My very first second crossbow! Also, hi.

First topic message reminder :

Hi guys! This is my first step out of the shadows here, so advice is very much the word of the day.

This is my second crossbow, after a wee little 1.5# toy i made from a scrap of bamboo. The point here is to aquire the skills and knowledge to move on to more "full size" bows. 

The prod is english oak that i aquired as a log, made a flimsy first shortbow out of, and then turned, as a sort of fun sunday afternoon experiment, into a small prodlike thing i backed with bamboo. It came out very surprisingly tough, reaching 35# at around 10 inches, being only 22inches long. 
Thus it became perfect for my learning process! 
One of the quarters of the split log quickly became a rough stock, and with some iron and steel parts i managed to make out of iron stock and waste sheet steel, using a push peg simple trigger, it all came together as a quite fun experiment.

Im working on a bridle block and stirrup, for confort mostly, and a sighting system of sorts, using the bolt clip probably.

Then its on to sanding, some detail carving and finishings. Planning on going linseed oil and clear varnish, to bring out the oak's grain, which i like very much.







So, what do you think?

Phuphu, thanks for all the info. I tried the sanding method, because sharpies are nowhere to be found around here, and i presume the particular composition of their ink is what gives you the "gauge" for that 700 F mark. 
Tempered yesterday, got that black iron look to it, like the bolt clip, going to re-sharpen today. 

C sitas, that is something i never thought of, dental floss! Reminds me of sinew as a lashing, don't know why. I'm sharpening on a whetstone, followed by some water sandpaper, up to around 600grit. Gives it a nice sharp contrast. 

Hermit, i've use brass wire before, on bow handles and such, thinking it might work, though not as pliable as copper. I hesitate to add more weight to the tip though, i think it's already a bit heavy for the prod.

Anyways, and with that in mind, yesterday i laminated a bit more oak and bamboo, thicker this time, also wider. I'm going to tinker with it for a bit, see if i can scale up the poundage a bit. I have to say though, it's very fun to shoot, and (some may say surprisingly) the trigger push is very smooth and satisfying.

Ill get some photos going, maybe a vid on shooting it.

Here is  a short edit showing my new toy. 
Btw, I'm making a new prod, same bamboo and oak combination, though considerably beefier, going on 55 pounds. 
Hoping to mount it soon.
Enjoy!

Just spending some time here  rereading things. Joaol , You no doubt know how hard the MDF is right. With the penetration you showed, that arrow head would most likely be lethal. I know  if you didn't bleed to death, you would catch pneumonia  from the hole it left. The thing ,back when I mentioned using dental floss for a lashing material for the head , the whole purpose of the stuff was to simulate  the sinew of old.The hairy little fibers stick out just great.Tiny carvings of raw hide will work to . install them wet , and it's like welding the head to the shaft.As I look back at this ,you done an exception job on the whole . Well done my friend.

Thank you very much sitas!

I've been tinkering on and off with this bow for a while, as I've learned a lot from my mistakes, this forum and some reading i've been doing on crossbows.

The first improvement was a new prod, which i made from a loose laminate of spring steel 2mmx50mm, 6 leaves. I cut a taper into the limbs, going from 40mm in the center to about 25mm in the tips. (Once i got a grip on using a scrap guide to cut with the angle grinder, it was 2 hours to do the lot. Thanks to whoever posted that on the wiki  )





This improved the poundage to around 85#, which, while still fairly low, is a big step, combined with some lower weight bolts (mine were too heavy by far, having a range of around 12 meters, although hitting quite hard in close close range...)

Next im going to raise string height a bit, to reduce track friction, which i think is slowing things down a fair bit.

The final step will be to drop a steel half pipe (which i just cut) into the bolt groove (which is too deep, adding more friction) .This will allow me to make thinner, and lighter, bolts of the same lenght, without compromising their durability too much by changing into a soft wood (i'm using beech). This is where DENTAL FLOSS *play trumpets* will make its appearance!

Also, 85# is kind of hard on my thigh to load without a stirrup, which is also in the making. 

So. That's all the news from the Portuguese front! 

I really have to thank all you guys for the advice, encouragement and knowledge you have compiled here, this is truly a Guild, in the best sense.

That is a beautiful looking prod, i was thinking of doing somthing like that using a bunch of old style wood saws becouse their kinda springy

Onager, thanks.

I made a saw blade prod a while back, on a small pistol bow. I'll link it: https://thearbalistguild.forumotion.com/t1365-small-pistol-crossbow

My advice for you is to get the thickest possible steel. Think old style 2 man lumber saws: 



 The one i used on the pistol bow was around 0.8mm thick, and it took me 6 leaves to get 30# from a 30cm long prod, at 17cm. What you might notice is that 17cm is quite a long draw length for a 30cm prod, which is the beauty of loose laminates. 30# at 17cm gives you a lot more arrow speed than 30# at 12-13cm (my estimate for a solid prod of same characteristics).

