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| Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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Grinding Wheels
Do any of you metalworkers know where I can get low cost grinding wheels, 5/8"
arbor, 1/4 and 1/2"thick, 6 or 8" diameter? Wheels need to be this thin so as to get the washers and nut back on the arbor. Also to grind a groove into the 1/2 - 3/4" round and flat high carbon steel. I'm trying to make some woodworking tools on an old 10" tablesaw. Sort of use it as a surface grinder. Cut a groove into an oak 2 X 4, embed and hot melt glue the stock into this and slide it back and forth over the wheel and slowly raise the wheel. I'll stand in back of the saw, not in front. Is this idea worthwhile or is it too dangerous? I would appreciate any guideance. I think it would be fun and save money at the same time. TIA Jim |
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Grinding Wheels
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Grinding Wheels
Do you have a video camera? The tape might help pay medical bills.
"Jamrelliot" wrote in message ... Do any of you metalworkers know where I can get low cost grinding wheels, 5/8" arbor, 1/4 and 1/2"thick, 6 or 8" diameter? Wheels need to be this thin so as to get the washers and nut back on the arbor. Also to grind a groove into the 1/2 - 3/4" round and flat high carbon steel. I'm trying to make some woodworking tools on an old 10" tablesaw. Sort of use it as a surface grinder. Cut a groove into an oak 2 X 4, embed and hot melt glue the stock into this and slide it back and forth over the wheel and slowly raise the wheel. I'll stand in back of the saw, not in front. Is this idea worthwhile or is it too dangerous? I would appreciate any guideance. I think it would be fun and save money at the same time. TIA Jim |
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Grinding Wheels
MSC has some ( www.MSCdirect.com ) but be careful with the rpm rating. The
grinding wheels on my grinder are rated for about 3600 rpm. My table saw's arbor is 4700 rpm. I know there are wheels rated to at least 6500 rpm, but man that's fast. Just my two cents. Eide "Jamrelliot" wrote in message ... Do any of you metalworkers know where I can get low cost grinding wheels, 5/8" arbor, 1/4 and 1/2"thick, 6 or 8" diameter? Wheels need to be this thin so as to get the washers and nut back on the arbor. Also to grind a groove into the 1/2 - 3/4" round and flat high carbon steel. I'm trying to make some woodworking tools on an old 10" tablesaw. Sort of use it as a surface grinder. Cut a groove into an oak 2 X 4, embed and hot melt glue the stock into this and slide it back and forth over the wheel and slowly raise the wheel. I'll stand in back of the saw, not in front. Is this idea worthwhile or is it too dangerous? I would appreciate any guideance. I think it would be fun and save money at the same time. TIA Jim |
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Grinding Wheels
Ever hear the comment, "Don't try this at home"? Have you ever seen a
wheel come apart? mj |
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Grinding Wheels
ROTFLMAO
greatest line yet. When I am setting up one of my "don't ever let me see you doing this" stunts, one of my co workers usually says, let me go dial 9, 1; so all we need to do is dial that last 1. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing. . . . DanG "Tom Gardner" wrote in message gy.com... Do you have a video camera? The tape might help pay medical bills. "Jamrelliot" wrote in message ... Do any of you metalworkers know where I can get low cost grinding wheels, 5/8" arbor, 1/4 and 1/2"thick, 6 or 8" diameter? Wheels need to be this thin so as to get the washers and nut back on the arbor. Also to grind a groove into the 1/2 - 3/4" round and flat high carbon steel. I'm trying to make some woodworking tools on an old 10" tablesaw. Sort of use it as a surface grinder. Cut a groove into an oak 2 X 4, embed and hot melt glue the stock into this and slide it back and forth over the wheel and slowly raise the wheel. I'll stand in back of the saw, not in front. Is this idea worthwhile or is it too dangerous? I would appreciate any guideance. I think it would be fun and save money at the same time. TIA Jim |
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Grinding Wheels
Ever hear the comment, "Don't try this at home"? Have you ever seen a
wheel come apart? I have yet to actually see one come apart. It happens so fast all you see is the resulting damage and carnage after the dust clears. Les |
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#9
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Grinding Wheels
