Rubber Backed Bristled floor Mats are TOUGH

H

HKGuns

Joined
Jan 28, 2019
Messages
141
I recently acquired my first ZT knife, the 0609 RJ Martin folder in 20CV.

I was cutting some (thick, rubber backed, natural bristle fiber) door mats for my mothers house and it stopped cutting after only 1.5 mats.

I expected 20CV to last far longer. It is so dull I can push my finger on it pretty hard without feeling an edge or getting cut. Under a loup it apeared there were very small chips out of the blade in the area where it was dulled, if that helps anyone who knows steel better than I do.

Should I question the heat treat on this blade?
Am I expecting too much from this steel?
Is ZT known for particularly good or marginal heat treats?

I emailed ZT customer service on Monday and nothing from them so far.......

Any experienced help or suggestions appreciated. Completely open to being told my expectations exceed reality.
 
HKGuns said:
I recently acquired my first ZT knife, the 0609 RJ Martin folder in 20CV.

I was cutting some (thick, rubber backed, natural bristle fiber) door mats for my mothers house and it stopped cutting after only 1.5 mats.

I expected 20CV to last far longer. It is so dull I can push my finger on it pretty hard without feeling an edge or getting cut. Under a loup it apeared there were very small chips out of the blade in the area where it was dulled, if that helps anyone who knows steel better than I do.

Should I question the heat treat on this blade?
Am I expecting too much from this steel?
Is ZT known for particularly good or marginal heat treats?

I emailed ZT customer service on Monday and nothing from them so far.......

Any experienced help or suggestions appreciated. Completely open to being told my expectations exceed reality.
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Man, you have to rule things out and you have to start with the sharpening.

1.Was it sharpened? OR just the factory edge?

2. How was it sharpened? Pull through sharpener? Freehand? Fixed angle system?

3. What abrasives where used to sharpen it? Ceramic, Diamond etc

4. What was the Geometry? 15dps Convex? 20dps flat from system? Random?

5. Is it sharp? Apex formation, burr removal

When you rule that out next is how was it being used? Was the edge making contact with metal, stone, the ground?

There is a list you have to go through to rule out HT. Otherwise you'll be bamboozled when something may have an awesome steel and HT but a poor sharpening job or is being sharpened incorrectly for the job it's being used for.
 
No need to question ZT’s heat treat, your expectations exceed reality. Cutting different media’s like what you’ve described is rough on most any steel. That’s where a disposable razor knife comes in handy. Unless you like sharpening your knives
 
DeadboxHero said:
Man, you have to rule things out and you have to start with the sharpening.

1.Was it sharpened? OR just the factory edge?
- Sharpened

2. How was it sharpened? Pull through sharpener? Freehand? Fixed angle system?
- Edge-Pro with Diamond stones up to 6000 grit tapes stropped on my 1 micron laced strop (I'm no pro, but can get a good consistent edge)

3. What abrasives where used to sharpen it? Ceramic, Diamond etc
- Diamond

4. What was the Geometry? 15dps Convex? 20dps flat from system? Random?
- Marked the edge with sharpie and followed the 21 degree factory angle

5. Is it sharp? Apex formation, burr removal
- It was razor sharp and went through paper like butter

When you rule that out next is how was it being used? Was the edge making contact with metal, stone, the ground?
- No metal contact held against a board to keep a fairly consistent line.

There is a list you have to go through to rule out HT. Otherwise you'll be bamboozled when something may have an awesome steel and HT but a poor sharpening job or is being sharpened incorrectly for the job it's being used for.
Click to expand...
 
Ajack60 said:
No need to question ZT’s heat treat, your expectations exceed reality. Cutting different media’s like what you’ve described is rough on most any steel. That’s where a disposable razor knife comes in handy. Unless you like sharpening your knives
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Yeah, a razor knife would have been the better tool for this job. I used what I had at hand, if I were to do it over again I'd have used the razor knife.

I do like sharpening knives, but it took a while to get the edge back using my edge-pro. Lots of edge damage, which I found surprising. (Especially after constantly watching the Aussie roll through thousands of feet of "Twisted Sissar" rope.

