Timing belt stretch measured

So GT2 belt didn’t work all that well. It’s plenty strong enough but even with some bearings pressing it against the pulley, there was plenty of slippage. Maybe with stronger support for the bearings it would work, but just a little flex of the bearing support is all that’s needed.

I will say that the use of a tape measure motor as a slack take-up device worked well. I cut up some $5 tape measures and attached 4-inch disks to both sides of the motor to create a large spool and it did a good job containing the slack belt. However, there was no counterforce of any significance acting upon the belts to help alleviate belt slippage… so bearings will be needed to keep the belt from slipping. I’ve ordered 5M HTD belts to try… slow boat from china. I’m hoping the larger teeth will stop the belt from slipping with the bearing setup I’m using.

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Where did you end up ordering the GT2 belt from?

Do you by any chance have pictures of the setup? I am curious to see how that works

I got interrupted last night so I didn’t get pictures or videos done. I’ll do some this weekend. When the sled was moving, it was pretty smooth. I didn’t have any issues with the PID controller… default values worked well so that’s an improvement. I also have a piece of HDPE under the sled as well.

I got GT2 15mm belt and pulleys from powge via aliexpress. The 5M HTD belts and pulleys are expected in mid-November. I still think for the bottom motors, GT2 6mm belts will work fine…

I used the exisiting Maslow to cut out the outline of the sled and then used a laser-cut drilling template I got from Ponoko to drill the necessary holes. I was able to significantly reduce cost by using ordering a 1/8" MDF piece and keeping it within their P2 (15"x15") dimensions. I have a set of metric drill bits so it was just a matter of swapping out bits to drill the holes. Ponoko is reasonable on the laser cutting, but shipping can double your cost if you don’t go over $100 (free shipping over $100). I think their shipping is really shipping+handling+profit :slight_smile:

Just looked at their (ponoko) new website (might be by invitation) and seems that reaching free shipping might be less now.

Here’s a video of it… you can see when it’s decending that the belt slips occasionally.