Hi
Im interested to know the fastest way to remove chips (damaged knives) as it sometimes takes 20 to 30 minutes, which i believe is way to long
I have a SG250 and a diamond wheel 600
Thanks in adance
Hi Wallydouglas,
I would go with the SG250 graded coarse and at a steeper sharpening angle - something like 25-30 degrees - alternating passes on each side until you've cleared the chip, then reset your desired edge angle. Time to complete will depend on the size of the chip and the hardness of the knife, but 20 minutes doesn't seem unreasonable. If you want to go quicker, you could consider a coarser grade of CBN wheel (80/160 grit) but not essential.
B
I've always been skeptical of this process of using a higher angle. Seems to me one still has to take the same amount of steel off one way or the other and the SG stone is just not that aggressive, regardless of coarse grading or truing.
For me, the fastest/best way to remove chips and/or repair tips is with a standard high speed grinding wheel fitted to run on a Tormek, in the water bath. Or by using a variable speed belt grinder set at its slowest speed to make controlling the heat easier. A standard high speed grinding wheel is very affordable (under $100 and often around $50) and takes only a minimal amount of fitting to work. I use the Tormek truing tool to dress it. Ken S. has long advocated this and has described his method of reaming out some PVC pipe to fit the 12mm shaft and using fender washers as spacers and flange washers.
Rick
I use the "higher angle" to remove damage... works great. In fact, if I'm doing a large repair, I'll freehand grind as close to 90° as I can.
Small chips you can just sharpen out at the angle you want to sharpen. But larger chips, setting the angle higher and removing them first, makes it go a lot faster.
There are obviously alternatives, but if all you have is the Tormek setup... give it a try. :)
My other advice... don't treat the Tormek like a belt sander... or something that generates heat. If I'm making a large repair... I'll work one side sometimes for... i dunno... over a minute or so... just working the knife on the stone, to grind out the damage. The Tormek is controllled and keeps the knife cool... so take advantage of it. When I started, I repaired knives like I was doing it on a belt sander... one pass / look / flip / repeat... until I realized I can work the knife for a longer period of time, and it goes a lot faster. Combined with raising the angle... you will see a significant reduction in the time. (Obviously... get a practice knife, to try it out).
When fixing larger chips you also may want to consider thinning the blade to retain the original cutting geometry.
Thanks for the advice guys
I will go with the greater angle and see how I go
a 2:30 video with english subtitles. Have fun ;)
https://youtu.be/-YEu8BNJho0 (https://youtu.be/-YEu8BNJho0)
Ok I'm impressed that's seems like the go then
Have messaged you Hanns
Quote from: RickKrung on January 14, 2021, 06:31:12 AM
I've always been skeptical of this process of using a higher angle. Seems to me one still has to take the same amount of steel off one way or the other and the SG stone is just not that aggressive, regardless of coarse grading or truing.
For me, the fastest/best way to remove chips and/or repair tips is with a standard high speed grinding wheel fitted to run on a Tormek, in the water bath. Or by using a variable speed belt grinder set at its slowest speed to make controlling the heat easier. A standard high speed grinding wheel is very affordable (under $100 and often around $50) and takes only a minimal amount of fitting to work. I use the Tormek truing tool to dress it. Ken S. has long advocated this and has described his method of reaming out some PVC pipe to fit the 12mm shaft and using fender washers as spacers and flange washers.
what type of grinding wheel and where would you find such a thing? for the high speed grinding wheel. Thanks
Rick
Quote from: RickKrung on January 14, 2021, 06:31:12 AM
I've always been skeptical of this process of using a higher angle. Seems to me one still has to take the same amount of steel off one way or the other and the SG stone is just not that aggressive, regardless of coarse grading or truing.
For me, the fastest/best way to remove chips and/or repair tips is with a standard high speed grinding wheel fitted to run on a Tormek, in the water bath. Or by using a variable speed belt grinder set at its slowest speed to make controlling the heat easier. A standard high speed grinding wheel is very affordable (under $100 and often around $50) and takes only a minimal amount of fitting to work. I use the Tormek truing tool to dress it. Ken S. has long advocated this and has described his method of reaming out some PVC pipe to fit the 12mm shaft and using fender washers as spacers and flange washers.
Rick
Quote from: Sean Maggi on March 15, 2021, 01:14:14 AM
what type of grinding wheel and where would you find such a thing? for the high speed grinding wheel. Thanks
Do a search on "norton 3x" and you will find dozens of posts where this is discussed, including photos of my setup, multiple times. If you cannot find what you are looking for that way, in a more generic sense, I would say that
ANY high speed grinding wheel, 8" or 10" would work, coarse grit, 64 or 80.
Norton 3X wheels are not hard to find. I strongly recommend you stick with them; I know they work well.
Here is a link:
https://www.packardwoodworks.com/sharp-n3xw.html
Lee Valley carries them, also.
I have used 80 and 46 grit. You really only need one. The 80 grit is the more conservative choice; the 46 is the more aggressive choice. Save these for heavy grinding.
Ken