Latchet Mechanism

Ref: Tod's Stuff Latchet Crossbow. The more I look at that the more intrigued I become with it. I have seen mention of a Latchet crossbow here but have not found anything about details.
Does anyone have information about the workings within it like, lever arm lengths and firing mechanism? Looks like a right decent project to tackle to me.

Tinker

I have thought about the latchet mechism a fair bit but like you I haven't found any exact details for one. There is a version in Payne-Gallway's Book on the Crossbow. That version is for a stone bow that has a trigger. Which does give some clues.

I have a couple of ideas for mechinisms for a latchet bow that has a button like the one listed on Tod's page. ranging from the supper simple to the slightly complex. When I get home I'll have to check through my notes and see if I can post some of them.

I am very interested in how you can make this mechanisme work!
So when someone has an idea or plan please share it with us

thanks

Zhangyimou

zhangyimou wrote:I am very interested in how you can make this mechanisme work!
So when someone has an idea or plan please share it with us

thanks

Zhangyimou

Perhaps those of us who are interested in the latchet bow mechanism could brainstorm how the innards might function.
I will start the ball rolling

From the posting on another forum HERE (about half way down) Tod has posted three pictures. From them I would suggest that the firing mechanism will not be simple (milling machine would be a really big help) and a retaining rail system would probably be needed on the bolt firing weapon. The rock-chucker does not have one but I would bet the other does have a way of keeping the firing block retained on the forward stroke to engage the string for cocking. The system might be a groove inside both sides for a rod on the block to engage... but making a uniform groove in the wood for a track would be a bugger. I would even question the durability of a wooden track in rock maple?!
Your turn?

Tinker

That are some very detailed pictures, specially the last one......

i guess it is simular to your firing mechanisme Tinker, complete in steel and overlaid with wood
somewhat like Todd's balestrino.

i guess you are right when you say one will need a milling machine.... challenging....

think i'm going to sketch and make a model one of looking at the pictures.... let you know the results

Man... studying that stone bow picture makes me wonder what velocity a .45-.50 caliber lead ball would roar out of it at? Ever see any details about making one of those rock-launching bowstrings, or is that still another of those 'wing it' things?

Tinker: I have made a number of stone-bows in the past. They throw bullets about as fast as a regular bow throws bolts. Payne-Gallwey has complete illustrations that will teach you to make pocketed strings for stonebows. You can also build rests and bolt-strings that will allow you to shoot knocked arrows from your stonebow.
There are two things you should know about stone-bows: First, bows that are built to do a number of things... like shoot shot, or single stones, or bolts interchangeably usually don't do any of those things terribly well. Specialization rules the day.
Second, and MOST important. It is possible to make a stonebow shoot balls backwards, right into your face. How do you think I know this? Because I have done so. I didn't quite lose my right eye, but I am now a left-eyed shooter because of the residual damage. (the double-string flipped over at the end of the throw... it only released to ball on rebound, right through my spectacles. I got an eye full of glasses-lense as well as a cat's eye marble at about 150 fps. This hurts, and will ruin you whole day... or weekend as the case may be, and will result in a trip to the emergency room to pick out the splinters.
If you want to make a bullet-bow, I recommend you look at Payne-Gallwey's plans for bullet-bows with slotted gun-type barrel. Bullet-bows will not shoot backwards, and they should give you hours of fun hurling marbles or pistol-balls downrange. They're particularly enjoyable as 'plinkers' for shooting at old soup-cans. Enjoy. Geezer

THANKS Geezer for the "how do I know" wisdom. I would not have expected such a reversal of target acquisition! The thought of making a rock-chucker was interesting but best forgotten

Tinker

Geezer - OUCH, Sorry to hear that your anouther member of the "Almost Lost an Eye Club". Thats a good warning all around. I was thinking a stone bow would be neat idea as well but will stick with a barreled version. You know for all of the pictures I have seen of stone bows "they" must have figured out how to reduce that issue.

So the long promised lock mechnism concepts. These are the really crappy MS Paint versions and yeah my Paint skills are pretty poor so hopefully everyone can figure out what I am trying to design.

