Well this part was replicated in another post
http://madmodder.net/index.php?topic=1959.msg21373#msg21373 and fitted to the Beaver gearbox.
You can just see it hiding in the background on the end of the motor shaft
All the time I have been thinking about making this item there has been something in the back of my mind telling me something wasn't right.
I suspected that the old worn part was not the original, it just didn't look right. In fact it looked just like the one I have just made, new and shiny, not old from the sixties.
I decided to take a closer look at the securing grub screw which turned out to be 5mm ... well unless there is an imperial equiv to 5mm this as I suspected was not the original part. Add to that the bearing surface showed no signs of wear. My gut feeling was that this worm was not very old at all.
So that leads me to my next worry, if this was a new part then why was it needed? The rest of the machine shows very little wear so why is it now on it's third worm?
Not wanting to put my new freshly made part in to be ruined quickly I decided to scrutinise the way the whole contraption worked and what if anything might be wrong. Contraption it is too, lots of gears, shafts, levers, dogs etc. Very complicated for what it does.
There are a few bits in the bed, gears, leavers, dogs etc but I couldn't find much wrong there.
So I decided to rebuild the gearbox carefully.
Found it .... only just mind ....
I assume originally the lid of the gearbox at one time had a paper gasket. It is no longer present and I'm assuming the worm problems began when it was first removed.
The problem is that when the lid is screwed down it pinches one of the shafts ever-so-slightly. Nip the screws down hard and it locks the shaft solid.
I'm assuming, yet again, that when someone took the gasket out and assembled without it the shaft turned so they didn't suspect anything. But as the gearbox motor runs constantly whenever the machine is powered up I suspect the parts heat up some. The shaft expands and the resistance increases possibly locking up solid.
So I made a gasket from a cereal box
0.5mm thickness.
Fitted it and tightened the screws down fully, no binding was felt
All back together and given a test, seems fine
I'm glad to say that it's now back on the machine and seems to be working fine. I'm hoping my gasket findings will prevent any further problem ...
Hope I've not bored you .....
but the thing is, if there is a problem then there is usually a reason. This one took me some finding and quite a few hours of scrutinising. I certainly wouldn't blame anyone missing the issue previously. but if there is a problem you really should try to find the cause ....
