made an ollie hammer

[Dewnmoutain]

ollie hammer? or oliver hammer? Or treadle hammer? i forget

 

It's got an 8lb sledge on it. My original hammer head was a 13lb, but it was really weirdly shaped and needs more work to make it usable. 

 

Just the couple times ive used it, i know i need to make the foot pedal longer because it forces me to be a bit unbalanced when i kick with my foot, and it's not allowing me to center my material when i hammer, allowing for mishits. But when it hits true, it really hits. 

[JHCC]

Yep, treadle hammer. Some people call it an Oliver, after one particular model of treadle hammer -- in other words, all Olivers are treadle hammers, but not all treadle hammers are Olivers.

I just call mine "the nodding donkey" and leave it at that. Great tool; it was a total game changer for me.

[Frosty]

Yeah, that looks pretty Olliver to me. Like all tools we make for ourselves a little tweaking and refinement will happen as you use it. 

Good job, keep it up. 

Frosty The Lucky.

[Dewnmoutain]

well, i thought id resurrect this old post as it pertains directly to this hammer. because of injury, i now have the (forced) free time to contemplate and work on this hammer.

so after a couple months of using this hammer, it was annoying me that no matter how hard id stomp my foot to get the hammer to impact the hot steel, it wasnt leaving much of a mark on the steel. my initial testing and uses were with pieces 1/4 to 3/8ths thick, so the hammer would do the job. But when i moved up above 1/2", especially 1" variety, the hammer wasnt hitting as "hard" as i thought it would. 

i monkied with the setup some more, and just couldnt, at first, figure out what was causing the softening. So, i just hung the thing up and said "meh, ill get to it later". That was back in January. Had a friend come over, and using my army tenacity and his nuclear engineering thinking, we figured out that the culprit is the springs itself. Turns out, they dont move until they have a 20+ lb load applied to them. So, they are too "weighty" (or resistant?).
i scrounged through my scrap steel, and found some old springs, but they too, have a higher load limit in the 20+ lb range.
 

so i thought id ask here, since i now have the free time to work on this, does anyone know where i can pick up some weak springs? ive already hit up the local hardware store, and the ones i picked up were also wound tight and would only extend half way out with a 20lb weight on them. i tried looking at some online websites that sell springs, but this is where my knowledge of choosing a spring is very lacking.

anybody have experience with finding or buying the types of springs im talking about? 

[ThomasPowers]

Screen Door Springs?   Make the mount so you can add and subtract them to get the force you need.  They are also designed to stretch out a lot in their normal use!

[Goods]

Might sound strange, but try shortening you connection points and put both springs in the picture on linked together end to end. That should give much more weight reaction. I believe the calculation for springs constants in series is the same as electrical resistors in parallel.

David

[Alan Evans]

Try moving the spring connection further down the the shaft away from the hammer head...you will have more leverage against the spring...

My return springs are off a pulley on the end of the hammer pivot spindle, and from memory is only Ø8-10" so the connection point is effectively 4" or 5" from the fulcrum.

I never reckoned you could get the same clout out of a foot hammer as you could from a hand hammer for drawing down etc. Standing on one leg and stamping down with the other is not the most efficient way of delivering energy by the body. What I use it for is the finesse of striking with both hands free to manipulate top tools and workpiece. And that was even before I had a power hammer

Just found some  photos and a sketch with dimensions if it helps. 

Alan

 

[Alan Evans]

The springs only have to lift the weight of the hammer against gravity and no more, a very light touch required. The hammer does not need to be held at rest at the full height of the stroke. The stroke of my hammer can be well over 20" when cycling but static is 15".

With your existing connection points something like a long length of bungee cord may provide that and not fight you so much?

It is 50 odd years since I first found the bits of shafting, plummer blocks and old car seat belts at the scrap yard to make my foot hammer, and just looking at it now I see I had forgotten some of the subtleties I had tried to incorporate in the operating and return linkage.

I was aware that with most (all?) spring return foot hammers the spring pressure increased as the hammer descends and it reduces your strike energy...you're fighting it all the way down. In the early 1970s I had probably heard of the compound bow invention which accelerated and increased power as the arrow went forward, and although I didn't know how it worked I made an attempt towards that concept in spirit if not mechanically.

My contribution was that the bottom spring attachment is on the opposite side of the treadle fulcrum so as the pedal goes down the spring goes up and the tension fighting against you is slightly reduced.

Now 50 years later I know how the compound bow cam wheels work, and also the oval Shimano bicycle chain wheels....I think it would be interesting to modify the pulley shape to a cam on my hammer design to further improve the treadle down and return spring dynamics.

Something for a younger man to explore!

Alan