Post by QuailRiver on Mar 7, 2013 16:59:58 GMT -5
AS I promised Sheltie in another post here are some of my experiences with MK/BD 301 Blades. I had long been a fan of MK 297 and MK 301 diamond blades. Every one of these blades that I had purchased while they were still being sold with the MK label were of good quality and gave great service. But quality control on MK/BD blades seems to have tanked! I believe all of their 301 blades are made in South Korea now. Over the last couple of years I've ordered six 301 blades (1-12", 3-14" and 2-18") and have had to send 3 of them back. Two of the three I kept, I had to replace the factory insert bushings in the arbor hole because they came not bored accurately. The 12" blade had a wobble in it but was still useable so I just kept it. Two of the 14" blades right out of the box had severe wobbles. Not that they were just bent (which they were) but also the metal seemed to not be tempered correctly and they flexed too easily which caused the blades to flutter severely when running. They were unusable so I returned both of them and ordered a 14" Raytech Black Blazer blade instead. Five of the six BD 301 blades I've ordered had a thicker kerf overhang on one side of the blade than on the other. And one of the 18" blades had little to no kerf overhang at all on either side. This blade would have become unusable long before the diamond edge wore away so I returned it.
For those that don't already know, on a diamond lapidary blade the kerf is the part of the cutting edge of the rim that contains the diamond and is thicker than the rest of the blade. It is very important that a blade have an adequate amount of kerf extend beyond the thickness of the blade core. And on a correctly manufactured blade the kerf overhang should be equal on both sides of the blade. The space that the kerf overhang provides prevents the body of the blade from friction rubbing against the body of the material being cut. It also provides space for adequate delivery of lubricant to the surface being cut and for the removal of the waste material produced while cutting. If a diamond blade does not have the proper amount of kerf overhang then it will generate more heat while cutting and will create more stress and wear on the arbor, the arbor bearings, and powerfeed components of the saw. And will cause the blade edge to round and wear out prematurely.
The MK/BD 301 blades that have an even kerf overhang on both sides are reversible. But based on my recent experiences with BD blades it would seem an absolute fluke to receive a new blade from them with a proper and even kerf. So if all of the new 301 blades now have more kerf overhang on one side of the blade than the other then the blade should be mounted on the arbor with the thicker kerf side facing the rock vise. If receiving a new diamond blade that does not have a distinct kerf that is wider that the blade core and can be felt on both sides by rubbing your finger across it then I would recommend returning it to the factory. And don't be surprised if you have to explain to the sales person or customer service rep exactly what the kerf is and what the kerf's purpose is, and why you are returning it.
After stating the negatives, to be fair I should mention the positives. So far I have been getting very good service out of the one 12" blade and the one 18" 301 blade that I kept. The one 14" 301 blade I kept gave good service for a while too but began having issues that I suspect are more related to my cutting hard Kentucky Agates with it while using the fixed (too fast) feed rate on my Lortone Panther, than it had to do with the blade itself.
For those that don't already know, on a diamond lapidary blade the kerf is the part of the cutting edge of the rim that contains the diamond and is thicker than the rest of the blade. It is very important that a blade have an adequate amount of kerf extend beyond the thickness of the blade core. And on a correctly manufactured blade the kerf overhang should be equal on both sides of the blade. The space that the kerf overhang provides prevents the body of the blade from friction rubbing against the body of the material being cut. It also provides space for adequate delivery of lubricant to the surface being cut and for the removal of the waste material produced while cutting. If a diamond blade does not have the proper amount of kerf overhang then it will generate more heat while cutting and will create more stress and wear on the arbor, the arbor bearings, and powerfeed components of the saw. And will cause the blade edge to round and wear out prematurely.
The MK/BD 301 blades that have an even kerf overhang on both sides are reversible. But based on my recent experiences with BD blades it would seem an absolute fluke to receive a new blade from them with a proper and even kerf. So if all of the new 301 blades now have more kerf overhang on one side of the blade than the other then the blade should be mounted on the arbor with the thicker kerf side facing the rock vise. If receiving a new diamond blade that does not have a distinct kerf that is wider that the blade core and can be felt on both sides by rubbing your finger across it then I would recommend returning it to the factory. And don't be surprised if you have to explain to the sales person or customer service rep exactly what the kerf is and what the kerf's purpose is, and why you are returning it.
After stating the negatives, to be fair I should mention the positives. So far I have been getting very good service out of the one 12" blade and the one 18" 301 blade that I kept. The one 14" 301 blade I kept gave good service for a while too but began having issues that I suspect are more related to my cutting hard Kentucky Agates with it while using the fixed (too fast) feed rate on my Lortone Panther, than it had to do with the blade itself.