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power hammer tooling question


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Gday all,

I was reading the winter 07 edition of the Hammer's Blow, the article "Power Hammering with Bob Patrick", the other day. The article mentions a tool called a snapper which is used with a hack to cut steel under the hammer. Can someone explain what a snapper is and how its used? Even with the photos I couldn't figure out how its used.

While were at it, please feel free to share pics and explainations of your specialised power hammer/treadle hammer tooling, I'd love to learn more.

Regards
Rusty_iron,
Brisbane, Oz.

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A snapper has a square edge and is used to pop of any burrs that result from a cut that is not perfectly clean. The cross section is square but the struck side is usually rounded so it won't kick when hit. It is also fairly small stock - maybe 3/8 to 1/2 at max.

For example, if the hack is used to cut straight through a piece, the cut will be wedge shaped and there will be a tail at the end of the cut. To use the snapper, the piece is flipped over so that side is upwards and the tool placed just over the remnant. The hammer strikes the snapper and shears the remnant away. In all cases, the snapper is relatively small and thinner than the stock size to be cut.

I made four different sized snappers about 20 years ago and have maybe used them once during that time but that could just be a result of the work I normally do. A lot of this type of tooling came into use in places where the hammer drivers had no access to other tools. Clifton Ralph has said the forge shop where he worked was not allowed to have a grinder and other tools so they used the hammer for everything - which is why he is so good with one.

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Snappers are also used for shearing material cold or at a black heat, you can snap small stuff on a small hammer. Clifton Ralph talks about shearing 4" square bar cold on the steam hammer with snappers. The snappers should have Nice Square edges, and when used to shear material they are lined up so that if they were sitting side by side the edges would be touching or would overlapp maybe a 1/16th. If you have everything lined up right it doesn't take a huge amount of movement to shear the bar, even on big stuff. I don't remember how big a set of snappers were used on the big bars, but as I remember it wasn't very big in comparision to the thickness of the bars...

I think I tried to set up to snap some material on my little 75# utility style air hammer a few years ago, and didn't have much luck. At the time I attributed it to poorly made and designed tools and a lack of three hands and two perspectives;-) Clifton and Kurt Farenback made it look real easy on a 250# LG ;-)

You can also look in Lillico's "Practiacal Blacksmithing Illustrated" he describes the use of snappers too.

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A bit more on hacks and snaps:

I use them both quite a bit. For a long time I just used the hack, but when the hack is taller than the work you are cutting, you risk driving the hack into the lower die. There are several problems with this. You can damage the hack, damage your lower (and or upper) die and the piece can shoot of like a rocket. If you use the hack to cut about 7/8 through the stock the flip the work over and use a snap the is SHORTER than the thickness of the work you can't damage your dies and the pieces being cut are trapped by the top and bottom die so they don't fly around the shop. If the alignment is correct, you also get a very clean square edge on both ends produced by the cut. A hack is tapered and a snap is square or rectangular. The ideal thickness of the snap would be just a little less than the big side of the notch that is created when the hack is driven into the work. I like to make my hacks and snaps from H13 because they hold up well to the type of work I do, but other alloys such as 5160 or 1095 will also work.
Since the hack is tapered, it can be used as a taper tool in a pinch. Also, if you want cut round bar without creating flat spots, you can support the bar in a V-block and use a hack. Rotate the work a bit after each blow and it should come out round.
Patrick

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