Dry Lubrication For Gearbox Internals

[500fps@50mtrs]

Firstly I would like to say that this is a continuation of a thread started by "deepsprayj" with technical information given by "docv400"

 

Some members have tried using dry lubrication for their gear sets and there have been some successes although most of the dry lubricants are only found in the U.S. The chemical lubricant in question is Molybendum Disulphide mso2. This is a type of pure Graphite that is many times slicker than Teflon or PTFE and of course Graphite. I wont go into the science just google it if you realy want to know

 

So having a G3 SG1 that is about to have all new internals I decided to strip the old gearbox and rebuild her using Molybendum Disulphide in a powder form (it is available as a spray).

 

So first things first strip the V2 Gearbox.

 

 

 

Remove all internal parts then inspect casing. In this case the casing is going to be renewed so the slight wear visible on the casing will be ignored.

 

 

 

Next the contact parts of the gearbox casing were cleaned, degreased and polished using a Dremmel and its various attachments.

 

 

 

Now the mso2 was applied. Firstly the casing was warmed up with a hot air gun then the lubricant was applied first with a small stipple brush then polished in with cotton buds. If you use the spray lubricant then this process will be much quicker and cleaner. The parts were then left to cool before re heating and re applying the mso2. Once cooled the parts were polished again.

 

 

 

Next came the gears. You may notice from the pictures that the gears are not in great condition but as I say they are going to be replaced and this may not work The gears were cleaned and degreased.

 

 

 

The gears are coated in the same way as the casing and then polished. Note the difference in colour after coating.

 

 

 

The gears were then test fitted into the casing. The bushings and shims were also coated. The gears were given a test spin Three complete revolutions from one flick

 

 

 

The other components coated were the spring, spring guide, piston, tappet plate, selector plate, nozzle, non return latch, trigger, and semi auto latch.

the gear box was then re-assembled.

 

 

 

Apart from looking much nicer the gearbox was very easy to re-assemble and shimming was done in seconds. Once the gearbox was back in the gun it was test fired and the rpm figure was checked.

 

The G3 runs an M100 spring metal bushings poly-piston and head and runs on a 8.4v 3300mah battery. Prior to the re-lube using a sound wave recording we measured the rate of fire at 17 rounds per second after the rebuild we recorded 16 rounds per second.

 

However I am fairly confidant that this reduction is a result of the method used to make the first sound recording and record the findings. The gun itself sounds different not sure how to explain it. It is maybe sharper though it's definitely quieter. It shoots as it has always done and I am going to hold of on the rebuild until our next skirmish as I would like to see what the gearbox looks like after a days use as a support gun.

 

As mentioned at the start of this post the question about dry lube was raised by "deepsprayj" thankyou for the idea. And the techno babble was from "docv400" cheers doc

 

This post was done as a technical exercise and I do not suggest that you carry out any of the listed procedures on your own guns nor do I except any responsibility for any mistakes omissions that may cause harm or damage to persons or property. Play Safe

[Joaz]

I noted less more accurate results when using the spray (used Molycote 321-R - not clean MoS2 - includes Graphite as well). The powder and a brush is more accurate and easier to dose.

[kdouglas]

so has anyone figured out where to get this stuff in the uk or ireland yet? wouldnt mind trying it out.

 

Edit: think i may have found some.. radionics.ie and search for 196-3491

[DarkLite]

Still can't get this stuff in the HK - EVEN THOUGH IT'S BLOODY MANUFACTURED HERE.

 

Aaaaaaaaaaaaaaaaaaaaaaaaaargh.

[500fps@50mtrs]

I have since taken the gearbox apart again and discovered that I didn't re-grease the piston

This will of slowed down the rate of fire so I will test it again tonight and see if there is in fact any improvement on the first test.

 

Also i would like to correct a spelling mistake in the chemicals name it is.

 

"Molybdenum Disulphide MoS2 "

[johnyew]

Still can't get this stuff in the HK - EVEN THOUGH IT'S BLOODY MANUFACTURED HERE.

 

Aaaaaaaaaaaaaaaaaaaaaaaaaargh.

<{POST_SNAPBACK}>

 

Go to www.rshongkong.com and search for Moly. You should find a page in paste form.

 

ETA - Part number 209-6974

[cire]

Can you expand on your method for polishing?

