stuarthesmith Posted June 1, 2012 Share Posted June 1, 2012 I do most of the cutting in my shop with a Radiac 7 1/2 Horsepower abrasive cut-off saw, which takes 16 inch wheels. In 35 years of constant use, I have never had any issues with this machine. Now I know why they have cast iron wheel covers over the blade. I was cutting pieces of 3 1/2 inch round 1080 tool steel for a job I have, and had put on a new saw blade for this purpose. About halfway through the heavy barstock, I heard a "boom", a loud explosion, and saw the brand new saw blade disintegrate, right before my eyes. Now I know why these machines have cast iron wheel covers. Had the safety covers not been on, I would be a dead man! If you calculate the radial velocity of the outside of a 16 inch wheel, you will see why it is imperative that you make good use of the safety guards on all machines in your shop! Quote Link to comment Share on other sites More sharing options...
jmccustomknives Posted June 1, 2012 Share Posted June 1, 2012 I know what you mean. Abrasive chop saw sales have been going down, this is the reason why. Those machines can be dangerous. You really don't have much choice though. I don't know how well the carbide blade saws would do on the high carbon steel, it would have to be anealed to do anything. In that the abrasive blades have the advantage. Quote Link to comment Share on other sites More sharing options...
divermike Posted June 1, 2012 Share Posted June 1, 2012 I have had many of those shred over the years, most often it is because the work piece shifts just a bit, or the speed is not respected. It is such a heart rate increaser when it goes pow! Newbies should not be allowed anywhere near those things. Quote Link to comment Share on other sites More sharing options...
pkrankow Posted June 1, 2012 Share Posted June 1, 2012 I have never blown up a big wheel, but even a 4 or 4 1/2 inch wheel going to pieces can be scary. Phil Quote Link to comment Share on other sites More sharing options...
JNewman Posted June 1, 2012 Share Posted June 1, 2012 I know what you mean. Abrasive chop saw sales have been going down, this is the reason why. Those machines can be dangerous. You really don't have much choice though. I don't know how well the carbide blade saws would do on the high carbon steel, it would have to be anealed to do anything. In that the abrasive blades have the advantage. I cut high carbon, alloy and tool steels with a bimetal band saw blade all the time. I almost never use my chop saw any more. I only use it on steel that has been hardened, or thin tool steels that have been forged so they air harden. Quote Link to comment Share on other sites More sharing options...
divermike Posted June 1, 2012 Share Posted June 1, 2012 sometimes when cutting a bundle of metal studs for framing, an edge would catch, and bam pow zing, exciting.. Quote Link to comment Share on other sites More sharing options...
clinton Posted June 2, 2012 Share Posted June 2, 2012 We had an apprentice blow up a 14 inch blade sending fragments though his hard hat that he had placed in front of the saw. Never saw him with out the new hard had after that Quote Link to comment Share on other sites More sharing options...
petere76 Posted June 2, 2012 Share Posted June 2, 2012 We have had several blades fracture where a large segment will seperate. It appeard to be the result of how they were made and not impact or a shifting workpiece. Both of these consditons will take a disc out very quickly. Rigidity and alignment are critical on the chop saws. The free hand cuts are where the guys get into trouble. Take the time to securely clamp the work. We noted the manufacturer of that particular blade and never purchased them again. Price point is always a consideration on consumables but we now stick with the high end discs. You will catch some debris if one of these things flys apart and you are in front of it. Peter Quote Link to comment Share on other sites More sharing options...
Glenn Posted June 2, 2012 Share Posted June 2, 2012 It is suggested that you run the blade at full power, no load, for a minute or so at the beginning of each days use. This should indicate if anything has happened since it was turned off after the last usage day(s) ago. There is a lot to be said about how a machine or blade sounds. Quote Link to comment Share on other sites More sharing options...
Frosty Posted June 2, 2012 Share Posted June 2, 2012 Having a hot saw disk cut loose is always a scary thing, happily I've never been more than bruised by one, thanks to PPE. I only use a hot saw on thin stock as my band saw with bi-metal blades will handle most anything else is it's not too hardened of course. I've never been holding onto a big hot saw that cut loose though, I'm pretty sure bruises would be the least of my worries were I in the way. Guards are a must and staying out of the plane of rotation as much as possible is highly desirable. At work we had a large hot saw, later converted to a dry saw and it had a long handle so you could stand well away from the action, later they put a treadle on it so you could be several feet out of the plane of rotation. It was a bad boy able to cut RR rail from the rail surface in about 4 seconds. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
DSW Posted June 4, 2012 Share Posted June 4, 2012 Abrasive blades for 12" or 14" gas saws have a higher rpm rating than those for chop saws and tend to take more abuse before grenading. I won't buy anything but the ones for the gas saws personally. I've had several bad experiences at work where the guys don't bother to pay attention to what abrasive blades they grab at the shop or at the store. Load a low RPM chop saw blade in a gas saw and spin it up full speed and it will grenade in seconds. Usually you get maybe 10-15 seconds as the blade gets all wobbly and starts to look like it's made of wet spegetti before it disintegrates if you don't kill the throttle. Quote Link to comment Share on other sites More sharing options...
Frank Turley Posted June 4, 2012 Share Posted June 4, 2012 In his own smithy, a Turley grad student was using a small, thin disc, cutoff on a side grinder. He thought he would do a touch-up by using it angled on its side like, for example, a 1/4 inch grinding wheel. It blew up and my friend lost one eye and had a shard in his forehead that stopped 1/8 inch from his brain. He was wearing a face shield, or it could've been worse. He is still working, but sans one eye. Moral: Thin cutoff wheels are for straight cutting, not side grinding. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted June 4, 2012 Share Posted June 4, 2012 In my experience the money for top brand abrasives is always saved several times over from using cheap ones. I remember getting some cheap ones once and watching the disks visibly decrease in size during a cut where a good brand did many cuts before getting noticeably smaller. (So I look for good brand abrasives at the fleamarket...) Quote Link to comment Share on other sites More sharing options...
JNewman Posted June 4, 2012 Share Posted June 4, 2012 In my experience the money for top brand abrasives is always saved several times over from using cheap ones. I remember getting some cheap ones once and watching the disks visibly decrease in size during a cut where a good brand did many cuts before getting noticeably smaller. (So I look for good brand abrasives at the fleamarket...) In something as potentially dangerous as grinding wheels and discs I would rather know the providence of the wheels I am using and would much rather pay a little more and buy them from a reputable industrial supplier. There are a lot of counterfeit products out there and you don't know how the wheels were handled before you got them buying them at a flea market. Quote Link to comment Share on other sites More sharing options...
ptree Posted June 4, 2012 Share Posted June 4, 2012 I am personally aware of 2 fatalities from 9" wheels used on 7" grinders without guards. Quote Link to comment Share on other sites More sharing options...
stuarthesmith Posted June 10, 2012 Author Share Posted June 10, 2012 I am posting pictures tonight of the wheel that exploded while I was cutting barstock while making very large hardies for anvils. The machine I am posting is a 7 1/2 horsepower Radiac. Take particular note of the lack of cutoff blade in the guard. That guard may have saved my life. I have been running in between raindrops for 35 years with this machine. The Good Lord was with me when I fastened the guard before I ran the machine. Who knows, after that incident, I might even re attach the guard that covers the belts! Quote Link to comment Share on other sites More sharing options...
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