On 04 Jan 2004 19:39:08 GMT, (Jamrelliot) wrote: ===Do any of you metalworkers know where I can get low cost grinding wheels, 5/8" ===arbor, 1/4 and 1/2"thick, 6 or 8" diameter? Wheels need to be this thin so as ===to get the washers and nut back on the arbor. Also to grind a groove into the ===1/2 - 3/4" round and flat high carbon steel. At times I wonder. Like the man said, run the video. It may help with the medical costs. Cheap wheels in an unguarded machine ... You may get away with it for years. May not get away with it the first time. -- Mark N.E. Ohio Never argue with a fool, a bystander can't tell you apart. (S. Clemens, A.K.A. Mark Twain) When in doubt hit the throttle. It may not help but it sure ends the suspense. (Gaz, r.moto) |
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Grinding Wheels
Personally, I would never use a grinding wheel at more than
its rated speed. Never. I am curious though why grinding wheels explode. What are the typical reasons for a wheel going (assuming it is not being spun faster than it was meant to) ? One fellow mentioned grinding aluminum. What happened there? What is the best way to get a wheel to go? I would imagine that it is not a common occurance when the wheel is not abused otherwise we'd hear about it more. I recently picked up a 3/4 HP Baldor pedastal grinder at Boeing Surplus that looked like a wheel blew up. The cast iron side guard is in 2 pieces and the wheel was fragmented when I got it. From what I've read, a good way to fix the side guard (cast iron?) would be with nickel rod--any comments? Jeff Dantzler Seattle, WA |
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#11
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Grinding Wheels
"Jeff Dantzler" wrote in message I am curious though why grinding wheels explode. It's down to the stress patern, the stress is greatest at the inside, so the crack starts there and grows outward.... when the crack reaches the outside........ Jeff Dantzler -- Jonathan Barnes's theorem; for every foolproof device there is a fool greater than the proof. To reply remove AT |
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#12
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Grinding Wheels
"Jeff Dantzler" wrote in message news:1073320981.674568@yasure... Personally, I would never use a grinding wheel at more than its rated speed. Never. I am curious though why grinding wheels explode. Centrifugal force? What are the typical reasons for a wheel going (assuming it is not being spun faster than it was meant to) ? One fellow mentioned grinding aluminum. What happened there? Grinding aluminum in and of itself will not cause a wheel to explode. I've ground aluminum in a centerless grinder, even with the wrong wheel selection (aluminum oxide when silicon carbide should have been used) for days on end and had no difficulties with the wheel aside from having to dress far more frequently due to wheel loading. My educated guess on a wheel that blows up from grinding aluminum is the higher forces applied to a wheel that didn't want to cut because of that condition. One might give a little consideration to the idea that the loading also behaves as a wedge and opens up a crack as the soft aluminum is driven deeper into the open structure of a wheel by the extra pressure applied by the operator in order to get the wheel to cut when it is fully loaded. . A harder, less friable wheel would likely reduce the chance of that happening. Regardless of the reason, grinding aluminum isn't a great idea, even with a silicon carbide wheel. Belt sanders are far more forgiving, likely because the belt won't permit deep loading. What is the best way to get a wheel to go? Mounting one that is known to be cracked. The forces are extreme on wheels because of their preferred operating speeds. The slightest defect will give the wheel a good reason to let go. Always "ring" a wheel before mounting it, and never run one that doesn't have a distinct ring to it. Don't just set it aside, break it so someone else won't try to run it. Never force a wheel on the arbor. If it won't go easily, look for the cause. In the old days of leaded bores, it was pretty easy to scrape the bore slightly until the wheel was an easy slip fit on the mounting arbor. You want it to be snug enough to locate, but not be forced in any way. That would be critical if the wheel tends to tip to a side and would be cracked when straightened. A sloppy bore would be far better. Mounting a wheel without the blotters. Those pieces of paper attached to grinding wheels aren't there for advertising. Wheels that have minor variations in their thickness can be cracked by the flanges if there's not something to average out the clamping forces. Never run grinding wheels without using a blotter on both faces. Use a cereal or shoe box if nothing else. You might get away with it a thousand times, but it's asking