[ThatBritishGuy]

You could also think about nesting a 1/2" brass pusher inside the 9/16 for MK.2 to avoid the polycarbonate ring, that's what most people use in angel breeches and the like and it really helps. It also reduces deadspace by a tad but it doesn't seem like you need to do that if your hitting 110!

Great idea by the way, i've always wondered if someone could make a replica of a longshot.

[HasreadCoC]

For every 200 FNG's, we get the next Captain Slug, or Ryan & Kane, or Boltsniper, and you seem to be one of those 1-in-200 FNG's sir. You know what? I think it's all worth it, all the other new guys with their thread necros and other trouble, when we get people like you.

All I can say is, keep up the good work, redesign, perfect, up the power, all that, and then open commissions. After that, design some other awesome thing and keep going.

Maybe you could do a Crossbow silhouetted blaster next?

[Ozymandias]

 HasreadCoC, on 11 February 2012 - 08:14 AM, said:

Maybe you could do a Crossbow silhouetted blaster next?

From the original +bow thread:

 CaptainSlug said:

Main Project Aim: Develop a homemade version of the Crossbow that has performance comparable to one modified to level 4.

On a similar note, if you haven't picked a name for this yet, might I suggest +shot?

[HasreadCoC]

 Ozymandias, on 11 February 2012 - 06:18 PM, said:

From the original +bow thread:

Meh, it should look more like a crossbow though. Theres I difference between having similar performance, and actually looking like it. I'm imagining Tracing the crossbow shell and doing it all polycarb. No nylon for the stock, polycarb side-plates. A full, exact, trace, but with maybe a well-done handle for comfort, possibly with a part-wood foregrip, and part-wood stock-plate.

What I love about his design is that it really *looks* like a longshot. I think we just need a specialized +bow to do the same for the Crossbow.

[KoRnEd]

 Ozymandias, on 11 February 2012 - 06:18 PM, said:

On a similar note, if you haven't picked a name for this yet, might I suggest +shot?

He should call it an L-Shot

Keep Doing good work!

[dapperrogue]

+Shot seems like I'm stepping on a few toes. Also, I always assumed the "+" represented the "cross" in "crossbow."

I was trying to come up with something that meant a million to one chance... e.g. a "long shot." The best I could come up with was "Hail Mary," but it sounded kinda religious.

I like the feel of L-Shot, but the "L" should stand for something. Lambda (the Greek letter) is often used for wavelength, which I like. Also failure rates in mechanical engineering, which is appropriate.

Lambda-Shot, L-Shot for short, it is.

It also gives a good nod to Captain Slug's +Bow, which is what inspired this project.

[Meaker VI]

 dapperrogue, on 10 February 2012 - 04:35 PM, said:

...Yes, it was relatively expensive, and yes, most of that was polycarbonate. The next revision of this will use less, but by its nature it will use more than a plusbow, due to the extra polycarbonate needed to support the barrel and house the movement of the air chamber.

Have you considered pricing out 1/4"-1/8" plywood, MDF, or hardboard/Masonite (the stuff they make pegboards out of)? I've gotten 4'x8' sheets of Masonite for ~$8, and for large surfaces like you've got, it'd be much cheaper than polycarb. Shoot, 1/2" furniture-grade plywood sheets might even be cheaper than polycarb; I think I got a 3/4" thick 4'x8' quarter-sawn Oak sheet for $60 (~$2 per sq. ft., for those who can't multiply and divide).

[dapperrogue]

Ok, got a bit of work done on the new version. Haven't had much time, but figured you'd want to see progress.

So, consider what I've already shown you the "L-Shot Prototype", and this "L-Shot Version 1." I'm making it in four parts, so it will be easier to explain/assemble: The stock (shown here), the reciever (middle bit that holds magazines), the barrel housing, and the action (part that moves back and forth).

Parts!


As before, but after a whole lot of cutting. I *would* have managed to get this whole thing out of two sheets of 1/8" polycarb, and one sheet of 1/4", but I screwed up one cut and will have to go get some more plastic. Ugh. The problem with no room for error, right? Side note: Don't use a fence to try and make straight cuts on a scroll saw. The blade will wander -- by as much as 1/8 of an inch in my case when I tested it on a piece of scrap. Straight cut, but not parallel.


Ok, business time. Here's a closeup of the new catch parts. This time, the catch will stick into the 1/4" catch tube, rather than catch once it protrudes. This will allow me to simply screw a wide washer into the catch end of the plunger rod, rather than dremelling the end of the rod as I did before.


Here's the catch assembled. Most of the machine screws are on the other side, but one of the screws holding the spring went in on this side.


Here it is actuated. By pushing back on the "L" shaped bit, the catch gets pulled down.


The catch is screwed to a back plate, along with the catch tube. In order to hold the catch tube in place, I used a disc of 1/4" polycarbonate that matched the inner diameter of the tube. A hole was added to allow the ramp of the catch to protrude into the tube.

