power tool in my shop I'll turn on and walk away from, the worst that can happen will cost me a blade but no blood will be spilt.

Hot saws in general are inherently dangerous, even working perfectly they throw a huge volume of fire lighting HOT sparks. Catastrophic blade failure is always a possibility so wear serious PPE.

Frosty the Lucky.

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Mad Dog,

At the motor you got the x axis, check the run out in the arbor with a dial indicator. The blade is the y axis. Both these have to be right. Mount a new blade and check the run out on that as well. If the arbor is bent, game over just get a new one and avoid the hassels. If the arbor is good and the blades out. Are you using the right arbor adapters and does the blade have a small metal furrel that interlocks with the adapter? Everything has to be tight and it has to fit correctly. Lacking the right fit up at the blade to arbor cause all sorts of issues, not the least of which is slipping and vibration.

Also consider offestting the stock in the vise by placing a piece of scrap behind the working piece. For thin stock consider two long piece of 1 inch tubing on either side of the stock. This may bring the cutting point of contact on your particular machine to a better performing posiion and further reduce vibration.

Cut angle iron from the point down, at least for me, it seems to works better that way. Doing it the other way, you can see the blade has a hard time at the juncture of the angle. Ridgidity and alignment are your keys to success in avoiding bad vibrations and getting relatively square cuts. Long pieces of stock need to be supported, they just can't be bouncing in the air off the end of the saw. The saw has to be well secured to something, bolt the thing down or use clamps, this aids in reducing vibration as well. Lastly, blade speed is a consideration. If the saw is bogging down, ease off and get the rotational speed get back up to operating RPM. Cutting slow and forcing the blade with excessive downward pressure will not do you and favors. I have an old POS B&D in the shop and it is has been beat to death for years but it still cuts true and the blades last a while. Hope this helps a bit.

Peter

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Thanks for all the advice:

The blades were a 10 pack of Norton and I am about to mount my last one.

I will check the alignment of the swing arm and the arbor. Though if the arbor is not running true, that ought to be quite noticeable on the edge of a 14" wheel.

I will be diligent about not applying too much pressure.

I will also be diligent about clamping securely. I definitely have been lazy with this.

I sometimes cut angle iron flat and sometimes on the diamond. I will be stricter about that too. A simple jig would help.


I'll report the results.

I've been using the stubs in an old cheapy table saw but at 5000 rpm they are not very effective.


I dont yet understand why a close fitting solid bushing should make the disc any less stable on a hand grinder.

I hate chopsaws, they are noisy, dirty, sparky and expensive. But I couldnt do without one. I try to use my hacksaw as much as possible. I would love to have a bandsaw. Some day I will built a cold saw.

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You might try a dry cut chop saw. Two popular ones are made by Dewalt and Milwaukee. They run a 14" carbide tooth blade and were design for cutting metal framing studs. I have a Milwaukee and have had it for a few years and have been very happy with it. You do have to be careful with it when cutting solid stock but it does work fine. I just take the blades in and have them resharpened. They run about $500.00 and replacment blades are $125.00. Better than an abrassive chop saw but not as good as a cold saw.

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See if you can fin 7/64" thick blades instead of 1/8". I think Metabo makes them, you may have to shop around. They give your motor a break and cut faster.

The best would be a bandsaw. If you do most of your cutting in a chop saw, you don't need a big bandsaw. I use a chopsaw only to cut very hard metal, or very thin stock, either of which will hurt a bandsaw blade.

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Arftist is right that the thinner blades cut better, and are easier on the motor. Two other things come to mind, how much pressure are you putting on the saw when cutting? To much down pressure doe not usually make it cut faster, just wears blade faster. Also what is the blade meant to cut? Some are designed to cut sheet metal like metal studs for construction and others for heavier iron like angle iron and pipe. Our local supply house had dewalt in both thin metal and thick metal, different part numbers on them but had to look in catalog to see what each was for. The proper blade material should help. I dont like using the dry cut saws on steel, one hard spot and the blade is toast.
Rob

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Hilti makes the best blades that I have found, they also have two types, the one that has a red color to it is the best blade out there.
Make sure that the blades have the fiberglass reinforcement in them, you can see the lines running through in an x pattern on some blades, other blades have little chunks of fiber in them. blades with the x pattern reinforcement last longer. and yes the thinner blades are better also as stated before

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My 2 cents: I used vermont america and norton in the past the vermont's run about $8.00 each. I bought some harbor freight blades and they lasted 3 to 1 I was cutting 1" bar stock. They proformed much better cutting and about $1.50 each. also you should check the stop gague your motor can go down to the vice and I have put blockes under the blade this will give you a few more cuts.

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The problem with putting hot saw blades in an angle grinder doesn't have to do with them fitting the arbor correctly, that's easily doable. What's dangerous is a human's ability to apply the blade in a plane, any side wobble and the blade comes apart in the BAD way.

Ever been hit by a hot saw blade that came apart? I have and it hurts through the PPE. I sure wouldn't want it to hit me through a shirt or beard.:blink:

Frosty the Lucky.

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Once more, thanks everyone for the tips and warnings. I learned a lot from this thread.

I will look for thinner blades. I will by a 10 pack of HF blades - for $20 its worth a try.

I am still thinking about a dry cutting blade. I would hate to trash a $150 blade while cutting a piece of rebar.

Seems to me that Frosty has become more cautious lately :) I will heed his warning especially since I dont have a beard to protect me. I might use them in a bench grinder as a notch grinder. Jerry Hoffman in Blacksmiths Journal suggested this.

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I had an experience that was a bit different yet still relates. I bought the 7/64 thick blade one time thinking less energy to push it because thinner means cutting less material out of the way. This is using a Makita 14" abrasive chop saw I have owned for years and has seen some use and abuse. The thinner blade didn't have the rigidity to stay straight as the 1/8" thick and would cut crooked. It didn't die much sooner than the thicker blade but I believe I get more life out of the thicker. I cut through 3-4" wide plate and with the thicker blade this thing is pretty square. My luck rides well with Dewalt brand purchased from Lowes for ~$8.00 and they aren't real far down the street. I won't be trying anymore 7/64" blades unless I can get a saw I know can hold rigid and perpendicular to the cut. Just my experience with what I use. Peace! Spears.

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Yeah, I use DeWalt's from Lowe's too. The Norton's didn't seem to be as good for the same money. Moderate pressure is the key, keep a constant shower of sparks and keep the motor speed up.

Bill

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Figure out how much you spend in wheels for the chop saw, and compare it to the price of a good used bandsaw. I have seen some nice units on Craigslist at reasonable prices.

I would even use a Porta-Band over a chop saw any day. I have seen used ones for as low as $50, and an average range of $125-$150 lately.

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On 10/20/2010 at 7:39 PM, Francis Trez Cole said:

My 2 cents: I used vermont america and norton in the past the vermont's run about $8.00 each. I bought some harbor freight blades and they lasted 3 to 1 I was cutting 1" bar stock. They proformed much better cutting and about $1.50 each. also you should check the stop gague your motor can go down to the vice and I have put blockes under the blade this will give you a few more cuts.

Francis, were you running the same number  of teeth for the 1" bar stock on the HB as in the Vermont and Norton?

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David: You might want to take a look at the date of the posts you're responding to, the one you quote is almost 10 years old, the other post you asked about is 9 years old if memory serves.

Frosty The Lucky.

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