View Full Version : Coastline San Mai WIP
08-02-2011, 08:42 AM
I was not exactly sure where to post this as it finished. But as far as working feedback, everything is a WIP
I got three knives out of this San mai billet. And the San mai looks nice but different on all of them, depending on the depth the blade and the grind. This one I think looks rather like a coastline.
The Materials are a bit of a collection. I used up an old 300 layer billet of Mild steel and en45 for the outside layers. The core is en42J with the weld line punched up with a slice or 2 of 15n20.
I've had mixed results with the non contasty damascus. On thicker blades you get an even pattern. Just couldn't get an even etch out of it on these thinner blades. It looks more like a crucible steel, with elements of pattern coming to the surface. This is probably telling me that the carbon has equalled out largely in the damascus. Anyway its subtle , I like it because of this but now I have some 15n20. I probably wont make it again.
The Billet was forged down with approximately 20mm diameter fullers in the hammer to get the ripples.
To the blade. Its a Bano Bocho, (I think). The Sharp is 185mm. 50mm deep at the back, 39 mm at the front. The blade is 2mm thick at the back tapering to 1.5mm. It light but doesn't flex too much. It balances 30mm in front of the handle.
The Handle is a single piece of Maple bur 120mm long, with the tang epoxied in.
I do all my grinding post HT on these types of blades.
Blade was full flat ground to 0.25mm then the last bit is convexed, on the grinder then by hand whilst polishing, honing in between grits then convexing in. Final honing after the etch was done on a cheapo 1K water stone. Then a Dragon Slate razor hone with slurry, then water. Then course strop with Starkie blue. Then bare leather. Its fairly sharp.:D Some pics at last...
All feedback most welcome.:biggrin:
08-02-2011, 09:00 AM
WOW! That is a spectacular looking knife. I just love the "coastline" pattern of the lamination line and the very discreet damascus pattern. The profile also looks very useable and versatile and the handle is very nice and fits the knife perfectly. I am a bit curious about the "hunchback" on the spine just above the heel. Is this a particular design feature with this blade?
Very nice work and a beautiful knife alltogether.
08-02-2011, 09:23 AM
Awesome, I like them alot! Great job.
08-02-2011, 10:04 AM
Thanks Guys. The Hunch is more out of necessity, its a meeting point of 2 angles. The blade tapering down and the taper into the tang has to go down slightly so the handle looks level when fitted. It could be blended in a bit more, but this doesn't quite look right. If I had a shoulder on the tang it could nearly disappear. I don't mind it too much, as a simple transition.
08-02-2011, 10:10 AM
The san mai pattern is cool but what I notice here the most is your smithing/grinding skills, this knife looks to be thin in the right places or at least you're in the zone from what I can see here.
08-02-2011, 10:34 AM
Thanks Dave, I'm happy the way the grind turned out on this one. Its nice and even and thin behind the edge. I have done a Gyto and a Santoku out of the same billet. The Gyto has by far the most flex, could be a bit thin for the depth of the blade. I think i'll start going a tad thicker on the back for the narrower blades. For this 2mm seems to give it plenty of strength. I've had the "Thin is best" idea in my head getting started. It certainly a challenge forging and HTing then sub 2mm. But as Mark Pointed out to me, too thin, too much flex might give it a flimsy feeling.
08-02-2011, 10:37 AM
There's a fine line between super thin and too flexy for sure. The 2mm mark is a good place to be at the handle/spine point and go from there.
08-02-2011, 03:34 PM
That is a beautiful knife, and I like the simple yet classy look -- nice lines (including coastline). That tree trunk though makes the knife look huge.
08-02-2011, 03:57 PM
Thanks Mr Dinky, ha ha, I see what you mean about the log. But its only a little log really. Its got quite a "Butcher Shop" profile in that front/side view.
08-02-2011, 10:00 PM
Great looking blade.
Bizarre but cool pattern in the steel (makes me think of a lava lamp)
The photo with the log makes it look like a giant log splitting cleaver.
08-03-2011, 12:50 AM
Looks awesome! Love the profile, Sweet work!
08-04-2011, 06:15 AM
Thanks Guys. The blade shape is really satisfying. Also I was really impressed with the edge it took. I tend to sharpe to the point where I can feel the edge dig in my skin from a slight touch on my thumb. A similar feeling to a razor with a mirror finished edge. In my mind it was "laser sharp", Having been looking at some of the tests and review you guys do for you go to kitchen knives. I became naturally curious and did some cutting and food prep with it. The first thing I noticed is food sticks to it in some situations. Not as bad as if it was just flat ground with a smaller bevel. The convex starts probably 10mm in from the edge. The next thing I noticed is it would not do the tomato push cut. I little movement and you can slice waffer thin but no push cut. I had expected it to sail through everything. Although it does seem to brake the skin straight off a 1K. I think i'm going to take it back to the hones and try some different angles. Maybe take the convex to a 7 degree bevel and then put a 14 degree micro bevel on that. Hopefully that will improve the push cut and the glide. What do you think? I'm sure every maker on here must have been through this at some point.
