Note: This is only a tiny part of my AM8 upgrades. You can find the links to the other parts at the bottom of the description.

** Now with upgraded tensioner (using 625 bearings and motor pulley) **

About

This upgrade intends to improve the stock AM8 Y-belt arrangement. The design goals were to improve the mounting position of the Y motor and to use the frame as a support and a heatsink for the motor. To reduce stress on the motor shaft and internal bearings a 625 bearing was integrated into the Motor mount above the gt2 pulley. Using the 625 bearing is optional, but strongly recommended.

** Note: This upgrade MAY not fit with your h-plate/heatbed carrier when it doesn't have a bit of space at the front and back. For example the carrier from the german supplier "Bohrers" is known to cause issues (tensioner and motor mount will collide with it). You'll need to either print some spacers to raise the carrier a few millimeters or you'll need to use a carrier which has a bit of space. The stock anet carrier will fit and most other carriers too. **

BOM

You will need these parts additionally to the printed ones, you should have most of them already on your AM8:

8x slot nut
8x screw for slot nut
4x M3x20 ISO 4762 for motor
4x M3 DIN 125 washer (optional, in case motor screws are too long)
1x 625 bearing (5x16x5mm)
1x M4x25 ISO 4762 screw
2x M4 DIN 934 nut
1x M3x18 ISO 4762 or ISO 7045 (you can also use a longer screw)
1x M3 DIN 934 nut
1x toothed Idler pulley T16
4x M4x12 ISO 4762 (you can also use a longer screws)

optional:
If you want to use the upgraded tensioner, you will need additionally:
1x 5mm shaft (approx 30mm length)
1x pulley
2x 625 bearings

Remix & Sources

There are STEP sources available in the files section. Happy to see improvements and remixes of this Y rework :)

Assembly Instructions

Instructions are available as PDF in the files section

Version History

• 12/2019: added improved belt tensioner bracket (V2)
• 10/2018: add upgrade tensioner with two 625 bearings and motor pulley
• 09/2018: added bracket for AM8L with 41mm hole spacing
• 07/2018: STEP Files 1.1: Added the longer belt bracket (38 instead of 25mm) with sligthly reduced belt groove width (1,6 instead of 1,8mm) to the STEP archive.

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You might also want to have a look at:

my reinforced Z axis with 12mm linear rods
https://www.thingiverse.com/thing:2971922

my Y axis 12mm upgrade
https://www.thingiverse.com/thing:3016011

my SC8UU compatible 12mm housings for sinter bearings:
https://www.thingiverse.com/thing:3016075

The upgraded X axis with 12mm rods
https://www.thingiverse.com/thing:3016379

The reinforced X tensioner using proper bearings and a motor pulley:
https://www.thingiverse.com/thing:3016345