A Chequered Chieftain at #10

[John Clarke]

......... I do use moly inside the gearbox and on the axle spindles but avoid wet lubricants like the plague. This has been longstanding advice from Armortek although I don't believe it's been re-validated recently.

Still very much our advice.
Unless you have a sealed environment, over time contaminants will mix with the wet lubricant and in-effect act as grinding paste.
Kian

I think this is very good advice for axles, spindles, shafts, bushes, pivots and any moving metal to metal surface parts, if anyone is going to leave their gearboxes open to the elements.

With the proviso to, strip clean and lubricate on a properly managed maintenance program dependent on use and time.

In my daily working environment, I support and maintain over a couple hundred motor and gearboxes, the majority are oil filled and a few are grease filled. All are sealed and to a certain extent sealed for life.

We only use quality lubricants namely Kluber lubricants. Though before Kluber became our universal supplier, we used many high quality Rocol products.

I cannot say I have ever used or come across Dry Moly lubrication sprays or dry Graphite as the primary gearbox lubricant.

That's not to say there are not any out there though.

I do consider the "Rub" effect on the gear teeth, it could over time remove the dry lubricant, leaving areas of metal to metal. Unlike cams, slides and plain bearings that can be coated, Gear teeth are constantly meshing with different surfaces, wet lubricants reduce transmission shock, reduce temperature and when kept clean, provide constant renewable lubrication between the gear teeth.

So I'll be sealing my gearboxes, and will use a semi fluid grease, designed for longevity and low gearbox maintenance

The rules of great gearbox maintenance, Quality parts, perfect alignment, cleanliness and quality lubricants. oh and no leaks.

Dragged this off the net for the open gearbox builders

Rocol Dry Moly Spray

Description

High purity, extreme load dry film molybdenum disulphide spray designed for use where a wet lubricant cannot be tolerated. Applied wet for great penetration, becoming touch dry within 2 - 3 minutes, leaving a dry protective film containing more than 70% molybdenum disulphide. Dry Moly Spray is an assembly lubricant for sliding surfaces such as plain bearings, pins, cams and slides intended to reduce friction and therefore increase life of moving parts in highly corrosive environments.

FEATURES AND BENEFITS:
Prevents galling, pick-up and seizure
Resistant to high loads (up to 7,000 kg/cm2)
Excellent wear resistance
Fast drying, over 70% molybdenum disulphide content once dry
Ideal for applications where a totally dry film lubricant is required
Temperature range -50ºC to +450ºC

[Richard Goodwin]

......... I do use moly inside the gearbox and on the axle spindles but avoid wet lubricants like the plague. This has been longstanding advice from Armortek although I don't believe it's been re-validated recently.

Still very much our advice.
Unless you have a sealed environment, over time contaminants will mix with the wet lubricant and in-effect act as grinding paste.
Kian

Thanks for your reply Kian although I have no intention of using a wet lubricant in something so exposed to the environment. I would however, be interested in your thoughts regarding the use of a dry lubricant on the pins and if it will reduce wear between the link and the pin?

[Richard Goodwin]

So I'm now considering the assembly of the track links and in particular, securing the pad to the link. Now Stephen has kindly advised that a split washer was fitted to the original but I don't believe there is sufficient thread available to include this unless of course you switch to using a half nut. The use of this washer should negate the use of any Loctite but I have decided that I will just fit the nut itself with no split washer; the only difference being that I will use a black stainless nut instead of the supplied nut; since my tracks are black, it makes sense to use. But the question now arises of what type of loctite to use! The nut is fairly close to the track guide rail (sorry, don't know what its proper name is) so you can't fit a socket in to tighten it up which means you have to use a spanner instead. Using Loctite Blue to secure the nut might however prove difficult to undo with a small spanner since the pad is a replaceable part, so I am considering using instead Loctite Purple and was wondering if anybody here has had any experience with it? Would it be suitable for this application?

Any comments good or bad appreciated.

[Richard Goodwin]

Time for an update methinks:

Having done a trial assembly, I found that when I screwed on the nut to hold the pad in place on the track link, it not only removed the primer but also the etch as well!

