Subject: Re: Air = "Aerotyke" / Electric = "Electrotyke"

From: [email-masked]
Date: Sat, 20 Jan 1996 16:57:04 -0500

David:  Actually, wouldn't it be great if we could make a mongo sewing
machine for sheet metal.  That would impress your wife and she would forgive
you for wrecking her machine.  The little incising hammer that I've been
thinking about would have a light ram, maybe five to ten lbs.  The
experimental one I now have has about a five pound ram and it may be a little
light.  You have to understand that this is more like a treadle hammer in
purpose rather than a power hammer.  As a power hammer, it  would not be very
functional.  It's used to tap the end of a hand held chisel for incised work
and I don't think we would want a massive ram (even 25lbs) coming down on our
hand held chisels.  The hammer wouldn't do much more than that but would save
a lot of wear and tear on the wrists and forearm muscles and possibly
forestall  carpal syndrom problems.  Well, it's not a great idea, but just
another approach to use for incised work.  
regards
Chris

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From: Steve Smith <[email-masked]>
Date: Tue, 23 Jan 96 10:05:11 MST

--
Steve Smith
[email-masked]

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From: Steve Smith <[email-masked]>
Date: Tue, 23 Jan 96 10:35:55 MST

Well, my previous message didn't work. I must have forgotten to save
the text. Here it is again as best as I remember it:

It seems to me that a small electric hammer for chiseling/chasing
could be made in a fashion similar to a power hammer (i.e. Little
Giant). You could make the eccentric motion by using a VW engine case
and crankshaft, taking the drive motion out one of the piston holes.
The main problem I see with this approach is speed control. Instead of
a slip clutch as on a power hammer, I think a speed controlled motor
might do the job. 

An AC motor is really tough to control speed on. A DC motor, on the
other hand, is really easy--just vary the voltage applied to the
motor, and the speed varies. The big advantage of DC motors in
variable speed applications is that their torque stays constant over a
very wide range of speeds. 

The trick here is getting a DC motor big enough to drive a 5-10 pound
hammer! Crawl around in the junk yards/surplus stores. 

I suspect that the traditional linkage on a power hammer might not be
the best for this use. Some kind of give is needed so you don't smash
the chisel through the work.

--
Steve Smith
[email-masked]