Need help on razor sharp sharpening wheels

G

Grussing_Custom_Knives

Well-Known Member
Recently I just ordered a set of 8" deluxe sharpening wheels from razor sharp on eBay. I don't have a buffer and I was wondering what one to get I found a 6" and a 8" buffer on harbor freight and I've seen people use them both and I was wondering would they both work and if so witch one would be better or something else that would be better than these both.
Thanks


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I have a HF buffer- I think an 8". It works out pretty well for me, but one with longer shafts would be nice sometimes to get the knife further away from the motor (especially on larger knives). I only use it for buffing, but the other issue for you would be the speed. A buffer must be about the most dangerous piece of equipment in your shop. I would think lower speeds would be better, more so for sharpening then buffing. I would be sure that the speed of the buffer is suited to the sharpening wheels and how you are going to use the wheels. I wouldn't sacrifice safety for the sake of getting the more affordable buffer.
 
Bill Hubbell said:
I have a HF buffer- I think an 8". It works out pretty well for me, but one with longer shafts would be nice sometimes to get the knife further away from the motor (especially on larger knives). I only use it for buffing, but the other issue for you would be the speed. A buffer must be about the most dangerous piece of equipment in your shop. I would think lower speeds would be better, more so for sharpening then buffing. I would be sure that the speed of the buffer is suited to the sharpening wheels and how you are going to use the wheels. I wouldn't sacrifice safety for the sake of getting the more affordable buffer.
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I don't know if it's true but i heard from multiple people saying it recommends a buffer or grinder with 3000-3700 rpms. What color is your buffer
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I put a set of razor sharp wheels on a Harbor Freight 6" buffer and it works fine. I have it dedicated to the sharpening system. I turned the motor around on the base so the switch is still in front, but the wheels turn away from you for sharpening. I have the $40 buffer like the gray one posted above. I went with the 6" because of the reason already mentioned, for more clearance over the motor.
 
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Melsdad said:
I put a set of razor sharp wheels on a Harbor Freight 6" buffer and it works fine. I have it dedicated to the sharpening system. I turned the motor around on the base so the switch is still in front, but the wheels turn away from you for sharpening. I have the $40 buffer like the gray one posted above. I went with the 6" because of the reason already mentioned, for more clearance over the motor.
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Cool you have the 8" deluxe razor sharp package right?


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Bill's right..... a buffer is the most dangerous piece of equipment a person can own, and the fact that the Harbor Freight buffers you mentioned are both 3450rpm, would simply disqualify both from being in my shop. I once owned a 3450rpm buffer (the first one I ever had), and after a close call, and a hole the size of my fist in the shop wall, never again.

OK, let's talk about those sharpening wheels..... I personally don't like or recommend them, simply because I've seen many people over the years "burn" the edges of blades when trying to use them, essentially ruining a good knife. In most cases a person can do a better job of sharpening, with less room for error, with a belt and a light buff or stropping. But, if you feel you must use the sharpening wheels, use the slowest RPM you can.....generally that's going to be about 1140rpm, unless you use some type of a gear reducer or a VFD setup. Most "slow speed" motors these days tend to be 1725-1800 RPM. I suspect your looking for an "economical" solution, but rather then looking for "inexpensive", focus on what will do the job correctly....most of the time that's the difference between success and failure.
 
EdCaffreyMS said:
Bill's right..... a buffer is the most dangerous piece of equipment a person can own, and the fact that the Harbor Freight buffers you mentioned are both 3450rpm, would simply disqualify both from being in my shop. I once owned a 3450rpm buffer (the first one I ever had), and after a close call, and a hole the size of my fist in the shop wall, never again.

OK, let's talk about those sharpening wheels..... I personally don't like or recommend them, simply because I've seen many people over the years "burn" the edges of blades when trying to use them, essentially ruining a good knife. In most cases a person can do a better job of sharpening, with less room for error, with a belt and a light buff or stropping. But, if you feel you must use the sharpening wheels, use the slowest RPM you can.....generally that's going to be about 1140rpm, unless you use some type of a gear reducer or a VFD setup. Most "slow speed" motors these days tend to be 1725-1800 RPM. I suspect your looking for an "economical" solution, but rather then looking for "inexpensive", focus on what will do the job correctly....most of the time that's the difference between success and failure.
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Yea you have to be careful using it to not burn out the edges. I have a kmg grinder but I never tried sharpening on it. I might sometime but I don't have a slak belt attachment to do so


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I forgot to say I have this buffer but I don't think there would be enough clearance from the top of the buffer to the top of the wheel


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You don't need a slack belt attachment.....I sharpen between the top wheel of the flat platen and the idler/tracking wheel (edge of the knife facing away from me/into the belt rotation..... but I'm assuming you have variable speed.... if not, then I'd consider it too fast.
 