[crablegs]

I have since taken the gearbox apart again and discovered that I didn't re-grease the piston 

This will of slowed down the rate of fire so I will test it again tonight and see if there is in fact any improvement on the first test.

 

Also i would like to correct a spelling mistake in the chemicals name it is.

 

"Molybdenum Disulphide MoS2 "

<{POST_SNAPBACK}>

In the other thread they didnt even use grease did they?

[infected]

I'm hoping he meant he didn't put the Moly on the piston.

[500fps@50mtrs]

Can you expand on your method for polishing?

<{POST_SNAPBACK}>

 

The method used for polishing is simply a small brush attachment for a rotary tool. Using this method smoothes and cleans any area of the casing where contact with moving parts will be made. After this initial polish the dry lubricant was worked into these areas first with a small stipple brush then with a cotton bud. After the heating any re-application of the dry lube these areas where buffed to a high shine with a small polishing mop attachment for the rotary tool.

 

You should see an almost instant result when the Molybdenum is applied.

[500fps@50mtrs]

I'm hoping he meant he didn't put the Moly on the piston.

<{POST_SNAPBACK}>

 

In my haste after cleaning all of the gearbox assembly I re-assembled the piston with an entirely dry O ring on the piston head. This has damaged the O ring sufficiently due to friction that it needs to be replaced. Wether or not this slowed the rate of fire after the rebuild test we will have to wait and see as I dont have a replacement O ring

 

In the other thread we toyed with the idea of a completely dry piston seal however after some research it became clear that you need some sort of "wet" seal between piston head and piston sleeve to ensure no air loss during the firing cycle. The piston itself is coated with Moly as are all other moving parts but as yet there is no evidence to suggest that a totally dry piston seal can be efficiently maintained.

 

When the new piston seal arrives I will re-test the rof and post the results.

 

If anyone has access to an airflow meter then some comparative test results between a dry and a traditionally wet-lubed piston would be interesting

[infected]

You know you can replace the o ring with a number 14 oring from a hardware store right?

[500fps@50mtrs]

You know you can replace the o ring with a number 14 oring from a hardware store right?

<{POST_SNAPBACK}>

 

Thanks for the info yeah I no its a fairly standard bit of kit but I have ordered parts from ehobby asia and they are due today or tomorrow.

 

Changing the subject you have a CA M15A4 R.I.S with a tight barrel and new hop rubber. How does it compare with the standard set as far as range and accuracy go. Thinking of the same parts for our CA M15A4 S.P.C and what battery size do you run?

[Docv400]

The piston head o-ring does indeed have to be kept wet.

I use a silicone spray, squirted into the BB delivery tube, with the gun held muzzle-up and the nozzle stopped in the retracted position.

A dry o-ring will slow the ROF a fair bit.

Dry rubber on smooth metal has a very high coefficient of friction...if it didn't, there'd be a lots of dead and injured cyclists all over the place

 

I've also toyed with the idea of coating the lower inner surface of the barrel, immediately under the hop rubber. The BBs will be pressed fairly hard against this area as they're forced past the hop 'protrusion', I just wondered if there was any fps gain to be had by coating it. You'd need to take the 'shine' off the surface to give the lube a key to adhere to, but I think it's worth a try.

[Burke]

what if you did it with a stock barrel myabe it would end up liek making your own custom dry lube tight bore....

[elmariachitw]

Another reason you need a wet seal is that there is a little bit of play that the piston has inside of the cylinder. So far, I use a CA's piston/cylinder lube or radio shack's lube gel. The gel is a little thicker and gives more resistance than the piston/cylinder lube, but it stays better.

 

I think dry lubing the gears is a great idea, but I'm just afraid that the tiny bit of play that the piston has in the gearbox (outside of the cylinder, by the piston guides) needs something wet that hampers the potential wobble a bit. Other than that, knowing that your lube isn't going to GO ANYWHERE since its 'baked' on to the mech/gears itself is awesome.

 

Right now I'm working on a friend's gearbox and have lubed the gears and piston guide area with fully synthetic motor oil. I've only ever seen it used so far in high-use mechboxes like an m249, but I'm giving it a shot.

 

Thanks for the post and 'guide'.

[infected]

Right now I'm working on a friend's gearbox and have lubed the gears and piston guide area with fully synthetic motor oil. I've only ever seen it used so far in high-use mechboxes like an m249, but I'm giving it a shot.

