Thursday, March 8, 2012

..But sometimes you just might find (?)

(Day 22/23 *a)

A second stab at creating a starting billet that would lead to one of the blades described earlier.

The key to getting this concept to work as envisioned is to actually intentionally be sloppy with the initial compaction steps. (At the risk of sounding arrogant, after so many years in the forge I find it hard to *purposefully* use bad technique - even when the desired effect calls for it.)

These are the two starting masses from Smelt 49, November 2011. This was a 'slag pit' furnace set up (rather than our usual 'slag tapping' type. Ore used was industrial taconite, with a 33% return yield of 6.4 kg total.

The starting bloom fragment weighed 573 gm, roughly fist sized (seen at the left, above). First heats were taken at welding temperature, with the two flatter surfaces worked and the edges left largely alone. Then the piece was worked on the air hammer into a flat plate.

From there the plate was cut with the hydraulic press. At this point the pair of pieces have the profile I had initially projected for the blade project : One more or less solid, straight edge, against a more ragged and irregular opposite. One of the pieces also has a major crack across it (right above), but I have decided just to leave this as is. The weight at this point is 433 gm.

Cutting the larger piece would be the first 'production' use of the new hydraulic forging press, built specifically for this project. *b

The starting mass (bulk of the bloom) was 4652 gms. The cutting process also compressed the spongy bloom slightly (no specific compression was undertaken). The bloom had been placed with the normal 'planno' surface downwards for the cutting. The roughly oval shape was first cut side to side, then the two half sections were then cut into two pieces. As expected, the pieces are only roughly quarters. As seen in the image above, the two pieces on the left are slightly denser than those seen on the right. The piece in the lower right is the most fragmented, the one on the upper left the most solid. I expect there will prove to be a variation in carbon content between the pieces as well.

Next step with these pieces is to consolidate each into working billets.

* a - The ordering is going to get messed up here! I was in the process of working this post up on day 22 when David Robertson showed up for our planned workshop day with the hydraulic press (more to come on that). So I finished this posting off the next morning (you will see two on Friday March 9).

*b - There have been a number of general descriptions of the work I've undertaken to convert a commercial 30 ton log splitter into a forging press , available on my longer term blog 'Hammered Out Bits' :
Log Splitter to Hydraulic Press
Hydraulic Forging Press (continues)

This work started before the project grant had been awarded.

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February 15 - May 15, 2012 : Supported by a Crafts Projects - Creation and Development Grant

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