Air hammer vs tire hammer in Power Hammers, Treadle Hammers, Olivers Posted September 14, 2009 Not quite. When you lessen the stroke of an air hammer you surely lessen the velocity of the tup, unless you are trying to tell me it reaches maximum velocity instantly. As far as the mechanical hammers go, if properly designed, there is no loss of throw whatsoever. The older hammers with the dupont linkage may suffer this limitation, as well as the tire hammers if they also have the dupont linkage, but helve hammers can easily be set up to have a six inch or more variation in bottom dead center. In addition to this adjustability, in my hammer (based on a rusty), I set the bottom of the stroke when adjusted all the way down on top of two 1.5" spacers, which I can remove anytime I need more height for tooling, thick stock or whatever. Air hammers dont reach full velocity, but they do keep pushing. They dont need the "slap" of the spring to move metal. If that spring cant expand and open up the energy never gets released. The beauty of making your own hammer is the ability to lower your anvil and step up the dies. It gives you that the versatility to be able to use tooling and not lose your blow. Beautiful thing if you know before you make it. Helve hammers have the ability to "open " up, as I stated. I love Helve hammers.