Plane Blade Question

[Dennis Burton]

I recently acquired a cobbled together Stanley No. 4 plane which had a Siegley blade on it .
It is marked , SsS with Siegley beneath . It was in pretty good shape so I gave it a sharpening and in the process it appears that this blade is two pieces of metal bonded /layered ? together . The new edge I created with a honing guide shows a definite difference in the texture of the steel across the newly sharpened area.
You can see a definite demarcation line across the face of the new edge.
I'm green as a gourd with my knowledge of wood planes , anyone shed some light on these blades ? It is 6.75" x 2" x 3/32 as I measure.279926279927279928 I've only taken the edge through 500 grit wet or dry paper.

[Mark Bolton]

You could google "laminated plane blade"

[Joe Ruden]

Dennis, you will probably get a lot more replies if you post this in the neanderthal forum.

[Dennis Burton]

Thanks Joe for the tip.

[Dave Zellers]

I can't help re what or why but I can say I have planer blades that are laminated.

It was a real head scratcher at first- I kept trying to sharpen away that line.:rolleyes:

I've got to believe the cutting edge side is better steel than the other.

Somebody was using that blade as a chisel.

[Dennis McDonaugh]

There are a few reasons for doing that. You can use a smaller amount of hardened steel for the cutting edge and they are easier to sharpen. The hard steel is brittle and the softer back makes it more durable and less likely to break. Japanese plane blades and chisels are mostly laminated.