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Post by deb193redux on Sept 25, 2008 19:36:08 GMT -5
On the front of the MK-225 HotDog, the colorful side w/o all the text, there is a counter-clockwise arrow - but only in gold paint. So you may not see it on a used blade.
So, would not reverse. Also, make sure you mounted with the text towards the arbor bearings and the colorful side towards the arbor nut.
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jimrbto
noticing nice landscape pebbles
Member since April 2007
Posts: 94
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Post by jimrbto on Sept 26, 2008 10:29:43 GMT -5
If your look carefully at a blade that is in use you will see that the "back ramp" is what is providing the majority of the support for the diamond in the cutting area of the blade. So long as that "ramp" stays no higher than the diamond or doesn't spread out so far so that is covers up other diamonds there is not problem. If the tail or ramp grows too long and covers up other diamonds-- GENTLE dressing will cure the problem. NOW when you reverse a blade and dress it you remove the tail and, unfortunately, some of the diamonds which get pulled out or broken off when the first cut is started. Ideally you should at all costs want to preserve every diamond for as long as possible, when a diamond is lost, for any reason, it has not performed its job efficiently. If you are cutting too fast and/or forcing the blade to cut you cause the matrix supporting the diamond to flow, this will happen no matter what you use for a lube/coolant. I was taught this by professional agate cutters in Idar-Oberstein, Germany when I was fortunate to be stationed near there in '56-'59. One of them, who did extensive blade repairs for the local cutters, showed me what happens to the blades by marking diamonds and observing the results in a lab scope. I would never reverse a blade. Of course if you are in a big hurry, always, and like to buy blades - by all means reverse them and coarse dress them often. Dose glazed tile really have a mohs hardness of 9?? Jim
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darrad
fully equipped rock polisher
Member since September 2006
Posts: 1,636
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Post by darrad on Sept 26, 2008 20:09:52 GMT -5
When I finally do need to dress a blade after using obsidian in between hard and soft stuff I use a fire brick. I posted this question a ways back and got different options and a fire brick was an option for a light dressing. SiC is up in the nines for hardnes. That is why we use it to grind up rocks for tumbling. I did not really want to put that to my blade. A red brick is just clay and would be gummy mud cut in oil in my opion. In my own research at the local club I was told to never reverse the blade as the back ramp would be complety removed causing diamond loss as stated be jimrbto. The fire brick works for me and if it aint broke I aint gonna fix it. Sorry Hope. This thread has turned into probaby way more than you are ready to absorb at this point. Bookmark it and save it for later. Dave.
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hope
spending too much on rocks
Member since May 2008
Posts: 477
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Post by hope on Oct 1, 2008 19:23:58 GMT -5
Thanks to everyone for all of the great information. I have definitely learned a lot.
Hope
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