Need help on reprofiling a blade

Izzyblanco123 · Jul 3, 2022

https://imgur.com/a/gUwVRU3

Hello, this is my first post here so apologies if I have posted in the wrong section. I am seeking help with reprofiling my mcusta blade, due to the tip getting damaged after I let a friend borrow it and he dropped it point down onto the concrete floor (my fault, I know). The damage isn't very noticeable to the naked eye however it is bugging me and I can't not look at it, I really like this blade so I want to repair it. My question is, would the best course of action be to grind down from the edge or the spine? I wanted to do the spine for two reasons: One, I don't want to lose any detail on that wavy damascus line which is just behind the edge, I worked out that some would be lost near the point (I really like it

) and two, the top of the spine seems to have taken some damage too (shown in last photo). What do you think the best course of action is? I have never done this before so I will need help on what tools to use also. Any help is much appreciated, glad to be part of this community that share my hobby

Barman1 · Jul 3, 2022

I would follow the spine profile and drop the point a bit to fix the spine damage then sharpen the edge damage out to redevelop a point.
Kind of 50-50 removal from the spine and edge to keep the original profile somewhat intact.
I've done it quite a few times and yours isn't all that bad.
There are quite a few folks around here that can do it for you if you're not comfortable.

killgar · Jul 3, 2022

I would definitely go from the spine. If you go from the edge you're going to have to re-grind the edge and it's doubtful you'd be able to reproduce or perfectly maintain the existing grind line.

For the task I would just use a coarse hone of some kind, and finish with a fine hone or some high grit sandpaper on a hard, smooth surface (metal or glass). Using what I have, a coarse DMT diamond hone, followed by a fine DMT hone.

me2 · Jul 3, 2022

I’d just keep it as is. If you use the knife and sharpen it as needed, that little bit of damage will be gone in a couple of sharpenings.

scdub · Jul 3, 2022

I’d grind down the spine also.

Go slow and use magnification and you should be good on your own.

Sandpaper of different grits will work too but you’ll want to have it wet (oil or water) and sticking to a very flat surface for the best finish.

…also - I’d suggest using a tip- trailing motion rather than back-and-forth…

3D Anvil · Jul 4, 2022

I'd probably split the baby, like

Barman1 . Take the spine down some and sharpen the blade some.

Izzyblanco123 · Jul 4, 2022

scdub said:
I’d grind down the spine also.

Go slow and use magnification and you should be good on your own.

Sandpaper of different grits will work too but you’ll want to have it wet (oil or water) and sticking to a very flat surface for the best finish.

…also - I’d suggest using a tip- trailing motion rather than back-and-forth…

Thank you for your help

That seems to be the accepted method here, and with each comment I'm learning more intricate details

Izzyblanco123 · Jul 4, 2022

killgar said:
I would definitely go from the spine. If you go from the edge you're going to have to re-grind the edge and it's doubtful you'd be able to reproduce or perfectly maintain the existing grind line.

For the task I would just use a coarse hone of some kind, and finish with a fine hone or some high grit sandpaper on a hard, smooth surface (metal or glass). Using what I have, a coarse DMT diamond hone, followed by a fine DMT hone.

Thank you for the help I greatly appreciate it

Izzyblanco123 · Jul 4, 2022

Barman1 said:
I would follow the spine profile and drop the point a bit to fix the spine damage then sharpen the edge damage out to redevelop a point.
Kind of 50-50 removal from the spine and edge to keep the original profile somewhat intact.
I've done it quite a few times and yours isn't all that bad.
There are quite a few folks around here that can do it for you if you're not comfortable.

Hmmm interesting, that's a clever idea to keep the profile, I will consider it. Thank you for your help I greatly appreciate it

Obsessed with Edges · Jul 4, 2022

I also advocate grinding from the spine side to re-point the tips. Then resharpen the cutting edge near the tip, if needed.

I fixed the broken tip on this Kershaw Leek in ZDP-189, by grinding from the spine side and following the natural profile of the spine's curvature, to meet the cutting edge just aft of the broken portion. I used a 120-grit alumina-ceramic grinding belt (3" x 21"), cut at the seam and glued flat to a 24" length of hardwood. First 2 pics below are before the repair. Last pic is the result. Before the tip broke, I'd previously just finishing reprofiling the cutting edge on that knife, using a guided setup (DMT Aligner clamp & DMT 8" x 3" Duo-Sharp C/F) - so it was already in very good shape and I had no interest in regrinding the edge all over again.

If the edge geometry is otherwise in good shape, there's no good reason to regrind the edge itself to fix issues like this. Grinding up from the cutting edge will remove a lot of the thinner steel that existed near the edge before. So, you want to do everything you can to preserve that thinner steel near the edge, in order to maintain good cutting geometry over the long run.