How to lash on a lath?

Hi everyone.  There's no Walmart equivalent in the UK that I can just pop into so I am about to order in the cordage to finish my current project, a wooden lath 15th century central european style crossbow. Can you advise me as to the correct cordage for binding on the lath? Also, any advise on making the string would be very welcome. Thanks in advance,
Andrew

I think hemp or linen should work fine for both the binding and the string. Wax the bindings with melted beeswax or some kind of oil once you are done lashing the prod to the stock. This is to protect it from the weather, and make it water proof.
Here's a video on the binding 
https://youtu.be/V2VDpAauAZI
And here's the video on the string 
https://youtu.be/wWiZpenRGx8?t=876
Also here's a two part series of building a medieval style crossbow string
https://youtu.be/grLsVCY8Y0w
https://youtu.be/muGha7a2mfU
All the videos I sent on how to build a string were the reinforced endless loop method. If you wanted to make a string with the continuous loop method here are two videos for that.
https://youtu.be/WV8m8Wkgilc
https://youtu.be/Vz8j9Harf_I
P.S. I apologize for most of the videos I sent being in German it's just the best ones I could find.

Yes: watch the German videos, they're the best/most authentic I have found. For many years, I had my own method of binding the prod.  When my apprentice found these videos, I changed my bridle/binding immediately.  Honestly, I think my system got things as tight, maybe tighter, but the system in the videos is clearly the common medieval/renaissance system.  Geezer.

Thanks for the links the videos were excellent.  So linen for the string, but what is the best for the bridle? I couldnt tell what it was he was using but I think it looked like it was about 3mm diameter hemp??? Any idea on the length of cord needed?

If you read the comments he said 18 meters.

Oh thats so cool, my phone didn't open the comments I'll check it out on a laptop later

Thanks, the comments were very useful, they even have the reduction in string length caused by the knots which is something I have been wondering about for a long time. Also, I have never been able to find part 2 of the string-making videos so I am VERY grateful for that link!

It seems that Jos uses hemp for his bow-string but Todd uses linen? Still haven't managed to work out the thickness of the cord for the bridle though.....

Linen I think is better for a bow string it has less stretch, and is stronger however, it's more expensive. If you want to go the cheaper route then use hemp.

I found a source that talked about the thickness of the cord bridle, but it was about the Padre Island crossbows I hope you don't mind. It said that the cord used to wrap the prod was 3/16" thick.

That's perfect! Thank you.

Yup: I wrote a fair amount of the Padre Island article, along with J. Barto Arnold, the archaeologist in charge.   Needless to say, the cord itself had long rotted away/eaten by bugs, but it left very clear castings/marks in the overburden of marine accretions that let us judge the diameter of the cord pretty accurately.   Geezer
ps: over the years I have come to the conclusion that what we thought might be a wedge safety for the trigger was merely a horn trigger spring.

Dont suppose you have a link to that article?

https://drive.google.com/file/d/188q0mgC6RIIzeMxVJZHCIfHREM_xjlB1/view?usp=sharing
I put it onto my drive just when you click it click on download afterwards. Don't click on open with google docs it screws up the file.

Thankyou  I'll enjoy reading this!

Fascinating.  Did you ever build replica 4?

I did build replica 4, but had a lot of trouble making a string the right size and then actually stringing.  After the article was published, the archaeologists kinda lost interest.  So no. 4 is still hanging on my shop wall.  
The other three all went to museums:  Two to Corpus Christi museum (one for display, one for docent demos) one bow went to the Turks and Caicos Islands museum.  And later, I made another for the Bob Bullock Museum here in Austin Tx.  It's in a display of stuff from early Texas conquistadores.

So sad but that kinda sums up academic interest in medieval ballistics - theories are much more interesting than actual hard evidence - a fully functional and accurate replica properly tested will destroy so many possible papers that could be written about the theoretical uses/capabilities of the weapon. As a trained archaeologist with a keen interest in experimental archaeology and having worked in a university as a support tutor, I am afraid I have a very low opinion on academic research -the majority of academics only want to compile and critique other academic papers, very,very few want to actually do any research themselves.......

Incidentally, what was the eventual draw weight of bow 4?

I don't know.  Never got a suitable string on it... didn't have a spanning bench strong enough to bend the prod for spanning.  I assume @ 350-400 lb.  That's what we were aiming for, and the spring maker was a reputable fellow. 
Eventually the project got dropped for other stuff of a more pressing nature.  Business is business in the end.
 Geezer.

Totally understand where you're coming from, you'd have spent a lot of time, effort and cash on a project where the clients had already walked away, wouldn't have made any sense to carry on without them.