Troubleshooting New Build 2.0: Opinions Requested!

[Flarebrass]

Hello ACS Community!,

So I am back for a second round of a high end build I am doing. I used everything I learned from my previous builds to this date, including my other troubleshooting thread, and everything worked as it has in the past or better; other than one thing.

I put everything together after modification and began testing. It shoots just below 400 FPS as intended consistently and seems almost every part if working correctly. Now, to the issue;

whether it be on semi or auto, there is a subtle "grinding" metal-on-metal noise when the trigger is pulled. I know this as some of my other build have a much "smoother" sound when pulling the trigger. This would seem to be from the pinion gear and the bevel gear.

I found this out the hard way after I pushed through a scrim testing it out, got home and found both the bevel and pinion gear beginning to strip and the gearbox was full of sheered metal (had already lost a mm or two of metal from each set of teeth). Since then, I have replaced the bevel with another one that is exactly the same but not stripped, and also switched the pinion. Neither are stripped now, but the grinding still exists.

Now, some of my in-house trouble shooting is as follows:

1) Recheck shimming: Checked and re-shimmed 3 times. Shimming every time was right on. I also triple checked the motor height on the right side of the gearbox with the grip and motor installed to confirm height. Everything was ok with that as well.

The thing that I did notice though was that when the motor test was done to check height, it pushed the bevel gear onto an angle (possible saying that the motor height was fine, but the width from side to side was off and creating additional pressure on the pinion and bevel teeth when installed which is a good probability to being the culprit). I tested the bevel with no shims on the fat side, and it still produced this result.

*The above is my best guess as to the issue, but I have not yet found a solution to relieve pressure from the teeth when the gearbox is assembles and the motor is installed as the bevel cannot go any lower*

2) tested what side the wires should go on. Tested all 3 in the grip; both wires front, one wire each side and both wires on the back. This produced the same result of grinding for each test.

3) I compared the pinion on the A1 to a spare SHS pinion I bought just incase I needed to replace one, they are both the same size and seemingly same angle.

4) I did NOT test another motor, as the A1 is the only one I own that can pull those gears.

5) checked the bearing to ensure that they are flush with the body of the gearbox. Test concluded to be ok.

Bellow is my complete gearbox setup for my other VFC 416 CQB:

Lonex Gearbox (bearings, not bushings)
SHS M4 nozzle
Lonex aluminum double o-ring cylinder head (equipped with 70D sorbo pad)
Stock VFC Cylinder with a type-1/2 slit (works the best with the short stroking set up for this particular build)
Siegetek Revolution 10.44:1 Gearset SSG (short stroked 3 teeth off pick up side)
Lonex Titan A1 Motor
SHS 15 tooth piston - full metal rack (filed 2 teeth after pickup tooth for AOE correction, short stroked 3 teeth off release side and fully swiss cheesed)
Lonex POM Ventilated Piston head (Ball bearings installed)
Lonex bearings spring guide
SHS tappet plate (modified to fit into Lonex reinforced gearbox)
Lonex selector plates
Lonex M120 non-linear spring
BTC Spectre MOSFET
Magpul PTS MOE grip

If you could please let me know your opinion on this matter and if you know what may help, it would be greatly appreciated. Thanks for your time.

Flarebrass

[Shamusodoofus]

Lonex 8mm bearing gearboxes are known to have bearing failures even on mild set ups. Have you inspected the bearings to ensure none of them have cracked/broken?

I should point out that grinding does NOT come from too much contact between gears. Quite the contrary; grinding occurs when the gears do not make enough contact and "slip". Too much contact (too tight) would either put strain on the motor and lug it, or simply seize from too much friction.

Keeping this in mind, you mentioned you have already gamed this rifle despite the grinding. It is very likely you have grinded either the pinion or bevel gear down to a point where it's not making enough contact to grip the gears.

[lurkingknight]

how are you shimming the gears? Which gear do you start with?

[Flarebrass]

@Shamusodoofus All bearings seems to be in running condition; no cracks or breaks. They also all sit flush to the gearbox.

Also to clarify, I replaced the bevel with another one that was exactly the same in good condition. I also replaced the pinion gear. Both new ones were used for this test. I have adjusted OP to reflect.

The slippage may very well may be the case, however I do not know how to make it so it is touching properly when the pinion and bevel gear mesh (as I think there is too much stress somewhere from the example given above with the grip pinion bevel test; its pushing the bevel to be on an angle. I have to apply equal force on the other side of the bevel to get it even in the test).

I have moved the motor higher just to see what happens, and it grinds and "lugs" as you say both at the same time. with current (proper) motor height, it just grinds.

Your also saying that it might just be a slightly off lemon gearbox? I should try another gearbox that I have just to test it.

Any other thoughts on what it could be before I do the swap?

