'Spare' gear wheels etc

I have finished the build but have a number of parts left over, including many plastic mouldings. In particular, I have (in a separate small bag) three small gears. The instructions specifically refer to those, saying not to use them. Now they are left over. What were they there for? Should I have lots of others?

Hold on to them as you may need them later.

Yes, but what for (particularly the small gear wheels in the bag)?

Yes, but what for (particularly the small gear wheels in the bag)?[/quote]
The small gearwheel is exposed to more forces, so the change it will be brake is bigger.
Velleman have give some extra to avoid frustration for waiting long times when the wheel is broken.

Follow the building instructions. When your build is complete you may have lots of black plastic parts left. They serve no purpose, yet they are there to make your printer cheaper (something about mass production).

Yes, understood, and as it happened I did over-tighten and break the belt clamp so I was very glad of the spares. But, the small gearwheels mystify me because the instructions particularly say ‘do NOT use the ones in the bag’. If they are replacements in case you break one then why make a point of do not use them in the build as they must be the same as the one that might need replacing. [EDIT: This point is actually a reply to the poster before the last one!]

Some plastic parts may look alike but are not exactly identical (small gear wheels). Others are identical and can serve as replacements.

Thanks very much for taking the trouble to reply, and I’m sorry to hammer the point. But if the small gear wheels in the packet (which the instructions say ‘DON’T use’ during the build) are not exactly identical (and therefore presumably cannot act as replacements) then what are they for?

Off to bed now (Australia!). Back to the machine tomorrow!

[quote]But if the small gear wheels in the packet (which the instructions say ‘DON’T use’ during the build) are not exactly identical (and therefore presumably cannot act as replacements) then what are they for?[/quote]As I said earlier, they are only there because of the way these plastic parts are produced. The excess parts are like the wood chippings that result from making a wooden sculpture.