How To Sharpening mystery/bad steel

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Securis

Joined
Jan 9, 2013
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All this while, i've been trying to improve my skills at sharpening high end steel, that i neglect the basic entry level steels. So i've been trying my hand at sharpening a few.

BUT,

I had a customer walk in a few days ago with a damascus blade. I'd call it Mysterymascus cause apparently, even the maker hasn't a clue what steel it is.

When i went at it with the 220 alumina stones, it just took steel off fast. I had my concerns about the quality of the HT. Nevermind that i found a 1 inch delamination line right on the edge.

I made sure i apexed the edges every time, and i finished at 600 alumina. removed the burr and made sure the edge was clean. Checked for flat spot with a flashlight, clean.

When i went to newsprint, it just could not cut.

I re-did the whole process again, this time with diamonds. 140, then 400. While it did improve slightly, it was far from effective. Again, same procedures for apexing and cleaning the edge.

I understand if it was improper HT, the edge would not last, but can it still be sharp? I just need the customer to see that it is sharp, edge retention really isn't my concern. I've already informed the customer that the edge would never last, and he's still adamant, just putting this out there that I've got my work ethics straight.

I'm at a loss. The only other time i faced problems like this was with a Boker Persian fixed blade in 440A and a Muela in...mysterymascus.

I've done 420HC's on leathermans, sandvik on mora's, AUS8's on Ontario's, 8CR13Mov's on spyderco's. I've never had issues with these steels.
 
Light touch and microbevel on your finest diamond following the 400 grit.

A few passes on a hard strop might improve it as well.

A pass or five on a smooth steel following the 400 grit might work too. Super light pressure or you'll draw out the edge.
 
Sounds like over sharpening. Maybe your finishing step is removing too much. Try finishing on a strop.
 
Look up Pakistan Damascus :eek:

Best way to "pretend" it's sharp is to strop it.... 'cause it usually leaves a weak burr or wire edge otherwise. I hit them on a paper wheel finish wheel. Edge won't last, but it'll glide thru paper a time or two.
 
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In past years, I remember seeing some vendors' damascus knives being sold with the warning not to sharpen them. At least with those, they were marketed as novelty/display knives, and likely hadn't been heat-treated to actually hold a sharp, durable edge.
If the maker of this particular knife doesn't even know what the steel is, I'd be inclined to believe it might be one of those display pieces, or at least aimed at that market of buyers.

That said, it doesn't otherwise surprise me if the 'Mysterymascus' won't sharpen up very well. Some damascus blades are kind of unpredictable anyway, even from otherwise recognized and/or reputable makers. I've always had mixed feelings about damascus, as a big part of the mix is there just to create the pattern, and really doesn't contribute anything useful to fine grain or edge-holding anyway.

In the end, about the only thing I can do with 'cheap' steel blades, or mystery steel, is to take it thin enough that the geometry alone can at least contribute something to some limited cutting ability. The steel is still junk; but, if the geometry is at least supportive of it, it might be useful for very light & simple cutting chores until the edge either folds or crumbles away. I've seen both; one of which was an edge that I could literally see bend & fold with thumbnail pressure, and another blade upon which the fine edge would literally crumble into dust with any abrasion at all. Neither one would make even one clean cut through paper, before failing one way or another.


David
 
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Hi,
How many grams force were you using on the 200 stone ?
(stone on scale, take a stroke or two to get a reading)
How big was the burr?
How did you deburr ?
 
Thanks for the responses.

I removed the Burr on a strop, CrO green 6k by BRK. I have finer diamonds, but i do not think that will make an improvement.

I might have been a bit heavy handed on the 600 alumina. I was getting tired and frustrated at that point, and the customer was waiting, so it wasn't like i could take a coffee break (wish i did now though)

Yeah, we've heard plenty about Pakimascus. One guy at our shop even paid 500usd for a block of pakimascus, thinking it was hot legendary stuff. He know better now, thankfully.

I'm not sure what pressure weight i applied as i use an EP set. I was a losing patience at the time, so i wasn't as disciplined as i normally would be, which is at most times, weight of the arm and stone and let it glide.

As i was rebevelling the thing to grind away the delamination, it did generate a rather large burr with the first stone. Subsequent progression, i wouldn't have kept the burr as small as possible, but still ensuring the whole edge is apexed.

From what i gather, i should try using light pressure? I also have a paperwheel, but am not really used to using it. I just got it and would rather not use it on a customers piece.
 
Hi,
Are you sure stropping removed the burr?

I've not found that to work reliably, esp on softer hrc steels.

My suggestion is try double angle deburring
  • - increased/high angle, like double, 40-45 degrees per side, or at least +5 degrees with jigs
  • - edge leading / edge into strokes
  • - ultra light force, think like touching the pointy tip of a pencil or nail or pushpin with your fingertip, if you press too hard you're bleeding :) so just do your best to go light ... under 4oz or 100 grams on a scale, as close to ~1oz or ~20 grams as you can get with control
  • - four alternating strokes
  • - short strokes for final strokes, like 1inch of travel on the stone
  • - cross the scratch pattern, cross hatch the grits
Using this approach its possible to get beard hair whittling / arm hair shaving, or better with unhardened mild steel.

Force when shaping the edge/raising a burr,
or at least the closer you get to the end/raising the burr ,
think like brushing your teeth,
which would work out to about 1lb or 0.5lb on a scale
-- yes thats numbers if you're working on about edge bevels around ~2mm wide ,
just enough force for the stone to start cutting the steel
 
Thanks, i'll try that. One of the 2 blades he brought was naturally high angled, came in about 45-50 inclusive.

I feel for the burr with my fingers, and i know that isn't fool proof. If it was a hardened edge, i'd run the edge over some wood and see if a flatspot occurs, then i know burr is still there.

bucketstove said:
Hi,
Are you sure stropping removed the burr?

I've not found that to work reliably, esp on softer hrc steels.

My suggestion is try double angle deburring
  • - increased/high angle, like double, 40-45 degrees per side, or at least +5 degrees with jigs
  • - edge leading / edge into strokes
  • - ultra light force, think like touching the pointy tip of a pencil or nail or pushpin with your fingertip, if you press too hard you're bleeding :) so just do your best to go light ... under 4oz or 100 grams on a scale, as close to ~1oz or ~20 grams as you can get with control
  • - four alternating strokes
  • - short strokes for final strokes, like 1inch of travel on the stone
  • - cross the scratch pattern, cross hatch the grits
Using this approach its possible to get beard hair whittling / arm hair shaving, or better with unhardened mild steel.

Force when shaping the edge/raising a burr,
or at least the closer you get to the end/raising the burr ,
think like brushing your teeth,
which would work out to about 1lb or 0.5lb on a scale
-- yes thats numbers if you're working on about edge bevels around ~2mm wide ,
just enough force for the stone to start cutting the steel
Click to expand...
 
Securis said:
Thanks, i'll try that. One of the 2 blades he brought was naturally high angled, came in about 45-50 inclusive.

I feel for the burr with my fingers, and i know that isn't fool proof. If it was a hardened edge, i'd run the edge over some wood and see if a flatspot occurs, then i know burr is still there.
Click to expand...

Normally on the really cheap stuff I stop at about 320 grit and strop or microbevel. It isn't worth trying to diagnose, the blade might be really soft, it might have massive grain structure, it might not be tempered properly, the steel itself might be very low carbon etc etc.

Grind a new apex, deburr, clean it up on a hard strop or very gently microbevel on a fine stone - leave plenty of the edge irregularities and slice easy on paper for a client demo.
 
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