Real Simple

Simple but worried about friction between the roller nut and release. This may also be a period concept for some of the early latchet bows.

Sort of simple

This one I like better as it removes the some of the friction issues. Yeah it would need some tweaking before being a usable design.

Concerning Stonebows:
Indeed there were lots of stonebows all over Europe and some in China as well from 15th through 19th centuries. How did they deal with the backwards misfire issue? Well, proper geometry of the stock helps to some extent (the bow that shot me in the eye didn't have enough clearance for its slightly over-long string, so the bottom of the string hit the stock at the end of its run and 'tripped' turning the pocket backward just in time to hurl the stone backward on recoil).
Also, you'll note that lots of Italian stonebows, at least have a large volute (or carved figure) that stands tall above the stock, just behind the lock. Others featured a rather large, spoon-shaped peep-sight. Either of these might have been intended to give some protection in case of a catastrophic misfire.
Based on historical evidence, I think it's possible to make a safe double-string stonebow, but an investment in a used fencing-mask for testing might be a good idea. Personally, I've done my time with stonebows... I find shooting sticks I can see in the target is more satisfying than shooting balls that I can't see in the target unless I get very-very close.
Anyhow, I think the barreled bullet-bow is safer, and it can be made to use a standard bowstring, which is a plus. Geezer.

Basilisk;
Either of those would function as a top trigger release, but I am thinking that for a Latchet it needs to be way thinner (top to bottom) like the innards shown in the one photo showing the stone bow's mechanism. A big block as you suggest would require a very large chunk of wood for a stock. And, the way my block retains the roller nut without an axle would require the front of that block to be seated against wood (inlet) to support it in the cocked position.
Personally, I think that the roller nut can not be made to function nearly as well in the Latchet application as would some sort of finger release assembly (complex multi-lever mechanism, probably).

Any thoughts about if/how the release block would be retained in the stock as it moves fore and aft with the cocking lever?

Geezer's story has made me lose interest in a stone bow. Now I'm focused on at least a 100# Latchet to loose bolts...

Let's keep the ball rolling....

Tinker

Regarding the ongoing conversation about the latch or latchet release. I had a small stonebow in my shop some years ago, that had a built-in cocking lever with push-button top release, as illustrated. I never had the authorization (from the owner) or inclination to take the lock apart... breaking it would result in substantial loss of value to the owner. Even so, I have a few observations based on fairly careful observation.
The lever/lock system was so arranged that releasing the lever allowed the shooter to move the entire lock forward so the single falling-finger of the lock could be snapped into the loop on the doubled string. Indeed, the little finger which holds the nut is quite small... much smaller than the smallest roller-lock I have seen. But here's the neat bit. Moving the lever forward also lowered (rocks forward) the standing peep-sight that was attached to the back of the lock assembly. Moving the sight served to reset the levers inside the lock-box so that the finger would reset automatically.
To load, the shooter simply released the catch at the end of the lever, and raised the lever up and forward, thereby automatically lowering the standing peep-sight, which actuated a lever that allowed the dropping-finger to snap back into place, snaring the loop on the back of the string. Then the shooter simply draws the lever back into place and locks it down. The string is now drawn, with the lock-finger in the appropriate loop. Push a baked-clay ball into the pocket and you're ready to go. Shoot, release lever, swing it forward and back, relock, and push ball into place. It's that easy.
Damned ingenious device. Geezer.

Those Barbarians WERE smarter than they looked.
Gonna havfta thunk abit on thattun...

sTinker

I was wondering if it would be possible to make a "normal"release mechanism on this type.......
i'm not so happy with the relase on top
what do you think?

zhangyimou wrote:I was wondering if it would be possible to make a "normal"release mechanism on this type.......
i'm not so happy with the relase on top
what do you think?

DAMN, I hate it when that happens... typed the reply then lost it

There is usually a "way". I can easily understand why the trigger was designed to be on the top of the block. To design a mechanism that would transfer the ticklers job from a moving block that has to be set returning from the forward stroke, then move back to battery and engage a bottom of the stock trigger is probably waaay beyond my imagination. Maybe not... but would the end justify the means, and would it be safe? To me it is logical to have a trigger on top if you shoot your xbow on the top of your shoulder; and probably less-apt to inadvertently bump the lever hanging along the bottom?!

