kitchen knives San Mai WIP

[Joshua States]

So I gave this a try: San Mai of 1095 core and 410SS jacket. Starting pieces are 3/16" thick and either 5-1/2" or 6" long by 1-1/2" wide

I then used the TIG welder to fuse all the edges closed.

And welded the billet to a handle.

After forge-welding in the press, I ground the edges clean (or sort of clean)

Intermediate forging pic of tapering the end to a point.

I didn't get many photos during the forging process, but eventually, I went to grinding and HT. Here are three blades at 320 grit finish.

The secret lies hidden.

Edited October 21, 2018 by Joshua States
forgot the pics

[Jan Ysselstein]

Is there a reason why you chose that SS and not say 304?

 

[Joshua States]

1 minute ago, Jan Ysselstein said:

Is there a reason why you chose that SS and not say 304?

 

It was recommended by a couple other smiths who have done this. Have you used the 304? What would be the main difference between the two? (as far as results go)

[Jan Ysselstein]

I have no idea but every piece of SS I see around here is 304 or 440 c...I will look up the difference.

 

[Jan Ysselstein]

I think the coeff. of expansion for 410 SS is closer to that of 1095 by a lot. 410 contains no Nickel and 1/2 the amount of Manganese. and has to be hardened for maximum corrosion protection.

 

[Brian Dougherty]

I don't know enough about this to claim it is a benefit, but the 300 series of stainless steels are annealed by quenching.  This makes the cladding dead soft after heat treating the blade.

In the very few I have done (5 or 6) I find that it makes straightening easier.  It also makes hand sanding easier.

That being said, the blades I have seen with the really wild carbon migration patterns tend to be clad in a 400 series steel.

[Jeremy Blohm]

In order for 300 series stainless to be properly annealed it takes an 1850°f quench.

[Salem Straub]

Another nice thing about 400 series is that, unlike 300's, they stick to a magnet... so if a surface grinder is a big part of your san mai process, like me, that works with the mag chuck on the machine.

[Joshua States]

18 hours ago, Salem Straub said:

Another nice thing about 400 series is that, unlike 300's, they stick to a magnet... so if a surface grinder is a big part of your san mai process, like me, that works with the mag chuck on the machine.

Yep. The surface grinder did a bit of work on these.

[Joshua States]

I took two of these to 400 grit finish and put guard, micarta spacer, and walnut handle material on them.

I like to finish my handles off the blade, so I blind pin the spacer to the walnut and go about shaping and hand sanding. These went to 600 grit before I applied a thin layer of Watco's.

Then I scribe the guard material to match the end of the handle and shape the guard.

The last thing I did tonight was to etch the blades in ferric. The top one is straight out of the etch and a hand wash with clean water.

The bottom one is after polishing with Blue Magic cream.

 

[Jeremy Blohm]

Wow. Those turned out awesome.

[Salem Straub]

Cool!

 

[Joshua States]

I didn't get the intermediate hazy area of decarb on one of them. The other (top one) has a bright line, even after scrubbing with the polishing cream. I'm going to try the coffee etch that @Salem Straub suggested in another post and see how that looks. I have a third blade that I just took to the disc and went to 220. It has a tiny, but visible, weld flaw so it may not make it to handle land.

One thing I learned about forging the bevels in on San Mai is the demarcation line gets much closer to the edge than if you do a heavy stock removal,

Thanks again Salem for the pointers.

Edited November 9, 2018 by Joshua States

[jake pogrebinsky]

Beautiful patterns in that material(-s),and such neat job....So,that is C diffused into SS a certain way?...And randomised by forging,or diffusion itself is randomly purty like dat?

Lovely looking steel in any case,right on!

 

 

[Joshua States]

A newer, better version after the coffee etch cycles. I do not know what that white dot is on the bottom blade, near the edge, in the first photo. I think it is a piece of isolated 410 that formed a minor island in the blade.

@jake pogrebinsky As I understand it, the C diffusion is normal carbon migration across the seam during forge welding. The hazy area is caused by the differential between carbon contents High>medium>low and thus appears to be a third layer of material. Another interesting aspect is the ghost lines that appear across the faces on the one blade and not so much on the other.

Edited November 12, 2018 by Joshua States

[jake pogrebinsky]

Thanks for the explanation.Again,beautiful material,good for you,it takes cohones and Much work, to get into such neat composites.

[Joshua States]

All three are done and just a little late. The art show opened this morning.

[larsjacobsen]

I have made several blades with stainless cladding over carbon steel. The different stainless steel types give different results. I have used 316L, 304, A-ebl, 12c27, 416 and 1.4034 ( a 420 series steel ) The 420, and all the other knifesteel  types all show carbon migration while almost none is found when using 316 stainless. A few examples shown - only one with 316 stainless ....2 pictures of the knife. I do not polish my knifeblades to a mirror polish ....theese blades were all hand finished to 800 grit except the 316 which was finished with a 400 belt finish. 

Edited December 11, 2018 by larsjacobsen

[Sylvain Perreault]

On 10/21/2018 at 12:32 AM, Joshua States said: