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Woodturning (rec.crafts.woodturning) To discuss tools, techniques, styles, materials, shows and competitions, education and educational materials related to woodturning. All skill levels are welcome, from art turners to production turners, beginners to masters. |
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#1
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Grinding Wheels
I am considering white Norton wheels from Lee Valley or Blue slowspeed
wheels from Oneway. Which stones are preferable for woodturning chisels and why are they preferable? |
#2
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I used the white wheels and found that they wore and grooved far too quickly
for my tastes. Now I use a regular aluminum oxide wheel, 80 grit. I think, and it is only my personal opinion, that any of the regular commercial wheels have a fiable enough bond for good turning use. I have not used the blue wheels. Note that the white, blue, etc colors are just a manufacturer's coding system. The cutting material is still aluminum oxide. -- God bless and safe turning Darrell Feltmate Truro, NS Canada www.aroundthewoods.com |
#3
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There is a lot to the selection of grinding wheels. Aluminum Oxide
comes in three or four basic colours - brown, blue and white. White is more friable (each crystal breaks off more easily) than brown while blue is in between. A grinding wheel consists of the material (Aluminum oxide or silicon carbide), the grit, the hardness, the structure and the type of bond (vitreous or resin). The harder the material that you want to grind, the more friable you want your wheel to be. When a grain becomes dull, you want it to break off and expose a new sharp surface. If this does not happen the wheel will glaze over and will not grind anymore. Thus white aluminum oxide will be suitable for harder material while brown aluminum oxide will be okay for softer material such as mild steel. Silicon carbide will be suitalbe for non-ferrous material such as aluminum. Similarly you have to choose the right hardness for the wheel and the right structure. Too hard a wheel will tend to glaze if the material ground is also hard. You will mostly use vitreous wheels for you grinding jobs. Resin based wheels are good for applications such as cut-off wheels. You may want to do a google search. I suggest entering a topic such as "Brown vs White Aluminum oxide". You should come up with a lot of information Chip |
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Chip
I believe that if you check you find that Aluminum oxide is a white crystalline substance and the various colors that are for sale are added by manufacturers for proprietary classification purposes. -- God bless and safe turning Darrell Feltmate Truro, NS Canada www.aroundthewoods.com |
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Hi Darrell I have worked in the metal industry and I do know that there are at least half a dozen different grinding wheel colors, and yes there is no standard as to exact hardness and friability between different manufacturers, but there is a general labeling standard on grit, material and hardness etc. and wheel colors are also indicative on bond strength/hardness, I have a nephew who makes his living in an R&D lab of a large electronics co. as a fine machinist and grinding as his specialty, and his take on the wheels he uses is that you really have to know from which manufacturer the wheels are, and experience has taught him they are not all the same, 2 wheels with the same color, grit size etc. and from different manufacturers makes for 2 different grinding characteristics. I have a link here to some more info if anyone is interested http://www.jjjtrain.com/vms/other_grind_wheels.html#8 Have fun and take care Leo Van Der Loo Darrell Feltmate wrote: Chip I believe that if you check you find that Aluminum oxide is a white crystalline substance and the various colors that are for sale are added by manufacturers for proprietary classification purposes. |
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"Leo Van Der Loo" wrote in message I have a link here to some more info if anyone is interested http://www.jjjtrain.com/vms/other_grind_wheels.html#8 Thanks for the link, Leo. Excellent--best and most concise treatise I've seen. Max |
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I'm going to make a comment here that is not exactly in line with the
question asked. You have to look at wheels and even gouges as consummables; both will wear awa;y if you are using them. If you avoid shaping and sharpening because you don't want to wear them out you are missing the point and maybe the fun. billh wrote in message oups.com... I am considering white Norton wheels from Lee Valley or Blue slowspeed wheels from Oneway. Which stones are preferable for woodturning chisels and why are they preferable? |
#9
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Why are they knocking us using aol off the ng?
Glenn Hodges Nashville, GA |
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Hi Ghodes2
It's not service that's important to them, you should know !! It's MORE MORE MORE, money is the only drive. Just make sure you keep that in mind when spending your money on so called "service providers". Have fun and take care Leo Van Der Loo Ghodges2 wrote: Why are they knocking us using aol off the ng? Glenn Hodges Nashville, GA |
#11
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Chip wrote:
: The harder the material that you want to grind, the more friable you : want your wheel to be. When a grain becomes dull, you want it to break : off and expose a new sharp surface. If this does not happen the wheel : will glaze over and will not grind anymore. Thus white aluminum oxide : will be suitable for harder material while brown aluminum oxide will be : okay for softer material such as mild steel. Silicon carbide will be : suitalbe for non-ferrous material such as aluminum. You bring up aluminum. There is a post at Lee Valley's website, stressing that you should never grind steel and aluminum on the same wheel. It apparently can create thermite, and the result can be an exploding wheel. -- Andy Barss |
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Hi Andrew
Good call I guess most of us have heard of termite and its use to weld rail tracks and other large pieces, when mixing very fine aluminium and iron oxide you make a 3500 degree C. flame and its essentially a flash. It will in my opinion not explode the wheel, however it will give you a scare as the compounds on your bench suddenly flare, and there is a good potential for a fire in the case of us wood turners/workers with all the shavings around. I have a link to government site if interested. http://www.hanford.gov/lessons/sitell/ll01/2001-36.htm Andrew Barss wrote: Chip wrote: : The harder the material that you want to grind, the more friable you : want your wheel to be. When a grain becomes dull, you want it to break : off and expose a new sharp surface. If this does not happen the wheel : will glaze over and will not grind anymore. Thus white aluminum oxide : will be suitable for harder material while brown aluminum oxide will be : okay for softer material such as mild steel. Silicon carbide will be : suitalbe for non-ferrous material such as aluminum. You bring up aluminum. There is a post at Lee Valley's website, stressing that you should never grind steel and aluminum on the same wheel. It apparently can create thermite, and the result can be an exploding wheel. -- Andy Barss |
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