How to cut wear resistant steels?

Taz said:
I had to cut out 8 S90V blades a few months ago. Blade would be cutting good and then just stop. I wondered if there were hard spots/carbides in the steel or something? I used a Dremel cut off wheel to do connect the dots and a hacksaw for some of the cutting. I think I went thru 2 blades to cut the 8 blanks? Now I gotta grind 8 blades in S90V after hardening. 2 of the blades are 18" x 2.5" wide, just under 1/8" thick. Not looking forward to that!
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Ouch! I grind all S90V/S110V and other high wear resistant steels pre HT and take them to a minimum 400 grit finish. saves belts, paper, elbows, wrists, sanity.....
 
Yeah, not looking forward to those! These are under 1/8" thick steel wise, and with the length, I was concerned with warpage if I ground pre HT. Got a bunch of VSM ActiRox Destroyer belts waiting! The others are 4-5" blades, they are Shechita, Kosher Slaughter knives. I am going to do these with a belt finish and call them good! I did up one in CPM20CV before as well, similar big dimensions. Hardest part was getting a nice finish on it with the belts, but with a leather platen, it is a bit easier with structured abrasives or compact grain abrasives! I usually grind Post HT anyway, but I am sure I am in for a few long grinding sessions! They are like big straight razors, so I will use my tilt table to grind them to keep the bevels even down the blade.
 
I started using EDM stones for post HT finish work and they have been a godsend!
 
Taz said:
Yeah, not looking forward to those! These are under 1/8" thick steel wise, and with the length, I was concerned with warpage if I ground pre HT. Got a bunch of VSM ActiRox Destroyer belts waiting! The others are 4-5" blades, they are Shechita, Kosher Slaughter knives. I am going to do these with a belt finish and call them good! I did up one in CPM20CV before as well, similar big dimensions. Hardest part was getting a nice finish on it with the belts, but with a leather platen, it is a bit easier with structured abrasives or compact grain abrasives! I usually grind Post HT anyway, but I am sure I am in for a few long grinding sessions! They are like big straight razors, so I will use my tilt table to grind them to keep the bevels even down the blade.
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I'm in a similar situation, but thankfully my initial stock is only 1" wide. A couple of the knives that I cut out will be fillet knives. I'm going to grind the thickness down on those by quite a bit before HT, but I'm not looking forward to tapering the blades when the come back. The other blades are slicers for the kitchen and game processing/butchering. They vary in length from 5" to 12". I plan to make a couple of passes on the bevels on everything pre HT, just to knock the corners off and get my initial plunge lines started. Either way, I'm anticipating some frustration along the way. :)
 
I used a CBright sharpening stone set of 10 on Magnacut. I used the 400 to work on a 4" Drop Point and it was about 10 minutes to go from the decent 400 belt finish (with some stray deeper scratches from coarser belts still) to the stone finish on one side. I did another Magnacut blade 63 hrc with a "dirtier" 320 finish (lots more deep scratches) and it took a little longer, but still MUCH faster than sandpaper!
 
DevinT said:
Please tell us the brand, type and grit.

Hoss
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Easy day Hoss! I use Falcon "N" series. progression (depending on how high I finished the blade before HT) 320-400-600-900-1200 with Wyndex as lubricant. For a nice satin I usually back it off and do sandpaper straight pulls with 500 or 800 grit dry paper.

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Same here. Falcon N stones. They really changed things for me as it sped up the hand sanding quite a bit.
 
How do you guys use those stones? I use the end to clean up tight areas like plunges lines, but didn't have great luck with wide open areas. Do you use the end or the sides? I keep breaking mine.
 
I get them from Congress tool in a fairly large size, 1/2" x 1" x 6". Quite hard to break. I can really lean on them and scrub using the 1/2" or 1" sides. I also use the front edge.
 
Michael Black said:
How do you guys use those stones? I use the end to clean up tight areas like plunges lines, but didn't have great luck with wide open areas. Do you use the end or the sides? I keep breaking mine.
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I use the end corner/edge (top/bottom edge) of the stone. Make sure they are WET and use short strokes. You are erasing scratches vice creating a uniform finish. Trollskey has a decent video on youtube about it. Just search "Trollskey knives"

Keep in mind these stones are frangible and are supposed to break down. The slurry that is created actually does the cutting.
 
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Taz said:
I used a CBright sharpening stone set of 10 on Magnacut. I used the 400 to work on a 4" Drop Point and it was about 10 minutes to go from the decent 400 belt finish (with some stray deeper scratches from coarser belts still) to the stone finish on one side. I did another Magnacut blade 63 hrc with a "dirtier" 320 finish (lots more deep scratches) and it took a little longer, but still MUCH faster than sandpaper!
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Thanks for the tip. I still have a set of polishing stones left over from my days of working in stamping and roll forming. I'll probably give them a try first. If it seems to be working out well, the time savings would be well worth another $20 set of stones.
 
navman said:
I use the end corner/edge (top/bottom edge) of the stone. Make sure they are WET and use short strokes. You are erasing scratches vice creating a uniform finish. Trollskey has a decent video on youtube about it. Just search "Trollskey knives"

Keep in mind these stones are frangible and are supposed to break down. The slurry that is created actually does the cutting.
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Got it, that's really helpful, thanks! Makes sense that they would be wet and create a slurry just like normal whetstones. Not sure why that didn't occur to me.
 
Yeah, I got some 2 Christmas ago and tried to use them flat on the blade and they sucked. Then I saw the videos to use them like a chisel and bingo, huge difference!!
 
I started on the S90V Shechita. Post HT. 5" long blade, 2" wide, spent around 2 hours at the grinder with 36 grit belts to get the blade rough ground. Ceramics worked OK to around 220 grit. AO belts I had here didn't really do much. Should have done the grinding pre HT!! The 18" ones are going to take forever!! Debating buying more steel, grinding them and sending them off for HT and cutting down the bigger pieces I have into smaller pieces with an angle grinder and making EDC or hunters out of them. Or having them water jet cut into different profiles...lol. Gotta order some of the Falcon N EDM stones now!
 
Just curious - why didn't you grind the bevels down to about .010 (ten thou edge) before hardening?
 
I am wondering the same? I was concerned about warping. I grind hardened cpm 20cv and m390 before, but this is so much worse!
 
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