Alldays & Onions 300# hammer: Die inserts

Side view of die inserts in place The Alldays & Onions came with half-flat/half-bevel dies. They are, I suppose, meant for heavy forging in a ship or railway shop, and that with a helper and maybe a hammer driver as well. They don't lend themselves to singlehanded, freehand forging very well. What to do?

I made several tools that clamped to the lower die with the band shown. The one shown here worked best but operations such as necking or drawing-out remained awkward with the asymmetrical flat-upper plus crowned-lower combination. This was reinforced at a recent hammer-in by watching Ian Hope-Simpson demo on his 100#, flat-die hammer with a crowned lower insert and flat upper die. He did it very well but deployed large amounts of effort and skill to cope with the asymmetry.

So here I've made inserts from segments cut from those heavy, dog-leg helper springs used on large trucks, compliments of my friendly neighborhood heavy equipment shop. Each piece is milled flat on one side.

Oops! That upper die didn't work. Scroll down to fail to read about it.

View of jack supporting die insert in place So here's the upper insert being installed. There's a 10 ga. bridge over the lower die to make a flat place for the jack. Jack is a Cavalier car jack with a pivoting table added to hold the upper die. Installation requires several steps:

Front view of die inserts in place If you're paying attention, you'll have noted, in the last pic, that the clamping bolt isn't centered on the lower insert tab. That's been fixed.

The sling in the 2nd and 3rd pics hangs from a jib crane made from an old gas station's hollow octagonal signpost sunk in an old washing machine shell full of concrete. It allows holding a heavy workpiece with one hand. Easy rotation around the long axis of the workpiece is provided by the lower chain loop which runs over the wheel seen in the photos.

The crane is so positioned as to allow access to the hammer from the front or from one side and swings away to where I can put a portable forge. It includes a light chainfall, resurrected from the junk heap, that allows adjusting the height of the sling to match the dies with or without inserts or tooling.

I didn't feel confident of my ability to tap 1/2x13 blind holes in hard steel and my machinist was himself doubtful. But it went well for him and the result is as you see, with two flathead cap screws on each end of the insert. It may be necessary to use some heat to tweak the fit of the insert to the die but I'll torque up the screws and give it a try before I fiddle with that.


Side view, pointer to badly placed component
Rear mounting tab interferes with guide
The rear tab or ear by which the upper die insert is screwed to the upper die lay on the rear face of the die, same as seen, for the front tab, in the first image. There was plenty of clearance in the hammer bore. That's fine in the front but in the rear, this tab interferes with the tup guide bar.

In the last photo, you can see the flats on the back of the tup where the bronze-faced guide bar rides. I stupidly failed to think of this beforehand.


Side view showing tab let into a rebate in the die  body
Mounting tab is recessed in rebate

So the insert attachment tab can't stand above the flat faces on the back of the tup. Here you can see that the mouting tab is no longer proud of the rear die face.

My machinist milled a rebate in the die -- hard stuff that gave a carbide cutter a hard work-out -- and deepened the threaded holes for the cap screws. Cut the insert down to match the die dimension, cut through the tab weld with a zizz wheel, reweld. The next photo shows the rear attachment in the rebate.

Rear view
showing tab screwed into rebate And there it is. The hammer works fine. I now have shaping dies suitable for interesting forgeing. (In this image, you can see the flats on the rear of te tup against which the guide bar rides.)

Oh, well, that was the "last" image but, just as proof of concept, I've finally actually forged something with this beast.

Fan shpe forged on 1.25 in. bar

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Created: Mike Spencer -- Wed 08 Oct 2014
Updated: Wed 22 Oct 2014