[TheForge] treadle hammer anvils

Fri Jan 10 10:44:00 2003

bruce,

no doubt you are correct but...how many spencer style swing arm hammers do you think have been built? how many grasshoppers?

'how many' may not be an indication of 'how good' (they sell truckloads of twinkies) but it is an indication of something.

i didn't think phil was denigrating your grasshopper or being snide. he was just posting his preferences. that's okay.

thanks for your comments on this subject.

bob s.
________

>As the designer of the Grasshopper, I have to take issue with this statement.  I'm not at all impressed by your denigrations of the machine.   I don't know whether you intended to be snide, but that's how it comes across in writing.
>
>The Grasshopper is a very simple design.  If you think it's complicated, you haven't looked past the surface.  Most of the seeming complication is really (1) the two front-mounted adjustment (which I consider very important safety features, but which could be simplified considerably by making them accessible only closer to the points of their actions, and (2) the small additional complication of the apparatus (eccentric pulley) that renders the ram completely weightless.  
>
>In judging the complication of a machine, consider the MOVING parts.  In the case of Spencer-type swing-arm hammers, there are six moving parts:  Ram, two arms, treadle, connecting rod, and spring(s).  In the case of the Grasshopper, there are 8 moving parts:  Ram, two arms, two cranks, two struts, treadle, treadle pulley and cable, and spring(s).  In the Spencer vertical TH, there are 14 moving parts:  Ram, 8 guide wheels, one arm, one strut, treadle, connecting rod, and spring(s).  (I've counted multiple springs as one moving part because in principle a single spring could replace multiple springs.)  Both the Spencer-type hammers and the Grasshopper hammer have adjustments.  
>
>On the Spencer-type swing arm machine, the head height and the connecting rod can be adjusted, but only from the side.  On the Spencer vertical-motion machine, the connecting rod can be adjusted, but only from the side.  On the Grasshopper, there is no need to adjust either of these, but the treadle height and the "kickback force" (needed only in a weightless treadle hammer) are adjustable from the front.  My principal reason for placing these at the front, at the cost of a few more parts and a  little more effort in fabrication, was to avoid the devastating accidents that can happen while adjusting a treadle hammer.  Safety first.
>
>If you think these "complications" aren't worth the trouble, then you're fooling yourself.  (You're free to fool yourself as much as you wish, just don't expect to propagate it over this group without rebuttal.)
>
>BTW, many of us have gimpy knees, rendering TH's difficult to use at best.  The Grasshopper is by far the best treadle hammer for persons who's knees are no longer as good as they were at age 20.
>
>Bruce Freeman
>NJ
>
>>>> [email protected] 01/09/03 06:26PM >>>
>Hi Bob -
>
><snip>
>    The grasshopper is to darn complicated a contraption(I spend most of my
>time in hi-tech advanced manufacturing and automation) and I guess I like
>things simple when I'm home in the shop. It looks like a nice science fair
>project. If you want to diddle, then the grasshopper will be interesting.
>Keep it simple. The leg exercise you get will be a benefit anyway - heck,
>I'm gettin' older and my wife seems to be gettin' faster!! :o))
><snip>
>
>
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