Questions before I start my First Crossbow

Hello, I have been eyeing up a crossbow for sometime and am considering making it one of my summer projects.  Now since I have never made a crossbow before I have a few questions. 

I am planning to base it off of the plans found here: http://www.alcheminc.com/plan.gif  I was going to get the parts from the same site. Side note* I wanted to use Bow Irons rather than the string or cord bound style.

Questions

1. What draw weight would be recommended for SCA target shooting? I would like it to be powerful enough to take longer range shots with ease but not too powerful that it's a pain to shoot or a danger to everyone around me. 

2. How does one make the tiller? My plan was to get 2 Pieces of ~1 inch thick walnut and glue it together with dowels, but the real question is how to cut the space needed for the nut, and lever mechanism. (if anyone has a template I can print this would be wicked helpful)

3. What tools would be required to make this build easy on myself? and am I missing anything major that I should be aware of?

Thanks for looking, if anything need clarification, please let me know (^_^)

Howdy! Welcome.
I make about half of my bows with 2 parts. I'll use a forstner bit to make the hole for the nut.
My daughter (9) used a 1/4" chisel, hand drill and a block plane to make hers. I love block planes. A drill press is really handy, but if you're careful not needed.
For the tickler (lever) channel I use a chisel. I make a paper template of what the tickler will look  like, set it on the wood. I'll use a pin at the pivot point and see how wide the channel needs to be. Follow?
Now, Where in Mn are you? In a week I'll be passing through Duluth and on up to Tower for a week and will have some bows with me. Perhaps we can meet up, but Mn is a big state.

I am in Central MN so Duluth is appx 2.5 - 3 Hours away but depending on when you come I will be at "Dub-Dub"

I am going to qualify this and say I don't have a ton of experience with tillers as I am also making my first crossbow! But I have made gun stocks. So here is my advice. You'll probably find a 2" wide stock is a bit large unless you are unusually gifted in  body mass. I would pick up a 3/4" board and laminate it so you'll be starting at 1 1/2" inches. This is where most rifle stocks start their life at. When looking for a board, check all the angles for warping, try to get the straightest piece. Most likely it will have to be the best of the lot rather than perfect. Highly figured wood is most often the prettiest but weakest wood. I would look for something that has grain lines echoing your tiller design or at least putting strait grain where the pressure of shooting will be the greatest.  I would get a single long board cut it in half and mirror the wood grain so the natural pressures of the wood work against each other. It'll help prevent the wood from further warping once the tiller is done. It will also help you square up any current warping in the wood (assuming you don't have a jointer that will square up the wood for you). You can do all the cutting out work first, the key is to have some kind of registration system so it all fits back together easily when you go to glue it up. Glue up is simple if you pieces fit together well, painful if they do not. You won't need dowels with a good wood glue like Titebond 2 or 3, just well mated surfaces. 

To do the job you would need a saw, sharp chisel, drill, clamps, and something to hold your work on. A plane and square would really help you to square the bits that need to be square. I find that is the toughest part of using hand tools getting thing square. A good rasp and cabinet scrapers are wonderful for shaping the wood where it needs to be shaped. I use a saw rasp (without the dorky handle from the link) cheap, very effective, and doesn't clog up much. Forstner bits are great for making pretty round holes. Drill presses, bandsaws, and plunge routers are all great tools that allow you destroy your work much more quickly than you can with standard hand tools. A good sturdy vice is a gift from the Gods. The one I use most is an angled drill press vice anchored to piece of plywood and then clamped to my work bench. Its very versatile and allows me to quickly pivot my work piece, rather than try to contort around it. But saying all this, most medieval style tillers are pretty simple from a design stand point and only need a minimum number of tools to get done. Other tools will just get it done quicker.

Twedzel speaks true.

Wonderful insight Twedzel, thank you!  Follow up question; Will 1 3/4" be enough if I use a 1 1/8" nut? On the thinnest spot that would leave only 1/32" on each side to hold the nut (check my math =P ) Plan: http://www.alcheminc.com/plan2.jpg front: http://www.alcheminc.com/plan1.5.jpg.

Short answer is yes. The long answer is the wood, not the pin holds the nut usually.

phuphuphnik, could you elaborate please?

Yes, sorry, had to do some work and just hit send. You usually want some overlap in the nut channel to hold it in, not flat sides. (Ivo posted this picture eons ago)
This holds the nut in, the pin or string keeps it from falling out. That said, if you use side plates of metal, a light bow (~100 lbs) should have no trouble having it held by the pin.
Also, check out the diagrams here:

https://thearbalistguild.forumotion.com/t22-medieval-crossbows-photos-drawings-diagrams

This is where someone who knows tillers would be better qualified to answer these questions. Keep in mind you can always laminate more wood or reinforce areas with metal/wood plates if you need to add strength.

Just a note I am really bad with fractions and hate the imperial system so I will use decimals and force you to do the conversions. I measured my own tiller and of course it is contrary to my own advice. My antler nut is 1.195", the nut hole (man that sounds bad) is 1.275" (opps bit of a gap), the tiller itself is 1.7" which leaves me with .2125" wood on either side of the roller nut. This seems like plenty to me, but 1/32" would be pretty thin without any reinforcement. However according to my math you actually have 1/8" on either side of your nut which may be enough without reinforcement. someone who knows tillers better could shed more light on this.

With this type of arrangement the nut itself is really the axle, not the small center hole through it. Most of the force is borne by the front side of the round recess (or nut hole  ) in the tiller, and the little 'axle' through the nut is just to hold it down (with a pin, or cordage binding) so it won't hop out when spinning.

I'm not sure how much, if any, side force is exerted on the tiller recess...however, I chose to narrow my nut a bit (1" wide, in a 1 1/2" wide tiller) to give more thickness to the 'cheeks'. If forced to have them only 1/32" thick, I would add metal sideplates. (Edit: as I read your dimensions, you actually have over 1/4" on each side, which is fine, I think.)

on my last build, which was a 2-piece tiller, I used a 1 1/2" hole saw in a drill press to cut out the recess, and chisels and knives to remove the waste and make the tickler (trigger) slot. A forstner bit would have worked maybe a bit better, but I didn't have the appropriate size.

I used a hole-saw and simple hand-held drill to make nut-sockets for a number of years, but a forstner-bitt in a drill press works better.  Simple spade-bits don't work worth a darn on a partial (2/3) hole.  They'll drift out... never cut straight. Don't bother to try them.  Geezer.

This is all very good information! Thank you all very much.  I think I have a good idea of how to make the tiller and a good base of tools that will be needed.  Now for the easy question.  What draw weight would everyone reccomend?

A single forstner bit that size is not all that expensive. It would give guranteed performance on the partial hole. Need a drill press though.With a drill press , it is nice to be able to control the depth exactly.