New Two part v2 mechbox

[Kokanee]

http://www.wgcshop.com/pcart/shopper...-VER2-L_srch_1

CnC machined, do it yourself style kit. Looks swank.

[CDN_Stalker]

Shit man, were yo uchatting with Vondnik same time as I was? He sent me that link an hour ago, I repied "WTF!?!?!" and he replied "My thoughts exactly!"

Sweet though, love to hear how those work out for people.

[Dozer_01]

That looks quite interesting, however, I would not purchase something like that.The more parts something is (generally) the more can go wrong. There could be alignment issues if the bolts are not properly torqued. Think of a car that is bolted together vs a car that is welded/molded. Of course the the weld/mold (if done professionally) will hold together better. Bonded molecules are the key. This is one reason why i wont go near the ICS split design.

[Kid]

Originally Posted by Dozer_01

That looks quite interesting, however, I would not purchase something like that.The more parts something is (generally) the more can go wrong. There could be alignment issues if the bolts are not properly torqued. Think of a car that is bolted together vs a car that is welded/molded. Of course the the weld/mold (if done professionally) will hold together better. Bonded molecules are the key. This is one reason why i wont go near the ICS split design.

This one actually fits together though, they will be connected. That's a giant step up from the ICS. They are quite poor if I may say, being held in place only by the body of the gun was not to my liking.
That was one of the major reasons I sold that... and the incompatibility of internals.

Also, the more parts looks like it could be a 'if it breaks, you can buy the part that breaks, instead of buying a whole new kit.'

[odp]

All the PGC stuff has been good so far. I'm not going to be one of the first though.

[eel one]

But on the positive side the PGC box does offer some features from different other brands integrated in one solution. Like spring release (from ISC) and integrated mechbox og barral (Star). The fact that the box uses almost only standard parts are also very positive.

I have already ordered one, some one have to be the first to try iy out.

[mthaynes]

Hello Folks

If you look up my posts you will see that we have been producing a machined alloy box for some time now. Although out tests of the PGC are VERY premature at this time we do have some notes that you may wish to consider. That said of course I am extremely biased to my own design so you should not consider me impartial. In any case following are initial findings on our test unit.

1.Integrated hop claims to improve FPS however the results posted do not support it. We have done tests with a deepfire 135 spring in a 6 MilSpec box and shot 465 with .25’s with .20’s that would be 515. (.5 = 50 fps).

2. Integrated hop has a high probability of feeding issues. The 1 piece hop in your gun floats on a spring. If you sick a screwdriver between your gearbox and hop you will note that the hop can move back and forth a bit. This ensures that the hop will align with the mag. By fixing the hop position you lose this flexibility. If your mags fit lose in your mag well no problem, however if you have a tight fit you could have issues.

3. The gear box is a copy of the ICS gearbox. It even incorporates a spring release mechanism. In short I think we all know how well the ICS performs …….

4. The system includes a head and nozzle. We have not been able to test to see if a bore up will fit properly. Since a bore up is 5k thou larger in diameter this could be an issue

5. It is in no way as strong as the 6 MilSpec box The rear spine uses a screw to fit the cylinder brace. (side note with out the brace it reminds me of an m14 gearbox). The structural integrity of the spine is therefore limited to the screw thread. In my gearbox the spine is machined as part of the casing for strength. It also does not use a fluted design like mine which also increases strength.

6. The tail cap design is potentially week – we have not finished testing on this yet

7. The 6 MilSpec box made several changes to the gears position in relation to the piston. The design ensures that all these parts maintain alignment. In the two part ICS system we have seen alignment issues between the piston & tappet and the sector gear. We expect the PGC to inherit the same issues.

8. The bearings supplied with the PGC gearbox are very cheap. They are a level 1 bearing. We use a level 3 to level 5 in our newest designs. A level 5 is 6 times the cost of a level 1. The Black 6 MilSpec box includes $30 worth of bearings at my cost.

