What to use to regrind

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Bob6794

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Apr 21, 2013
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I am curious as what would work best for regrinding a blade to thin it down so I can get some better cutting performance out of them. I can already put a pretty good edge on knives with my Sharpmaker which is my preferred method and I have diamond stones for that and my DMT Aligner so sharpening is not an issue but the heavy metal removal for thinning the blade is as this is new territory for me which I want to learn to do. I have only thinned down a Victorinox paring knife with a silicon carbide norton economy stone and sandpaper that was quite time consuming so I imagine doing that with D2 is out of the question.

I have actually found a D2 knife that caught my interest, 2 of the Colt D2 knives if you must know and they both look interesting to experiment on and maybe make a decent EDC out of one of them. Only thing is I hate using power tools for this type of thing so my thinking was a metal file and than clean it up afterwords with a stone but I like to hear suggestions on what would work. And preferably not something overly elaborate or expensive as I don't know if I will keep thinning down knives as I generally go out of my way to buy ones with the blade geometry I like from the start.

Thanks for the help, and any additional help in getting some good cutting performance out of a knife is greatly appreciated.
 
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Belt sander/grinder. You could get by with a cheap 1x30 but 'best' would probably be a 2x72.

I've restored and mirror-polished blades by hand and it is very labor intensive. Very. Enough that I dread having to do it.
 
Bob6794 said:
I am curious as what would work best for regrinding a blade to thin it down so I can get some better cutting performance out of them. I can already put a pretty good edge on knives with my Sharpmaker which is my preferred method and I have diamond stones for that and my DMT Aligner so sharpening is not an issue but the heavy metal removal for thinning the blade is as this is new territory for me which I want to learn to do. I have only thinned down a Victorinox paring knife with a silicon carbide norton economy stone and sandpaper that was quite time consuming so I imagine doing that with D2 is out of the question.
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I think it depends on how much thinning you have to do.
If you're just changing the edge angle from 20dps to 10dps,
I guess (based on my small experience), with appropriate amount of force, maybe 5min to an hour or two with the norton economy stone.


But if you're shooting for 10dps but in order to reach it you have to grind some flats behind the edge (wider area), I'd say buy a different knife :)
 
It's not the edge angle but the metal behind the edge I want to thin down. I was basically inspired by this post http://www.bladeforums.com/forums/showthread.php/793481-Ranking-of-Steels-in-Categories-based-on-Edge-Retention-cutting-5-8-quot-rope how lower in the OP's post it shows performance for the S110V Manix 2 before and after regrinding and my own experience in thinning down that paring knife and turning it into the best performing knife I have in terms of slicing ability. I found it a little slow going even with the relatively low wear resistant steel to thin it down with that stone and even 40grit sandpaper and I know D2 is leaps and bounds more wear resistant and I will have more to remove.

Different knife isn't too much of an option as I really like to test out that Colt D2 knife to see what it can do, and to see what I can make it do. I have a weird desire to make inexpensive things far outperform more expensive/better/sophisticated stuff for fun by modifying them and that looks like a potentially fun test bed to do this on.

I take a look into the 1x30 or 2x72 but I really like to save those as a last option. I greatly prefer working with my hands with knives as I feel I have more control and even though I've worked with power tools a lot before taking a knife to one never sat well with me. More of a mental thing than practical as I know it's not as bad as it sounds.
 
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It's a finished folding knife ready to go once it reaches me via mail. So yeah I am planning on having a bit more of a tough time doing than than before and maybe take a few days to finish this project once I get it started. It's actually why I started this post I figured with there being such a large difference in wear resistance I better ask what will work instead of trial and error as that just sounded like the wrong way to go about it this time.

Looks like belt grinder is the recommended way so far. I don't think the wheel is a good option for me, that is one of the tools I have no experience on. I should've reformed what I said on power tools on experience I have, I am used to using handheld power tools for the most part. I didn't think of that till I read your post.
 
TravisH said:
. You could get by with a cheap 1x30 but 'best' would probably be a 2x72.

I've restored and mirror-polished blades by hand and it is very labor intensive. Very. Enough that I dread having to do it.
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Exactly, extremely labor intensive instead I use a 2 X 72 Belt sander/grinder with 3M Trizact belts. They are not as aggressive as most other mediums and leave a very nice finish requiring little had work.
 
If you want it to look nice and go much quicker use a belt sander... if don't mind the slow method that doesn't look as neat but performs just as good, use a stone. Cliff Stamp and others do this all the time w/ stones only.
 
