Microscope straight razor progression

[Josh]

Ok. So last night I had a nice straight razor to sharpen, made by Theirs Issard. It was actually in decent quality to begin with, here is the progression I went through. I want to also say that I was trying some glass plates on my paddles w/ lapping film and ran into a rather strange phenomenon for which I have no explanation. So here we go… keep in mind I reversed stroke direction so I could ensure where my stones were hitting and to make sure I was reaching all the way to the edge…

The lapping film I was using was purchased from this page.

Pre-sharpening to it, it looked pretty good! (compared to some razors I sharpen!)

800 grit Chosera waterstones:

2k Choseras:

5k Choseras:

10k Choseras (note that I increased the bevel angle around 1 dps to make sure I was hitting the very edge as this is the part that actually shaves):

At this point I decided to go to my glass blocks w/ lapping film to see what happened… first up was the 5um film. It looks about right and worked nicely! Notice that it even blended both the bevels into one:

Then I went to 1um lapping film. Keep in mind this is FRESH film, never used before and just put onto the glass. It didn’t get all of the scratches out for how many passes I did (roughly 40 per side):

Ok, so I wanted to do more passes to remove the 5um scratches. I put a little bit of water on the film and wiped it off with a clean paper towel, then put a tad more water on it (to just help a bit w/ lubrication and smoothness of the pass). This may have been caused by switching to edge leading passes, but I think I did edge leading with the 5um film too and didn’t get this. I will have to experiment around w/ this more!! This is what I got :ohmy: :

Wow, what just happened?!?! I have no idea how those big chunks got missing out of the edge but it was crazy, and they were pretty large (you still could not see them w/ the naked eye though I don’t believe). Somehow I am guessing my lapping film got contaminated? So I went back to the 2k and spent about 50 passes per side, note that they are pretty deep and still not removed!

So I used my 2k stone and ground the edge flat (made a couple light passes perpendicular on the edge) and then redid my bevels until they were all cleaned up:

Back to 5k choseras:

Then the 10k Choseras, followed by 1.5um/.5um strops followed by .125CBN spray on Kangaroo leather:

Any ideas?

[Gib Curry]

Weird. It looks like chunks, hunks, clods or something just got exposed “fell” or “torn” out of the edge of the edge….

I was talking metallurgy yesterday with a nephew. It quickly got to the point of sounding like alchemy.

And what didn’t sound like alchemy was clearly over my expertise level. So, I don’t have a clue…

Was it all along the edge or just in a spot or two?

Do you still have those plates and/or film? Did you put them under the scope to look for contamination?

