Tony, what happened to your last post? I got an email of it, but haven't had time to respond. Now it's gone. Your post was a little "brisk", but it was honest and to the point. I sure don't have a problem with that. I appreciate your experience and input. I'm an ex-marine. I'm used to being yelled at. :saluteflag:
Actually, I agree with most of what you said. Perhaps I should explain my reasons for going against your recommendations.
This isn't a commercial endeavor. It's a favor for a friend. I'll only charge him enough to cover costs... including a low cost grinder for me. His cost will be less than half the price he currently pays and the punches will be as good as I can make them. I do hope and expect they will be close to commercial quality. But, if they only last half as long, he'll still come out ahead... and I'll have a new grinder.
) Worst case, if I completely fail, I'm out a few bucks... and I'll pay for my own grinder.
M2 temperatures are a little high but within my furnace's rated capability. Element life certainly is a valid concern. Fortunately, I won't be doing this often. If I burn out an element, I'll replace it. Not a huge loss.
The furnace is computer controlled and gives repeatable results. I'll heat treat samples and have my friend try them. If they don't perform well, I'll have one tested to see what went wrong. If they do perform well, I don't need to know the hardness. I'll just heat treat the rest the same way. Of course, if this were a commercial endeavor, I certainly would do regular testing and quality control. But it's not. In this case, good enough is good enough. Still, depending on cost, I may do testing out of curiosity.
I plan on building a CNC plasma table this spring. That will replace the nibbler for most tasks. Making punches is a one time or maybe a once a year project. We're talking about 20 punches and a couple days work. I'm not trying to out perform the competition or gain repeat business and it's not a big expenditure of time or resources. It's the challenge of doing something I haven't done before that appeals to me... plus a new grinder.
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I have the M2 data sheet with recommendations from the steel manufacturer. I also talked with a shop who regularly does M2. They use a salt quench. The manufacturer recommends an oil quench to obtain maximum hardness. Some people recommend a two step quench (oil until no glow then air to 50 C). Supposedly that reduces stress and deformation. The punches are small and a fairly uniform shape. I don't foresee deformation being a problem. I'll stick with an oil quench then three tempers, unless someone sees a problem with that.
The bottom line is that I'm doing this for fun. My decisions on how to do stuff, like heat treating in house, aren't necessarily the most practical or the best financial decisions. They may or may not yield the best possible product, but good results are achievable. I will do the best I can. I like learning new skills and I like challenges. If I want to learn to treat M2, I have to start somewhere. This is where I am.
My main concern remains finding a decent tool sharpener / grinder for a reasonable price. Something for $500-$600. I'm still cruising Craigslist.
