Sprocket Assembly

[David Merritt]

Hi All,
This may be an obvious answer to this question but this is the first large tank I have built.
Under the taper lock instructions, "Item 5 Fit Sprocket with bush onto the shaft and locate in the desired position."
What it the "Desired Position"? It can be mounted anywhere along the shaft within reason.
Is there a recommended distance between the inner sprocket and the side of the Hull?
This distance/position must effect the alignment with the Road Wheels to enable the Tank to run correctly.

Thanks in advance.

David

[Paul Sparkes]

David,

The dimension should be provided in the manual, it normally is. But more importantly you need to make sure everything is inline for the tracks to run smoothly.

I dont have a Leopard so its not specific, but the same applies to all models.

[David Merritt]

Hi Paul.
The distance is not specified in the Manual. It just says "desired position"

David

[Mark Heaps]

Not sure if correct, so wait & see if there are other suggestions, but what I would do is slide the sprocket and taper lock on, fit the tracks, lift the hull and spin the track by hand from the idler wheel end several times and allow the track to pull the sprocket to a position.

[Peter Quambusch]

Hi David,

As Paul already mentioned, it is importand that the tracks are running in a straight line, when all wheels, idlers, sprockets and return rollers are installed. Thus I have the tank sitt on the lower parts of the tracks and then bend the tracks over the sprockets, adjust them to be center line and then tighten the screws for the taper lock. This has worked many times on all my models.

Cheers

Peter

[Mark Heaps]

Hi Peter,
Best to hear from someone that has used a method that works for them.
Did you have the whole track assembled at this stage ? So you could have best alignment between road, idler and sprocket wheels or just under the road wheels and over the sprocket, best alignment at that point ?
Mark

[Peter Quambusch]

Hi Mark,

Both fully assembled tracks are stretched out strait to full lengh. 1) to check if they are evenly long and 2) to see if the tracks are straight and not curved. The second is sometimes an issue, when the holes are not drilled at 90 deg.

When both is checked satisfactory, the tank is rolled onto the tracks, front first, over the entire lengh to see if the tracks stay put. At the front end of the tracks the tank is stopped so that the front end barely touches the sprockets from below. Once that is ok, the rear ends are pulled over the idler, road wheels and sprockes, so they hand down. The, with the helh of a pair of pliers the two ends are pulled together and the pin inserted. Lastly the washer and the splitpin are added. Done.
I hope I made the process clear with my limited English...

Cheers

Peter

[Steve Stuart]

I recommend Slip-Jaw Pliers for bringing track links together, because you can adjust the width of the jaws to allow for differing track tensions.
I would that my French is as bad as Peter's English! He does an excellent job of explaining.
Steve

[Aaron Cheng]

I don't have the running gear fully assembled to confirm, but here would be my method of doing it:

Since we know the center line of the road wheels, the idler and the sprocket should be aligned, you can use the hull side plate as a datum to measure the distance from plate to roadwheel center, and plate to sprocket center. Just do some simple addition and subtraction to get the distance, and check with a ruler, caliper, or gage block set if you have them. If I remember correctly for other Armortek kits the tolerance was plus or minus 0.5mm, so you have plenty of space either way.

Another way would be to measure the sprocket assembly section drawing (11B.) itself: measure the distance from the leftmost face of the drive case (CV0110) to the leftmost face of the inner sprocket ring (CV0112B) on the drawing itself, then compare a feature in the drawing to the actual part (for example, the thickness of the drive case flange). Once you have your conversion factor, take the earlier measurement, apply the conversion factor, and space the inner sprocket ring from the hull side by that amount.

A quick check using the latter method on my example gives a hull to sprocket distance of 6.96mm, which is pretty close to the measurement I get for the idler spacing (sprocket center line of 58.56mm compared to the idler's 58.36mm from the hull side plate), so well within tolerance. Remember that there will be lateral play for the track links as well, so getting it very close will improve the longevity of the running gear, but for what we are doing a half mil either way should be more than enough.

[David Merritt]

Thank you all for your replies, it is as I thought something that can only be established once the road wheels are installed and the centre line taken from them to find the position the sprocket. Then checking with the tracks installed that they are all running smoothly.

Thanks

David

[Mark Heaps]

Whilst using the hull as a datum, measuring the distances and calculating the desired position will work, I feel that Peter´s method would be simpler and easier to apply, use the track coming up off the roadwheels to establish the position, the track over the sprocket wheel will also stop the sprocket wheel moving inwards/outwards whilst the taper lock is being tightened.
What I would like to know from Peter as he has used this method very successfully many times, is, because there can be some flex in the track, if track from roadwheel up and over sprocket enough, or best then track also over the nearest top-roller (if the model has one ), or track fully complete.
I had attempted to place this question in a previous post on this thread but, obviously to me, misphrased it causing a misunderstanding and a thread-drift about how to connect the track.
My fault entirely, I have met Peter in person and his english is excellent. I had phrased the question wrong.

[Peter Quambusch]

Hi Mark,

Thanks for you compliments about my English, but now I have a serious problem.... I don´t get the meaning of your sentence:

"What I would like to know from Peter as he has used this method very successfully many times, is, because there can be some flex in the track, if track from roadwheel up and over sprocket enough, or best then track also over the nearest top-roller (if the model has one ), or track fully complete."

But I try to explain (hopefully in the right way to nyour question) how I do it: Most of my tanks don´t have return rollers. Thus I have the idlers in the foremost position and the track as slack as possible. I insert the taper lock with key into the sprocket housing and slide the assembly loosely over the axel. Then I pull the lower part upwards, so the sprocket teeth grab into the first track link holes with the lower part of the track in a straight line with the housing. Then I lightly tighten the two grub screws so everything stays in place, but still can be moved. Now I pull the upper part of the track over the sprockets so that the two ends almost meet. If minor corrections to the sprocket alighnment have to be made, now is the time. Then tighteneing the grubs so nothing moves any more. Finally taking the adjustable pliers come into otion to squeeze the two track ends together, followed by pin insertion. Done.
For the Stug III with it´s return rollers, I basically did it the same way, only that the upper track part run over the rollers.

I hope that answers what you were asking for. If not, pls let me know.

Cheers

Peter

p.s.: This method is also used for repairs in the field, when lacking propper measuring equipent...

[Mark Heaps]

Hi Peter,
Sorry for not replying sooner but only saw your response today. As I thought, full track to get the sprocket into the optimum position and then tighten the grub screws to keep it there.
Mark