Weird.

~~~~
For Now,

Gib

Φ

"Everyday edge for the bevel headed"

"Things work out best for those who make the best out of the way things work out."

[wickededge]

I’m guessing that you’re right about the films being contaminated. It looks like the big hunks missing are at the end of some pretty big scratches. Even one big particle could do that over a series of strokes. Maybe there was some large silica particle on the towel from airborne dust or some mineral from the water. I’ve read that airborne dust particles, including silica, can be many microns in size.

-Clay

[Josh]

Weird. It looks like chunks, hunks, clods or something just got exposed “fell” or “torn” out of the edge of the edge….

I was talking metallurgy yesterday with a nephew. It quickly got to the point of sounding like alchemy.

And what didn’t sound like alchemy was clearly over my expertise level. So, I don’t have a clue…

Was it all along the edge or just in a spot or two?

Do you still have those plates and/or film? Did you put them under the scope to look for contamination?

Weird.

I didn’t look all along the edge but in the couple places I did it was there…

Yes! I still have them, I am going to clean them and try it again at some point in the near future hopefully, as long as Tom doesn’t mind me keeping his paddles a bit longer 😉

[tcmeyer]

Josh: Did this by any chance happen with the wood blocks I sent you? Take a close look at the edges of the glass. Could be there’s a sharp edge and the gouges are a “once per stroke” thing – maybe related to your hold position or sweep technique. You may be hitting the edge with a corner of the glass on the return stroke.

I once caused a bad scratch on a new blade when I slipped off the edge and the corner of the glass scratched a single line down along the face of the blade. After that, I deburred all of the glass plates on my Garolite blocks on my sander, but I never went back to deburr the old wood blocks, because I didn’t think I’d ever use them again.

BTW those blocks are yours to keep. I’ve got several more sets of the wood blocks you can have, too. My position is that you need enough glass blocks to hold all of the films that you use. It doesn’t make sense to me to have to change films until they’re worn out.

[Josh]

Josh: Did this by any chance happen with the wood blocks I sent you? Take a close look at the edges of the glass. Could be there’s a sharp edge and the gouges are a “once per stroke” thing – maybe related to your hold position or sweep technique. You may be hitting the edge with a corner of the glass on the return stroke.

I once caused a bad scratch on a new blade when I slipped off the edge and the corner of the glass scratched a single line down along the face of the blade. After that, I deburred all of the glass plates on my Garolite blocks on my sander, but I never went back to deburr the old wood blocks, because I didn’t think I’d ever use them again.

BTW those blocks are yours to keep. I’ve got several more sets of the wood blocks you can have, too. My position is that you need enough glass blocks to hold all of the films that you use. It doesn’t make sense to me to have to change films until they’re worn out.

Tom, you’re simply brilliant… I am smacking myself in the head for not thinking of that!

I got three paddles from you… this was done with the two that were alike (with the darker wood, not the single lighter wood paddle.) I think these were the gen 2 models. I will definitely be examining the edges when I get home tonight!! I am almost positive this is what it is. I felt the edges a little bit when I first got them and felt a few nicks I do believe… any thoughts on deburring the edges? Should I do it on my DMT course/fine stone or on a belt sander w/ a fine grit belt?

[tcmeyer]

That’s how I ended up with that one block on my bench. As I was rolling them up in the packing material, I must have skipped one. You were supposed to get two pairs.

The “light wood” is actually poplar, which is a very soft wood I use for jigs and set-ups. The “dark wood” isn’t wood at all. It’s Garolite, a modern substitute for bakelite. Its really tough stuff, but still machinable.

I “deburred” my glass blocks on my drum sander. Coarse grits like 80 – 120 seem to work best. Finer grits don’t seem to stand up to the abuse very well. If you have an old belt laying around that you don’t use anymore, try that. You don’t want to wreck a good belt. I’ll send you some more stuff. This time, I’ll deburr the glass first. And I’ll toss in the block that missed the last shipment.

Oh, and I’m not brilliant. Just old.

[Josh]

That’s how I ended up with that one block on my bench. As I was rolling them up in the packing material, I must have skipped one. You were supposed to get two pairs.

The “light wood” is actually poplar, which is a very soft wood I use for jigs and set-ups. The “dark wood” isn’t wood at all. It’s Garolite, a modern substitute for bakelite. Its really tough stuff, but still machinable.

I “deburred” my glass blocks on my drum sander. Coarse grits like 80 – 120 seem to work best. Finer grits don’t seem to stand up to the abuse very well. If you have an old belt laying around that you don’t use anymore, try that. You don’t want to wreck a good belt. I’ll send you some more stuff. This time, I’ll deburr the glass first. And I’ll toss in the block that missed the last shipment.

Oh, and I’m not brilliant. Just old.

ahhhh gotcha! Yeah like I said, that wooden one actually is smoother (because it is bored out a tad bit more) but I didn’t have the other one to use it with lol. Sounds good on the deburring! Thanks for the insight!

[Josh]

Ok, I checked the glass plates last night. I took my fingernail and scraped it along all of the edges and I could not find any nicks or anything noticeable… Neverthaless, I think I will debur the edges amd smoothen them out a tad bit more and see if that helps.

[Author]

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