Armortek

Hey Vince, I glued the bearings into my drive cases before I saw the oil seal. I thought it was to be placed outside the outer bearing. That was my impression after looking at the diagram in the instructions. Are you saying there is a space for it behind the bearing I don’t see anywhere on my drive case like that. I am confused.

Yes Brian. There is a recess for the oil seal just below the outer bearing. Looking at the diagram on page 15 I had exactly the same impression as you did. On page 16 the seal is shown in the proper place but not labelled. So I asked Kian to confirm the proper place of this particular seal. Personally, I would not worry too much if the seal is not there. If anything, the sprocket will turn more freely without the seal.

Vince

Caution!
I have used the washer method although it is against Armortek's explicit instructions. I can't recommend it, since you can ruin your bearings and potentially motors and electronics if not done properly. The danger is that, as you tighten the bushings, the bearings will be squeezed axially and bind. You would need to sense very carefully with your fingers as you tighten the bushing, that there is still an ever so slight axial play and that the sprocket turns freely. To do that, the motors need to be removed and it takes several tries before perfect. I used aluminum washers filed to the exact thickness required to maintain the sprocket to hull clearance. I think it was 16 mm on my 2010 tiger. Don't know if it has changed over the years, but you can measure with your track in place when everything is straight.
After many years of running, I had to remove the gear casings and found that there had been no rubbing against the hull and that the gears looked like new, so it works, for what it's worth. I have also found that there is no need to tighten the bushings for king and fatherland. Just snug produces a very good squeeze on the shaft, indeed.
I hope this helps in making an informed decision on how to proceed, but keep in mind: If you choose to use washers, you are on your own!

Good luck!

Thanks Christoffer for the tip and the words of warning which I will be taking seriously. I still have some time to consider everything and take a decision on which method to use.

Vince

Today I managed to fit all the road wheels to the model. With the swing arms set at 30 degrees it is very difficult to fit the wheels with the tank hull right way up, so with the help of my wife I put the tank hull upside down to fit the wheels. Removed all the masking tape from the axles and with some 400 grit sand paper removed any signs of rust and wiped them with some acetone.
This next step is not recommended by Armortek but I did it for rust protection. I live close to the sea with high humidity so rust is a big concern to me. I applied to each axle some general purpose grease.
Fitted the wide spaced road wheels. At this stage they are just resting on the inner bearing.
Fitted the first narrow road wheel between the wide spaced wheels. This is also just resting on the inner bearing.
Continued with the rest of the narrow road wheels.
All road wheels were inched inwards until the axle shoulder was reached.
Wheels were locked in place with the kit supplied fittings and using 0.1mm shim washers so that when the screw is tight the road wheel will still turn freely. Most wheels only needed one shim washer but three wheels needed more than one shim washer.
Cleaned any excess grease from the back of the wheels.

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Vince

Need to temporarily build a length of track for testing purposes especially for when I put the idler and sprockets on. Today I found some M3 washers leftover from a previous model. They are smaller then the standard M3 washers and I was thinking of using them.
The one on the left is the smaller M3 washer and the one on the right is the standard size M3 washer.

Tiger looking disappointingly at the tracks.
Vince

Fantastic update. I am jealous.

Vince,
It's difficult to keep up with your posts but regarding your thoughts on fixing the drive shaft, unless Armortek jump in and say to the contrary, I understand that it should be glued in place to the two bearings. As an alternative to packing washers between the taper lock and outer bearing, some builders have cut a groove in the shaft just in front of the outer bearing and used a circlip to fix the shaft in place.
Either way, as per your measurement, the clearance is very tight and as in Adrian's picture even when glued in place , there is often sufficient end-float in the bearings to allow the gear to scrape away at the hull side. As long as the shaft stays fixed, the extent of wear should be limited, but it does still increase friction when rubbing and fill the gear case with alloy filings.

To try and eliminate any contact from happening, I added a thrust pad between the gear face and hull side so that they cannot touch. The pad is made from a hard wearing plastic and screwed onto the hull side. The inside of the gear face is recessed to provide the space needed for the pad. I made the clearance between the pad and the gear recess the same as the original clearance between gear face and hull side, which on my kit was only 0.5mm. Then to make sure the pad comes into play first, I refaced the gear by 0.6mm to remove the lead in chamfer to the gear teeth, which meant that the final clearnce between gear an hull side was increased 1.1mm.
How well this works at eliminating contact with the hull side, time will tell - however, on a dry run assembly before I finally glued the drive shaft to the bearings the sprocket turned very freely even when pushing it hard into the hull side.
David

this modification will no doubt make a huge difference, a possible upgrade to future releases

Thanks David for the great ideas. More food for thought.

Vince

I wanted to mention something yesterday when I was doing my last post about the tracks but I forgot it and remembered this morning about it.

This is for the newbie tank builders (like myself) and hopefully might avoid track problems further down the line. When I was washing the individual track links (actually I still got a few track packets to do yet), I used to do a test assembly with just the track pin being used and I bend inwards the newly fitted track to check for free movement. I wanted to see if the track horn touches the horn of the adjacent track just like the photo below.
I have seen track links which do not manage to do this. No problem. Just put this offending track aside and try it again with other track links. This usually (in my case) solves the problem.

Vince

Fitted the idlers and their hubcaps.
Tried the length of track I assembled and it runs freely between the road wheels and idler.

Vince

Vince I can’t tell if that’s the real thing or not!

Thanks for the compliment Brian. I am just trying to emulate some of the master builders here.

Vince

The build was on hold for the last two days trying to decide the best (and easiest) way forward regarding the method of removing the endplay from the driven gear and hence avoiding as much as possible the driven gear from grinding into the hull.

Various methods were suggested to me either here on this thread or via PM and I would like to take this opportunity to thank all that sent their suggestions. Thank you guys. The method I chose was using an external circlip, in fact this morning I bought some 15mm external circlips. This afternoon I did a test run on a piece of 15mm BMS. I was lucky that I already had a custom made HSS tool to cut the 1mm groove for the circlip. I had made it some years ago to cut the piston ring grooves in a model engine.

The test piece was a success, so I decided to do both driven gear shafts. It took less than 30 minutes to do them.
Checking with a feeler gauge there is a 0.1mm distance between the circlip and the bearing. I think I will order some shim washers.

Vince