Hello!

Quite a few printers require two or more belts cut to equal length.
With belt lengths of more than two meters the arm length of a normal human being isn't enough to hold both belts on both ends to make sure they are nice and equal.

This is the Belt Aligner - a very small tool that holds two Gates GT2 6 or 9mm belts in place so that they can be cut to equal length. Print this tool a few times (4 of them take roughly 30 minutes) and it should make this process a lot easier.
It depends on the belt length (and on your confidence) how many instances of this tool you will need.

Start with a clean cut on one end of the two belts and slide them into the tool with the teeth facing outwards to have a reference point. You will see the teeth are perfectly aligned.
Now use your fingers (pointer and thumb), move them slowly along the belts making sure to have one belt above the other and slide them into the second Belt Aligner. Do this for the full belt length, sliding in a new tool every every 20 or so centimeters.
If you haven't printed enough parts you can remove a Belt Aligner and re-use it but leave the first one in place for reference. Just make sure the grab both belts tightly so that they don't slip and get out of place. Every tooth counts, as my granny used to say.

If you see one of the belts bulging between two tools chances are you are off by a teeth. (see second photo). You don't have to check the full belt length anymore, just the (short) distance between two tools.

Printing instructions:

• WRONG ORIENTATION: Make sure to print it in an upwards position with the opening to the top.
• It prints without supports relatively fast.
• They are small, print a few of them in one go to have a good layer time.