In depth V2 part dimensions needed

[slipstream]

Hey guys, I'm planning on creating a 3d model of a V2 gearbox with a quick change spring system for a modeling class. I need as close to the exact part sizes as possible because I will be stress-test modeling as well. This is going to be a complete, cycling model that could work if it was actually made. I'll even post the recording of the model cycling if this comes into fruition.

I'm thinking about doing something sort of along the lines of this, but less janky and a little more refined.

[Raging Hormann]

Wow. That's actually quite intriguing. While I cannot give you exact dimensions now, I dig the idea. Hooray for a useless post, perhaps.

[Cap n pickles]

That is very cool man!

[john boy]

It looks like a version III gearbox to me..
Just, make sure you don't misalign that spring guide or you will be replacing a piston body and maybe other internals..
Also, The version III is one of the most easiest gearbox to work on.. If you want an easy spring switch platform go for M249 or the Star L85.. Almost every version III platform, you will need to extract the gearbox from the body to remove the spring any ways. This just changed the tolerance of the gearbox's strength and possible will produce problems..
Nice job though..

[Raging Hormann]

This won't work on any M4/M16 platform, the stock or buffer tube is secured by a screw that goes into the spring guide itself. Now, if you were to drill a hole in that plate that secures the spring guide, it could possibly be made to work.

[slipstream]

This won't work on any M4/M16 platform, the stock or buffer tube is secured by a screw that goes into the spring guide itself. Now, if you were to drill a hole in that plate that secures the spring guide, it could possibly be made to work.

That was the main thing I was planning to work around, right now I am planning on replacing the spring guide with an aluminum one (if the gun does not already have one) and just having it screw into that, since the buffer tube screw threads into the back of the GB shell. I had considered just replacing the buffer tube screw with a shorter one and having it screw into the body of the gun instead, but I am leaving that as a last resort. Luckily I can create stress models for screw threading as well, so that could be a possibility.

It looks like a version III gearbox to me..
Just, make sure you don't misalign that spring guide or you will be replacing a piston body and maybe other internals..
Also, The version III is one of the most easiest gearbox to work on.. If you want an easy spring switch platform go for M249 or the Star L85.. Almost every version III platform, you will need to extract the gearbox from the body to remove the spring any ways. This just changed the tolerance of the gearbox's strength and possible will produce problems..
Nice job though..

Yes I am aware of the advantages of the V3 design and yes, that is not a V2 gearbox, that was just for visual inspiration. The whole purpose of this idea was so that you would not have to change platforms to have access to a quick change spring feature. Extracting the gearbox from the body of an AR based gun is not a big deal anyways, it is pretty easy. I am aware that a change to the original design of the gearbox may weaken it's strength, that is why I am using a top of the line 3D modeling program to design and simulate the loads placed on parts.

[Raging Hormann]

I would love to see entire uppers for a quick swap. Pop your pins, and toss on your CQB Upper with included upper half of gearbox. It would have an M100 in it.

After you cleared the building, toss on your ol' trusty Field upper with a longer barrel and M120 in it.
Ah the joys of real steel, or since the re-inception of GBBRs, the WEtech M4.

Either way, keep this going, man! Looks like it would be an awesome project.

[slipstream]

I would love to see entire uppers for a quick swap. Pop your pins, and toss on your CQB Upper with included upper half of gearbox. It would have an M100 in it.

After you cleared the building, toss on your ol' trusty Field upper with a longer barrel and M120 in it.
Ah the joys of real steel, or since the re-inception of GBBRs, the WEtech M4.

Either way, keep this going, man! Looks like it would be an awesome project.

A split gearbox design that simply comes apart like how you describe (to just have the upper GB slide off the lower with no screws) would rely on the body holding the two pieces of the GB together. Also, considering how much upper and lower receiver wobble some guns have, I can say your gears and/or piston would eat it pretty quick. A split GB design reliant on screws holding the two halves together would come after this if I ever have the time or chance.

I can start making the gears and other individual part models as soon as I get the data.

[Raging Hormann]

When they start doing what I described, they will have to actually make use of the rear body pin.

However, it seems to me that the metal bodies that still use a "tab" design (My TSD HK146 comes to mind) it could possibly work. I'm sure there would be all sorts of neat things you could do involving channels and nobs and different mechanisms that mate together between the upper and lower parts of the gearboxes.

Slipstream, if you can pull this off, you could make a lot of money with it.

[slipstream]

When they start doing what I described, they will have to actually make use of the rear body pin.

However, it seems to me that the metal bodies that still use a "tab" design (My TSD HK146 comes to mind) it could possibly work. I'm sure there would be all sorts of neat things you could do involving channels and nobs and different mechanisms that mate together between the upper and lower parts of the gearboxes.

Slipstream, if you can pull this off, you could make a lot of money with it.

Yeah, the metal body on my CA uses little pins that stick from the rear of the upper receiver into the upper part of the rear of the lower receiver, rather than using the TM tab design, so I can't shotgun it (but it wouldn't be able to anyways because it has a 1 piece hop-up =p ).

I highly doubt there will be any money in this. From what I gather, it takes thousands of dollars for machining or if you need to get anything manufactured, and will take hundreds if not thousands of units sold to even break even.

[Bulldog]

Why reinvent the wheel, just model it after the ICS split gearbox.

If not, Im sure your more then able to grab a caliper, micrometer, dial gauge, tape measure, ruler, angle finder. Whatever you wanna use and have at it.

[Nec]

Great idea! just a few days ago, I was thinking about do that same thing but since you beat me to it I'll let you be the test subject.

How are you going to get the spring guide out? Ever seen the SAWs quick change spring? They use a flat head screw driver, maybe you could incorpate a phillips for better stability when taking out the spring guide.

How are you going to prevent the piston from twisting when reinstalling the spring guide?

[LiquidSnak]

The piston rests on its guides even when fully forward, by the way.

[slipstream]

Great idea! just a few days ago, I was thinking about do that same thing but since you beat me to it I'll let you be the test subject.

How are you going to get the spring guide out? Ever seen the SAWs quick change spring? They use a flat head screw driver, maybe you could incorpate a phillips for better stability when taking out the spring guide.

How are you going to prevent the piston from twisting when reinstalling the spring guide?

No, I have not seen a SAW spring system.

Well, the gear box would be staying together, the back portion would just open up. The piston would not twist since it is held in place by the little slots it rides on. Further, a ball bearing spring guide would ease that issue, letting the bearing twist instead of the spring. Right now, I am just working on the basic concept.

Edit: Snak beat me to it

[Cap n pickles]

Great idea! just a few days ago, I was thinking about do that same thing but since you beat me to it I'll let you be the test subject.

How are you going to get the spring guide out? Ever seen the SAWs quick change spring? They use a flat head screw driver, maybe you could incorpate a phillips for better stability when taking out the spring guide.

How are you going to prevent the piston from twisting when reinstalling the spring guide?

It shouldn't be hard to screw in a Flat head and gorilla glue it in place. Good idea.