GEEZER posted this in another thread if you missed it: "ps. I've got that stone-bow back... we're gonna take pictures of the lock and post 'em on lightly's flickr site." --THREAD- I am looking forward to see the 'innards' on it

Thanks for hanging in here on this brainstorming project guys, Tinker

Hellow fellow crossbow fiends, Geezer here.
Payne Gallwey's "The Crossbow" features diagrams of stonebow/bullet-bow/latch locks in his section on bullet bows. There is at least one that features alternative top-buttons and a trigger at the bottom. Take your pick.
Those of you who don't have Payne Gallwey? Shame-shame! Call yourself a crossbow nut, but don't own the fountainhead of modern crossbow enthusiasts. Just remember, PG isn't always right, occasionally he's downright wrong-headed, but "The Crossbow" or "The Book of the Crossbow" is one of the most useful, easiest to find works on medieval and modern crossbows (up to 1903 or so) If you don't have a copy, go look on Amazon, get a copy and then just sit there turning pages.... Oooh, I think I'll try this one next! Geezer

Geezer; You have me pegged. I don't have P-G but have pondered buying one. Actually, I have an acquaintance who offered to give me his old hard-backed version but it would require a long drive and a lunch to retrieve it. Reason for hesitation is that I have Longrifle books up the wazoo. They were all very interesting and I have no plans to get rid of them, but with the forums putting out so much great information the necessity to increase the technical literature pile is questionable.

Hello Tinker,

You can download a PG copy and die armbrust copy at one of the other crossbow forums, somewhere here at this forum you can find the directions. Unfortunately i cannot remember where i found it.

Geezer:
i really missed it in the PG book(?!) that both ways are available -> technical interesting!

Well now, I didn't know PG and Harmuth's "Die Armbrust" were available anywhere online. If somebody would be kind enough to post the location, I'm sure a lot of people would be gratified.
Those of you who haven't seen the Harmuth book, the edition (1986, ADEVA press) I have is only available in German, but even if you can't read a word of the text, you'll find the illustrations alone very worthwhile. This is the book PG would have written if he had lived 80 years later. Check it out! Geezer.

https://thearbalistguild.forumotion.com/history-literature-movies-art-f7/crossbow-books-t27.htm
So that is the link to the Crossbow Books Topic, the in last post is Ivo linking to a Russian crossbow forum that has a bunch of links to down load books. I don't speak any Russian at all (though I can now pick out the Russian word for arbalist) so had fun poking through each link. Near the bottom of the topic are some links to were Die Armbrust can be downloaded straight. some of the top ones point to a bittorrent file which doesn't appear to be seeded. Version of Die Armbrust I downloaded appears to contain just the pages with illustrations not all the text. Kind of annoying even thought I don't read German either and the text would be pointless.

*Edited to add* One of the downloads on the site above is the entire Die Armbrust. the file had a funky Russian title "АrmbrustИгонаХармута.rar" for those looking would be the one to download.


As for Payne-Gallway, I have come across several sites online that have the book posted.
http://www.crossbowbook.com/ is one place. Not as convient as having the book in hand but not a bad start.

Ok hope that helps.

Ok and now back on topic, Seriously this time
Tinker-
Here is another lock for a latchet type crossbow this is from Die Armbrust
I believe it is from the all metal stonebow so once again it may not be exactly what you are looking for but hey more inspiration is always better, right.

I shall try to 'digest' all of that data

Tinker

Tinker wrote:Man... studying that stone bow picture makes me wonder what velocity a .45-.50 caliber lead ball would roar out of it at? Ever see any details about making one of those rock-launching bowstrings, or is that still another of those 'wing it' things?

Robin Allen is the man!!!

Bullet bow String making(Video)>>>LINK

PS: Tinker and Gents..."Firing" isn't exactly a term for crossbows....use something like : Shoots, or flings, or hurls...etc.