Edit: The catch tube is 1 1/4" OD, 1/16" wall, and is 7 1/2" inches long.


Here's the trigger and handle assembly. I made it a bit fancier this time, but still hollow in the middle. I happen to like the totally clear look, and once sanded they feel pretty good. Speaking of which, I still need to sand it down so the edges aren't sharp.


And here I've added the sides to test fitment. Also added here are the air-chamber guides. They are two pieces of 1/4" x 6" x 1.5" polycarbonate to form a box around the air chamber. This helps it slide back perfectly straight. The trigger is screwed into the lower one, so the air chamber will actually slide on the screw heads. Note that the trigger isn't connected to the catch yet. I will add a linkage using 1/8" polycarbonate pieces. However, other than that, this piece is done.



That's all I got done this weekend. Next I'm going to work on the action next (air chamber/breech/handle assembly, along with the plunger rod). Expect the next installment Wednesday or so.



Before I go: I want to make templates for you guys. What should I use to do so? Don't say paint.

This post has been edited by dapperrogue: 23 February 2012 - 09:58 PM

[Meaker VI]

 dapperrogue, on 20 February 2012 - 09:09 AM, said:

Before I go: I want to make templates for you guys. What should I use to do so? Don't say paint.

Sketchup. It's free, easy, draws straight lines that are easily controlled, its got built-in file distribution (3d warehouse), and it can provide a nice 3d model too. If you don't think you're skilled enough in it, I could probably draft the thing up off of several sketches in an hour or so.

I'm pretty interested in this project because I'm currently working on something similar; though I'm trying to use wood and PVC instead of polycarb and brass. I'm struggling with getting everything anchored to a frame so I can get a trigger and slide motion going, so I'm going to try to build a cardboard model and then use 1/4" or 1/2" plywood and 1/8" hardboard. If yours works with 1/4" / 1/8" polycarb, I can probably just swap those parts out directly.

As for your blade-wander, try using a wider blade and just follow the lines you've drawn. Fences don't work well on bandsaws either, and I suspect the mechanics behind that are similar for scroll/jig saws.

Will it be pump-action in the final version?

[shardbearer]

This looks pretty cool. I would suggest using PVC for structural instead of Polycarb to reduce cost and machining time. Also dont try to replicate the LS design, but instead make the best possible blaster.

I would suggest OpenSCAD or SketchUp for 3D modeling.

OpenSCAD takes a programmer's approach, which I find much easier and totally unambiguous, which was my gripe with SketchUp, but if you are not a programmer it would have a fairly steep learning curve. Everything is typed out, and the graphical interface is only for viewing your creation. For example, here's what I type to make a 1 1/4" plunger tube that is 12" long:

difference(){
	cylinder(h=12, r=.83);
	cylinder(h=12, r=.69);
	}

Wonderfully easy and concise, much easier than mucking around with an inaccurate mouse. I typed that out in 30 seconds, and before I found OpenSCAD, I tried for an hour to get that in SketchUp.

And I like both LibreOffice-Draw and Inkscape for 2D Templates. Though Inkscape on Mac is very ugly.

[Meaker VI]

 shardbearer, on 21 February 2012 - 07:30 PM, said:

And I like both LibreOffice-Draw and Inkscape for 2D Templates. Though Inkscape on Mac is very ugly.

I'd agree that Inkscape is a good program for making quality 2D templates, though it's learning curve - especially for making measured drawings - will be more steep than Sketchup unless you're already using Adobe Illustrator (also good if you have it, it's just not freeware). Sketchup is great for easy plan/model distribution, but getting templates set up to work for everyone could be hairy for a new user (Use a scene tab). I haven't used LibreOffice-Draw. AutoCAD printing to .pdf would be best for 2D templates, but it doesn't sound like you have access to that if you're asking.

All that said, if you posted some complete annotated and dimensioned sketches of the thing, I could get a model up and .pdf templates sent to you pretty quick.

It's a separate issue, but I disagree with shardbearer that a programmer's approach is easier to use than a modeler's approach for 3d modeling. Obviously, that's an opinion, but I've used type-input with CAD programs (AutoCAD and MasterCAM), and it is much slower to use than a mouse-keyboard setup.

[Exo]

Seeing as how you are making a 2nd version, I would suggest a desing that needs only one shaft collar to keep the barrel in place by placing the panels closer togther, and maybe the use of CPVC as a barrel material. I have found that when CPVC is drilled out with a 1/2" spade bit, then 1/2" brass fits nicely inside the new ID. Also, I'd look at Datum's N-STEN for a few engineering ideas to shrink the overall length.

[dapperrogue]

Revised version done-ish. Need to work out a few issues, but:



So, continuing the writeup. Here are the parts for the 'receiver':


Start by assembling the mag slot. This is a good time to test that your magazine will actually load. Finish tightening all the screws, then stick your 9/16 brass through the holes and attempt to load a mag. Hopefully, it snaps right in. Mine didn't, and I had to re-do the middle pieces. The inner-width should be just over 1"... I went with 1 1/16".


Remove all but the "middle" screws, and add the side plates.


Then insert guides. These should be 1/4" wider than the front and rear of the mag slot, to account for the 1/8" mag slot sides. This bit is done.



Now to work on the 'action'. I don't have pictures of this, but now's the time to cut your 1 1/2" polycarbonate tube down to 11".

Cut your 9/16" brass down to 11" long. Add a 3" dart slot (smaller if you are using Stefans) starting 1" from the end. Your 1/2" brass needs to be cut into a 1", a 2", and a 3" section. Slice down the side of the 1" and 2" sections. Set the 2" part aside for now. Grind everything smooth, and polish all of it.


To make the dart pusher, wrap the 1" section with the slice around the 3" section. I don't know if 3" is the best length. The goal is to push the dart partway into the 17/32 barrel, without pinching the foam on the rear.


Insert that assembly into the back of the 9/16 breech. Drill a 1/8" hole through both sides, horizontally, 1/2" an inch from the end.


Here are the parts that are going around that to reduce the air chamber down to the brass. I made the circles by cutting a hole in 1/4" polcarb with a 1 1/2" hole saw. Drill about half way through to make a good groove, stop, drill the middle out with a 9/16" spade bit, then resume with the hole saw.


Slide a polycarbonate ring and a rubber washer (1 3/8" od, 1/2" id -- stretch it) over the end.


Add the "flattened" ring, and use screws to hold it and the dart pusher in place.


Add the remaining rubber washer and ring.


Hose it down with silicon lube, and insert it into your 1 1/2" polycarbonate tube.


Drill holes through the tube, then screw these cross-shapes onto the outside. I suggest drilling the back ones first, securing that ring in first, then pushing on the front ring to compress the assembly before drilling the second set of holes in your tube. These cross-shaped bits are 1" x 1", with 1/4" corners cut out.


Sorry for the blurry photo. Add the handle attachment pieces now. The ears on these holes go over the sides of the cross-shapes.


Add your priming handle, plus a 1" x 1/2" piece on the opposite side to compress the attachment pieces.


Cut a 10 1/2" piece of nylon rod. Add a Split plunger head on one end (mine is made with 1/8").


Then put a K26 over it, add a polycarbonate ring (this one with a 1/2" hole in the middle), and a 3/4" washer to act as a catch.



Almost done. Moving on to the front. Take your 2" piece of brass (with the slit), and slide it over your 17/32" brass barrel. Secure with shaft collars. I use two, rather than one, so that small alignment errors aren't magnified greatly. Note that the barrel sticks out 1/4" from the front of the blaster.


Hold it in place, and add some hex standoffs now for looks/rigidity/foregrip. No photo of the other side, but I think you can figure out how it goes.


Combine all four parts, and you get a completed blaster! Yes, that's the same photo again.


(It looks longer because it is skinnier. 3" side panels vs 4". They are actually the same length).


...and confession time: It doesn't actually fire, and it's past quiet hours so I can't bust out the power tools and fix it. Bummer. The issue is this piece in the revised catch:


Quick explanation: Under the tension of the spring, the forward pull at the end of the "ramp" causes the tall, skinny piece in the middle to torque against the two screws holding it in place. There's so much friction, it won't move downward unless I stick a screwdriver in there, catch the bottom hook, and lever it down. Here's it holding the plunger back:


So now, I need to make modify the catch to eliminate that binding. Probably going to go with a single pivoting piece. Stupid quiet hours.


Anyway, will sketch up some templates and get those uploaded soon, but only after I get the catch to work. There's a high probability I'll include a "carbine" version (alternate build) that's shorter up front.

[Meaker VI]

 dapperrogue, on 22 February 2012 - 09:44 PM, said:

So now, I need to make modify the catch to eliminate that binding. Probably going to go with a single pivoting piece. Stupid quiet hours.


Anyway, will sketch up some templates and get those uploaded soon, but only after I get the catch to work. There's a high probability I'll include a "carbine" version (alternate build) that's shorter up front.

It's not 100% clear to me, but would a rainbow-style catch work? It shouldn't bind since it's sliding up and down rather than pivoting.

Am I correct that you're using the plunger tube to draw back the plunger, and that you have another tube holding the spring in place? It doesn't look like you mention what tube size or length you are using if that's the case, though you show the polycarb disc that is holding the spring back. It also seems that you could reduce the length by using a different plunger-charging system; I've been playing with having the dart-pusher tube prime the plunger (and possibly having a stub-plunger rod), but I'm using a different plunger head so that may not be possible for me.

Anyway, looks awesome, I look forward to seeing more.

[shardbearer]

I would suggest putting the catch between to peices of polycarb, similar to a rainbow catch. Or you could make a HEC.