Sen construction question

quint

quint

Joined
Nov 29, 2011
Messages
1,396
Hey guys, sure not alot of you use these but hopefully enough to answer my questions. I wanna play with one but am unsure on what the back side of the blade is suppose to be like. I have read flat and also that it has a convex (hollow ground) back side with roughly a 30 degree bevel on the top edges. Curious what you all prefer.

Thanks for your input.
 
I looked thru those threads and links just cant seem to find a cross section view. I dont go as well off descriptions and all the pictures are from the top of the sen. I know it is a relatively simple tool just wanna try and get it right.

I made these crosssections up in paint going off of what descriptions I have scene. Are any of these about right?

sen profiles.jpg
 
In the first post of the thread I linked there is a cross section pic. The easy way is to take a large half round file and grind a 10" hollow on the back (flat) side just to the edges and put a slightly less than 90* edge. It I quicker to make one than to learn to use one. But it is still pretty easy.

In your X-sectional views, the second and third ones have an appropriate edge angle, more so th third one.


-Xander
 
OK I think I would have to register to see the pic. May do that. Thanks that clears it up for me. Ill give it a shot and see what happens. Thanks Xander.
 
quint said:
Hey guys, sure not alot of you use these but hopefully enough to answer my questions. I wanna play with one but am unsure on what the back side of the blade is suppose to be like. I have read flat and also that it has a convex (hollow ground) back side with roughly a 30 degree bevel on the top edges. Curious what you all prefer.

Thanks for your input.
Click to expand...

Probably a typo but hollow grinds are concave. Convex is the opposite.
 
Yeah my mistake, I know the difference just screw up the terminology between the two often. I meant concave.
 
just take an old file, grind the teeth off of both sides. Grind bottom so it is flat and polished to about 400 grit or so. Grind about a 75-80 degree flat or convex bevel on the sides. Takes about 4 minutes to make one. Just don't let the file get too hot. Play with it. Rock it up some and cut on the pull stroke most of the time. Also, it takes awhile for the sen to start really cutting well on a new blade (one that hasn't been scraped some already). It is easy to make and use. They will shave curls off of the top of a piece of blade blank.
have fun with it. they get really hot, too.'
 
Thanks for the help. I just made a quick one with an older half round file. Seems to work pretty good considering first try at it. Once the high spots get knocked down it really starts taking off some metal. I am definitely gonna keep playing with these guys.
 
I tried making one today, I'm still a little confused. Would anyone mind showing a close up of the grind I tried looking but couldn't find any. They do seem really cool and I want to try one.

Thanks a lot.
 
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