My A8 - of which I am very fond - well it may not be the best but it's all mine - has encountered a mishap, and I cannot find my original construction files.
It uses a Comet two-stage gear box with extender. and the idler gear directly beneath the worm has partially stripped (or at least worn very heavily.)
I am not sure what the specification of the gearbox is. It is certainly a Comet design, and (I think) is either a GB3/20 or a GB5/20.
Before I contact Wizard Models (who I think have taken on the illustrious mantle of Comet) I would be very grateful as to which the gearbox is, and also (if possible) what the dimensions of the idler gear are.
If that gear has a grub screw through the teeth then it's a GB5 type. If the gear has a boss with the screw then you have either a GB1 (50:1) or GB3 (38:1). I think the gears with the boss are stamped with a number which might be worth looking into.
nzpaul wrote: ↑Sat Oct 05, 2019 8:29 pm
If that gear has a grub screw through the teeth then it's a GB5 type. If the gear has a boss with the screw then you have either a GB1 (50:1) or GB3 (38:1). I think the gears with the boss are stamped with a number which might be worth looking into.
Cheers
Paul
Thank you Paul. It does indeed have a hole through the teeth, and it is the teeth weakened by the hole which have failed.
I will have to contact Wizard models ( who I think now sell the Comet range) and see if they can help.
I remember avoiding using the grub screw, and I think I used Loctite to retain the layshaft. Now I have to work out how to remove it!
No problem, happy to help. Having some experience (chewed teeth) with the GB5 and its intermediate gear arrangement, I'd be tempted to upgrade to one of the heftier GB1 gearboxes if it's not too much of a drama to fit it in. Maybe even one of those High Level types (high riders or load haulers I think they're called) not much difference in price last time I looked.
Andrew at Wizard is good to deal with so he'll help you out with that gear or another gearbox I'm sure, Wizard have almost become as useful as what Mainly Trains used to be.
