Del's Archery Adventures - Crossbow Refurb (Part 2)

Here's a shot of the "false string" clamped onto the limbs of the crossbow that I built 25 years ago. This false string enabled the crossbow that I recently refurbished to be re-strung. The image below also shows how the bending lever is used.

There are several steps to cocking the bow. First, the "nut" (a big steel roller block) is rotated so that it is ready to receive the string.

The lever is hooked on the D-ring with the ends of the short arm pressing onto the string. As the lever is pulled back, it pushes the string until it meets the nut.

The string sits in the transverse groove and then carries on back, rotating the nut until the trigger lever clicks into place. In turn, the trigger lever engages with the groove on the underside of the nut. The bending lever can then be removed.

Click here for a video that shows the whole process, including a shot.

The bending lever isn't finished to the same standard as the rest of the bow, but it does its job. A bit of reshaping was done to make sure it wasn't fouling the stock or hitting the bolt clip. The tip of the hook was also trimmed back a bit to make it unhook more easily after cocking.

Bolt and Test Shots

The bolt (arrow) has a tapered shaft which is slightly elliptical at the back so that it fits nicely into the nut. The string sits against it. I forged the head to be reasonably authentic. There are only 2 flights, which were often made of card or leather. I've used feather, and they are applied at an angle to make the bolt spin.

The rate of spin is tested in my special test facility. That is to say, I lob it up in the air and watch it spin like a top on the way down. Because it's heavy, it throws very nicely. It's quite a good game for two people throwing one back and forth. (OK, it's a tad more dangerous than a Frisbee!)

So how did it work? The first shot went through three layers of target foam and penetrated the leg of my Workmate folding bench!

I tested the crossbow in my garage. After all, it's a problem to find somewhere safe to test such a powerful weapon. While shooting at slight longer ranges (3 or 4 paces), I noticed that the bolt seemed to be hitting the target at an angle. To test this out, I shot at the face-of by chopping block (a piece of log). The bolt smashed, but I could see it had struck at 45-degrees.

I figured there were two reasons.

1. Though pretty, the forged arrowhead wasn't symmetrical or evenly-balanced.
2. The ivory bolt-rest at the fore end was lifting the bolt too high because it had been shaped for smaller-diameter bolts.

To confirm my findings, I first made a tougher bolt using the forged head. (Yes, this also smashed!) I then made a head out of some steel tube with a piece of rod glued into the end. It wasn't so pretty, but it was much better balanced. I also reshaped the Ivory rest. A test shot confirmed a fast, true flight.

Hope you enjoy the video. Here's the link again.

Del

Editor's Note: Click here for Part 1.