Tormek Community Forum

In the Shop => Knife Sharpening => Topic started by: Ken S on July 21, 2024, 02:01:19 PM

Title: convexing edges with the KS-123
Post by: Ken S on July 21, 2024, 02:01:19 PM
EDIT: When I first posted this topic, I inadvertently typed "KS-123" instead of ?"KJ-45".

Now that we have had the chance to use the KJ-45 knife setting jig, I am curious to know your experiences with using it for convexing edges.

Have you used it to convex edges?

If so, did you use it once out of curiosity or has convexing become part of your regular sharpening program?

If convexing is now part of your regular sharpening program, which knives do you convex? (function and thickness)

For those of you who sharpen professionally, do your customers request convexing, and do you add a surcharge for it?

I have no hidden agenda pro or con, just curiosity to learn the wisdom and experience of the forum.

Ken
Title: Re: convexing edges with the KS-123
Post by: cbwx34 on July 21, 2024, 09:03:31 PM
Quote from: Ken S on July 21, 2024, 02:01:19 PMNow that we have had the chance to use the KS-123 knife setting jig, I am curious to know your experiences with using it for convexing edges.

Have you used it to convex edges?

If so, did you use it once out of curiosity or has convexing become part of your regular sharpening program?

If convexing is now part of your regular sharpening program, which knives do you convex? (function and thickness)

For those of you who sharpen professionally, do your customers request convexing, and do you add a surcharge for it?

I have no hidden agenda pro or con, just curiosity to learn the wisdom and experience of the forum.

Ken


I'm not sure there's a real correlation between the KS-123 and convex sharpening?  It does (obviously) make the angle setting more accurate (and consistent), but the convex process itself didn't really change.

Tormek probably should point out that measuring the "Protrusion" will be a bit different if someone wants to convex an edge... I didn't see it in the instructions or the live demo that I can recall.

Edit:  p.s.  Did you ever convex the knife you bought to test (https://forum.tormek.com/index.php/topic,5382.msg39290.html#msg39290)?
Title: Re: convexing edges with the KS-123
Post by: John_B on July 21, 2024, 09:09:17 PM
Ken do you mean creating two outward arcs that slope in and intersect at the edge. The edge of the knife would
resemble the slope of an airplane wing. If so is there a video on how to achieve this shape using the KS-123? I normally sharpen regular steels using a double angle. For most knives 15° for the main bevel and 16.5° for deburring bevel. I have never had anyone ask for a specific grind or sharpening angle. The most instruction I remember receiving is please make them as sharp as last time.
Title: Re: convexing edges with the KS-123
Post by: cbwx34 on July 21, 2024, 09:19:17 PM
Quote from: John_B on July 21, 2024, 09:09:17 PM...
 If so is there a video on how to achieve this shape using the KS-123?
...

Convexing an edge is done with the KJ-45, as seen here: 

https://www.youtube.com/live/JFHqQg5wZEg?si=HOQB8o3-sP6wyQOu&t=1996
Title: Re: convexing edges with the KS-123
Post by: Ken S on July 21, 2024, 09:46:41 PM
ERROR:

I inadvertently used "KS-123" instead of "KJ-45". Mea culpa.

Ken

PS to CB: No, I have not convexed that knife yet. I hadhoped that whatever this malady is that has been effecting my balance would have cleared up before this. As of now, it does seem to be very gradually clearing up.
Title: Re: convexing edges with the KS-123
Post by: John_B on July 21, 2024, 09:46:59 PM
Quote from: cbwx34 on July 21, 2024, 09:19:17 PM
Quote from: John_B on July 21, 2024, 09:09:17 PM...
 If so is there a video on how to achieve this shape using the KS-123?
...

Convexing an edge is done with the KJ-45, as seen here: 

https://www.youtube.com/live/JFHqQg5wZEg?si=HOQB8o3-sP6wyQOu&t=1996

Thanks CB. I haven't bought the KJ-45 which is probably why I hadn't seen the video. I can't see doing this on a knife that didn't come this way. Perhaps if it had been sharpened enough to need thinning it would leave a robust edge.
Title: Re: convexing edges with the KS-123
Post by: 3D Anvil on July 22, 2024, 05:32:14 AM
I convexed a couple pocket knives out of curiosity.  It worked pretty well, but it's quite a slow process if you want to get nice looking results.  It's not something I plan on doing again.  I also don't think it's a good solution for knives that already have convex edges, because there's no way to match the height of the existing convex section.  To be truly useful for that purpose, you'd need to be able to adjust the distance between the stops.