So grabbing another batch of pads that had been etch primed, I added a nut to each pad and screwed it down to roughly the position it would be when in position. I then primed up to the bottom of the nut. If you look carefully on the left of the picture, you can see the etch still in place.

With the delivery of the Loctite Purple and the black stainless washers and nuts, final assembly could now start. With the track pads inserted in the track links, Loctite Purple was applied to each screw thread before securing the pad using the black stainless nuts. Once dry, the top of the screw threads were finished off with a little primer applied via a cotton bud and when dry, each track link was given two coats of satin varnish over the top and sides.

Finally, the tracks were joined together using the link pins which have only been etch primed (no lubricant) with the exception of the ends that had been painted black and held in place using the 1x6 mm stainless cotter pins (unpainted) not forgetting the black stainless washer beforehand! This is how it looks:

I don't know how long this paint will stay in place for once in use; I hope it lasts a while at least but if it doesn't, it wasn't for the lack of trying!

Just another 183 + spares to go

[Stephen White]

Nicely done, Richard, a lot of hard work there. As soon as you run on a hard surface, you'll probably lose the paint on the spuds. Which is a prompt for some terminology:

Track.jpg (75.57 KiB) Viewed 3227 times

The horns are designed to keep the track centred on the running gear under sideways load. The spuds are designed to improve traction on soft ground. A form of detachable spud was patented by William Tritton during the design of the first tanks. Why spud? One explanation is that the original Tritton spuds resembled the spades used to dig potatoes, which were known as spuds (the spade, that is). Which is why potatoes became "spuds" and hence the spud on the tank track. Over to our brains trust - any more tank tract trivia?

[Richard Goodwin]

Thank you for your kind words Stephen and the history lesson as well; always useful to know the correct terminology, somehow, thingummy bob doesn't quite cut it does it You are quite correct, I do expect some wear regardless of the extra coats of paint and varnish that I have applied in certain areas. The spud, top half of the horn and the sprocket slots I would expect to wear quite quickly so hopefully, I'll have the au natural look develop naturally to my new tracks just like the original did. Only time will tell

[Richard Goodwin]

Having spent a few days golfing in a warmer part of the world with a good mix of people and of course, the all inclusive deal, the batteries are now sufficiently recharged (albeit with a little hangover ) to allow full scale track production to commence

Am probably stating the obvious here but when doing batch production, it is easy to get confused as to what stage each batch is at so the simplest way to remember is to make up some labels of the steps required and then place the appropriate label of the next step required of that batch by it. In that way, you wont forget if you leave it a couple of days before going back and doing some more!

Loving this new compressor!

[John Clarke]

Hi Richard, having just put the sprockets together I checked them against the tracks finding that they rub (pinch) on the inside edge face of the sprocket teeth. So instead of taking a little material off the sprocket inner face, I took a needle file to the inner edges of the track slots. It's such a tiny amount of material you have to take off the track, but it makes a lot of difference on the sprocket.
It will of course save on premature wear on the sprocket rings.

This might not be the case for other owners as the there may be minor differences in the manufacture of the parts. but it's what I found with my bits.

It shouldn't spoil your paint job on the tracks as it's all on the inside edges.

[Richard Goodwin]

Hi John. Apologies for the delay in replying, I've not been very well.

Many thanks for the info. Have checked some of the tracks and found that some do indeed appear to have a little lip on the inside edge. With me adding paint and varnish into the slots as well will only aggravate the problem more. I'll need to assemble a sprocket properly including paint and varnish to assess the full impact. Perhaps it was a little vain of me to think that the tracks and drive mechanisms would find their own level and bed in smoothly

Reading the instructions for sprocket assembly, I see the instructions say to break the edges to avoid track climbing! Firstly, is this the inner and outer edge of each tooth and not the front and trailing edge of each tooth? Secondly, any idea as to how much should be taken off?

As always, many thanks

[John Clarke]

The tracks look beautiful, the needle filing won't make a difference to them outwardly and no need to repaint if your going to actually fit them and not frame them.
The sprockets will soon rub off any new paint once they get churning round.
Better to fettle the chunky tracks than grind to much off the sprockets.

