I just joined this forum because I wanted to share this project with you guys. Then once I started looking through other posts I realized how much more advanced the other members are. Hopefully this crossbow will become something as impressive as the other ones I've seen on here.

anyway...

I started with this...



Just a rough sketch of a simple trigger mechanism.

so today I set out to build me a crossbow and this is what I have so far...

I made something that looked like this...



Into this...



I still have lots to do in the shaping and beautifying department but I want to make sure all my stuff functions before I get to crazy on the detail.

It's gonna have a pistol-ish grip with a thumbhole stock. I've never made a thumbhole stock before but all I need is a good dowel sander or something along those lines and I think I can crank something nice out (I've done more with less).

Here's what I have so far on the grip.





I also started by making the fletch groove thingie (you guys are gonna have to help me out with fancy terms) first, so that if I screwed that up I wouldn't have to start all over. I used a skill saw with the guard set so that it didn't go to deep. I still have to go a bit farther down the stock. I didn't know the trigger would be back so far when I made the groove.



You can also see in that picture, a big rectangular hole towards the back of the stock. That's where the trigger mech is gonna go. It's gonna be a bullpup style trigger, meaning (or at least I think it does) that the trigger sits in front of the release mech.

I finished the trigger today, or at least the releasing end.



I made this thingie...



Into this (springs sold seperatley)



I made the sear (haha, I do know one fancy crossbow term, thank you Ivo!) out of the metal slab in the next picture.



and here they are all together...



I'm gonna use small washers to space everything out and make room for everything to work properly of course.

The coolest thing about all these things and parts is that I looked at no prints or plans. It's all coming from my noodle

Tommorow I'm heading to Home depot to get me a long ass drill bit to make the housing for the bullpup bar thing that goes from the trigger to the sear.

The trigger is gonna be a double finger style like that on a paintball gun. With the spaning bar going underneath the thumbhole

I'll try to keep you guys posted on my progress... wish me luck!

Reasonable lock mechanism. And original. You can draw a string just over a nut, it will bend down and then rise again..
If in any case this mech will have a heavy trigger, then I would
recommend to move a pivot point of a trigger piece little downward, and
also to make one arm of a L-shaped piece shorter (one that supports a
nut).

Interesting project, what are you planning to use for a prod?



Todd

Day two:

Well it's actually starting to look like a crossbow!

here's a group photo of all the pieces

@Todd I'm just using one of those cheap taiwan fiberglass prods for this little guy.



Kindof a shitty pic but ah well I got more. As you can see I chopped the thing down a bit, the prod I'm using has a pretty short draw so this thing is gonna end up being pretty stumpy. It's got a shit load of power though. I got it to a point where I could load it today and it's a little bastard.

I also found a neat set of round sanding tube things at homedepot so I was able to make the thumbhole look a little better.



Here's pic of the inside of the constructed trigger mech.



and a top view



The best part of the day was having this work out. It's the bullpup mech that goes underneath instead of above the thumbhole.



I bought a long ass drill bit at home depot and also found this square bar. It took one try and crossing my fingers pretty hard but it worked out amazingly.







I was gonna make that video into a .gif file but I couldn't resist leaving that music in the background. Oh yeah Oh yeah!

anywho...

here's a pic of it all put together with what I have so far...





I still have to do some finishing touches on it of course and a little fine tuning. The important thing is that it works!

tomorrow is another day and hopefully I can finish it up so that I can goof of over the weekend.

That thing looks cool. what do use to make the triggers and stuff what tools

A disc grinder, bench grinder, and a drill press. Gotta works with what ya got.

pretty cool, let us know how it shoots. How is the trigger pull?



Todd

Day three:

Today I built some of the crossbow neccessitys, a foot stirrup and a bolt holder down thing. I also painted it and I'm sorta happy with how it came out.

Again, I started with this.



did an enamel red base coat.



Layed down some masking tape in a random pattern... mmm... bacon.




Then went over everything with black.


I also painted the stirrup black.


I made the tongue out of a saw blade (my favorite source of spring steel)



Slap everything together and it's looking pretty awesome if I do say so myself. Although The red pattern could've been a little better.





I'm having a major issue that makes this thing a little slow to reload. Everytime I shoot it the spring that keeps the rotating nut up and down explodes and becomes unusable. Meaning I've had to take it apart all three times I shot it.
What's happening is that the 150lb bow is so powerful that it makes the rotating nut spin so hard that it rips the spring all the way around it and basically stretches it out to become useless. :dno:

It's the only hiccup I've had on this build and I'm trying to think of a solution.

Rubber bands would work but they lack longevity.

I have to work all weekend so the project will be put on hold until hopefully next wednesday. Then I'll make a video for it. It's been a while since my last vid so it's about time for a new one.

Need to put a stop in. I think about were your thumb is would work, well lets say at the tip of the thumb at 2 O'clock or so. Other wise it looks pretty dang stylish

Basilisk beat me to it. Inertia is to blame.

If you take that tywanese bow you got lying around there and look at the trigger...if you try to rotate the nut past horizontal position, it just won't go - the rod that keeps the torsion springs loaded blocks the nut... Haha, Bastards thought of everything. I'd also switch up to the lighter nut design(tywanese style)...HD has this square pipe that is just the perfect size. *I'm on the phone, so reminder to insert an image of the latches that just came back from sandblasting*

It's a minor hick up, the build is going great...and fast! That's got to be some kind of record.

Love the bacon joke by the way, with that mind set you'll be Master Chef in no time.

Ivo

I would try heavier springs but to me the position of the springs looks unworkable. The dilemma is if you make the springs too strong you will cause the string to jump the catch a little. I would think of another way to reset the catch.

If the action is a little heavy / slow would lightening the transfer bar help? I was thinking drilling holes in or fluting the bar might reduce its mass enough to make a difference in trigger pull/ lock time.

To lighten your trigger response file carefully shaping both surfaces to keep minimal contact while still keeping the loads where you want them. Drilling parts to lighten them is not a good idea in this type of trigger in my opinion.

reminder to insert an image

This might look like it's not much, but it's quite sufficient for low to medium draw weight (I never went past 175lb during testing) and the lightest latch that I know of....here's the material/layout.



For this build what you already have is plenty good and I love that spring idea...just needs a stop - keep rolling man! Good luck.

Ivo

PS: I remember the days...feeling like I was this world's one and only crossbow creep on the net...here I am now - being proven wrong more and more with every post....you guys are awesome!!!

Another bullpup?

mmm... bacon.

not JUST bacon. That looks like Daedric Bacon.

Spoiler:

I pronounce today (or the day this topic was started) a Holiday - !!!The Daedric Bacon Bullpup Day!!! It's going on our forum Calendar, lol.

Antho