Beiträge von kwakster

I own several vintage Gerbers in M2 steel, both outdoor & kitchen models, and this Durendal slicer model from the '60's does duty in our kitchen.
Opening all kinds of paper & plastic food packages, slicing bags with espresso beans, cutting up larger fruits like melons & pineapples, slicing bread loafs and hamburger buns without crumbling, cutting sausages, etc.
Not every day, but at least several times a week.

I bought this Gerber about 2 years ago on E-Bay completely blunt, so i reprofiled & sharpened it with a SiC grit Paper Wheel, then refined the edge with 15 micron diamond compound on a second Paper Wheel, and then again with 6 micron diamond compound on a third Paper Wheel.
The tiny burr was removed with a fourth Paper Wheel coated with 0,25 micron diamond compound.
The idea was to get something of a semi-polish that would protect the exposed M2 edge better against corrosion issues during kitchen use, while still having some degree of bite.

The knife was then used for about 2 years in our kitchen, and when not in use stored on a magnet strip on our kitchen wall.
After those 2 years the edge only had a few very minor dings/flat spots in it (in the tiny belly area), but it could still shave the hair on the back of my hand on skin level quite well with about 90-95 % of the edge.
When cutting tomatoes however the edge tended to slide a bit over the skin before it started to cut.
The main reason for this kind of edgeholding is of course the fact that most of the edge on a slicer like this never touches a cutting board, only the belly area does, but the M2 steel performed quite admirably in my book.

A few weeks ago i resharpened the edge, this time only with 15 micron diamond compound, then deburred with 0,25 micron diamond compound, as i want to try the knife with some more bite.
Will have to find out if there will be corrosion issues or not.
So far i've only used it on food packaging (both paper & plastic, no fruit or other things yet), but here are a few pics how the knife & edge look now.
The edge feels sticky and is still treetopping sharp.

Specs:

Blade steel: hard chromed M2 steel
Hardness: 60-62 HRC
Handle material: cast on aluminum, chromed.
Overall length: 29,5 cm
Blade length: 16,5 cm
Blade thickness: 1,36 mm in front of the handle tapering to 0,84 mm close to the point
Thickness behind the edge: 0,5 mm
Edge angle: +/- 30 degrees inclusive, slightly convex

Das ist auch mein Problem; ein USB-Microscop zu finden der compatible mit mein Macbook Pro ist.
Was ich jetzt habe wirkt auch nür mit ein PC, und der ist schon ganz alt.

The WM-200 came with my Tormek T7 machine and it's simple and easy to use, just like this one that Spyderco made some time ago: https://www.spyderco.com/forumII/viewtopic.php?t=43017
Or this one: https://www.amazon.com/home-improvement/dp/B000CER0MK

However, i do keep my eyes open for a more precise method, which would be a laser goniometer.
Here is an example that is sold by CATRA: http://www.catra.org/pages/products/kniveslevel1/lgpm.htm
Much cheaper versions seem to exist, but i haven't found an acceptable one yet.

This just came in, and it should be more than enough to coat both a Paper Wheel as well as a Rubber Wheel using the 3-step process.
According to my digital scale it weighs +/- 40 grams.

Measuring the edge angle with my USB-microscope isn't possible of course, so for that i use a Tormek WM200 Anglemaster:

In dieser YouTube clip wird erklärt welche Vorteile CBN hat über Aluminium-Oxid (im kurzem: CBN hat eine viel höhere Härte zusammen mit eine viel bessere Wärmeleitfähigkeit)
Es wird English gesprochen, leider könnte ich kein Deutsche Version finden.

Spyderco Military S90V/Carbon Fiber.
The factory edge on this knife still has a burr attached almost along it's entire length, and also some brownish discoloration in some area's.

Why would it be too slow in your opinion ?

Abboniert auf diesem thread.
I have & use my Tormek T7 with an SB-250 stone several times per week, and i'm very happy with what it can do.
Currently looking around for a CBN wheel for it, especially for knives made from full hard high speed steels.

Zitat von Oachkatzlschwoaf

There is only one proper redneck techique for sharpening your tools...
https://www.youtube.com/watch?v=wdoAVHUFNwM
https://www.youtube.com/watch?v=wdoAVHUFNwM

Okay, you win.
No doubt about it,

A follow-up took some time, but here it is.
After some cutting tests with this M2 knife i arrived at a measured edge angle between 22.5 and 25 degrees inclusive, as this seems to be right at the balance point between as thin as possible, yet thick enough.
This edge survives multiple full force cuts into my wooden testblock (a piece of laminated desktop) without chipping or noticeable loss of sharpness.
Afterwards the knife could also still pushcut through this paperback.

Found this gem on YouTube:

Below you see 3 different viewing angles of the edge i recently put on a brand new Sebenza 25 (which had a subpar factory edge)

The owner of the knife took the pictures with a very expensive Leica camera to capture the different looks this edge type can have when seen from different angles.