[Richard Goodwin]

Ummmmm.......I have been playing in regard to the sprockets rings! Without touching the rings other than making them fit the hub, I tried out an assembly on a length of 40 tracks whereby it occasionally jammed and locked in. So i did a little fettling around the sprocket teeth ie removing the sharp corners, flattening the teeth tops and putting a slight bevel on them before finally running a flat file across the teeth to ensure flatness. The end result was that one assembly flowed freely from end to end, the other jammed once. If i pick the track up and roll the assemblies from end to end, no such problems at all and I've not yet edged the teeth to prevent track climbing. Admittedly, they are not painted yet! I have been having trouble with the tracks themselves which has resulted in me doing a little grinding so I'll take the opportunity to removed the edge at the same time so then it should be super smooth. My next post will cover the track issues and the one after that, with what I did to the sprocket rings! I'll await the obscenities

[Richard Goodwin]

Time for a track update methinks...........despite conducting my test trial, I've been unable to insert the cotter pin i,to the track pin on about 50% of the tracks produced. Now clearly, there are tolerances in the tracks and track pins themselves, in addition, I am also using a different washer and cotter pin to that supplied; that said they should be the same size so shouldn't be a problem. Therefore the only reason remaining as to why I'm having this problem must be due to the fact that I am painting and varnishing before final assembly! The trial should've found this out but maybe, it looks as if I just got luck in my track selection and found the smaller ones Now the manual does recognise that some grinding may be necessary if the cotter pin is difficult to insert as shown below:

So by trial and error, the best track width I found which works with the way I'm doing the tracks and enables easy fitment of the cotter pin is 90.5mm which should result in a finished track width of around 90.7mm as shown. Looks like the track work just became even more labour intensive; as if the painting and varnishing wasn't enough

[Richard Goodwin]

The tracks look beautiful, the needle filing won't make a difference to them outwardly and no need to repaint if your going to actually fit them and not frame them.
The sprockets will soon rub off any new paint once they get churning round.
Better to fettle the chunky tracks than grind to much off the sprockets.

John, further to my earlier response I've examined the length of track I used to check the sprockets and as you can see from the picture below, there is witness marks where the sprocket catching. Now I'm not sure if this was pre or post me filing the sprocket rings but it does show that the ridge may indeed be a source of contact. Now I've already made a conscious decision to strip down the track I have already constructed to allow for dry lubricating the track pins; I consider that since I processing these in batches, that I should be able to group the batches together and thereby minimise waste of what is a very expensive lubricant. I did however spot that some tracks had a similar ridge on the outside edge of the sprocket slot so will be tackling that at the same time as the inner edge. Thanks again for the tip.............and the extra work and yes I know, black shows every mark

[Richard Goodwin]

As promised, this is what I did to my sprocket rings! Apologies for some of the poor photo's, regrettably, the camera focus point shifted half way through but the gist of it is still there!

Firstly, I removed any burs from the hubs and cleaned them up with degreaser. The holes in the rings were were also cleared of burrs and any waste material

When I tried to fit the rings to the hub, they would'nt fit, so I took equal amounts off of each securing tab until it did!

At the same time, I also put a slight chamfer on each corner of the tab to remove the sharp corners. If you look at a real hub, you'll see that there is a radius on these corners and by putting a slight chamfer on, gives the same impression or so I think anyway.

Next, I removed the sharp edge off of each side of each tooth

Before then flattening the top of each tooth

and ensuring there was a chamfer on the leading and trailing edges of each tooth.

Finally, I ran a flat file across the seide of several teeth at the same time to ensure they were levelish and all burrs were removed.

The only thing I haven't done yet is the chamfering of the side of the teeth to prevent track climb because I don't know how much to take off and how deep down the tooth it should be. Now I'm guessing this is an adjust on test sort of thing i.e. if the track climbs, file it down some more but can anybody that has experience of this issue advise of a starting point?

[John Clarke]

You'll have to wait for Phil or Youngjae to fit their option pack for that one Richard. I've only used a dremel type surface abrasive wheel so far on the sprockets and will give track a lot of attention. Spending a lot of time on the wheel hub gaps at the moment and working out how much suspension travel I can get on the front bogies which is limited by the "damper arm slot"