twar

Bending alloy/tool steel

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I'd like to stamp sheet metal blanks using my fly press. If I make a "blade" out of e.g. H13, can I bend it (hot or cold?) in to shape (also with the press) as I would mild steel?  Thanks.

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H-13 can certainly be forged, hot, but you need to take some care with temperature control.  In my experience, if you get it too hot (yellow white range) it crumbles like cottage cheese, but it is tough steel to work below a cool orange as well.  Bottom line is that it has a tight hot working range.  Annealing is also tricky since this is an air hardening steel.

I would not try to bend it cold.

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Are you actually going to make a blade or is it just an example?  H-13 is alloyed for use in situations where it will be getting hot, up to red hot and will retain it's hardness. If you have a bunch of it laying around I wouldn't see it as a problem but it's more suited for hot work tools like punches and drifts, but if you're just using "blade" as an example then the previous posts have answered your question. I did notice the quotes around blade that is why I'm asking. Good luck and remember it's supposed to be fun.

Pnut

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My "blade" is a thin piece of steel with a ground sharp edge that I want to press/cut through cold sheet metal. My cut will not be a straight line, and that's why I am asking about the bending. I have enough H13 on hand, but if I didn't what would be a better choice? Thank you for the help.

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Let me start by saying I don't have a ton of experience I just didn't want to see you use a hot work steel for cold work.  H-13 is more valuable in situations where the tools will heat up but it won't lose its hardness, H-13 would definitely work I would save it for hot work though.With that being said, 5160, 4140,  1045 up to 1095 there's many good option. I would bend it hot in the forge and heat treat per requirement for the specific alloy you choose and then draw a temper back to a dark straw or maybe just a bit farther. There's many more experienced members here that can expand on or correct anything I've overlooked. I have a cold chisel made from H-13 and while it does work I'm afraid it may chip so I don't use it much. I hope I've been of some assistance. 

Pnut

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I’m a journeyman tool and die maker. There are many better steel types better for cutting than H13. It really depends on what you want to cut. Seems simple but as we have come to learn steel can be fickle. Happy to help where I can. 

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Thanks ForgeDad. What would the blade of sheet metal cutter/shear be typically made of?

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It is hard to tell from your description exactly what you are planning on doing with the fly press and sheet metal.  If you are planning on cold punching out shapes, I agree  that H-13 would be a waste.  You would probably be better off with a shock resistant steel (possibly S-7).  I've seen commercial pill punches made out of that.  You will likely also need a female die to punch into, which can call for some rather precise machining.  The previous owners of my small fly press intended to use it to blank out custom fishing lures.  To my knowledge they were never successful, which is why I was able to get it so cheaply.  I'm sure it can be done, it just needs some careful planning.

I've not seen a fly press used for chiseling out sheet metal shapes, if that is your goal.  I suppose it is possible, but feel a treadle hammer is better optimized, since you can more easily switch out chisels to get different radius curves, or longer and shorter straight lines.

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2 hours ago, ForgeDad said:

I’m a journeyman tool and die maker.

Good to know; looking forward to your adding your expertise to the forum.

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Thank you Latticino. Think for example something like a simple hinge blank where a 3x3"(+/-) piece of 12-14g sheet metal is cut in to two hinge halves. No curves, just straight lines and right angles.

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Not sure, but my gut tells me that cutting out a ~3" length of 12 g sheetmetal in one blow will take a significant amount of force.  Is this a manual fly press or motorized?  If an irregular cut you will need top and bottom cutters.  This sounds like a good application for a punch-press.

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Before we get to worried about what steel to use for the blade some more important things for the success of the project. What equipment do you have available to use?  Are you able to work down to tolerances of .001?  What is the tonnage your press can generate? 

But back to your original question a good heat treat of 55Rc or better will work fine. A2 would be the choice in my shop. H13 is a high performance option for shock resistance better than S7  

Interesting point Holland Anvil here in West Michigan uses cast H13 for their anvils

Now im rambling  sorry.......

 

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Are you planning on a production run for an entire house or something even larger maybe? For one or two I'd just use a hammer and chisel and clean up the edges with a file or grinder.

Pnut

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This is merely a beginner’s experiment to see what I can do with my newly acquired 120-year-old H-frame manual press (guessing it to be about 5t). I know I can punch, bend and form, but can I cut/shear sheet metal in a way similar to a bench-mounted, levered metal shear—but on a smaller/finer scale. So, no major project—I’m just learning. And I’m not trying to stamp straight though sheet metal, but rather shear progressively throught it (if that makes any sense). I may fail spectacularly, but I will learn (maybe). My original question was, what kind of steel is typically used in sheet metal shears? I have H13 on hand, but understand that it’s not the best choice. Thank you all for your feedback.

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This is the «before picture». This what it looked like when I picked it up—not all that beautiful. It’s currently in pieces, so I’ll get back with an «after picture» when I’m done cleaning it up. It’s 3’ across the top/fly and 30´´ tall. The screw is 2-1/2´´, 3-threaded.

 

 

73422246-61C9-4C31-81D6-BC1AA4C5D657.jpeg

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I used to make die sets when I had my machine and fab shop. When it comes to shearing and punching you have some critical things to consider. Alloy, thickness of material, tonnage required, etc... If you want nice clean edges you need tight tolerances between the punch and die... .001" or so. To keep these tolerances you build up a die set that is put into the press, and keeps everything aligned. The tolerance between the punch and die will vary depending on the tonnage and edge requirements. Speed is also a big factor, and speed is your friend.  Much easier to punch a hole fast than slowly. There are charts that you can reference for tonnage required depending on the size of part being cut.

 

I mainly used D-2 for steel cutting punches and dies. I also bought my die sets from Anchor Danly.

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In all probability you're wanting to "Die Blank" hinge preforms but I strongly doubt your fly press is anywhere near enough. Cabinet hinges sure but not something 3" on any side from 14 gauge and 12 is WAY out of the question.

This isn't a matter of a blade cutting steel, it's something entirely different, shearing. Tolerances between the female and male dies are in the 0.0001" range and how they impact is more critical still. 

I'm not trying to discourage you but shearing something like you describe is NOT a beginner's project and not trivial for the experienced. I'd LOVE to have a fly press to experiment with and you should explore it to your limits. One step at a time though, less frustration and a faster learning curve that way. ;)

Frosty The Lucky.

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