08-04-2011, 06:50 AM
I think for the average domestic user, this would be the sharpest thing they would ever use in the kitchen. But the bar seems dramatically higher here and having tested it I can see why. The things about it which seem to work in its favor are the thickness at the back and the nice progressive taper. This is something I will keep for this type of blade. Hopefully I can dramatically improve this on the hones. Bringing the convex flatter and back a bit to a thinner finer edge.
The polished edge/non push cut is getting me. My early feedback on T.B london's damascus petty was that it did not push cut at first, which surprised me as I felt it was surely as sharp as it could be. He said after a little tickle on the hones it went through like a laser and that maybe the edge was too shiny creating surface tension. This is hurting my head a little compared to my razor experiences. But then hairs don't tend to flex much near their base.
So for future I will try a partial flat grind , and a blended secondary to a finer final edge. I have read Del's post on this and it makes more sense to me now.
I think what is needed is a couple of mock ups in monosteel, with handle that I can remove to play with the grind. Then some helpful testers. I have had a local offer to look and compare to some other Knives, some made by makers on here, so I will take advantage of that.
08-04-2011, 06:58 AM
Send it to me and I'll have it gliding through food :D
My santoku and petty perform excellently so the steel is capable of it. I didn't need to adjust the angles either so if the grind on it is the same it's just the sharpening.
My suggestion would be careful of over stropping on leather, you can round the edge and lose the "bite"
08-04-2011, 07:06 AM
Mmm thats encouraging. I can see some investment in hones coming on. What hone did you finish on when you gave the Petty a wee tickle? My razor hone is hard, but probably only 5K or so on slurry. I have a synthetic Nagura and the yellow mud from that on the slate seems to give the edge more bite. I'm off to buy some tomatoes as well to do some testing:D
08-04-2011, 07:38 AM
I dropped down to 400 chosera to set the bevel, then work up through 1000 chosera, a 6000 ish artificial I picked up in japan, and then I'll either
-strop leather with poly diamond 0.5 micron and then bare leather.
- or work through an 8000 from jck and a 12000 shapton pro then strop as above
I'll usually do both and see which I prefer in use. Usually the 6k is as far as I go.
The stones I use are relatively quick cutting, compared to razor hones I've tried, which I prefer, the 6k is also very soft. How do you find the feedback on the slate?
08-04-2011, 09:04 AM
The slate is very hard. And won't give much feedback until you have worked a good slurry. But with slurry it cuts pretty quick for a hard stone. I can see the grit pattern change through my Loupe after a few firm strokes forward and back on every part of the bevel. For £7 or so its certainly not bad at all, but wether its more suited as a mid progression razor hone than a Final knife stone i'm not sure. When I've done the job properly on 1K it does seem to give a very nice refined edge after only a few strokes on slurry. Some more experimenting I feel coming on.....
08-04-2011, 12:09 PM
I've had a little play with the bevels. I have replaced the convex edge with a slightly higher secondary bevel about 7 degrees per side. This taken to a very fine edge just becoming sharp. Then I have put the primary in micro-bevel form at about 11 degrees per side. This barely required stropping after the slate hone with nagura stuff. But I polished the secondary on the course side of the leather. Then gently stropped the primary on smooth being very careful of the angle. It worked!! Yay. I just prepared a late lunch with it and it push cuts thin slices of ripe tomato. The difference in feel is marked going through food as well, with less suction being created on the blade. Makes it lovely to use doing horizontal onion cuts. I noticed no dulling what so ever after food prep, so hopefully the edge will last and will be easy to top up every now and then on the strop. I guess it will be easier to maintain also? As when the primary becomes a tad thick from multiple hone touch ups, the secondary can be worked till its nice and thin again.
Here's some pics attempting to show the new bevel.
08-04-2011, 01:09 PM
Sounds like success :D, 7 degrees per side should make it very slicey......
do you deburr on cork (or felt) or rely on the microbevel/final strop to clean the edge up? I haven't played much with microbevels, maybe I should give them a go again
08-04-2011, 01:17 PM
The cork sounds like a good trick. If I feel like I may have created a bur I tend to do a strop stroke on the stone im using followed by a normal stroke on the opposite side. I tend to have a peak through a Loupe every now and then to check progress, (Handy little thing). Burs and flat spots show up straight away. I don't see there can be that much danger of creating a wire edge on a micro bevel as they can be done with a pretty fine stone and with little not much pressure if your nearly there anyway.
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