Project Pneupack

[FiXeL]

Well atleast it didnt blow.

I have been rethinking my design a little today, and i've made some improvements. I really wanted a macroline fitting on the outside of the pack to connect the air in, but this would make ULE milling the insides of the lower part very difficult. And the macroline between the pack and the asa has to be so short, it would be impossible to remove without dissasembeling the gun. Also i've used 4 8-32 UNC screws to connect the lowers to the top because there was a o-ring to be sealed. All of this is becomes obsolete if you connect the macroline directly to the top part, and making a slot for it to go in, in the lower part.

This is what i mean:





You would still need 4 screws to fit it all together, but this way i can mill alot more material out of the lower part, and don't have to worry about an o-ring that needs a perfect seal. This could even be put a step farther, and just make the top, and modify the lowers of an original Emag battery pack to fit. The only thing that would need milling on the lowers is a slot in the back, some extra room for the LPR (it does not fit inside a emag pack) and a hole in the end cap for LPR adjustment.

Also another idea is to fit the LPR up front on the top part of the pneupack, where the thumbscrew would be on a Emag, and use the empty space inside the lowers for a EP setup. It's big enough to hold most of the parts needed.

[ElPanda]

machinist pRon

nice work so far

[gunangel]

definitely pretty!

if you wouldn't mind posting the cad's up this may be something for me to try. it's nice when you have access to a walk in basis machine shop, not so much fun when you suck balls at 3D modeling tho...(talking about myself by the way...)

[ElPanda]

it's nice when you have access to a walk in basis machine shop

rub it in

[FiXeL]

definitely pretty!

if you wouldn't mind posting the cad's up this may be something for me to try. it's nice when you have access to a walk in basis machine shop, not so much fun when you suck balls at 3D modeling tho...(talking about myself by the way...)

Strictly speaking i don't have access to a machine shop, i work in one.

Well i could post the 3dsmax file, but you can only use it in 3dsmax and no other 3D moddeling software i know of. Also the version i'm using is ancient, so i'm not totally sure if it's compatible with the later versions of max. Besides that, the model only holds a few primitive shapes because i suck at cad too... I've made it just so i would have a guideline to program the CNC code with. It's not a drawing, nor is there a drawing. I've used the model to see if all the holes i would drill in the pieces would fit without intersecting unintentionally. If i was any good with cad, i would have made a decent drawing in .dxf file format.

The coding was done in Cimco Edit V.5.0 and was basicly writing machine code, like i would if i was at the TNC control panel of the machine.

The rest of the code, and final touching up were done at the machine, editing the rough CNC file i made at home. I'm still working on it so i'm not going to publish it yet. Also i will have to make drawings and setup sheets for all the milling operations. For the top part only there are 6 different setups to be milled. And, the CNC code is now in metric values for Heidenhain CNC controlls and not compatible with ISO coded controlls like Fanuc. I'll have a look if there are conversion tools available.

Latest Developments

- Edited the CNC file to the latest design without a o-ring seal
- Started programming the ULE contours of the lowers
- Partially hacked up the stash of billet alumium for workpiece material
- Doing a initial run of 4 pneupacks first (and material for 4 more)

I hope to have some pics and maybe a vid of the CNC doing it's work tomorrow.

Also i have a question: How easy is it for your regular joe to get a hold of 10-32 UNF setscrews? Because i'm doing a small run there is a possibility that i have a few for sale, but those set screws are hard to get in this metric part of the world... I can chase the threads of my personal pack with a M5 tap, and get it done, but to remove it (if you ever wanted to) you would need metric allen wrenches. I'm sure most of you don't have them, and personally i hate it to use 2 different sets of wrenches to work on a gun.

[edit] Nevermind, i've found a source nearby enough for these screws: http://www.modelfixings.co.uk/

[MechMags]

if you are able to do a limited run, i would like to go on your list of recipients, and yeah those screws shouldnt be too big a deal to find or come by.

thanks

nice progress.... a little vid would be pretty cool if you can swing it in.

[rastamag]

interasted

if you are able to do a limited run, i would like to go on your list of recipients

[FiXeL]

I'm not sure yet howmany i will make of these. All of this started because i wanted something like this, and i have the tools and machinery available. But i'm still not allowed to do commercial work, and that is also one of the reasons why i am giving the design to the AO community so others can reproduce and improve, or customise the design to their liking.

But anyways... I have the first 4... errr 3 off the mill!



There are four here, but i've screwed up on the first one, and it's unusable as a gas trough grip. The ULE milling is to blame, i've kept the first hole for the LPR in mind when programming the ULE contours, but after changing the design, i forgot that i drilled the air in hole at the same depth, and did not leave enough material on the other side.





