Some beginner questions

Hi everyone,

I'm a new member here and I'm keen to get started on my crossbow making journey.

I've been watching youtube videos all night, and have been reading the wiki, as well as other posts to try and get as much information as possible.

So far I've worked out all the parts of a crossbow, and how exactly each component works.

I've seen designs where the tiller is made from 3 pieces of wood, and some designs where only 1 piece of wood is used.

What are the advantages/disadvantages of each design?

My initial thoughts are that the 3 ply method would mean that it would make accessing the nut and trigger components much easier, however overall it's not as robust as a one piece build.

For a beginner, would you recommend a 3 piece body or a 1 piece to start with? From reading the wiki it looks like cutting out the groove for the nut and the trigger seem rather fiddly.

Looking forward to any feedback from the seasoned builders here.

Cheers,

Kwandokun

My personal take is that the "three ply" or more tiller makes accessing components and component assembly much easier. Although, cutting a socket for a nut can be as easy as drilling the right sized hole with a Forstner bit. Modern glues like Titebond woodworking glues, are generally stronger than the woods they join.

My idea of a multi-ply tiller is using two side pieces of say 1/2" stock for the gross overall shape, and a 'track width' piece of about 1/8" thickness sandwiched between which is cut away for the 1/8" thick trigger bits to function. The nut socket is drilled across the whole 1-1/8"thickness and then covered with thin removeable 'side or lock plates', similar to a muzzleloader, to access the action.

i made my first crossbow out of 3 layers of wood meranti on the sides and oak in the middle. the idea is that the wood maintans its shape, and does not "work".
if you use just one piece of wood you could get a curve in the wood, because of the water in the air.

(i will update this one when i get home and asked my dad how it works exactly)

Here is one way I have done it. Drill for the nut all the way across and cover with "cover plates" very simple to do.





For the tickler/trigger drill and motise a slot underneath and make a cover plate for that as well.





There are of course other methods this is just one way I have done it.



Todd

Thanks guys, that's some great information.

Do I understand correctly that for the trigger component only the bottom of the tiller is cut for the trigger to slide in?

Yes

I made my first crossbow by chiselling out two rectangles, a squarer one for the nut, and a slender one for the trigger, which is a relatively easy way of making the recesses. Drlling some holes first makes this easier.
This method was used for lower powered medieval bows or those with more complicated triggers; and sideplates as show by Todd for more powerful bows.

If you have a router this makes cutting flat-bottomed mortises very easy and is a also a good way to cut the groove if you have a round nosed bit.

Cheers.

I think I've decided on a single body with the nut housing drilled through on the side.

Regarding the lock plates, are they expected to take any strain? Or are they just for mounting the nut bolt and covering the sides? I'd like to use brass for my plates.

The side plates don't take any real strain if the rest of the stock has enough wood around the nut. Look at my first picture, that stock doesn't have a lot around the nut and has held up fine with prods over 150 pounds.



Todd

Awesome.

Thanks Todd. It's all coming together now.

Can't wait for the supply run this weekend.

Ok, before I head to the hardware store, I wanted to ask if there are any specialty tools/hardware I should get which would make my life easier during the build.

I was already going to get a drill press, and I already have a dremel set at home.

I'm going to pick up a forstner bit as well, for drilling out the nut housing. I've got saws, chisels, hammers at home already.

Anything I'm missing?

Think about how you are going to make the groove for the bolt or arrow. What about the stirrup?

Todd

Don't have the necessary tools for metal working so I've ordered a set of bow irons from Alchem.

Good point about the groove. What's the best tool for that job?

I haven't decided if I'm going to recess the wood or just add two pieces of brass to make the groove. Either way I'll need to cut some of the groove anyway.

A router is the best way to make groove, however it can be done with table saw but you have to be careful!
Todd

As an alternative you could use a bolt rest instead of a groove for the bolt.
It only needs to be very narrow,can be filed and then glued to the tiller. Just a very short groove really.
Here's a photo of the bolt rest I made for my last crossbow:


I'd recommed the drill press and I also like to use spokeshaves or cabinet scrapers to finish the stock and remove small amounts of wood.

Thanks Taxus, this is the first I've seen of the bolt rest.

