Sunday, December 09, 2007

The windbüchse of Prostl - Part 5
A fictional account of the development of an early airgun

by Tom Gaylord

Part 1
Part 2
Part 3
Part 4

Could a spring be larger than the lock it powers? Why not, he wondered? Why not reverse the working of the entire lock and put all the springs and levers on the outside where they could be as big as they needed to be? It would be like the sawmill that had so captivated him. Instantly, much of his already fabricated lock dissolved in front of his eyes and re-formed in a simpler yet far more elegant fashion. An outside lock! It might work at that!

Most of the work he had done on the lock to this point would be undone by this change, but the new idea was worth far more than the extra effort it took to accomplish. Only the heart of the lock, the essence of its operation, would remain, but with this new revelation, Bidderman finally knew he could make the gun exactly as he had imagined it many months earlier. Simply turning the lock inside-out made everything possible. He set to work at once.

He used the last of his precious steel for the new parts. The other parts for the first lock which were now unused would supply him with more than what he needed to finish the job. The hammer spring was fashioned from an immensely thick bar of steel, but this time he didn’t fold the metal with the craft he had learned from the Spaniards. While Damascus steel is strong, it doesn’t have the resiliency of a homogeneous steel bar, so the spring had to be made of a single unfolded piece.

And August knew a thing or two himself, so even here he improvised in ways no gunsmith had ever dreamed. Instead of just attaching his spring to the hammer in the usual fashion, he rigged a unique arrangement of force multiplication, by adjusting the geometry of the main spring on the hammer as it traveled through its arc. At the start of its journey, when he wanted to generate the greatest force, he made the spring be its strongest, with compound angles only the finest craftsman would be astute enough to ascertain. Power was provided not only by the conventional V at the apex of the triangular spring, but also by the lower arm into which Bidderman forged a slight arch. When the two arms came together, he could get still more power from the lower arm, by making it flex against the upper arm in the manner of a flat spring. In effect, he had combined the power of two springs into one! But that wasn't all.

The end of the spring that bore against the hammer was not attached to it directly. Instead, it slid along an inclined shelf at the bottom of the hammer as it moved through its arc. The point of contact was at a variable, increasing distance from the fulcrum, so, as the force gradually lessened from the expansion of the spring, the mechanical advantage became ever greater. That, coupled with the inertia of both the moving hammer and the valve lever, kept the force driving the connecting rod constant. The effect was one of continuous force, rather than the simple banging of a heavy weight against a valve stem in one uncontrolled punch, and it was the essential thing that differentiated Bidderman's lock from any other. Centuries later, only a few makers would be able to discern the mastery of design that went into it.

The butt and valve could remain as they were. The outside lock pattern had no real impact on them, other than to reverse the direction of the valve lever, which now had to pass through the lock body, itself. He worked for three weeks making the special tools required to cut a perfectly square channel, yet having the same curve as the lock body. Through this channel passed the square-sectioned rod that connected the valve lever to the valve. The rod had to be fitted tightly to the channel or else the wind would escape that way and fail to act on the ball in the breech. It was a most complex cut to make—one that tested the skill of even the master. Until this point he imagined that music boxes were the most complex devices he had ever worked upon, but this single rod made him change his opinion in favor of the wind gun. A perfectly square channel cut on a curve. Was there ever a thing harder to do? If there was, he fervently hoped he might never encounter it.

With all his work keeping him long hours at the bench, old Bidderman took sick and was abed for several weeks. The neighbor wife who looked in on him from time to time now came by twice a day with food and to check on his condition. When the Baron learned of his illness, he sent his personal physician over to attend the old man, but, alas, the news was not good. Bidderman had the coughing sickness that usually meant the end of life for one as old and frail as he.

The Baron himself came round to see his faithful servant and was distressed to see that his physician had told the truth. The old man was dying, and from the look of him it wouldn't be too long in coming. He dispatched three of his servants to attend to the old man night and day, to make sure that he did nothing but lie in bed and try to fight the cough that racked his body.

For three weeks everything in the village was suspended as the life of August Bidderman played out in his humble cottage. But finally there dawned a day when he was well enough to be up and about. That day signaled the start of his long recovery to such health as he could be expected to attain with the coughing sickness.

Two weeks after getting up from his bed, old August worked in his shop for a short period. He was as fearful of his frailty as anyone, so he didn't try to push himself. Slowly, he worked himself back to a pace that was, if reduced from before, still a full day for any other man.

The components of the valve and butt were joined by brazing-in the threaded connection, which provided a place for the joining of the butt to the lock. The valve was screwed into the butt threads provided in this joint.

The barrel was threaded on the other end of the lock and the new gun was nearly complete. Sights were fashioned for both front and rear, as this was a rifle and not a smoothbore. For both sights, Bidderman used a material which looked like modern African ivory, but was actually much older. It had been obtained from the tusks of long-dead elephants found frozen in the eastern lands. He purchased a thick wedge of the yellowing material in a specialty shop in Vienna, along with some special figured wood he needed for music boxes.

The trigger was the finest feature of all. It curved backward and down, so that the tip was exactly in the middle of the piece. Like the powerful crossbows in the royal armory, this gun could be fired easily by a person holding it on either shoulder. As his patron favored the use of his sinister hand, this ensured he could use the piece as easily as the maker or anyone else, for that matter.

When all was done on the rifle, August Bidderman quickly fashioned a condensing syringe from the notes he had gathered while still in possession of the first wind gun. He made his pump a little longer and thinner, to make the effort less, and he lapped in the head of the piston with the dust of fine casting sand, which was the finest scouring material known to exist. When he was finished, the pump rod operated without a sound and could be stopped cold by holding one's thumb over the air hole.

Finally came the moment he had been waiting for. It was time to shoot the gun. From a mold he made, he had cast some lead balls which fit the bore perfectly when patched in the Dutch style with a linen patch soaked in sperm oil. Then he withdrew the hammer until the trigger caught it. Taking aim at the wall opposite his bench, a length of seven long strides, he shot at a knot in the wood. The gun roared, but not as much as he remembered the first one doing. The ball struck the knot on one side, so he corrected the rear sight leaf a small amount and fired a second shot. Two things now surprised him: one—the gun shot as strong as at first, and two—the ball struck close to the center of the knot.

Since this was a test of the gun, August reloaded and shot a third time. Amazingly, that shot was just as powerful as numbers one and two, and the strike of the ball blew the knot clear out of the plank.

In all, there proved to be four shots that had good force in that rifle, before the butt had to be removed and filled with more wind. Four shots! And each was powered by a substance so ethereal as to be invisible. Old Bidderman was pleased beyond his wildest hopes, and he knew his noble patron would be pleased, as well. No wind gun had ever performed as well as this one, which made the appearance of the mechanism outside the lock all the more bearable. In fact, he thought, it was very pleasant to see the workings of a machine that could produce results as dramatic as these. He couldn't wait to see the Baron's reaction to the piece when he presented him with it.

3 Comments:

At 7:35 AM, Blogger JoeG said...

Tom,
Great Story as always. I started reading at the start of you writing it, and check every week for the update.

Im glad Bidderman was able to finish the rifle. I was starting to worry there for a second.

JoeG from Jersey

 
At 8:21 AM, Blogger Tom Gaylord said...

Jersey Joe,

Oh, he finished the rifle all right. I held it in my hand!

After this story is complete I will show the inspiration.

Tom

 
At 10:48 PM, Blogger Kevin said...

Tom,
I have read them all 5 or 6 times. Please don't make me wait too long to hear the Barons reaction. :-)
Best regards,
Kevin

 

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