Knife project #5: first attempt with RWL34 stainless

[zambezi]

I have made a handful of knives in high carbon steel and every one taught me a bit more in terms of method, finishes, hardening, optimum sequencing of tasks, etc.

High carbon steel is cheapish, makes an excellent blade but it takes some maintenance to keep blemish-free and sharp [at circa 55Hrc].

There are a myriad stainless steel options but all are expensive. And their hardening regimes are not as simple as for most high carbon steels. But I want a low-maintenance stainless hand-made knife so I took the plunge and bought some RWL34. If it all comes together, this will be hard to beat for durability and edge-retention.

Here we go...




Oh...and I treated myself to a bandsaw. It is a stellar performer on wood so rectilinear slabs that do not require too much hand truing should be a given [previously hacked slabs out with a jigsaw]. Plus less wasteful cuts on valuable stocks of ebony,genge, chestnut. The only fly in the ointment so far is that the blade [Starrets] that I bought to cut steel is rubbish. So I had to rough out this knife blank with the angle grinder again.

Any recomendations for a good metal cutting blade for a bandsaw? [2360mm/93"]

 

[tusker]

let me know how the heat treat goes please.
Tusker

 

[zambezi]

let me know how the heat treat goes please.

Will do. I plan to follow the Aussie chap's guide :

How To Heat Treat RWL 34 In A Gas Forge

Heat Treating RWL 34 In A Gas Forge:RWL 34 can be heat treated in a gas forge by using a thermocouple as temperature control.History:Swedish makers Damasteel are famous for their stainless steel damascus in amazing patterns. Central to their Damasteel products is the RWL 34 steel, by many...

creativeman.com.au

 

[snake_2586]

I will be watching with interest as usual.

I don't know about metal cutting blades, but I buy all my wood cutting bandsaw blades from these guys, and they are always helpful so may be worth a call and see what they recommend, Trucut, The Narrow Bandsaw Specialists - Home

 

[zambezi]

they are always helpful so may be worth a call and see what they recommend, Trucut, The Narrow Bandsaw Specialists - Home

Ordered a blade from Trucut today. It should arrive next week. It was not cheap, but the lady assures me of quality.

 

[Griggo06]

I have had good service from these guys.
Tell them what machine you have and stuff you need to cutt and they'll sort you out

Bandsaws Blades

east midlands saw service bandsaw blades by dakin flathers, stocked in sheffield, woodcutting, and bi metal m42 for steel,meat and fish cutting, blades,blades made to your machine spec

eastmidsaws.co.uk

 

[zambezi]

Good progress today. But before I post pics of that, I want to share one of the things learnt during the previous knife builds. It might help others.

Plunge line protection.

On the knife-filing jig I built, I have added a file-stop so that the file cannot engage the metal beyong your chosen plunge line. What I had not factored in was that most of my files taper somewhat at the end furthest from the handle. It is a common feature.

What that means is that when you are filing the edge bevel close to the ricasso, you must reduce the file stroke length so that only the straight length of the file references the file stop.

If you draw the file too far back, the area where the file tapers engages the file stop and that allows the handle end of the file to bite further than you want. Your plunge line becomes a lazy lower case "L" rather than a straight line.

File stop limits file range, keeps plunge line straight as long as straight edge in contact at all times. If file is drawn all the way back, the stop references the file's slopey shoulder, and the handle end jags towards the ricasso . The effect is this :

 

[zambezi]

First I tidied up the blank roughed out by angle grinder yesterday using file , Dremel and wet-n-dry. I dusted off my knife-filing jig and clamped the blade in situ Next I marked the midline of the edge and worked down to that line with barstard and then fine files .

After lunch I will flip the piece in the jig and repeat the beveling on that side. Who knows, heat treat may even happen today . But I won't rush as I am more keen on a good finish than a fast completion.

 

[bowji john]

Very very very impressed

 

[Griggo06]

First I tidied up the blank roughed out by angle grinder yesterday using file View attachment 176144 , Dremel View attachment 176145 and wet-n-dry. I dusted off my knife-filing jig and clamped the blade in situ View attachment 176147 Next I marked the midline of the edge and worked down to that line with barstard and then fine files View attachment 176146.

After lunch I will flip the piece in the jig and repeat the beveling on that side. Who knows, heat treat may even happen today . But I won't rush as I am more keen on a good finish than a fast completion.

So I've have found get hold of some old carbide drills and taken them to a green grindstone and giving them a flat spot along its length clamp these to next to the ricasso and the file can't add any extra unwanted scratch marks.
I think you can probably buy file guides that do something similar I just had short arms and deep pockets.

 

[zambezi]

We have an amazing Bramley-hybrid apple tree that yields ridiculous weights of fruit every year. It has just decided to start dropping its best offerings, so my morning was devoted to pre-emptive picking and prep for the freezer. Knife work resumed p.m. ...


First up I gave the blank a 150 grit polish to remove all remaining tool scoring. Next I cut ebony slabs from my stock and using my new bandsaw was able to shape them fairly closely to final profile which was helpful because it revealed a hidden issue . [New RWL34 knife pictured at left, previous high carbon steel knife made using same template at right for reference] Once slabs were trimmed I discovered a punky section lying just above the area I require . As far as I can discern, it is a shallow blemish which does not pass all the way througn the slab. I will sand it back a bit to confirm timber is sound where it has to be before committing to use it. Last job today: drilling the tang and countersinking holes. Note leather glove to hold workpiece in case bit bites and blade rotates violently. Drilling through the tang is less for weight reduction [2.6mm RWL34 is lightweight] but more about allowing epoxy to have largest possible purchase on steel and through tang to marry both slabs. As before, this is a pinless design. I believe that is neater on a slender handle, plus the previous builds shows strategy is strong enough. I am busy this weekend, but blade is now ready for heat treat on Monday

 

[Longstrider]

The best bandsaw blades I've come across for metal are bi-metal blades. We buy them from Bedford Saw and Tool for work, and I have them for my saw at home too. Most proper metal blades will cut annealed tool steel OK, but these last far longer with a decent cut than any others we have tried. BS&T will make them up to spec for you if you know what length you need, they know their stuff.

 

[zambezi]

Heat-treat day has arrived.

I set the forge up with the thermocouple probe passing through a hole in a brick such that it would sit very close to the blade in the forge . It took a long time for the diminutive forge to reach my revised target temp of 1050ْ C and it looked to be under some stress . In my head I could hear Scotty admonishing Kirk that the vessel's limits were about to be exceeded. I left the knife in for 7.5 mins and quenched in the rye oil followed by a vertical plunge into a bucket of water to ensure steel at room temp inside 120 secs from emerging from forge. After that, I popped it in the freezer at -18ْ C for 90 mins. The final phase will be a couple of hours at 175ْ C per my revised schedule which seeks to secure a 62Hrc finish

 

[deerstalker.308]

Question, and please bear in mind my bladesmithing knowledge consists solely of what I’ve gleaned from watching forged in fire, but does that pair of holes not create excessive weakness at a fairly critical place on the blade/handle junction?

 

[zambezi]

Question, and please bear in mind my bladesmithing knowledge consists solely of what I’ve gleaned from watching forged in fire, but does that pair of holes not create excessive weakness at a fairly critical place on the blade/handle junction?

Fair question.

If this was a scandi grind bushcrafting blade, I would agree with you. I.e. if I was ever going to baton or lever this blade, that level of material removal at that point would probably be unwise.

This is a 2.6mm gralloch knife that I intend to sharpen to scalpel sharp. As such, I doubt very much force will ever be transferred through that point.

Furthermore, I have usually found that assembled objects become much stronger when laminated. So if the strength of the metal was considered in isolation, or that of either slab, they would be significantly weaker than the three bonded together. In this dynamic, I reasoned that the greatest epoxy-to-steel-to-slab surface area at this point would grant the most significant laminate marriage.

Time will tell...

 

[zambezi]

I decided to clean up the slabs whilst the blade ran through its tempering cycle. The first part was to use the linisher to see how deep the punky wood runs in the slab . It was shallow. The Sabah ebony is lustrous . Next I placed a sheet of 100 grit sandpaper on a piece of glass and started to true up the slab faces that will be offered up to the tang . The grain looks wonderfully rich.

 

[bowji john]

Stunning work

I’m fascinated

 

[zambezi]

After the heat treat, there is always clag on the steel which has to be removed starting with 150 grit and then moving up the grits until you have the finish you want. I did the last pass with 600 grit. The next thing to do is to profile the slab ends nearest the ricasso as they are the hardest to work on once glued up. I sketched a curve and then clamped slabs together before using the linisher to apply the profile . After that...

 

[zambezi]

...it was time to apply a key to the tang faces for the epoxy to grip , mix the epoxy, apply liberally and clamp . What I now realise I forgot to do was test the hardness of the heat treat before glueing the slabs. Urgh. Skating calibration files over the 600 grit polished blade faces is not an option! What I might do is a edge of tang test. Tomorrow will be the sculpting on the handle's "coke bottle" profile and Lansky edge sharpening.

 

[zambezi]

Like a kid at Christmas I sprung out of bed as soon as my eyes opened to retrieve the knife from the clamps and inspect the epoxy cure.

Frankly, a little dismayed. It looks ok overall [RWL34 project to left of high carbon prototype I made a month ago] . I had run out of the Gorilla epoxy I used on all previous knives, so bought some Araldite instead. On paper it is the same thing. In practice it is not: Where the Gorilla epoxy dried to a translucent finish , the Araldite has dried to a milky white. That is still fine as you won't really see it. However, where the Gorilla dried to a glass-hard finish overnight, the Araldite can still be marked with my fingernail which is ominous. That may mean that the Araldite will accommodate some movement and hence this is a virtue, but I doubt it. None of the Gorilla-made knives have any issues and that is a better finish.