cutting steel plate with circular saw?

Don't do that with carbide-------you'll pull the brazed inserts off, or destroy them if they refuse to yield.

Harold

Don, very nice, thank you. I will make something similar. I got my plasma cutter to work [somewhat], will ask more in sci.engr.joining.welding.

By the way, you can just apply a light coating of heavy oil (like HD-40 or 80w90) to those things and they will never rust.

i

Back sometime in the 70's before abrasive blades became popular and dirt cheap, I bought a metal cutting blade from the Sears Tool Catalog. It fits on a 7¼ circle saw, and the blade only has four teeth. Well they are not really teeth just slits. The blade is smooth and at four places it has a ½ slit cut into it. I have used it to cut up to 3/8-inch thick steel plate. The way it works is that the blade cuts by friction. The edge touching the metal being cut, gets it red hot or hotter and is pushed away by the blade. The blade doesn't get hot enough to damage it because it only has a small area in contact at any time.

The last two years I have used it a number of times cutting 250-300 gal tanks lengthwise to make large BBQ grills/Pig Cookers. I make one cut length wise down one side which usually takes a couple of minutes to do say a five foot cut. After I weld braces/hinges on, I then cut the sides and front. It works a lot better than a cutting torch or plasma cutter as the edges are smooth and there is no distortion from heat. It is better than abrasive blades, because there is a lot less dust and dirt, it's quicker, and easier.

A couple of buddies have seen me cut with this blade and have made their own metal cutting blades out of old circle saw blades. The just ground the teeth off by reversing the blade in the saw and using it against a grinding wheel. Their blades work as well and my Sears one does.

BUT IT IS SO LOUD THAT YOU CAN FEEL THE SOUND IN YOUR BODY! I wear ear plugs, and shooters ear muffs when cutting with this. Don't try this near a cemetery, you might wake the dead.

--Oh hey yeah; forgot about those. Saw a demo last year at WESTEC; very impressive! Still I'd hate to have to cut out a circle with one, heh.

I ruined a great B&D Quantum saw with one of those blades. Fried the commutator . Not sure if it was from overheating or from metallic dust contamination . Or maybe a combination of both . I suggest the original poster look in the phone book for a shop with a brake shear to cut his stuff .

A lot of these supposedly fried drills can be fixed by blowing dust out with a compressor. I fixed two such drills this way (a drill and a grinder).

i

Beleveve it or not I read about it I think in Mother Earth News, and was just to take a plywood blade lots of teeth no tungsten and just start cutting the teeth will go and the blade will get red hot and start cutting the metal. Have only used it on thin metal, may work with thicker. Noisy though. Ed ke6bnl

Diam> > Hi,

That's called "friction sawing"

I would not use abrasive wheels. I would not use friction blades. I would not use plasma if you want a cut that shows.

You can get a finish cut with a steel cutting carbide blade. There are several manufacturers. DML, Tenryu, etc. I prefer the Morse brand Metal Devil blades. I use it on a worm drive saw. It is best to use an edge guide and keep a steady pressure on the saw. The blades are a bit pricey at about $50, but the resulting cut is excellent.

If you do much of this, it may well be worth buying a dedicated saw made for this like an Evolution. Here is a site:

These catch all the chips, though the chips from a worm drive aren't bad. If you use it on a table saw, make sure to monitor saw dust and make sure to wear eye protection.

When you need to cut a panel out of a wreck at the scrappy, nothing beats a good battery powere recip saw.

Mount the blade backwards - especially on thin metals - to prevent it grabbing.

For thin sheet metal, the blade acts like a "nibbler" and may even be sharpened by the experience.

For thicker metal, it acts as a friction cutter and will last a bit longer if cuts are made halfway to the center about every 30 degrees to keep the center of the blade cooler.

I wish it was that simple . There are commutator segments missing , not repairable short of a new armature . Which costs more than it's worth .

I "did in" my good rockwell saw cutting aluminum. The armature was worth more than many replacement saws, but I decided it was worth fixing and have not been sorry. That saw will likely outlast me (as long as I don't cut metal with it again).