Sunday, April 29, 2012

Working the Press 2

 (slightly modified from the post on Bloom 2 Bar)
Something I saw at the  Corning Glass Museum (on the combined Smeltfest / Research trip in March).

F- 'Split Fire Riser'
R- 'Solar Riser LH4'
Thomas Patti - 1943
(Sorry - its a horrible image)

When I saw these glass objects by Patti at the Corning Glass Museum, I immediately thought of how the hydraulic press could alter the shape of a block of steel in a similar way.

So this is what became of the concept (Very, very, first renditions)

The left corner is the result of the very first experimenting with the press day I did with David Robertson. (David had consulted heavily with me on the construction of the press before this OAC project begain.)
The tool was originally produced for potential use with my small air hammer. I never use secondary tools that much with the air hammer, primarily because of the small die surface (as repeatedly mentioned, only 1 1/2 " wide by 4 " long). Although it is true that lack of practice is part of that problem! It has a slightly tapered shaft forged from 1 1/4 ' round stock, so the working end is roughly 1 inch diameter. The shaft length is roughly 3 inches, made of mild steel. The handle is piece of flat stock, wrapped around and MIG welded on the top surface, then ground flush.

The starting block was a piece of 1/2 thick by  roughly 2 inch square.
The resulting shape was made by setting the tool on the orange hot block, then driving it downwards. I used the full power of the press (to 3000 psi), primarily to see how far through I could push the tool.
As you can see, what happened is that the tool 'bottomed out' at about 3/16 thickness. At that point the metal below the tool had most of its heat pulled off through contact with the tool and bed of the press. The increasing pressure then simply started to bend the shaft itself.

Obviously not the way to go. Interesting potential however.

The second test , at the upper right, (done April 17) started with modifying a tool. This small (cheap) ball peen hammer had been used for a different impression test initially. Result was that the pressure collapsed the walls of the eye around the original wooden handle. First I used a drift to re-open the eye and straighten the bent head. The hammer face side was forged down to approximately the same shape and size as a standard 3/4 inch taper base candle.  Last I forged down a piece of solid 5/8 " round to fit, then drove that into the eye hot to seat it.
The starting block this time was a piece of 1 inch square, about three inches long.
First the hot block was collapsed downwards into itself. With a second heat, the tool was pressed down into the block.
One unexpected result was that the ball top end actually left an impression into the mild steel top flat plate die set in the press. Not good. 

But the finished object? Closer, but still not quite.

Both tool and object prototyping continues...

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

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