I do not have the genius of Leonard da Quirm, but I do share one trait with him – I get easily distracted and sometimes spend several days trying to shave off a few minutes of some task or save a few bucks. Sometimes the effort definitively pays off – as in the case of my belt grinder or my forge burner, sometimes it is a success but with a question mark whether it was worth it – like the unbender (now I know it was worth it, btw, I have used it several times already and it is time-saver), and sometimes it is a bit of a flop, as when building a vacuum pump. If I had a definitive fail, I do not remember it, and so I allowed myself to get distracted again these last two days.
I have a problem with making metal bolsters, handguards, end-caps, and pommels. As in, it is difficult to get material thick enough to make them pretty, and even if it were not difficult, the result would be overtly heavy and thus would put the knife balance totally out of whack. The proper way to make bolsters and end caps is to make them hollow, and there are techniques for that. One of them is forging – as I did in the rondel dagger project. But that is labor-intensive, has poor reproducibility, and requires special tools anyway. Or I could buy prefabricates and adjust my design(s) to fit what is already on the market. Screw that!
So I have decided to make some new tools, and test them. The inspiration was a technique of minting coins before the invention of fly screw-press, which I have seen as a child in some black and white movie which has shown the making of Prague groschen at Kutná Hora. I remember nothing else about the movie except the part where they strike a punch on a silver blank with a hammer and thus make a coin. I think there was some drama and history in there too…
First I have made a die out of 5 mm high-carbon tooling steel. It consists simply of two holes – one for the bolster and one for the end-cap (I have chosen my small hunting knife as a pilot project because I think the design will be improved a lot by it and because I do plan to make more of these knives in the future). Second I have ground two punches out of square stock of high carbon tooling steel that I have scrounged at my previous job. Grinding the forms with angle grinder was not easy, but it was not insurmountably difficult either. I had actually a lot more trouble with welding onto it the 15 mm round stock for holding the punch in place and for striking – my welding sucks, bigly. And because at least the first strike needs to be real mighty, I have built a small wooden stand to hold the punch in place for that.
© Charly, all rights reserved. Click for full size.
With the assembly on the concrete floor, as you see it in the photo, I have given it a mighty whack with my puny Mjolnir. And I rejoiced because it was a success. To protect the floor from damage I have put it on a steel plate for subsequent tries and I went and punched four sets for the four blades that I have currently in making, three out of brass and one out of pakfong.
© Charly, all rights reserved. Click for full size.
The pakfong was a bit thicker than the brass so it gave me some grief, thus the surface is not so smooth on the end-cap – I had to whack it several times and it wandered off the die and I struck it without noticing it. But that should not be a problem, there is enough material in there to polish these dents out.
It took me mere minutes to punch all these, and after a long time, I was really, really happy for a bit. There are a few details to iron out – like making a better stand for the punch, making it so I can put it safely on my anvil, figuring out the ideal amount of overhang and so forth – but it functions as it is and it is a massive saving in time already. Whether the knives will really look better remains to be seen, but I am confident they will. Further, this opens a lot of new possibilities for knife designs for me.
An other approach is to make a silicone mold and cast wax for investment casting. It’s clock-time consuming but very low effort.
@Marcus, I have tried metal casting yonks ago, with disastrous results. So that option is moot, for now at least. It requires more specialized equipment and experience than I currently have -- I do not think I could pull off four sets with just two days’ preparation and ten minutes of work afterward. As you say, it is time consuming even with the appropriate equipment (and experience). I think it would be a too big a waste of time at this moment -- I need to build up a bit of stock and perfect the techniques I already know before going on a limb exploring new territory.
But I will revisit that theme at some time in the future. Only, for now, cold forming, when possible, is definitively the right way to go for me.
It all looks suitably sturdy, jolly well done I’d say.
Yup, cold forming is very cool. The fittings on Japanese blades are traditionally hammered from flat plate. If you haven’t watched any of Ford Hallam’s work, it’s amazing.
I believe the state of the art is moving toward 3D printing metal alloys or wax for investment casting. That’s a dismaying option for me since it means becoming system administrator for yet another device.
Cold forming is a good idea. Impact driving is not the way to go.
Way back we used to only occasionally need to use large, 4-0 to 1000MCM, terminals and splices. So the boss got a deal on some hammer driven crimpers. These units were spring-loaded jaws welded onto a heavy steel plate. put your cable into the terminal and the terminal into the crimper and drive the jaws closed with a heavy hammer. Good news is that with a bit of luck, and someone brave enough to hold the proper alignment as you swing a hammer close to their hands, they can be made to work. Down side is they were prone to shifting as the driving was just taking hold, you really needed a flat, hard and heavy surface to work on (even some concrete slabs were not ideal) and terminations tended to get more exciting and difficult if at the end on a long, hard day. For non-critical work (precious little of that when dealing with such large cable cross-sections) where you need to just one or two crimps they worked almost well enough if you were willing to fail and have to redo it about 10% of the time.
The boss finally broke down and got hydraulic crimpers and everything got much more productive and predictable.
What you want is something like an arbor press. Preferably one with a massively oversized hydraulic cylinder. Good news is that a decent arbor press can be had cheap or assembled. Harbor Freight or Northern Tools are good for such ironmongery. The entire unit (now that I looked it up) goes for less than $200 at HF. On such things always go for overkill. A 20T can do everything a 1T press can do, and more. And it will last with lower loads even if it isn’t all that well designed.
https://www.harborfreight.com/automotive/auto-body-trim/metalwork-tools/20-ton-shop-press-32879.html
I understand that with some judicious reinforcement and upgraded of the shear bolts they can be worked at several times their original rated capacity but I’m not sure how far I’d push that. I’m willing to sweat to get a job done. I’m less enthusiastic about bleeding.
A hydraulic press is a much more manageable and controlled process. Less chance of random slips and things bouncing around. More reliable, repeatable, and safer.
@lorn, I do agree that hydraulic press is a much better way to go, unfortunately not only I do not have any disposable income right now, I also do not have enough space for even a small press. I had trouble find space even for this assembly. My workshop is so tiny I have to store tools that are not used very often in the house, like a small belt sander, angle-grinder, and welder. And the house is starting to get pretty full too.
If I start to make money (which I do not believe I will) then I will expand the workshop a little. A hydraulic press is definitively on the list of devices I would very much love to have.
Could the cold forming be done with a hydraulic bottle jack (you know, those things that are meant for lifting a car to change tyres) and your punching assembly. That could be more precise than hitting multiple times. Bottle jacks seem to cost here 12 € -- 100 €.
Of course, the jack and the assembly would have to be between two immovable points of support, which may not be easy.
Looks good to me!
Don’t get me started about space. Is there ever enough of it?
@Ice Swimmer, I was thinking about using car jack, but I would have to build a scaffolding around it and thus the space problem would not be solved. But it remains a possibility, that’s for sure.
@Giliell, no there is never enough space. Never, ever.
Well done, Charly. It’s fabulous when you find a method that works, saves time and opens up new possibilities.