Grafting Knife Logistics

[Case_D]

Hey everyone, I’d like some advice on one of my future projects. The plan is to make some grafting knives from several CPM Magnacut cut-off scraps. This project will have a lot of firsts for me. For those of you not aware of what a grafting knife is, it is a knife used for grafting (duh).
Really though, grafting is taking a bud or young-growth stick from one tree and transplanting it onto another. This allows for a particular fruit to always come true to variety, and the understock may allow for enhanced properties like cold-hardiness or disease resistance.
Grafting knives are usually single bevel, wharncliffe or sheepsfoot in profile, and about 2.5”x0.75”x0.094” - this is appropriate for the magnacut stock i have remaining

A grafting knife should create an exceptionally clean and precise cut in a piece of wood, so that any wounds heal as well as possible. It should also be well polished to prevent contaminants from find a place to live on the blade.

Every grafting knife I have come across has been made from either low-alloy carbon steel or relatively soft stainless steel. I’m planning on giving these improved grafting knives to some of the many tree nurseries to which I have connections.

The overall profile and design isn’t an issue. It’s quite simple. The thing I’m thinking about is the back side of the single bevel. Do I leave it flat or put in a urasuki like Japanese single bevel knives?
I figured an urasuki would be an advantage since flattening the back on a wear resistant steel like magnacut may be difficult for most people. I’ve never seen a western grafting knife with an Urasuki but some Japanese ones do come that way.

If you think I should do an urasuki, how do you suggest I do it?

I thought hollow grinding the backside might be difficult for a piece this small. I only have 2” contact wheels, but I’m not opposed to obtaining larger diameter wheels or a radius platten (I needed them anyway for other things) If that’s what this requires.

I thought perhaps I could forge in a simple urasuki with a cross-peen hammer. I’m not sure how magnacut would respond to a little cold forging, but I’m assuming not well. I don’t do my own heat treating, but I know heat treaters can provide the initial prep for heat treating for a little extra $, so some heat shouldn’t be a problem so long as I grind off the decarb, right?

Anyway, thanks for reading through my thoughts, and thanks for whatever advice you can give

 

[Stacy E. Apelt - Bladesmith]

Forget urasuki. Not needed here.
A shallow bevel with a a very thin edge before final sharpening.

One reason they are normally pretty soft as far as knives go is they are sharpened before day's each use. Ease of sharpening is more important than edge life. Polishing with a paste is also a lot easier on a Rc 54 blade than an Rc 64 one.

Making yours out of magnacut is a different thing. Austenitize at 2050°and temper at 300° for a really hard blade. Use dry-ice or cryo if you can.
It may take a good set of diamond stones to get to get the edge you want, and lapping on diamond film or paste to make it shine, but that edge should hold up well in the hands of a pro grafter.

 

[Case_D]

Forget urasuki. Not needed here.
A shallow bevel with a a very thin edge before final sharpening.

One reason they are normally pretty soft as far as knives go is they are sharpened before day's each use. Ease of sharpening is more important than edge life. Polishing with a paste is also a lot easier on a Rc 54 blade than an Rc 64 one.

Making yours out of magnacut is a different thing. Austenitize at 2050°and temper at 300° for a really hard blade. Use dry-ice or cryo if you can.
It may take a good set of diamond stones to get to get the edge you want, and lapping on diamond film or paste to make it shine, but that edge should hold up well in the hands of a pro grafter.

Thanks for the input. I've done hundreds of grafts myself and worked with people who've done innumerable. I'm pretty comfortable working with Magnacut now (~20 knives so far)

One of the main reasons for making grafting knives is the number of requests I've gotten for them with higher wear resistant steels.
Yet I was always hesitant because, in my opinion, they still need high toughness and corrosion resistance. It wasn't as easy until Magnacut
Super thin edge when cutting tons of hard wood like pecan? It'll ruin something like S110V or M390
And even stainless knives are usually rusty when I get them for sharpening (I sharpen professionally on the side). My dad's stainless grafting knife patina'd after doing about 60 citrus grafts. Gunk from the trees is one factor, but blood is also common (also found from my dad's). It's easy to forget to clean your knife when you gotta get your hand stitched back up lol

As far as sharpening goes, I was more worried about the customer. I've got vitrified diamond, resin diamond, the works. In my opinion, Magnacut sharpens easily enough with silicon carbide stones at the very least.

I think the delimma I was having stemmed from a younger generation's desire to innovate. Both my side of the work and the grafter's. Many of the guys looking for these are younger and are into modern knives

Anyway thanks again for the tips