@lurkingknight hello again . My shimming is done by bevel with motor test -> spur -> sector. In a spin test, with all 3 properly shimmed, it spins roughly 4-5 times with a decent finger pull. I do not believe this to be the issue.

Thanks guys and keep the ideas coming!

Flarebrass

[lurkingknight]

when you check your bevel to pinion, are you screwing the grip onto the half gearbox shell and checking the play in the bevel? It should have enough room to rock a bit under the pinion. If sitting teeth side up, the bevel should not be disturbed by the pinion gear so much that it gets pushed off axis. If it does, it is shimmed too high.

Depending on if your bevel and pinion are the same brand or not, you may get some whine/grind no matter what. Matching the pinion gear to the bevel means the 2 will meet at proper angles. Not all pinion gears have the same angle.

[pestobanana]

Regardless of the condition of your bearings, check them to see how many ball bearings they have. If they have 8 ball bearings, get rid of them immediately. Lonex is a mediocre brand at best, and their ball bearings are honestly some of the worst on the market. I've seen them break left and right in sub 20 RPS 380 FPS guns running on 7.4 Li-Pos. If they have 7 ball bearings each, they are less shitty, but I still don't trust Lonex bearings since I've seen an 80% failure rate on them in mild setups. If you insist on using them, at minimum put a steel bushing under the spur and under the sector.

Try a different pistol grip. I've found that some HK grips from VFC give a proper motor angle while some do not, I'm not sure why. I had some M27 and 416 builds that sounded great, however when I used a Lonex gearbox shell and 10:1 DSG with the HK grip in my clearsoft gun, it grinded. I swapped to a standard A2 grip and the grinding went away.

SHS pinion is not even remotely similar to the Lonex one. SHS pinion teeth are much thinner as they are probably sintered, Lonex pinions are CNCed and much thicker.

Also, when you test bevel-pinion shimming, you have to test with a wattmeter, and JUST the motor and bevel gear. If you have shimmed it properly, the amp draw should be only slightly more than running the motor on no load.

[Flarebrass]

@lurkingknight I know exactly what you are saying. It IS off axis but I cannot shim it any lower as I have tested it with no shims on the fat side and it still pushes it off axis. Bevel gear is Siegetek and pinion right now is the stock Lonex A1 (about to try my SHS one on a different A1 motor). This may definitely be the problem.

@pestobanana hey again haha. I am going to try the other gearbox (Stock VFC gearbox with bushings) and see what happens with that.

I get what you are saying about the grips as I was thinking of that as well. I might give that a shot if the gearbox swap doesn't work and see what happens.


When I get some time tonight or tomorrow ill work on all this and report back. Thanks for the ideas guys, much appreciated!

Flarebrass

[pestobanana]

I honestly think you'd benefit more from trying a different grip than doing a full gearbox swap. One takes two minutes, the other takes an hour. This is coming from someone that experienced your exact problem with the exact same bevel gear, pinion gears, gearbox shell, and grip.

[Flarebrass]

@pestobanana So I did what you said and put on the original 416 grip that I had lying around. This drastically reduced the grinding overall. With a little fiddling, I can probably make it even better.

Do you have any tricks for getting the PTS MOE grip to work (as it is my preferred gaming grip)? What did you end up changing, part wise, to make the grip work? I know Siegeteks are best of the best, but would I be better off with a slower, more stable gearset from lonex or the 13:1 SHS gears and having it mesh properly?

Also, you said the Lonex boxes are sub-par; What is your preferred gearbox?

Thanks.

Flarebrass

[lurkingknight]

if the gear is shimmed as low as it will go, check the gear axles and bushings to see if they are being pushed in by your motor grip. Sometimes it's necessary to dremel out a gap that allows the gear to sit at lowest point. The grip can push the gear off the bottom of the gearbox sometimes.

the MOE grips are notorious for that, as well as the ACM ones not letting the motors sit as low as they should.

[pestobanana]

The only part that needs to be changed is the grip. You need a gen 2 genuine PTS grips that are textured with little magpul logos. The gen1 grips are terrible, you have to loosen the two plate screws to get rid of some of your gun's screeching.

[pestobanana]

As for Lonex gearboxes, they're not bad, they're just not necessarily good. They're no better than the stock VFC shell. They're just shiny. The only "good" mechbox shells are made of billet aluminum and cost a lot.

[Flarebrass]

@pestobanana The MOE grip is a gen 2. I just wish it worked with this set up lol.

[pestobanana]

That's odd because I'm using 4 gen2 grips without issue... Two of them with siegeteks.

Do you have gen1 or gen2 siegeteks?

[Flarebrass]

Don't know about the Siegeteks. this is where I bought them from. http://www.airsoftstore.ca/index.php...roducts_id=216