Stropping Angles

[wickededge]

I cleaned up the cross section of the sample a little more and took a few more photos of the at-angle stropped edge:

Attachments:

• AtAngle-Cleaned.jpg
• AtAngle-Cleanedb.jpg

-Clay

[wickededge]

I reestablished the 20 dps angle and cleaned up the cross section a little more:

This second image is from the side at 2000x. The line you see at the edge is the reflection caused by the immersion oil. Everything to the left of that line should be ignored as an artifact.

Attachments:

• BeginningSampleb.jpg
• 20-dps-1000-2000x-b.jpg

-Clay

[Zamfir]

So are these last 2 pictures of the 1000 grit diamond plates or were they stropped again?

[wickededge]

So are these last 2 pictures of the 1000 grit diamond plates or were they stropped again?

You’re correct – they’re of the 1000 grit diamond plates. I wanted to reestablish the 20 dps bevel with the 1000 grit diamonds after I’d cleaned up the cross section. Now I’m off to strop it again and will post new pics as soon as I’ve got that done.

-Clay

[wickededge]

The sharpness of the 20 dps with 1000# diamond plate finish is 236. I’ll test it again after stropping it at the same angle.

-Clay

[wickededge]

I stropped it again at 20 dps, fairly hard pressure, around 75 strokes per side:

Attachments:

• AtAngleb.jpg
• AtAnglec.jpg

-Clay

[Josh]

Clay, can you explain the TA1 and TA0?

[wickededge]

Those are just the two angles I measured. The software assigned the letters to the sides TA automatically and one measurement is labeled 0 and the other is labeled 1. The letters are arbitrary, the could easily be AB or any other designation you’d want to give each of the sides of the angle.

-Clay

[Josh]

Those are just the two angles I measured. The software assigned the letters to the sides TA automatically and one measurement is labeled 0 and the other is labeled 1. The letters are arbitrary, the could easily be AB or any other designation you’d want to give each of the sides of the angle.

but which is which? or am i missing something

edit: oh i see, TA0 is the vinal edge angle, TA1 is the overall bevel angle… right?

[wickededge]

Got it!

1. TA1 is closest to the original bevel of 20 dps with the 1000# diamonds. A little widening occurred with stropping that affected even this angle, probably because the tip is now a tiny bit closer to the shoulder of the 20 dps bevel.
2. TA0 is the angle closest to the tip that shows the widening edge after stropping with the 14um strops.

This gives me a nice thought. Maybe I can make a little mark in the blade some distance from the very edge and then periodically measure the distance from edge to mark to see how much steel is being lost.

-Clay

[Zamfir]

ohhhhh neat! So will you do another one of them side pictures again like you did for the 1000 grit plate? It would be interesting to compare.

Also, what paste are you using? And is it the normal leather or kangaroo or balsa? Just one strop and grit or multiple? This cross section side view is a great way to see exactly what is going on there!

[wickededge]

I measured the sharpness after stropping at the same angle. The blade scored 363 vs. 236 with the 1000# diamonds at the same angle e.g. after stropping at the same angle, the blade required 53% more force to cut through the media.

Next, I’ll flatten out the bevels and restore the blade to 20 dps with the 1000# diamonds. Then I’ll lower the angle by 1 dps and strop it.

-Clay

[wickededge]

ohhhhh neat! So will you do another one of them side pictures again like you did for the 1000 grit plate? It would be interesting to compare.

Also, what paste are you using? And is it the normal leather or kangaroo or balsa? Just one strop and grit or multiple? This cross section side view is a great way to see exactly what is going on there!

I did put it back under the scope to show the side of the bevel. There is enough curvature that it’s hard to get a clear picture. I had to take three images at different distances, one showing the edge, one showing the middle of the bevel and the last showing the shoulder of the bevel. Here they are:

Attachments:

• 20-dps-14um-2000x-c-sm.jpg

-Clay

[wickededge]

Attachments:

• 20-dps-14um-2000x-b-sm.jpg
• 20-dps-14um-2000x-a-s.jpg

-Clay

[Mark76]

A note on the angles in the photos:

The primary grind is somewhere around 11 degrees though you can’t see it in the photos. Then there is a 15 dps bevel that drops to a 20 dps bevel. Once the stropping was completed, the final edge bevel is around 24.175 dps.

Very interesting. I had first missed you had put a 20 degree microbevel on the 15 degree edge. But what is interesting is that the convexing seems to take place on the entire bevel, not just on the place where originally the transition from 15 to 20 degrees was.

The sharpness of the 20 dps with 1000# diamond plate finish is 236. I’ll test it again after stropping it at the same angle.

Is that the sharpness measured with Dan’s jig?

Hahah! You did it again! 😆 A nice convex edge and down from 20 to 25 degrees without blunting the edge. I’d really like to know how much pressure you used. And I assume you used plain cow leather?

Molecule Polishing: my blog about sharpening with the Wicked Edge

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