Monday, February 1, 2010

Blacksmith Spring Fuller Questions

Spring Fuller Suggestions for Blacksmithing

Mr. Robertson,
I would like to fabricate a hardy spring fuller.

I have several leafsprings from an old truck that I can use for the spring portion. I had figured I would shape each end of the spring in a swage to fit a 3/4" diameter bar and then weld 3 or so inches of the bar in place at each end of the spring. I would then bend the spring so that the round bars come together and finish by welding a piece of square stockon the outside of the spring to fit my hardy hole.

I have two questions. First, is it acceptable to use mild steel for the 3/4"fullers provided I keep them cool during use?

Second, what sort of heat treatment do I need to do on the leaf springs where they were heated and bent?

A couple of things.
The leaf spring may be too heavy to get a good spring action. I usually use a coil spring that I straighten out. Then flatten out the midle section to a thickness of about 1/4 inch. This gives enough of a spring.When welding either the hardy stem or the "jaws" onto the spring steel, preheat the spring steel to at least 500 degrees F. I will usually take them up untill they just show a bit of color perhaps 1200 F. This seems to work pretty well for me.

The mild steel will work fine for the jaws, at least for quite a while. Expect some wear though.

Once the spring is forged flat and bent to shape, Take an even dull orange heat on it and just let it air cool and it seems to work fine. The steel itself is springy will work just with normalizing. If you want to heat treat, temper to about 500 degrees F but this is not really required on this tool.

I have also made spring fullers using mild steel flat bar as the spring. 3/16 by 1.5 inches or 1/4 by 1 inch Both of these have worked as well.

Hope this helps.