Reply to post: Re: I'm assuming

Man jailed for 3 days after Texas cops confuse cat litter for meth

Kiwi Silver badge
Boffin

Re: I'm assuming

I would like to play with shaped charge explosives though as a way of cutting metal in the workshop... the hacksaw makes my arm tired.

I too would love to play with some HE.. Just for fun and research purposes mind.. Like how much of a bang causes an involuntary download of brownware in passers by... :)

While explosively cutting stuff can be much more fun than labouriously cutting away with a hacksaw, you could perhaps make a cheap version of a device I only knew of as a "powersaw" (and not the circular type chippies use either). You could probably use repurposed bits for it easily enough, as the one I saw was effectively a larger version of a hacksaw blade.

So, make a carrier for a hacksaw blade (even if it's just a normal hacksaw itself, whatever you can make work). At one end it has to take a drive system and at the other a weight. You'll need something to give it a back'n'forth motion for the cutting action - perhaps the mechanics from a car's screen wipers will do for this for small applications, see parts from an old washing machine for larger applications. A feed of lubricating fluid would also be helpful, to keep the blade and the metal being cut cool and to keep the blade moving. A car's screen washer bottle with pump and the tubing going to just above and to either side of the blade would work well here, you can then have it drain (through some sort of filter - a wire mesh or various types of cloth could work well here) back into the bottle directly. Would have to be a light oil as the pump will probably not handle heavier stuff much. Oh, the blade has to be hinged so you can lift the end opposite the drive and drop it on the work easily. Then you just need a table and clamp for the work - and just resting the work on your normal bench and using a G clamp will do that well enough.

Set the work in the machine, start the machine, bugger off for a few minutes. The machine might take a while to cut but you can do other stuff. We used to use one to cut very large bar stock that would not fit in other machines and take a while to cut with a cutting blade on a grinder (not to mention the waste of metal that would cause), and would kill several hacksaw blades (not to mention arms) trying to cut it manually. The machine would take maybe 20 minutes but would do it itself. IIRC the stroke would be about 2", and the cycle would be about a second (so it would go forward and back in 1 second, and a line marked on the blade would travel about 2 inches). IIRC we would've had about a pound or less in weight keeping the blade on the work (or rather, stroke would be about 50mm/5cm, and around 500gms of weight on the end of the blade - but you guys work in that weird imperial system so I'm roughly converting :) )

DisclaimersThis probably is covered by a few patents so be careful if you try to sell this to anyone. The home brew version of this design I only thought of today in response to the message I am replying to, I have not built such a device myself and there could be flaws in my design I haven't yet conceived of - use at own risk. If you do find a commercial application and wish to thank me for savings/profits, then consider giving money to charities which help elderly or poor people, or cats. CATS ARE NICE.

And damn it, I like things that go Bang!

Easy. One weekend, spill your beer into the oversized 3-phase motor you chose to power the above..

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