for trouble, and is generally not forgiving when it occurs. Always stand to the side of any grinding wheel when you first start it, allowing it to run for an honest minute before stepping in front of it. That's especially important with a new wheel that has not been run since being tested at the manufacturing facility. Running wheels beyond their rated RPM is also a dumb trick, in spite of the fact that they are typically run at 150% of their rated speed in testing. Side loading on a type 1 wheel can cause a wheel to come apart, and is likely the chief cause in many instances. If one is to do grinding that requires pressures in that direction, there are wheels designed for the load. A good example would be the steel backed type 6 found on carbide tool sharpening grinders. I would imagine that it is not a common occurance when the wheel is not abused otherwise we'd hear about it more. If you consider the number of wheels in proper use, you're absolutely correct. However, it's like an airplane that goes down. Because it doesn't happen routinely, when it does happen it's big news, and is typically fatal to the operator. After all, in most instances the wheel is aimed at the operator. A centerless grinder is one exception, as is a normal reciprocating surface grinder. I recently picked up a 3/4 HP Baldor pedastal grinder at Boeing Surplus that looked like a wheel blew up. The cast iron side guard is in 2 pieces and the wheel was fragmented when I got it. From what I've read, a good way to fix the side guard (cast iron?) would be with nickel rod--any comments? Yes, a comment that in your instance the grinder was most likely tipped over or was otherwise struck with something. When a wheel lets go I would expect that you would find little of the wheel on the arbor, and the cast iron guard would likely be more like a do-it-yourself kit, certainly not just broken in half. I'll defer to those with welding expertise where it comes to fixing the guard. Jeff Dantzler Seattle, WA Harold |
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#13
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Grinding Wheels
Harold & Susan Vordos wrote:
[snip] Thanks for your informative post. You're probably right about the tipped over pedastal grinder as the wheel wasn't in that many pieces. Cheers--Jeff Dantzler |
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#14
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Grinding Wheels
"Jeff Dantzler" wrote in message news:1073343377.125711@yasure... Harold & Susan Vordos wrote: [snip] Thanks for your informative post. You're probably right about the tipped over pedastal grinder as the wheel wasn't in that many pieces. Cheers--Jeff Dantzler You're very welcome, Jeff. Harold |
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#15
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Grinding Wheels
On Mon, 5 Jan 2004 09:55:07 -0800, "Harold & Susan Vordos"
wrote: === ==="Jeff Dantzler" wrote in message ===news:1073320981.674568@yasure... === Personally, I would never use a grinding wheel at more than === its rated speed. Never. === === I am curious though why grinding wheels explode. === ===Centrifugal force? === === === What are the typical reasons for a wheel going (assuming === it is not being spun faster than it was meant to) ? === === One fellow mentioned grinding aluminum. What happened there? === ===Grinding aluminum in and of itself will not cause a wheel to explode. I've ===ground aluminum in a centerless grinder, even with the wrong wheel ===selection (aluminum oxide when silicon carbide should have been used) for ===days on end and had no difficulties with the wheel aside from having to ===dress far more frequently due to wheel loading. My educated guess on a ===wheel that blows up from grinding aluminum is the higher forces applied to a ===wheel that didn't want to cut because of that condition. One might give ===a little consideration to the idea that the loading also behaves as a wedge ===and opens up a crack as the soft aluminum is driven deeper into the open ===structure of a wheel by the extra pressure applied by the operator in order ===to get the wheel to cut when it is fully loaded. . A harder, less friable ===wheel would likely reduce the chance of that happening. Regardless of the ===reason, grinding aluminum isn't a great idea, even with a silicon carbide ===wheel. Belt sanders are far more forgiving, likely because the belt won't ===permit deep loading. === === What is the best way to get a wheel to go? === ===Mounting one that is known to be cracked. The forces are extreme on ===wheels because of their preferred operating speeds. The slightest ===defect will give the wheel a good reason to let go. Always "ring" a ===wheel before mounting it, and never run one that doesn't have a distinct ===ring to it. Don't just set it aside, break it so someone else won't try ===to run it. === ===Never force a wheel on the arbor. If it won't go easily, look for the ===cause. In the old days of leaded bores, it was pretty easy to scrape the ===bore slightly until the wheel was an easy slip fit on the mounting arbor. ===You want it to be snug enough to locate, but not be forced in any way. ===That would be critical if the wheel tends to tip to a side and would be ===cracked when straightened. A sloppy bore would be far better. === ===Mounting a wheel without the blotters. Those pieces of paper attached to ===grinding wheels aren't there for advertising. Wheels that have minor ===variations in their thickness can be cracked by the flanges if there's not ===something to average out the clamping forces. Never run grinding wheels ===without using a blotter on both faces. Use a cereal or shoe box if nothing ===else. You might get away with it a thousand times, but it's asking for ===trouble, and is generally not forgiving when it occurs. === ===Always stand to the side of any grinding wheel when you first start it, ===allowing it to run for an honest minute before stepping in front of it. ===That's especially important with a new wheel that has not been run since ===being tested at the manufacturing facility. === ===Running wheels beyond their rated RPM is also a dumb trick, in spite of the ===fact that they are typically run at 150% of their rated speed in testing. === ===Side loading on a type 1 wheel can cause a wheel to come apart, and is ===likely the chief cause in many instances. If one is to do grinding that ===requires pressures in that direction, there are wheels designed for the ===load. A good example would be the steel backed type 6 found on carbide ===tool sharpening grinders. === === I would imagine that it is not a common occurance when the wheel === is not abused otherwise we'd hear about it more. === ===If you consider the number of wheels in proper use, you're absolutely ===correct. However, it's like an airplane that goes down. Because it ===doesn't happen routinely, when it does happen it's big news, and is ===typically fatal to the operator. After all, in most instances the wheel ===is aimed at the operator. A centerless grinder is one exception, as is a ===normal reciprocating surface grinder. === === I recently picked up a 3/4 HP Baldor pedastal grinder at Boeing === Surplus that looked like a wheel blew up. The cast iron side guard === is in 2 pieces and the wheel was fragmented when I got it. From what === I've read, a good way to fix the side guard (cast iron?) would be === with nickel rod--any comments? === ===Yes, a comment that in your instance the grinder was most likely tipped over ===or was otherwise struck with something. When a wheel lets go I would ===expect that you would find little of the wheel on the arbor, and the cast ===iron guard would likely be more like a do-it-yourself kit, certainly not ===just broken in half. I'll defer to those with welding expertise where it ===comes to fixing the guard. === === Jeff Dantzler === Seattle, WA === ===Harold === === === === === === === I agree blotters a re important, and need to be used. Same for a ring test before a wheel is installed and always stand off to the side when its run or started initially, and even though I am the only one here that uses my grinders, I always let it run up to speed for awhile before I use it. The lousy minute or two spent waiting is better than any amount of time in the emergency room or worse yet a morgue. From what I have heard and was told in tech school, the grey aluminum oxide wheel especially, as commonly found on most folks grinders can get loaded up with aluminum or even brass etc. This hyinders the abrasives cutting action, and increases heat generated during grinding. Same as any abrasive will get loaded up and cause heat buildup, but on a vitreous stone it expands in the pores between the abrasive particles and exerts pressure on the stone which can cause fracture of the wheel. This is still another reason to keep a grinding wheel dressed up, especially those cheap ones that are not as friable as the better grade of wheels. Cheap wheels are not as friable as a good wheel and are prone to loading and by not exposing clean sharp abrasive girt, more often than not they run hotter. Its hard to beat a good grinding stone. I learned that from my friend who is in the grinding business. I thought I had some great wheels until he gave me a few that he uses. World of difference in how they cut and the finish they leave. No more cheap wheels for me no matter what the cost is. Visit my website: http://www.frugalmachinist.com Opinions expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy. |
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Grinding Wheels