9. It is clear from folks investigation that the PGC unit preferences the Hurricane body. We partially believe this to be related to note 2 above. The 6 MilSpec box is field proven in the Hurricane, Systema, G&P, Guarder, and CA. At this time we are unaware of any body that the box does not fit in.

10. The PGC will only fit in the m16 receiver. The 6 MilSpec box was designed as a Version 2 replacement so it will fit in the g3 / mp5 family of receivers with some modification.

That said yes at $250 we are more expensive. Part of that is due to cheaper machining costs in Asia. But as we all have learned in Airsoft - you don’t get something for nothing.

[MMMiles!]

/edit I assume this is the box you're referring to? http://www.andairsoft.com/preoraaexv2b.html

Nice looking piece.

On topic of the PGC, pretty impressive... looking. eel one here's hoping you get good results with it.

[mthaynes]

Sure John

http://www.airsoftcanada.com/showthread.php?t=8914

This is the topic that we announced our product. please feel free to email me at mthaynes@comcast.net if you have questions.

Or one more push for our box over the competition – how many times has an AS manufacture registered on your boards and fielded questions about their product?

[MadMax]

I have a few misgivings with the way aftermarket hop up (HU) designs have gone.

In HU design, you're faced with two alignment issues: registering to the mechbox, registering to the mag. Most AEGs do not register the mechbox to the receiver all that well. Throw in an aftermarket receiver and you get to experience someone else's interpretation on TM's original intent so mechbox-rec'r registration gets even more funny. Then add in the location of the mag outlet in the receiver which has to be loose to allow easy mag changes.

A single piece HU rigidly attempts to register to both mechbox and mag which is rather impossible. If you wiggle your mag around in the well, it'll move the base of the HU and affect registration to the mechbox.

The stock split HU allows floating registration to the mechbox so wiggling the mag around does not affect HU-mechbox registration. The lower screws into the rec'r (in armalites) which is the closest thing registered to the mag.

On point 8: have you measured the radial strength of airsoft ball bearings? I would be interested to know how various airsoft ball bearings compare. ABEC (I'm guessing you're referring to ABEC anyways) specify only radial tolerance. They do not address radial strength.

[mthaynes]

Your right about the alignment issue with STD boxes. You do get a separation between the HU and the gearbox. This separation or twist in some cases will create a loss in air seal between the nozzle and the bucking. In its most extreme case (the early model CA’s) you could get as much as 1/8 inch worth of back and forth movement on the hop.

When we designed our box we extended the length of the gearbox casing to achieve a significantly tighter fit. Our goal was to limit this movement in the hurricane (the loosest body we found) to approximately 1/32 when coupled with a systema hop. This minimizes air loss but affords you a bit of play we found necessary to manage the various magazine manufactures (AE, TM, CA, G&P, etc)

If you want a tighter fit you can try this little trick (did this with a few of the CA’s).
On the upper receiver remove a very small amount of material from the front of the barrel nut threads. This will allow the outer barrel / chamber block to sit further back in the upper receiver. This will in turn move the HU towards the gear box. Provided your mag will fit the well correctly you should have minimal feeding issues. We generally don’t recommend less than 1/64 of play.

On your second question we tested some to failure and they are consistent with level 1 specifications. We were also able to work backwards by getting a part numbers from a couple of AS manufactures – those also are level 1. While level 1’s vary a bit specifications were about 15lb standing 35lb rolling as I remember. I have a link to a bearing manufacture that lists the tolerances and weights for a number of miniature bearings. I will try and find the link for you and post it up. Its useful stuff. Oh and level 1’s run about $.75 a piece at 100up with another break at 1k

It was out experience that as soon as we made a gearbox that could not break, folks went crazy with big springs. 130 to 150 became std. equipment in our neck of the woods. Add to that the tighter tolerances and the 10.8 - 12 volt and before you could blink the m130 with torque ups and 11.1 li-poly became the everyday build. This is when we started to see the bearings die so we moved to the higher levels in an effort to keep up with the new builds.

