Spyderco Forums

I've been thinking about grinding mine until the sides are flat. Anyone try this yet?

crazywednesday wrote: ↑

Fri Nov 15, 2019 9:06 pm

I've been thinking about grinding mine until the sides are flat. Anyone try this yet?

I've thought about doing it but never have yet.

It has been done. Tom Krein used to do them for reasonable prices. You need to alternate sides and cool frequently.

yablanowitz wrote: ↑

Fri Nov 15, 2019 9:12 pm

It has been done. Tom Krein used to do them for reasonable prices. You need to alternate sides and cool frequently.

Can a sabre / HOLLOW (!) grind technically be regrinded into a really true ffg (as in full FLAT)? And if so, wouldn´t it be a very/too thin grind?

Wartstein wrote: ↑

Sat Nov 16, 2019 1:49 am

Can a sabre / HOLLOW (!) grind technically be regrinded into a really true ffg (as in full FLAT)? And if so, wouldn´t it be a very/too thin grind?

Saber defiintely can. I suspect hollow depends on both the height and depth of the hollow grind. I can tell you the Kiwi pictured below that was reground for me by Tom Krein looks flat to me and is incredibly thin behind the edge. There are things I wouldn't do with it, but I've used it a fair bit and have yet to chip or roll the edge, or break the blade.

The Deacon wrote: ↑

Sat Nov 16, 2019 4:11 am

Wartstein wrote: ↑

Sat Nov 16, 2019 1:49 am

Can a sabre / HOLLOW (!) grind technically be regrinded into a really true ffg (as in full FLAT)? And if so, wouldn´t it be a very/too thin grind?

Saber defiintely can. I suspect hollow depends on both the height and depth of the hollow grind. I can tell you the Kiwi pictured below that was reground for me by Tom Krein looks flat to me and is incredibly thin behind the edge. There are things I wouldn't do with it, but I've used it a fair bit and have yet to chip or roll

Thanks and that knife does look good!!

My question is really more about if a HOLLOW grind can be turned tnto a true ffg realisticallly without getting TOO thin (and I am all for thin blades... viewtopic.php?f=2&t=85342)

Wartstein wrote: ↑

Sat Nov 16, 2019 4:24 am

Thanks and that knife does look good!!

My question is really more about if a HOLLOW grind can be turned tnto a true ffg realisticallly without getting TOO thin (and I am all for thin blades... viewtopic.php?f=2&t=85342)

Thanks.

Like I said, turning a hollow grind into a flat grind without it being too thin behind the edge is going to depend entirely on how high and how deep the hollow grind is. I think it's safe to say that converting hollow to FFG can only make it thinner behind the edge that it already is, so if the grind is high, or the blade is already very thin behind the edge, you're going to wind up with a FFG razor, or worse yet, trash the blade. Tom was reluctant to do the Kiwi for that reason but I told him to go ahead and try. Glad I did, but I decided after that not to risk having the same thing done to any of my fancier Kiwis. On the other hand, the behind the edge thickness of the Schempp Persian pictured below, while thin, is still fairly robust and it too started out as a hollow grind.

The Endura I had Tom do for me is still 0.015" behind the edge bevel. I had him stop there because I use the knife for general utility and didn't trust ZDP-189 any thinner. H-1 is very tough and strong so it should be able to go down to 0.010" easily. I've seen pictures here of full flat regrinds of H-1 blades, but it has been a few years. I seem to recall Brad Southard doing a few, but I could be mistaken.

yablanowitz wrote: ↑

Sat Nov 16, 2019 8:16 am

The Endura I had Tom do for me is still 0.015" behind the edge bevel. I had him stop there because I use the knife for general utility and didn't trust ZDP-189 any thinner. H-1 is very tough and strong so it should be able to go down to 0.010" easily. I've seen pictures here of full flat regrinds of H-1 blades, but it has been a few years. I seem to recall Brad Southard doing a few, but I could be mistaken.

Do you happen to know if the H1 blades were really and totally full FLAT and not still a bit "hollow" / concave?
For me it is just hard to imagine that one could reshape the "inward curve" of the hollow grind H1 Salt blades into a totally flat grind.

There was no visible dip left in the blade, the grind lines ran straight from edge bevel to spine. I didn't have the knife in hand to examine with a certified straightedge and a microscope, so I can't swear that it was absolutely truly dead flat. The Salt series hollow grinds are low saber grinds and not deeply hollow. The blades do not get thinner behind the edge bevel, so why would it be hard to believe they can be made full flat?

yablanowitz wrote: ↑

Sat Nov 16, 2019 8:39 am

There was no visible dip left in the blade, the grind lines ran straight from edge bevel to spine. I didn't have the knife in hand to examine with a certified straightedge and a microscope, so I can't swear that it was absolutely truly dead flat. The Salt series hollow grinds are low saber grinds and not deeply hollow. The blades do not get thinner behind the edge bevel, so why would it be hard to believe they can be made full flat?

To be honest: Just a guess and what my uneducated gut instincts figured...
Right now i am holding my Pac Salt in hands and can see that you´re most likely right!

What I don´t fully understand: What is the matter then with that "H1 CANNOT be done in ffg, but has to be hollow", due to that "work hardening thing"?
IF you can turn a H1 hollow grind into an ffg, and you still wanted to have a not really thin blade (let´s say Endura thickness): Why not just as a first step do a thicker hollow grind (if that is mandatory for that "work hardening) than the current Pac Salt has, and as a second step grind it into an Endura thickness ffg? Would that "ruin" the work hardening? Don´t think so.