I took a hollow ground manix2 and used stone to make it flat ground, I will never do that again. My fingers ached and I had rubbed several fingers bloody.
 
I found out that Colt makes a CBN sharpening stone for $11 so I just placed an order for that, no clue as to the grit rating but I am hoping it's coarse. It's a 4 x 2 stone, considering the fact that my favorite stone size is 6x2 and I've freehand on the smaller dmt aligner stones in the past this hopefully won't prove too difficult. And I can't deny getting a chance to test out CBN for such a price was too hard to pass up, so I think I will put this through it's paces and see what this can do for this task as it sounded far too interesting to not try. I am hoping for dumb luck that it cuts far faster than the norton economy stone but I am not holding my breath on that.

Oh forgot to mention it's called , Colt® C-BNX7 Sharpener.
 
No denying that, but it caught my interest. Thanks I am hoping that by some long shot it works out.
 
If doing it by hand, a DMT XXC would be a nice tool to have. It can be done on coarse vitreous stones like a Silicon Carbide, and I have done a few this way. If a lot of stock has to come off, the diamonds get it done with less fuss.
 
The DMT XXC crossed my mind and would be my first choice if price was not an issue. But I am afraid I put too much pressure on it while regrinding as this is a new skill I am trying to learn, for normal sharpening I am not concerned about that as I know better and have more control. And trashing a new DMT XXC would make me a little sad, so right now I'm going to avoid that all together till I get my skill up.

The CBN stone I am excited about getting but I be honest it's more of a experiment and I don't have too high hopes that it work better than a coarse silicon carbide, but excited about it none the less. I was thinking about picking up a Norton 8x3 coarse stone to do the work on as I would have more surface area to work with in terms of width, length wise anything larger than 6in and I tend to not use the entire stone lengthwise. But I am still debating on if that be worth it or if there are coarser silicon carbide stones out there that would work better for just heavy metal removal like this.
 
Norton makes a boat stone that runs about $50. The rating seems to vary, but the one I have is about 80 grit. It works. The problem with most of the vitreous stones is that they will leave heavy scratches in the surface and along any angle transitions. They also tend to load up with prolonged use.

I have leaned on my DMT XXC quite a bit. Nothing too terrible, but definitely not a light touch. When working such a wide area, the pressure is distributed across a large region - the amount of force directed at any given spot on the abrasives is proportionately lower. Consider 1/2" x 1/2" of contact area on the primary compared to maybe a square mm at the edge.
 
A couple weeks ago I reground a knife. When I started it was .035 behind the edge. Now it's .015. Took me 10 minutes on the 1x42 belt grinder. I would've never done that on a stone or plate. I also changed it to a full convex grind. It cuts like a kitchen knife now and the edge actually golds up better . And a belt grinder is a very useful tool to have around. Have a lawnmower blade that's 1/8" at the edge? 5 minutes later it's razor sharp with a mirror bevel if you want to. I know I did. ☺ ect
 
Vicv said:
A couple weeks ago I reground a knife. When I started it was .035 behind the edge. Now it's .015. Took me 10 minutes on the 1x42 belt grinder. I would've never done that on a stone or plate. I also changed it to a full convex grind. It cuts like a kitchen knife now and the edge actually golds up better . And a belt grinder is a very useful tool to have around. Have a lawnmower blade that's 1/8" at the edge? 5 minutes later it's razor sharp with a mirror bevel if you want to. I know I did. ☺ ect
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vic, I'm sure it goes fast, especially on teh HF 1x30 (not sure what it's running at sfpm wise) but I don't know if that's exactly accurate... unless you are going screaming fast not worried about temper damage at all. I just recently sharpened some lawn mower blades from a riding lawn mower that was about 1/8" across at the edge after I flattened it to remove chips. It took me about 10 min per blade at almost 5000 sfpm w/ a 36 grit water cooled belt and I still had to stop quite frequently to dip in water to avoid temper damage, and that was finishing on a 60 grit belt followed by a leather belt w/ compound.
 
I may have over exaggerated a bit on a mower blade in that kind of shape but it's still fast. Same here a 36 grit blaze belt. Then all the way through the progression to a6 trizact and then 1u and 5u on linen. Very sharp. That would've taken about s week on a Norton India stone and it wouldn't be close to as sharp or perfectly convex. And yes I kept it cool. I know mower blades and knives are not exactly just suggesting other uses for a grinder. Also wood and other material shaping, glass polishing, etc. And yes if you're not paying attention edge tempering
 
My sfm is 2500 or so. 1725 rpm motor and 6" pulley. I use belt dressing on my coarse belts and dip in water often
 
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