For obvious reasons i named this a bling & bite finish, and it performs very well on especially high (vanadium) carbide steels.

I first reprofiled the factory edge from 35 degrees inclusive to 30 degrees inclusive with a Rubber Wheel coated with 230 grit diamond powder, then refined it with a Paper Wheel coated with 15 micron diamond compound, and lastly removed the tiny burr with a second Paper Wheel coated with 0.25 micron diamond compound.

The new and ever so slightly convex edge could treetop the hair on the back of my hand (even whittle it a bit) and easily slice single ply toilet paper.

And this was after i tested the edge with a few firm cuts into the edge of a piece of laminated desktop.

Did these chisel ground edges a a few years ago with a Paper Wheel coated with 15 micron diamond compound, and then stropped the burr on the other side off on hard leather with some 1 micron diamond compound.

Both knives were quite blunt, one even more than the other.

The knives are owned by two Dutch Special Forces guys who used & sharpened them while on tour in Afghanistan, and they wanted the new edges to have a little bling.

This second hand Spyderco Military in CPM-D2 steel was one of the first knives i ever sharpened on my standard set of Paper Wheels back in 2009.

It had some blade play (fixed it), some discoloration on the blade (left that) and it wasn't quite sharp (fixed that with the Wheels)

Was part of my edc for several years.

Yes, some time ago i even bought a large piece of MDF to possibly make some wheels out of somewhere in the future.
But at this moment i have some doubts if this material is a truly safe option for that purpose, as i'm not sure if the MDF material will be able to hold up to the centrifugal forces generated by the benchgrinder.
The last thing i want is that MDF pieces would come flying at me at high speeds in the event that such a wheel disintegrates while spinning at between 1400-1700 rpm, especially since there are no steel guards on the machine (like there would be when using the original stone wheels)

There are however people who use home made MDF Wheels for sharpening knives:

A small container filled with SiC particles comes with each set of Paper Wheels, and it's enough to re-coat the sharpening Wheel several times.

Since i started working with Paper Wheels back in 2009 i've experimented with quite a few regritting methods, and the recipe below is what has been working best & longest for me:

1 - First remove all traces of the old wax layer.
For this i use a steel wire brush on the spinning Wheel until most is gone, then i shut the machine down and remove the last remnants with an old rag & brake cleaner.

2 - Then remove all traces of grit & glue until you get to the bare cardboard surface.
For this i use an old coarse silicon carbide stone first and a semi-coarse diamond stone second, but coarse sandpaper on a piece of wood also works well.

3 - Take a good quality water resistant wood glue and coat the bare cardboard surface evenly.
I just use a clean finger while turning the Wheel with my other hand.
Let dry at least overnight.

4 - The next day apply a new and just a little thicker layer of the same glue, and immediately after coat the surface with the grit.
For this i put a thick layer of grit in a small rectangle box or a deep plastic lid from a jar and gently push the surface of the wheel in it, evenly and all the way around.
Put the wheel back on the machine and let dry at least overnight.

5 - The next day run the machine with the wheel for just a few seconds so any loose grit particles fly off.
I also hold my diamond stone shortly to the sides of the Wheel to remove grit particles that stick out there.
Stop the wheel and coat the gritted surface with a very thin & even layer of the same wood glue, so thin you can still feel the grit under your fingertips when you're done.
Let it dry at least overnight.

6 - The next day run the machine and hold an old junk knife a few seconds to the wheel (still without the wax), as this will lay bare the highest points of the grit particles.
Now you can put some wax on the surface (don't overdo it) and sharpen away.

As you can see the process takes some time, but to me it's worth it.
The triple layer of glue makes for a much stronger bond of the SiC grit to the cardboard surface compared to just one layer of glue, and each grit particle is also held better in the glue since it's almost completely encapsulated by it, while the glue itself will wear away easily during sharpening.
This method provides me with a grit Wheel that works perfectly and also lasts longer between regrittings.

Before i completely finished the edge to 15 micron i decided to use it just once, cutting up a box of mushrooms, some bell peppers, and some onions on my end grain wooden cutting board.
The 3 pics below show the result: not only microchips, but larger sections of the apex measuring several millimeters have completely broken off.
I think it's safe to say that a 15 micron edge finish is a bit too coarse for this ceramic material.

New & unused 420HC blade made in 2010 for a Buck 110, and the edge can shave armhair.
The first picture was an attempt to get the lens as close as possible to the point of the blade, while at the same time trying to focus as best as i could, so this is about the maximum enlargement.

New & unused Leatherman Wave 420 steel blade from around 2008:
The edge can hardly cut copy paper due to a rather large burr.

These also belong in this thread:

A new edge for a Sebenza 25

Recreating the factory edge on a Sebenza 25