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Sprocket Spacing Spec

Posted: Tue Dec 23, 2008 6:44 pm
by Sean Cleary
Page 23 of the Late Tiger Assembly Instructions states:

"The bush must be allowed to find its own position along the driven gear shaft such the sprocket is set with the inside face 16.5mm from the hull side."

Does this measurement refer to the distance between the hull side and the assembled sprocket in which case it would be measured from the inner sprocket ring to the hull or...

does it refer to the distance between the sprocket center and the hull in which case the distance between the inner sprocket ring and the hull would then be approximately 13.5mm?

There is some play between the driven gear and the gear housing allowing the sprocket to move in and out a couple of millimeters. Should the sprocket measurement be taken when the sprocket is nearest to the hull or farthest from the hull?

In other words is the 16.5mm spec a minimum or a maximum value?

Posted: Tue Dec 23, 2008 8:19 pm
by leesellars
Hello Sean

If i remember right. Its the distance from the hull side to the outside of the sprocket. You must check this when it is running. when everything is bedded in.

Lee

Posted: Tue Dec 23, 2008 9:42 pm
by Sean Cleary
Hi Lee:

You mean the sprocket ring, right i.e. the assembled sprocket?
How is the play in the axle factored in? Is the measurement taken with the sprocket pulled out or pushed in?

Posted: Tue Dec 23, 2008 10:07 pm
by leesellars
Hello Sean

Its with the sprocket made up and fitted. With gear shaft in the middle.
Make sure it well lubricated up with Universal grease.

Lee

Posted: Wed Dec 24, 2008 8:57 am
by Allan Richards
Sean,

The distance varies slightly with each model but the other problem I found on my early Tiger was that the only thing preventing the sproket shaft moving in and out was the fit of the shaft in the bearings, so I made up a washer to fit between the sprocket taper lock bush and bearing to prevent any movement. I made up a simple block of wood which was a tight fit between the sprocket rings and marked a centre on it (ie centre of the sprocket) I then measureed the distance from the side of the hull to the centre of the two road wheels that fit between the track horns and then set the centre of the sprocket to this distance.

Hope that makes sense.

Posted: Wed Dec 24, 2008 8:57 am
by Allan Richards
Sean,

The distance varies slightly with each model but the other problem I found on my early Tiger was that the only thing preventing the sproket shaft moving in and out was the fit of the shaft in the bearings, so I made up a washer to fit between the sprocket taper lock bush and bearing to prevent any movement. I made up a simple block of wood which was a tight fit between the sprocket rings and marked a centre on it (ie centre of the sprocket) I then measureed the distance from the side of the hull to the centre of the two road wheels that fit between the track horns and then set the centre of the sprocket to this distance.

Hope that makes sense.

Posted: Wed Dec 24, 2008 9:49 am
by Sean Cleary
Thank you Lee and thank you Allan.

Yes Allan. That makes perfect sense.

It also circumvents the frustration associated with deciphering and then attempting to follow written instructions rather than determining and proceeding with a mechanically sound method, just as you did and as I'd have preferred to have done in the first place.

Posted: Wed Dec 24, 2008 7:05 pm
by Rich Stinchcomb
I used the same technique as Allen did by fitting an assortment of thin washers between the taper lock and bearing. The washers came from Maryland Metrics but they had a quantity of 50 as an order minimum. They worked out great by preventing the gear from rubbing against the hull. I've got lots of them left over if you need some.

Rich

Posted: Wed Dec 24, 2008 9:39 pm
by Sean Cleary
Thanks Rich. That would be great.
I'm visiting my parents in Springfield MA next week as it turns out. Perhaps I can stop by and pick up the washers, if you like. Where in Conn. are you.