Spyderco Forums

bolster wrote:

get outta here! Seriously? Can we see photos?

+1!!!!!!!!!

Sorry, I did not see the request the other day.

This thread has gotten me re-interested in low angles. Several people played with them several months ago including videos of cutting tires and stuff. The only steel I've had any problems with at low angles is ZDP-189. I think I'll take one of my S30V knives to a really low angle. I have to decide which one.

I don't need low angles. The biggest enjoyment I've gotten from really low angles is watching someone's face that uses my knife that is not used to a really sharp one. I had an Endura 3 that I took down real low but I don't remember how low. 24 deg. inclusive maybe. I have never gone as low as 20 inclusive. I might try that.

I have a mission. :) I SHOULD GET a job. :D

Jack

jackknifeh wrote:This thread has gotten me re-interested in low angles. Several people played with them several months ago including videos of cutting tires and stuff. The only steel I've had any problems with at low angles is ZDP-189. I think I'll take one of my S30V knives to a really low angle. I have to decide which one.

I don't need low angles. The biggest enjoyment I've gotten from really low angles is watching someone's face that uses my knife that is not used to a really sharp one. I had an Endura 3 that I took down real low but I don't remember how low. 24 deg. inclusive maybe. I have never gone as low as 20 inclusive. I might try that.

I have a mission. :) I SHOULD GET a job. :D

Jack

Interesting.

ZDP-189 is one of the few steels I like to take to low angles. It has a huge dependence on what you intend to use the knife to do though. I would be interested to hear what you learn from S30V and lower angles...my experiences have not been positive

I have made several videos on the topic...perhaps some are worth sharing again?

Video of low angle ZDP-189, what I use it for, and how it holds up to cutting tires. (video was made when the knife was profiled a little more obtuse than it is now).
http://www.youtube.com/user/ewerstruly? ... 5_b9aF2dLM

The first video in an old series I did on edge geometry and cut performance related to edge geometry.
http://www.youtube.com/user/ewerstruly? ... 4rDIFFyXVk

This one is a rambling discussion of various blade steels and some ideas that should be considered when comparing them (largely the edge geometry and intended use of the knife)
http://youtu.be/FeNNNyZdCn0

I would embed these videos, but I am having trouble doing it successfully. All of the above links take you to youtube videos I made.

unit wrote:Interesting.

ZDP-189 is one of the few steels I like to take to low angles. It has a huge dependence on what you intend to use the knife to do though. I would be interested to hear what you learn from S30V and lower angles...my experiences have not been positive

I have made several videos on the topic...perhaps some are worth sharing again?

Video of low angle ZDP-189, what I use it for, and how it holds up to cutting tires. (video was made when the knife was profiled a little more obtuse than it is now).
http://www.youtube.com/user/ewerstruly? ... 5_b9aF2dLM

The first video in an old series I did on edge geometry and cut performance related to edge geometry.
http://www.youtube.com/user/ewerstruly? ... 4rDIFFyXVk

This one is a rambling discussion of various blade steels and some ideas that should be considered when comparing them (largely the edge geometry and intended use of the knife)
http://youtu.be/FeNNNyZdCn0

I would embed these videos, but I am having trouble doing it successfully. All of the above links take you to youtube videos I made.

The problem with ZDP at low angles was only right on the edge. Micro chipping right on the edge. Small chips that were barely visible without looking closely and cutting performance wasn't impacted unless cutting something like very thin paper. Then you could feel the chips. Some chips may be big enough to start tearing Christmas wrapping paper instead of continuing to cut. By putting a 20 deg. per side edge bevel on ZDP I solved this issue and kept very low back bevel. My Michael Walker now has a 12 deg. per side back bevel and 20 per side edge bevel. Needless to say, it cuts like a dream.

In the past few minutes I've been thinking about maybe using my GB and going to 12 per side. If you had poor success with S30V that's good enough for me to assume I'd have similar results. M4 would probably hold up better and the GB at that edge angle would be a cutting/slicing god (little g). It already cuts kind of ok for a junk knife. :D

Jack

Jack, I have a pile of new videos of M4 in HARD action if you are interested. M4 is great for various tasks and I find it to be a great "all arounder".

However, there are many options for M4 out there, and even among the Gayle Bradley examples, I believe hardness can not be assumed to be constant (some samples seem harder than others). I have used (and own) some custom blades in M4 and there are a few philosophies regarding ideal hardness for this steel relative to intended use. What I am getting at here is...the failure you will experience (all edges fail in use at some point...at least the ones I have tried ) will be dictated largely by the hardness of the M4 (rolling vs. chipping). I have found that M4 seems to do most things (I do) really well at 15 DPS...and should be ground very thin behind the edge.

I hope you play around with angles and share your results!

unit wrote:Jack, I have a pile of new videos of M4 in HARD action if you are interested. M4 is great for various tasks and I find it to be a great "all arounder".

However, there are many options for M4 out there, and even among the Gayle Bradley examples, I believe hardness can not be assumed to be constant (some samples seem harder than others). I have used (and own) some custom blades in M4 and there are a few philosophies regarding ideal hardness for this steel relative to intended use. What I am getting at here is...the failure you will experience (all edges fail in use at some point...at least the ones I have tried ) will be dictated largely by the hardness of the M4 (rolling vs. chipping). I have found that M4 seems to do most things (I do) really well at 15 DPS...and should be ground very thin behind the edge.

