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View Full Version : Make a shear using planer blades?



darryl
01-13-2014, 10:24 PM
I have a number of planer blades that will never be used in a planer again. Today I was thinking about making a shear that would cut up to perhaps 16 ga in stainless sheet, maybe 14 in steel. My current shear is hard pressed to part paper, let alone any substantial sheet material:) At any rate, I can just barely manage 18 ga steel in it, and I need to be able to cut this stainless. I'm thinking of an open-ended design, which would work much like ordinary tin snips, but built like a brict shik house using leverage, etc. I'm wondering if the planer blades would be up to the task.

These are a cast material which is quite hard. Last time I used some of this, I had to cut it with a cutoff disc- mind you I didn't try to anneal it as I didn't want to mess with the heat treat. In this application I can bolt two blades together using existing holes, and I'll get a good scissor action over a good five or six inches. I'm just concerned whether the blades are tough enough for stainless.

RussZHC
01-13-2014, 10:46 PM
http://www.practicalmachinist.com/vb/general/proper-material-shear-blades-195922/

some discussion there but not sure if it is 100% relevant as the shear in question is more bar stock/flats as opposed to sheet though, based on reading that thread, there are some subtle differences even if the material is the same...to me it comes down to knowing more precisely what that blade material you have is, or likely is and how much time you may want to spend to find out in the end, not so much...and I suppose at some point it also comes down to how long said pieces might be.

mixdenny
01-13-2014, 11:15 PM
Sounds like a bench shear. Mine will cut 16 gauge stainless effortlessly.

http://www.grizzly.com/products/H0732

C_lazy_F_Guns
01-14-2014, 12:10 AM
Or a beverley shear, they let you turn the work.
Here is a cheap China one.
http://www.harborfreight.com/throatless-shear-38413.html


Plainer blades would be a bit brittle I think, I think they will chip off unless you temper them off some. It doesn’t so much need to be a hard steel that ill take an edge, more dense, the kind of stuff that that doesn’t like to give to a hammer even when good and hot. I made a heavy shear to go in a press and used snow plow blade edge and that works fine to all my press can do, “ hot roll. I have seen small light ones made from automotive leaf springs too, not tempered just normalized but a file wont touch it.

darryl
01-14-2014, 12:31 AM
Hmm- me thinks I should look at what's available before I try to build something. Thanks for the ideas-

davidh
01-14-2014, 10:12 AM
wear blades from your local city, town, province, federal gov, snow plow garage. . . . . . im sure someone there would know of someone that has taken the worn ones. you could then find them and ask for a few short lengths to make your blades from. . . . . I would think that cobalt drills in a mill would drill your mounting holes.

I think I have one leaning against a big ol tree I got from the neighboring town garage. . . too bad your not a whole bunch closer.

lbender
01-14-2014, 11:31 AM
I can bolt two blades together using existing holes

If you only support the blades with the bolt holes, I am certain that they will fracture through the bolt holes under load. A machined blade holder that applies the load uniformly across the back of the blade would be a better idea.

dian
01-14-2014, 01:08 PM
" not tempered just normalized but a file wont touch it."

what does that really mean?

C_lazy_F_Guns
01-14-2014, 10:32 PM
" not tempered just normalized but a file wont touch it."

what does that really mean?

To temper first you harden by heating to non-magnetic and quenching, rapidly cooling. Then you have a hard part, usually too hard and needs to be tempered or softened by another heat process, varies by marital but heat to something like 6-900f for a set time.

Annealed is softened, heated to non-magnetic then cooled very slowly.


Normalize is heat to non magnetic then allow to cool normally in ambient room temperature air. It’s not hardened/tempered or annealed but someplace between at about it’s normal hardness.


Of curse this is steel, non-ferrous mettles are different, they anneal with quenching and never acutely harden.


By “a file won’t touch it” I mean it is too hard for a file to cut, slides over just dulling the file.