[Mantelope]

Originally Posted by mthaynes

It was out experience that as soon as we made a gearbox that could not break, folks went crazy with big springs. 130 to 150 became std. equipment in our neck of the woods. Add to that the tighter tolerances and the 10.8 - 12 volt and before you could blink the m130 with torque ups and 11.1 li-poly became the everyday build. This is when we started to see the bearings die so we moved to the higher levels in an effort to keep up with the new builds.

Fortunately, I don't think this situation will become the norm here in Canada, even if we start using your box. Most hosts and fields feel the FPS limits are pretty much set in stone; the reason we want a stronger mechbox is because of the heightened failure rates due to the cold.

[MadMax]

The usual failure point on a mechbox is at be the lower front corner of the cylinder window.

You could gain significant fatigue resistance by continuing the lower cylinder shelf forward just past the corner by about 0.1".

This would require a modified tappet plate with notch cutouts in the upright panel to pass the continued cyl' shelf, but the amount of material removal is probably not critical to the tappet plate. The strength of the remaining upright would probably significantly exceed the strength of the spaghetti rear arm which bears the sector cam triangle.

I'm surprised that no manufacturer extends the cylinder shelf past the window to address the fatigue issue. That fix would probably address most of the usual fatigue problem. They could also round the front corners of the cyl' window to reduce stress concentration. I'm guessing that your window corners are rounded as your mechbox is manufactured with a milling cutter. The rounding probably makes a greater contribution than polishing the exterior to reduce remove surface start cracks. Have you considered shot peening? I think shot peening would be a more easily applied surface treatment than polishing. The compressive prestress might also make a greater strength contribution than polishing.

[mthaynes]

Originally Posted by harleyb

Fortunately, I don't think this situation will become the norm here in Canada, even if we start using your box. Most hosts and fields feel the FPS limits are pretty much set in stone; the reason we want a stronger mechbox is because of the heightened failure rates due to the cold.

Yes we have similar rules, but when given the tools folks when kind of nuts. Also we found that when it gets real cold, O-rings don’t expand well so larger springs are needed to maintain FPS on the cold days. But mostly folks are nuts. Our snipers are legit to 550 fps with .25 after manditory safety cert.

[mthaynes]

Originally Posted by MadMax

The usual failure point on a mechbox is at be the lower front corner of the cylinder window.

You could gain significant fatigue resistance by continuing the lower cylinder shelf forward just past the corner by about 0.1".

This would require a modified tappet plate with notch cutouts in the upright panel to pass the continued cyl' shelf, but the amount of material removal is probably not critical to the tappet plate. The strength of the remaining upright would probably significantly exceed the strength of the spaghetti rear arm which bears the sector cam triangle.

The std cast gear box molds are ages old and to be honest have been copied from the original. I don’t believe anyone that does gear box casting has thought to change the basic design. If they just changed the material from Zinc (yes they are zinc) to a more substantial metal such as aluminum we probably would not have the problem

Originally Posted by MadMax

I'm guessing that your window corners are rounded as your mechbox is manufactured with a milling cutter. The rounding probably makes a greater contribution than polishing the exterior to reduce remove surface start cracks. Have you considered shot peening? I think shot peening would be a more easily applied surface treatment than polishing. The compressive prestress might also make a greater strength contribution than polishing.

No we don’t round the corners – several folks have asked but the design does not warrant that change. However, and you will find this in our design. At key points we have incorporated more material than required. This is so the owner can remove the material with a file to properly fit their selection of internal components. A prime example is the semi cut off lever. Depending on manufacture, these levers vary wildly in thickness. Our approach is t leave the boss for the lever long so you can file to fit your lever precisely. Rounding the corners would also fit into this category. If you would like to do it you can.

The gearbox is not polished in the senesce that it is polished to a mirror finish (although we do have folks in the NE that have done this. I guess you can call it a move from mil-sim to mil-bling) We do have a routine in th program that takes a finishing pass on key internal area to make sure thy are very clean. We don’t have any start or stop cracks in the finished box – again we are very delicate with the machining. We have not done shot penning although some models have been anodized black