I hope you play around with angles and share your results!

I'd love to see the videos. I won't be able to sharpen anything right now. My grandson is here and he wants to help. :eek: See avatar. He's not 2 yet. He needs to be a few days older before I let him play with knives. :D

My GB has a single 15 deg per side edge now. I'll start with a 12 deg back bevel. Might go down to 10 later.

Jack

jackknifeh wrote:I'd love to see the videos. I won't be able to sharpen anything right now. My grandson is here and he wants to help. :eek: See avatar. He's not 2 yet. He needs to be a few days older before I let him play with knives. :D

My GB has a single 15 deg per side edge now. I'll start with a 12 deg back bevel. Might go down to 10 later.

Jack

We are going off topic I fear...

This is M4 (not Spyderco unfortunately), and this video documents a VERY small amount of use and how well a fairly fine (30 degree inclusive) edge is retained immediately afterward (it also shaves cleanly in a single pass). By very small amount of use, I mean that this is only a single run that was recorded (I probably had done 5 more un-recorded runs immediately prior to this demonstration).
http://www.youtube.com/watch?v=CR0jbSQghPk

(I have quite a few other videos with subjects made from M4 on my youtube page if you are interested)

Hey, I was hoping to get an opinion on this belt sander to see if it would be any good for sharpening knives. Probably for convex edges for fixed blades, tools and folders if it could. I do have a sharpmaker which I enjoy because it's so good and easy but wanted to supplement my sharpening equipment. Thanks for comments.
http://www.amazon.com/Mini-Belt-Sander- ... M0T1O41Y18

No, and the reason is the direct drive power wheel with high RPM. You'll burn your blade. If you want to use a belt grinder on a blade, calculate SFPM (not RPM) and get it into the 1000 SFPM range. Metal should come off like dust, not sparks (or rarely, a spark).

For my machine, which will do 1400 SFPM on low, the RPMs are down around 860. I don't know what size drive wheel that has, but if that 3400 RPM motor were on my machine (6" drive wheel) that RPM would be giving me 5400 SFPM, way too fast for sharpening.

FWIW, the only thing I sharpen on my belt grinder are rough tools like hatchets and axes (at the lowest speed), or to re-profile a chisel, etc. For a fine cutting tool I want to put the edge on by hand, so there's no heat on the edge.

Think of how fine the edge is. Now think of how quickly something that fine would heat.

Thanks for the photos, Unit! Interesting edge, looks almost like an appleseed edge to me.

I guess you buffed and polished that blade, yes? Very nice!!

I sharpened my GB (M4) at 13 degrees per side with a single bevel. The only thing I've done so far is a significant amount of whittling on a small pecan tree branch. After about 15 minutes of whittling then slicing a piece of printer paper I couldn't tell ANY difference in how easy the blade went through the paper. By coincidence my wife asked me to saw a paint stirrer (5 gal. stirrer) for her. I had the GB on me and put enough slices in the wood to break it off at the right length. Then I whittled what was left on the back side of the stick. That left the end of the wood as smooth as if I had used 1500 grit sandpaper on it. It felt smooth as glass. Wife was impressed as was I. That little job took less than 1 minute. Normally I would have gone to the work bench, used a jig-saw (making sawdust), then a little sanding. 10 to 15 minutes probably. I know this was not much testing but for what it was the M4 did a great job.

Normally I would have expected an edge at this angle to loose at least the razor edge after the amount of cutting wood that I did. The M4 still had a hair-popping edge. I'm very happy with that. After all that is the reason I decided to start buying better quality knives a few years ago. The $10-$20 knives I've bought all my life would have been extremely dull.

If interested I used Congress Tools, moldmaster 320, 400 and 600 grit stones only. Also, a few strokes on a strop (1 micron dia-paste). Reprofiling from 15 per side to 13 per side took about 40 minutes I think.

Jack

Bolster wrote:No, and the reason is the direct drive power wheel with high RPM. You'll burn your blade. If you want to use a belt grinder on a blade, calculate SFPM (not RPM) and get it into the 1000 SFPM range. Metal should come off like dust, not sparks (or rarely, a spark).

For my machine, which will do 1400 SFPM on low, the RPMs are down around 860. I don't know what size drive wheel that has, but if that 3400 RPM motor were on my machine (6" drive wheel) that RPM would be giving me 5400 SFPM, way too fast for sharpening.

FWIW, the only thing I sharpen on my belt grinder are rough tools like hatchets and axes (at the lowest speed), or to re-profile a chisel, etc. For a fine cutting tool I want to put the edge on by hand, so there's no heat on the edge.

Think of how fine the edge is. Now think of how quickly something that fine would heat.

Bolster, thanks for that. I'll stick to my sharpmaker for now, but now know what to look for on a belt grinder. :) I'm glad I asked first, this forum/ (forumites) is a truly good place for knife and steel related information.

Unit, That is one nice looking blade, bet it's better than a scalpel sharp! :eek: