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Duncan Hill
Location: Guelph, Ontario, Canada Joined: 31 Oct 2019
Posts: 31
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 Posted: Fri 22 Nov, 2019 2:21 pm Post subject: 15th (ish) century crossbow! |
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Hi gang- I’m pretty jazzed about this: I’ve just competed my second crossbow; it’s a vaguely 15th century central European bow with a flat self-prod of ash. The draw weight is 100lbs, with a 25cm draw, and 20cm power stroke; about 750 inch-pounds of power. It was pretty nerve wracking tillering the prod; I had 2 that exploded, then I realized it would help to steam and bend in a little deflex first. It shoots well and HARD, with even a bit of recoil. The tiller is maple and the tickler is also ash; the nut and inlays are all black walnut.
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Michael Beeching
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| Posted: Fri 22 Nov, 2019 3:41 pm Post subject: |
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That's a lovely crossbow - I will state that you have rather strong nerves to make the nut and trigger out of wood!
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Duncan Hill
Location: Guelph, Ontario, Canada Joined: 31 Oct 2019
Posts: 31
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| Posted: Sat 23 Nov, 2019 2:36 pm Post subject: |
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| Michael Beeching wrote: | | That's a lovely crossbow - I will state that you have rather strong nerves to make the nut and trigger out of wood! |
Thank you! Relooking at those photos, I realize the bridle looks pretty anemic so I’m going to redo it.
The 100 lb draw is well within the limits of the walnut nut, and I constructed the ash tickler (!) in such a way that the wood grain is oriented optimally for the load at each point. But it’s a fair point; I don’t think I would go much above 150 lbs with those components still of wood.
I’m very interested in the load limits of a self-prod with rectangular cross-section. I think the deflex is a critical part of this, so the next one I do I’ll aim for higher weight and more deflex steamed in.
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This is a standard topic