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Japanese Sen Build

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I would like to build a Japanese Sen as a means to cut bevels verses filing and grinding. There are different 

designs. One is 85* front cutting edge and 90 rear, another is 35 and 35 respectively. I have reasoned a compromise

of 67.5 and 90 front and back. Basically a concave blade side down riding on the cutting edges. im

also planning on using an old file. blade dimensions will roughly 1.5 in x 3. This is what i have chose.

Any thoughts, experience, or advise?

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Scrapers don't generally work well with hollow ground faces. You want the edge to cut what's sticking above the general body of the preform. Flat faces provide a base of support to allow you to feel the edge cut and not dig in without a deliberate effort on your part. Lastly a hollow ground edge cuts softer material well because the edge is so thin. Unfortunately cutting steel puts more force on the edge and it needs support as closely line as possible. In high school we made and used 90* scrapers with surprising effect though they didn't penetrate below a flat surface. 

I'm not a bladesmith, just a metal head who's tried a thing or two. When guys experienced using a sen speak up I'll happily concede to experience.

Frosty The Lucky.

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On 10/3/2020 at 2:19 PM, Frosty said:

Scrapers don't generally work well with hollow ground faces.

Japanese plane blades and woodworking chisels have a hollow (called an urasuki) ground into the back to relieve friction, but with flat edges to support the blade, like this:


Which I think this is what Canton Little is talking about, rather than like this:


Which I think is what Frosty is (rightly) cautioning against.

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14 hours ago, Canton Little said:

The Sen is for working cold steel. 

Your post is not about using a sen, but making one, which is the point I was making about where to post the thread, we  would not post about making a hand saw in wood working

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