Fortunatly i've noticed the small hole before continuing the run, and the easiest fix was to drill the holes for the LPR and air in 13mm deep instead of 15mm as intended. All the 1/8" NPT treads arent tapped to depth yet, but i dont forsee any problems with it. The first prototype was drilled at 15mm, and there was still some hole left to tap.

The reason why i didn't tap them to depth in one go is because of 3 things: First there are chips produced by the tap, and with the kind of tap i'm using, the chips stay in the hole, so it could cause problems. The second reason is that it is a tapered tread, meaning that the cutting force increases the deeper you go, and the third is that it must be within a certain depth. Too deep or shallow means it will not seal properly, and this depth has to be measured with a caliber. With small runs i prefer to tap just a lead in, and do the rest by hand to make sure the tap does not break, loosing the workpiece and the tap.



Top view...



Rear view. I've tapped the hole in the prototype with M5 threads because this was the easiest thing to do. But all of these have 10-32 UNF threads now. And if i choose to use M5 instead, the theads can be chased with a M5 tap. The diameter and pitch is almost the same. (about 0.0001" pitch difference)

I'm not sure if i'm going to sell the remaining 2, there are some marks left that i'm not really sathisfied with, and this is due to hasty workmanship and one radius mill that was a bit on the blunt side... It mills good when climb milling, but for the other side i've mirrored my subprogram, and upcutting looks like a massacre. It can be sanded smooth, but i prefer to do as little afterwork as possible.

Video bonus:



This is the second setup after milling the top view of the part. In this setup it will be milled to the correct hight, removing the extra material used for clamping, and the radius of the "trigger guard guide" is milled. (roughing, finishing and radiussing) And finally a quick deburr so i can clamp it for the next setup without deburring it manually. It's a fairly quick cycle and i wished i could have taken more vids, but the battery of my cell phone was almost spent.

All the setups:

1 - Mill the outer contour and top view
2 - Mill to height and radius the trigger guard guide
3 - Mill out the back side for the trigger guard and drill air channel
4 - Mill radiussed contour on the passenger side
5 - Mill radiussed contour on the driver side + 1/8" air out hole (to valve)
6 - Mill the underside with the holes for LPR and air in.

Next week i'll start on milling the lower parts of the pneupack. Thanks for looking!

[gunangel]

surprisingly our university lets anyone use the shop as long as you take the course, bring your own materials and sign up for the tools before you use them.

that vid was really cool, makes me want to get off my lazy bum and take the safety course!
keep up the good work!

[drewkroeker]

This is a very impressive project IMO. Nice video too. I have great respect for people who can turn an idea in their head into a finished professional looking product (well, it's not quite finished, but you know what I mean).
Keep up the good work.

[MechMags]

thanks for the vid, very cool to see it coming along.

[outreach]

thats awsome. hurray for mag users who continually inivate instead of waiting for the newest thin form pe or tadao lol.

[snoopay700]

thats awsome. hurray for mag users who continually inivate instead of waiting for the newest thin form pe or tadao lol.

Innovate. And yeah, i have to say i wish i could make one of these.

[FiXeL]

Back with another partial update:



I've strarted milling the lowers, but they are only partially milled. I still have to do the other end and i'm not sure when i will have the time for it. Last friday my co-worker had a day off, so i could use his machine to mill the packs. Unfortunatly milling a cavety like you see on the next 2 pictures takes longer than i would have liked, due to the length and diameter of the tool. I'm milling 2" deep with a mill that is a bit less than 1/4" in diameter. (1/4" = 6,35mm, the tool is 6mm)



Due to the length of the tool, small cuts have to be made to prevent tool breakage. Its a carbide endmill, and therefore extra sensitive to breaking due to tool chatter. (look at the corners, where the tool allready chatters) The only way to mill this is by using small cuts. I could have used a bigger tool, but this would also mean the radiusses in the corners will be bigger.



I've allready programmed the other side (mirrored) but i will have to make a clamping jig first. If i was to clamp this as is, the vise would crush the pack. Also i need to get a hold of some 3/8 allen screws to see howmuch i will have to move the rear screwhole, so that the head does not come out of the rear of the end cap. I will order those screws this weekend, so hopefully i'll have them by next week.

Hopefully i will have another update next week, but please don't count on it.

[Hilltop Customs]

you can always use a larger tool to cut meat then step down for the final perimeter pass...or hell since its inside and will really never be seen use a larger tool then just trim down the radius's with a smaller tool.

If your using coding software it shouldnt take but a few seconds and a tool addition.....by hand would take a complete re-write, but it would probably save you time in the long run. Plus you should be pretty good at the code by now

I'm going to miss mastercam

Great job BTW, coming together very nicely

ps if you wanted to send me the dimensions I could create the NC code for the geometry for the pocket with whatever tooling you have available....pm me if your interested