"Krusty" - The Mechanical Powerhammer

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Powerhammers have been around for quite some time - there are historic find dating back well over a thousand years, and most likely powerhammers have been in use basically since man started to work hot metals. The simplest and most likely first designs were basically so called "trip hammers" - just a big wood-log with a massive metal (or even stone) head mounted to the front part. The whole thing was hinged towards the back and a large water powered rotary wheel provided for the movement. What such a hammer lacked in speed it usually made good by providing a very heavy hammer head.
If a powerhammer was not available a smith would have to rely on trained strikers, apprentices and other personell to get the work done, however more than three or four strikers usuaully have not much space around even a large anvil - and their power, whilst amazing, is still often not enough.

During the early industrial days with the famous steam powered machines there were also huge steam powered hammers - and shortly after airpressure powered ones.
They were more accurate, offered a higher amount of control and a lot of power.
Besides these, a bit longer around were plain mechanical powerhammer of various types.
The idea behing all powerhammers is the same: use some sort of motor, air pressure, steam,... to generate a controllable movement of the ram.
here's a great old video (youtube) showing off a large old steam hammer: 



 
What we will discuss here is a mechanical "spring-type" hammer with roughly 100pound ram weight.



A few technical things in advance...
if you want a powerhammer perfoming optimal the ration between the ram-weight and the base-anvil should AT LEAST be 1:10 (this is still "suboptimal") an 1:18 if you want optimal use of force and rebound power.
Taking that figure you see that a 100pound ram would need at least a 1000pound anvil - or even better a 1800pound anvil. That is a massive amount of steel not easily found unless you cast the base or work at a rather large industrial smithy.
What I can say, that if you go with less than that you will loose an aweful lot of power.
now, 100 pounds ram weight aren't little either.
When I built the hammer discussed below, I didn't have too much information or practical experience with BUILDING powerhammers... I basically took what my local junk-yard offered and gave it a go... with the experience I've gained from this, I would however recommend a few changes.

What are good specs for a "junk-yard" hammer imho:
  • Ram weight in the 25-50 pound range 
    Yes, this is less than what I've used - but less ram weight means less anvil weight needed.
  • Increase speed, my hammer was tuned in to operate at 180 beats per minute - up this to at least 250 to 270 bpm
    This is quite some increase in speed, but speed will give you more power - it hit's faster (weight * speed = more force)... you will be amazed at how much more work can be done.
  • Stop block, larger drive- & flywheels 
    Try to think of a basic rubber coated counter block which will press on the fly-wheel when you release the foot treadle, keeping the hammer from going up or down again... this will enable you to rest the ram at the top.
  • Motor - 1,5kw (2HP) isn't bad - but go with 2 or even 3kw if you can afford it.

 

The changes above should yield you a much better working hammer than the original design here.
I thus strongly suggest that you include the modifications listed above when you make a "copy" of "Krusty"...  The hammer will work better and also be a bit less problematic in a few aspects! 

 

 

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