Jeff Dantzler wrote: Personally, I would never use a grinding wheel at more than its rated speed. Never. I am curious though why grinding wheels explode. To add to what Roy wrote, What I usually saw was someone would load the wheel with aluminum, brass or rubber then turn around and grind iron. Sparks carry heat from the wheel, if theres something in the wheel to hold the sparks the heat stays with the wheel. With something like aluminum or brass I think it would be friction causing heat buildup. What is the best way to get a wheel to go? You mean blow up?? Drop a chisel between a badly adjusted tool rest and the wheel. Sudden stoppage will usually do it. -- Mark N.E. Ohio Never argue with a fool, a bystander can't tell you apart. (S. Clemens, A.K.A. Mark Twain) When in doubt hit the throttle. It may not help but it sure ends the suspense. (Gaz, r.moto) |
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#17
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Grinding Wheels
Another point that only use coolant on those rated for that - and only have
it flow on to never sit into a pool. A stopped wheel will be heavy on one side if stopped in a pool. That will shift the balance out... Martin Jeff Dantzler wrote: Personally, I would never use a grinding wheel at more than its rated speed. Never. I am curious though why grinding wheels explode. What are the typical reasons for a wheel going (assuming it is not being spun faster than it was meant to) ? One fellow mentioned grinding aluminum. What happened there? What is the best way to get a wheel to go? I would imagine that it is not a common occurance when the wheel is not abused otherwise we'd hear about it more. I recently picked up a 3/4 HP Baldor pedastal grinder at Boeing Surplus that looked like a wheel blew up. The cast iron side guard is in 2 pieces and the wheel was fragmented when I got it. From what I've read, a good way to fix the side guard (cast iron?) would be with nickel rod--any comments? Jeff Dantzler Seattle, WA -- Martin Eastburn, Barbara Eastburn @ home at Lion's Lair with our computer NRA LOH, NRA Life NRA Second Amendment Task Force Charter Founder |
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#18
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Grinding Wheels
"Mark" wrote in message ... snip---- What is the best way to get a wheel to go? You mean blow up?? Drop a chisel between a badly adjusted tool rest and the wheel. Sudden stoppage will usually do it. Mark The stop isn't a problem. The damage done to a wheel when the wedging action occurs certainly can be. I recall an incident many years ago in which we routinely ground a short piece of 3-1/2" diameter steel, three inches long, in a centerless (Cincinnati #2). Because the size was beyond the rated capacity of the grinder, even using our lowest height blade, the part rode too far above center, yielding an operation running on the edge where one shouldn't be running. The parts would traverse the blade with a rumbling sound, one that you knew was caused by the part starting to jump up, but always falling back in place, gradually running through the grinder. One fateful night that was not the case. I was, fortunately, not the guy running the job when it happened, it was on the opposite shift. One of the parts finally made the leap out of the machine, coming back down sideways. The grinding wheel, 6" wide and 20" diameter, driven with a 15 horse motor, was slammed to an immediate stop, wedging between the grinding and regulating wheel on top of the carbide blade, which was shattered. Messelman, the operator, was very pale, I was told. Go figure! The grinding wheel had a divot removed, but after dressing to get down to a full wheel the wheel was used again. Stopping them fast doesn't do any damage. Apparently when they're well made, neither does wedging them! g Harold |
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#19
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Grinding Wheels
Roy wrote:
[big snip] friable as the better grade of wheels. Cheap wheels are not as friable as a good wheel and are prone to loading and by not exposing clean sharp abrasive girt, more often than not they run hotter. Its hard to beat a good grinding stone. I learned that from my friend who is in the grinding business. I thought I had some great wheels until he gave me a few that he uses. World of difference in how they cut and the finish they leave. No more cheap wheels for me no matter what the cost is. Okay, I'll bite. What are considered the "better grade" of wheels? I picked up a Norton Alundum course wheel to fit on a recently acquired pedastal grinder. I've heard good things about them, but would like to know what wheels you folks consider good. I usually run a course wheel and a wire wheel on my bench/pedastal grinders and grind exclusively mild steel. A machinist friend recently showed me how to dress a wheel and it definately made a difference on the grey wheel on my cheap, old, 6" Jet grinder. He is also turning some spacers and a 1" to 3/4" adaptor so I can get the pedastal grinder up and going. I'm looking forward to turning the old Jet into a tungston grinder. I guess all I need at this point is a TIG setup--any one got a Miller Dynasty that's gathering dust at the back of the shop?  BTW one of my favorite abrasives is a good flap wheel (Pferd or Tiger) on an angle grinder. These can make a bead disappear quick if I'm so inclined (though I usually just leave them.) Cheers--Jeff Dantzler |