I take it this only works with bolts with 3 fletchings though?

No,it works fine with just two fletches. I do all of my shooting with this bolt rest crossbow with bolts that have just two fletches.

Hi Everyone,

I'm back with some more newbie questions...

So, I've decided my first build will be based around the Alchem plans for a medieval crossbow. I've ordered the bow irons + stirrup from them and have a Delrin rod on the way from ebay.

I will be fabricating my own tiller, tickler & prod.

Prod Questions -

As per the resources available on this forum, and with the help of some members, I've decided a leaf spring is to be the first prod material I use.

I have found these two springs which I can get locally.

http://www.etrailerparts.com.au/index.html?c310.html&1 (Click the first on top left)

http://www.etrailerparts.com.au/index.html?c312.html&1 (Click the first on top left)

1. Can I cut the Slipper spring (link 2) down to size and ensure to keep the hole in the middle or must I use the eye to eye spring (link 1) for the sake of symmetry?

2. The load ratings on these springs are either 300kg or 425kg per spring. Does this translate to 'poundage'? I want something that can be hand cocked if possible.

3. How does one go abouts cutting these to shape since they're already curved? The wiki shows the steel being flat when cut.

Any help on the above questions would be really appreciated!

Thanks everyone,

Kwando

Use double eye trailer springs. They are symmetrical. Use a flexible straight edge to mark the spring. 1kg= 2.2lbs.

Thanks Zardoz,

My question regarding the load rating was in relation to determining the poundage from the leaf springs somehow. I'm not sure a 400kg (936 pound) prod would be very sensible for hand spanning...

For the cutting, I was thinking to print out and stick on a template, and then cut it with a dremel disc.

kwandokun wrote:Thanks Zardoz,

My question regarding the load rating was in relation to determining the poundage from the leaf springs somehow. I'm not sure a 400kg (936 pound) prod would be very sensible for hand spanning...

For the cutting, I was thinking to print out and stick on a template, and then cut it with a dremel disc.

Maybe 936lbs is too much for YOU to span by hand. The Dremel is too small and weak. You will burn it out or use a million of those little girly-discs. Get a cheap Harbor Freight 4 1/2" angle grinder and a few thin cutting discs. You can then put a grinding disc to clean up the cuts and edge tiller the prod.

Kwandokun, one more thing. The 425kg rating is for the entire stack of 3 leaves. you only need one. A leaf that is 1/4", 7/32", or 3/16" thick will get you in the range you are looking for depending on the length and width. Remember: 2x as thick equals 8x as stiff. Increasing thickness by 1/8th doubles draw weight. Decreasing thickness by 1/8th cuts draw weight in half. Look at the total thickness of the leaf stack and divide by the number of leaves to get the thickness of each spring. One inch equals about 25mm.

Awesome. Exactly the info I was after. Thanks Zardoz!

And here I was thinking I needed to hit the weights more often...

Ok, so I've been down to the hardware store (or two) and as expected, I've spent much more than I should have.

Managed to get everything I need except something to be the tickler. The store only had 12mm steel rod and that felt a bit thick.

Question: if my Nut and tickler bolts are 6.35mm in diameter then a 10mm tickler should alright yeah?

I haven't found any good tutorials on making a tickler. Do people usually just bend steel rod into shape?

Steel rod triggers: I use 3/8 in. square steel bar, purchased at my local steelyard. (That's approx. 9 mm) I heat that in my forge... nowadays I have a real gas forge, but up to a year ago, I used a barbeque pit with coal or charcoal, with air provided by a shop vaccuum. A good hair dryer will suffice. For your purposes, if you can only get round stock, I'd go for 10 mm. Round bar is harder to get precise bends than square, it tends to gravitate toward helical curves.
I usually flatten the forward 3 inches or so of my square-bar, so it's a bit thinner and broader where the trigger-pivot goes in. That gives me more fudge-factor for centering. For the trigger-pivot, I usually use a no. 12/24 machine-screw or 3/16 in. stainless rod, supported at the ends by drilled-out 12/24 nuts. That gives plenty of solid steel support around the ends of the trigger-pin, so it won't wallow out in time, due to the loads on it. Does this make sense?
Geezer