Wartstein wrote: ↑

Sat Nov 16, 2019 8:49 am

yablanowitz wrote: ↑

Sat Nov 16, 2019 8:39 am

There was no visible dip left in the blade, the grind lines ran straight from edge bevel to spine. I didn't have the knife in hand to examine with a certified straightedge and a microscope, so I can't swear that it was absolutely truly dead flat. The Salt series hollow grinds are low saber grinds and not deeply hollow. The blades do not get thinner behind the edge bevel, so why would it be hard to believe they can be made full flat?

To be honest: Just a guess and what my uneducated gut instincts figured...
Right now i am holding my Pac Salt in hands and can see that you´re most likely right!

What I don´t fully understand: What is the matter then with that "H1 CANNOT be done in ffg, but has to be hollow", due to that "work hardening thing"?
IF you can turn a H1 hollow grind into an ffg, and you still wanted to have a not really thin blade (let´s say Endura thickness): Why not just as a first step do a thicker hollow grind (if that is mandatory for that "work hardening) than the current Pac Salt has, and as a second step grind it into an Endura thickness ffg? Would that "ruin" the work hardening? Don´t think so.

From what I've read, the reason Spyderco doesn't FFG H-1 is because of warping issues (not work hardening). It's not impossible to full flat grind H-1, it's just that it would take too much time and care to make it feasible in a mass-production setting.

The Meat man wrote: ↑

Sat Nov 16, 2019 9:06 am

Wartstein wrote: ↑

Sat Nov 16, 2019 8:49 am

yablanowitz wrote: ↑

Sat Nov 16, 2019 8:39 am

From what I've read, the reason Spyderco doesn't FFG H-1 is because of warping issues (not work hardening). It's not impossible to full flat grind H-1, it's just that it would take too much time and care to make it feasible in a mass-production setting.

Thanks, very interesting! Never heard of that before.

Still, I think I´ll never fully understand the "work hardening thing"... :o
Prior to Spyderco and H1 "work hardening" on blades for me was,what they did in ancient times with bronce swords: Hammering the edge in order to make the material more dense and by that harder. But that is NOT what happens with H1 and work hardening..

Wartstein wrote: ↑

Sat Nov 16, 2019 8:49 am

yablanowitz wrote: ↑

Sat Nov 16, 2019 8:39 am

There was no visible dip left in the blade, the grind lines ran straight from edge bevel to spine. I didn't have the knife in hand to examine with a certified straightedge and a microscope, so I can't swear that it was absolutely truly dead flat. The Salt series hollow grinds are low saber grinds and not deeply hollow. The blades do not get thinner behind the edge bevel, so why would it be hard to believe they can be made full flat?

To be honest: Just a guess and what my uneducated gut instincts figured...
Right now i am holding my Pac Salt in hands and can see that you´re most likely right!

What I don´t fully understand: What is the matter then with that "H1 CANNOT be done in ffg, but has to be hollow", due to that "work hardening thing"?
IF you can turn a H1 hollow grind into an ffg, and you still wanted to have a not really thin blade (let´s say Endura thickness): Why not just as a first step do a thicker hollow grind (if that is mandatory for that "work hardening) than the current Pac Salt has, and as a second step grind it into an Endura thickness ffg? Would that "ruin" the work hardening? Don´t think so.

In a production line setting, hollow grinding is done on both sides at once, so work hardening is even. Flat grinding is done on one side at a time, so when the blade is turned over to grind the second side it has already had a lot of work hardening occur. Grinding the second side becomes much more difficult and is likely to result in blades overheating and warping. This can be avoided by alternating sides, grinding a little off each side at a time to keep the hardening even.

In other words, yes they could do it, but each blade would take about ten times as long to grind as it does now. How many $500 Pacific Salts are you going to step up and commit to buying?

I did this with benchstones.

Took forever. Cut really nice, but I ended up selling it as I never reached for it over my delicas

It looks like this guy managed to keep pretty much all of the spine thickness. I would consider maybe convexing the edge if the blade gets too thin. I remember pics years ago of someone warping the crap out of a Rock Salt. I think they were chopping a coconut which is a whole other world than you'll probably put a folder in but it's something to consider. I know I talked to at least one guy who had a Pacific reground and he said he saw no noticeable difference in edge retention, so who knows if work hardening occurred.

https://youtu.be/lNk17ebocEc

Evil D wrote: ↑

Sat Nov 16, 2019 6:18 pm

It looks like this guy managed to keep pretty much all of the spine thickness. I would consider maybe convexing the edge if the blade gets too thin. I remember pics years ago of someone warping the crap out of a Rock Salt. I think they were chopping a coconut which is a whole other world than you'll probably put a folder in but it's something to consider. I know I talked to at least one guy who had a Pacific reground and he said he saw no noticeable difference in edge retention, so who knows if work hardening occurred.

Thanks for sharing!
That looks really good... and the guy in the vid says it only took two hours to complete, using stone, file and sandpaper... (and he actually DID convex it with just a very small bevel left)

A few years ago BIg Chris did a regrind for me on a Pac Salt. It was ground to a high saber flat grind. Yes it was completely flat. The stock hollow grind is not especially deep.
It cut very well of course but H1 plain edge holding is mediocre at best and was not improved from the regrind. I was hoping there would be an uplift from "work hardening."

I've owned a couple of reground Pacific Salts. Both were nicely done and made it better, but it was basically twice the price of a VG10 Endura by that point (had I not got deals on both Pacific Salts) and not nearly it's equal.

The H1 SE Pac Salt if a great tool. If I want PE I'll go for a VG10 Endura everytime.