Had to start all over again with the 250 stone after first trying to touch up with 600.
 
This isn’t the first time I’ve read that 20CV/M390/204P has chipped, when you mentioned the natural bristle I figured the edge wouldn’t last very long. Yesterday, we killed 3 deer, field dressed them and on the third deer, my Spyderco military in M4 was struggling to cut through the hair. Spyderco does a good job on their heat treat. Didn’t have any edge chipping, but it didn’t take long to dull the knife to a somewhat working edge.
 
it's always possible the blade edge was affected by factory sharpening ... if that's the case a few sharpenings will most likely get better results ... but the rubber backing like that can have very abrasive materials in it too that will really affect an edge quickly ...

I would give it a good sharpening ... and see if it improves.
 
Ajack60 said:
This isn’t the first time I’ve read that 20CV/M390/204P has chipped, when you mentioned the natural bristle I figured the edge wouldn’t last very long. Yesterday, we killed 3 deer, field dressed them and on the third deer, my Spyderco military in M4 was struggling to cut through the hair. Spyderco does a good job on their heat treat. Didn’t have any edge chipping, but it didn’t take long to dull the knife to a somewhat working edge.
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Cutting through deer/moose/bear hide will take the edge off just about anything in my experience -- there's a lot of embedded grit in the hair.
 
I dulled the tip of my 0562cf cutting a sandwich on a plate. One time, just lightly hitting the plate. It didn't make me question the heat treat of the blade because it was steel on ceramic. If you cut tough, dirty material like you did it's going to be rough on the blade. That's when a razor comes out. Cheap, disposable blades.

Other than the plate incident I haven't had any problems with my ZT 20cv blades. Or their s35vn.
 
I only question heat treatment when I see the steel chipping or the blade breaks . Getting dull from cutting recycled rubber for outdoor mats I think is normal .
 
HKGuns said:
Looks like all the YouTube knife guys should be cutting rubber-fiber mats instead of cardboard and rope.
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You used an EDC knife for a specialty job.

They test with cardboard/rope because it's a more common material that most people will use an EDC knife to cut.

I mean, I wouldn't use my EDC knives to cut shingles or carpet. I'd use a utility/razor knife.
 
AKnife said:
I mean, I wouldn't use my EDC knives to cut shingles or carpet. I'd use a utility/razor knife.
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I cut very little cardboard or rope. Does every knife buyer work in a warehouse or on a boat? As stated above, processing an animal would likely be my hardest use if I had actually bagged a deer over the weekend.

Like me, you would use what you had at hand if you were in the middle of no-where, like I was, without a utility knife and something needed to get done for the safety of someone in your family.
 
HKGuns said:
I cut very little cardboard or rope. Does every knife buyer work in a warehouse or on a boat? As stated above, processing an animal would likely be my hardest use if I had actually bagged a deer over the weekend.

Like me, you would use what you had at hand if you were in the middle of no-where, like I was, without a utility knife and something needed to get done for the safety of someone in your family.
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Absolutely, I’ve trimmed shingles because I didn’t want to climb down I’d get a razor knife, but I also knew it would destroy the edge regardless of the steel. Sheetrock will also dull a blade in a hurry, sometimes I don’t remember to bring one of the several razor knives I keep in the work truck
 
Ajack60 said:
Absolutely, I’ve trimmed shingles because I didn’t want to climb down I’d get a razor knife, but I also knew it would destroy the edge regardless of the steel. Sheetrock will also dull a blade in a hurry, sometimes I don’t remember to bring one of the several razor knives I keep in the work truck
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I pried open a paint can with my Umnumzaan the other day, and actually I stupidly cut myself while doing so because I was trying to pry with the swedge and the blade slipped down:eek:

Point being, sometimes our knives will work in a pinch but they aren’t always the right tool for the job.
 
I fought it for years but sometimes a utility knife is the right tool for the job.

So I try to have the finest utility knife I can find. Just to satisfy the knife nerd in me. My current favorite is a Milwaukee, but I had a Klein I really liked too.
 
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