EdCaffreyMS said:
You don't need a slack belt attachment.....I sharpen between the top wheel of the flat platen and the idler/tracking wheel (edge of the knife facing away from me/into the belt rotation..... but I'm assuming you have variable speed.... if not, then I'd consider it too fast.
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Yep I have a variable speed, for most of my blade grinding I grind at 50


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OK, then you're set! Depending on how thick you leave the edge prior to sharpening (I try to have my carbon steel blades, with a convex edge "sharp" when I come off a 600 grit belt during finish grinding). When sharpening on the belt, I start with a worn out 400 grit (for carbon steels), and have the grinder running about 15-25% on the controller. With the edge into the direction of the belt travel (in the slack area between the top wheel on the flat platen and the idler/tracking wheel), and not much more then the weight of the knife for pressure, I make a single pass from plunge cut to tip on each side. Normally that's all I need, then, depending on who the knife is going to, it either gets a VERY LIGHT strop, or a single, light pass on each side, with a loose buff with pink No-Scratch.

If you leave any "flat" on your finished blades prior to sharpening, you MIGHT need to start with a heavier grit, and find the succession of grits works best for you/your blades.

Things are different for Stainless steels....those blades generally require starting at 320-400 grit, and then "step" through the grits to 1200. Again, it all depends on how much "flat" is left on the edge prior to sharpening. Generally because of the "target hardness" that most Stainless steels require, most will require some degree of edge bevel to be durable. Trying to take most stainless steels to a "zero" edge bevel, will often result in edges that chip during use. It's just a different animal from carbon steels, and must be treated/worked accordingly.
 
Grussing_Custom_Knives said:
Yep I have a variable speed, for most of my blade grinding I grind at 50
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50% or 50Hz? As has been said many times, speed kills. In this case, high speed on belt or sharpening wheel can very easily overheat your edge. I have a low speed set-up for my 2x72 that uses an 800rpm motor w/VFD and a 3" drive wheel so getting belt speed of 400 to 500 fpm is easy. I guess you are talking about these http://www.ebay.com/sch/i.html?_fro...S0&_nkw=razor+sharp+sharpening+wheel&_sacat=0 i read the fine print on a couple of these and they are using 180 grit compound. be careful and let us know if they work
 
EdCaffreyMS said:
OK, then you're set! Depending on how thick you leave the edge prior to sharpening (I try to have my carbon steel blades, with a convex edge "sharp" when I come off a 600 grit belt during finish grinding). When sharpening on the belt, I start with a worn out 400 grit (for carbon steels), and have the grinder running about 15-25% on the controller. With the edge into the direction of the belt travel (in the slack area between the top wheel on the flat platen and the idler/tracking wheel), and not much more then the weight of the knife for pressure, I make a single pass from plunge cut to tip on each side. Normally that's all I need, then, depending on who the knife is going to, it either gets a VERY LIGHT strop, or a single, light pass on each side, with a loose buff with pink No-Scratch.

If you leave any "flat" on your finished blades prior to sharpening, you MIGHT need to start with a heavier grit, and find the succession of grits works best for you/your blades.

Things are different for Stainless steels....those blades generally require starting at 320-400 grit, and then "step" through the grits to 1200. Again, it all depends on how much "flat" is left on the edge prior to sharpening. Generally because of the "target hardness" that most Stainless steels require, most will require some degree of edge bevel to be durable. Trying to take most stainless steels to a "zero" edge bevel, will often result in edges that chip during use. It's just a different animal from carbon steels, and must be treated/worked accordingly.
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Ok I'll give it a shot the highest grit I have is 400


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Do you have a flat platen on the KMG? If so, you've got a slack belt - just remove the platen. Turn the speed down to "pretty low", and go from there with belts from 400 up to 1,000 grit (or more) and you're in business.
 
KenH said:
Do you have a flat platen on the KMG? If so, you've got a slack belt - just remove the platen. Turn the speed down to "pretty low", and go from there with belts from 400 up to 1,000 grit (or more) and you're in business.
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Yea but it's a pain to do. I'll get a dedicated slak belt attachment some time.


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EdCaffreyMS said:
OK, then you're set! Depending on how thick you leave the edge prior to sharpening (I try to have my carbon steel blades, with a convex edge "sharp" when I come off a 600 grit belt during finish grinding). When sharpening on the belt, I start with a worn out 400 grit (for carbon steels), and have the grinder running about 15-25% on the controller. With the edge into the direction of the belt travel (in the slack area between the top wheel on the flat platen and the idler/tracking wheel), and not much more then the weight of the knife for pressure, I make a single pass from plunge cut to tip on each side. Normally that's all I need, then, depending on who the knife is going to, it either gets a VERY LIGHT strop, or a single, light pass on each side, with a loose buff with pink No-Scratch.

If you leave any "flat" on your finished blades prior to sharpening, you MIGHT need to start with a heavier grit, and find the succession of grits works best for you/your blades.

Things are different for Stainless steels....those blades generally require starting at 320-400 grit, and then "step" through the grits to 1200. Again, it all depends on how much "flat" is left on the edge prior to sharpening. Generally because of the "target hardness" that most Stainless steels require, most will require some degree of edge bevel to be durable. Trying to take most stainless steels to a "zero" edge bevel, will often result in edges that chip during use. It's just a different animal from carbon steels, and must be treated/worked accordingly.
Click to expand...

What stropping compound do you use?


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