<{POST_SNAPBACK}>

 

Would that stay where you put it? I'd think not. After a while it'd fling off.

[elmariachitw]

Would that stay where you put it?  I'd think not.  After a while it'd fling off.

<{POST_SNAPBACK}>

 

I'm afraid of that too, believe it or not. I'm checking the box after a thousand or so rounds to see how it sticks.

[500fps@50mtrs]

I have since added wet lube to the piston and a new O ring, ROF is hovering around the 17/18 rounds per second. I think I was secretly wishing that dry lube was the holy grail of gearbox building and although the benefits are not immediately apparent I believe that there are benefits to be had.

 

So far the testing with my G3 has brought up the following points.

 

1) Dry lube definitely works

 

2) Any increase in ROF is in rounds per minute rather than rounds per second.

 

3) After putting around three thousand rounds through it under skirmish conditions there appears to be no wear, flaking, blistering or any other signs that the gearbox has been cycled even once. This despite the fact that the gearbox was not in the best condition to begin with and the gears needed replacing very soon.

 

Will I dry lube another gearbox? Yes Absolutely

 

If for no other reason than when it becomes time to upgrade or repair the gearbox then a clean, dry and unsticky (not sure thats a word) set of gun internals is a pleasant place to work.

 

As I stated before this was an exercise to test what was mostly forum rumors and a few attempts with variations on a theme. I cant take any credit for the idea or for the methods used but I would strongly recommend to anyone who likes to play with their guns innards to have a go. It is a very rewarding task and because of the somewhat delicate nature of the job you get to know your guns internals up close and personal.

 

I Will shortly be rebuilding the internals on a couple of Chinese guns. From what I have read and seen almost all lower cost chinese clones would benefit from a gearbox overhaul and I intend to dry lube them from new. I will post the rebuilds and any benefits or drawbacks recorded. If anyone else wants to go Dry then please read through this thread and the original posting and heed what Docv400 has to say and please post your results and methods along with gains or losses and any tips or problems.

 

I would just like to send my sympathies to Charlie and his team at Ambush Adventures in Chobham. A few weeks ago some local Scum broke in to the Chobham site and after helping themselves to a few guns and piro's they burnt the shop and office to the ground. Some lads were arrested a few days later after shooting a woman in the face with a pistol taken from the site but apparently in this day and age that isn't enough to arrest people so they got away scot free. Despite this Charlie, Dave and the boys put on a good show with a young guns event and a makeshift office/shop with a couple of hastily erected tents (Ten men, Eight teenagers, One mum, No idea) and a smile on there faces.

 

Thanks for a fun day guys hope to be back soon.

 

Phil Adam Emma...

[greatwatermelon]

Hey,

 

I bet u can get more benefits with dry lube

 

Have you tested to see if your fps is more consistant?

 

because if its less friction from no more displaced lube in different spots of gears and such, then your fps would be more consistant right?

 

and if ur fps is more consistant that could also mean better consistant accuracy/range

 

 

try and test those things out

[infected]

There should be no change in the FPS as FPS is based on the volume of air moved through the system and the speed at which it is moved. The gears only compress the spring, they do not do anything to affect the speed at which it propels the piston forward. This does not increase the volume of air either.

 

I would not think that this would improve consistency, but rather rate of fire, longer MTBF (mean time between failures), and easier gearbox work.

[Docv400]

But you may get a slight improvement if there's less resistance to the movement of the piston.

 

The main reasons I tried the dry lube originally are

1. It's dry and doesn't attract or hold dust/dirt/grit etc.

2. It's very tough, and will keep my gear teeth, piston rails and gearbox internals operating like new for as long as possible.

3. It's not messy to work with (see 1) and when you strip it down again it's just like when you put it together.

4. I had some available.

5. Everything spins/slides much more smoothly, optimising performance and consistency.

I'm not after high ROF (I'm mainly a semi-auto type player anyway) I just don't like stuff wearing out if I can prevent it.

[cire]

Anyone know of a local place that sells Molybdenum Disulfide in the states? It's not hard to find it online, but do I really want to do that?

[Burke]

I got soem dupont dry lube that ahs moly in it, gunk also sells one I got it walmart while loews sell the gunk dry lube. I dunno if they will work or not im goign to try and test them out.

[Kingmob3]

When in doubt McMaster Carr has everything. I intend on doing my new CA36 later this coming week and getting the moly lube there.

KM