Happy blade hunting!
Joao

Got the prod mounted and the new string made. Next up, the groove and front sight, as well as the prod bindings.

It's looking better all the time.  By the way, I've actually seen at least one medieval/renaissance crossbow with the butt bent off line, much as you have done.  I've also seen some with butt bent downward in a gentle curve.  Geezer.

Joao; You have a gorgeous   bow my friend. I have a similar saw and I am going to sacrifice it to the bow gods. You have shown me the way. Say ,back to your broad head, there are some old heads and some new ones now,that are sharpened only on one side. They use these on large dangerous game. In use they make an awesome wound. Just google "single edge broad head."Easier than me trying to explain. Thanks.

I have an old book on Gunsmithing,and back in the day,gunstocks were made with an offset,so it's not a stretch to see that Jao's bow is an accurate reproduction.I'm not really into the old style crossbows,but dedication and good craftsmanship deserve recognition,very nice work Jao
                                                            Hermit.

The offset is still used in gun stocks today. Its called cast on or cast off (depending on which way the stock is offset). In rifle/shotgun stocks it not used as an aid for aiming but is used for felt recoil management in hard kicking cartridges.

Cast on ,I believe ,throws the barrel more in front of your face. It gives quicker a sight picture. If your not used to seeing this ,you'll the stock is really warped cause, you have no trouble seeing it.Some of it has to do with your neck ,and reach and so on.

Gentlemen, thank you very much for the input! 

Things stand like this, on this forsaken piece of land the ocean doesn't seem to want: Groove done, string failure, stirrup done and mounted, string failure, bindings tightened, made a ponpon.

Any thoughts on string failure(s) cause, aside from bolts being too light and string to weak to withstand the tension at the end of the shot? (both strings were 22 strands of 1mm flax (11 loops)) 

What do you guys think of ponpons? I can't make up my mind on whether i like them or not....

Here are some pics, as tired fingers cannot explain very much by way of typing.

Oh, i must alert you all that my offset stock was a product of the natural bend in the oak log it was carved from. I did take into account which side to make the top side, so that the curve could fit my stance, but at the time i had no idea what i was doing. 











João

Joao; By golly you really fancied that bow up . She's fit for a knight. I'm an archer and I make all kinds of different bow strings . Anything from 25# up to and including 100#. In a regular bow 100# is considered almost impossible to pull but, there are men that can do it.For your type of bow I'd say to use B50 Dacron fiber.Dacron has the ability to absorb a lot of punishment and still perform. For instance I know of people that have dry fired , and the bow  survived .Can't do that with most other material. Where exactly do you live? I'm in the United States. What I'm getting at is maybe some simple way I could help you out. If this is possible ,I would be honored to be of use.By the way, how much did you end up pulling for your bow? Also ,back further in the post you made mention of using sharpies. I think you didn't quite get the point. What I think was meant was-- you can buy what is called temp-slik. They look like a sharpie. You mark your metal piece to be heated with them.When that temp is reached the marker melts. It's pretty accurate too. A poor man's thermometer for metal working, and quite cheap really.

Sitas, thank you:) I live in Lisbon, Portugal, we are half a world apart! I have made a new flax string, thicker this time (around 8mm), which made me go back to the thicker, heavier bolts. So now i have to find a way of getting a durable thinner string (around 4mm dia), to use the thinner bolts.

My prod is pulling around 80#, so my guess for the string break was the near dry-fire that came from using the very light bolts as an experiment, seeing that the string broke 1/3 of the way from the nock.

I went on a bit of a research and found out this video on youtube, describing what seems like a solution for my problem, a knotted string, where the nocks are the same thickness as the center. What i'm still experimenting is how long the skein has to be before knotting to get the required length in the end. My figures are somewhere around 10-16cm longer, depending on thickness.



If someone knows German, i think he explains something about the extra length, in the beginning.

I searched the forum for a bit and didn´t find anything related to this kind of string, of which Payne apparently had no knowledge of, according to his chapter on bowstrings, where he says something along the lines of "i have no idea how this (same thickness on nocks and center) could have been done except for an auxilliary loop" . I have seen this string on a few german crossbow images before, but never could make out how to do the knot. Maybe this will add to the general knowlegde, and perhaps you or others who have made this kind of string can give me a tip or two.

Ps.: Thank you very much for the offer Sitas! Would you like to trade a couple of broadheads for a string?

Pps.: Dum me, i had no idea such a nifty thing as that kind of pen existed!

João

Joao, You hit the nail on the head. I was thinking more like trying to send you a roll of proper material. I could send a couple of strings to get you started. In the mean time ,I will check and see what it takes to do this. Just glance back from time to time while I check . I'll go about it right away.

Joao please send me a message.