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#20
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Grinding Wheels
On Tue, 06 Jan 2004 16:04:24 -0000, Jeff Dantzler
wrote: snip ===Okay, I'll bite. === ===What are considered the "better grade" of wheels? I would assume what they mean by better grades of wheels are those normally sold by major companies with a brand name on them and not the el cheapo china import wheels. As good a grinder as Baldor makes, they still supply a pi$$ poor stone on them. Not even a manufacturers name on these wheels. I was really dissappointed in my 7" Baldors performance when I first got it, until I got rid of the no name wheels and put on some DoAll brand and Norton wheels. The same is true with grinding wheels as everything else you buy. You get what you pay for 99% of the time. Visit my website: http://www.frugalmachinist.com Opinions expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy. |
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#21
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Grinding Wheels
Harold & Susan Vordos wrote: The grinding wheel had a divot removed, but after dressing to get down to a full wheel the wheel was used again. Stopping them fast doesn't do any damage. Apparently when they're well made, neither does wedging them! g Geez, what can I write? If you want to trust your life and limb to a stressed wheel go right ahead. God watches out for fools and drunks. Makes me wish I saved the manual with graphics of grenaded wheels. Had one picture of a wedge dropped between a rest and wheel to illustrate the need for a guard. Thousand words omitted. -- Mark N.E. Ohio Never argue with a fool, a bystander can't tell you apart. (S. Clemens, A.K.A. Mark Twain) When in doubt hit the throttle. It may not help but it sure ends the suspense. (Gaz, r.moto) |
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#22
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Grinding Wheels
"Mark" wrote in message ... Harold & Susan Vordos wrote: The grinding wheel had a divot removed, but after dressing to get down to a full wheel the wheel was used again. Stopping them fast doesn't do any damage. Apparently when they're well made, neither does wedging them! g Geez, what can I write? Agreed! I'm not sure who had the courage (or stupidity) to start the wheel once the part was removed. As I stated, the crash occurred on the opposite shift. However, when you come in to find the machine has been running for hours, seems to me the wheel has been through the trial period that says it's likely to stay together. It did. If you want to trust your life and limb to a stressed wheel go right ahead. God watches out for fools and drunks. I'd like to think I was neither of them. I know I wasn't a drunk. On the other hand, I'm not sure there's a God. We agnostics are like that. Makes me wish I saved the manual with graphics of grenaded wheels. Had one picture of a wedge dropped between a rest and wheel to illustrate the need for a guard. Thousand words omitted. You're talking with someone that has used grinding wheels long enough to more than understand your point. A point I had concluded way back in the early 60's, in fact. Ever had any wheels blow on you? I've had two. One was on an internal grinder with a spindle speed of 18,000 RPM. We had used the wheel way too long (production job) and had dressed it down until it was just a thin shell. When it blew I was standing right over it and the effect was much like a fly landing on you. Seems all the energy was spent coming apart, with particles so small they didn't do any damage. Call me lucky! Second one was on a tool post grinder when I started it up without changing the pulleys (it had been used previously for some internal work). Talk about having your head in a dark place. A portion of the small diameter wheel (roughly 4" diameter) was buried about 2" deep in the edge of a piece of 3/4" plywood, a bench top. All I could visualize was my head in place of the plywood. I'm more careful now! :-) Harold |
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