Anet A8 X-axis and Y-axis tensioners for 20T x 3mm toothed idlers

thingiverse

I decided to upgrade my Anet A8 X-axis and Y-Axis belt tensioners with 20T x 3mm idlers. Many discussions have taken place about which is better, smooth or toothed, but I'm not going into that here. If you choose to go with 20T toothed, these prints will work well for you. You can get these 20T idlers from various places like Amazon, Gearbest, Banggood, and Aliexpress, etc. As long as the width of the pulley is just under 9mm (pretty standard), these prints will work. It's suggested to check the bearing smoothness of rotation by using the spindle bolt and nut lightly tightened, then rotation. Some of those bearings are either damaged on install or junk, so beware not to use ones that don't spin freely and get a few extras. Props go out to: - X-axis tensioner concept from freemark My design is completely new, but based on freemark's concept (improvements to accommodate the 20T pulley and X-axis belt clearance when belt is in "slack" mode. Hardware needed: - M5x0.8mmx30mm bolts/screws (x2), M5x0.8mm nuts (x2, I chose Aero nuts to keep bolts fixed in place under vibration, but you can use regular nuts, if desired.) - For 20T pulley spindle, use M3x0.5mmx25mm or 30mm and nut. If you can find a M3 Aero nut, get that. Alternatively use 2 nuts and a dab of crazy glue on the flats to lock in place or loctite threadlocker. - Tighten the spindle screw sufficiently to achieve desired side lash and still turn freely. Also, keep in mind that your X-axis belt length will become longer. If yours is too short, you will need to replace with a longer one. Good time to refresh your belt anyway. Y-axis tensioner concept by CH35C0 for first posting the original and audiogod for the pushbar addition. My remix is to increase the anchor clearance for the 20T idler, modify the pushbar to always stay in place with land area for the 8mm bolt end, modify the plate to accept the 8mm bolt thread, and knob for 8mm bolt. Don't bother trying to print simple hardware like threads (more of a headache and not durable). Plate hole is proper size before tapping for M8x1.25mm thread. Carefully tap, slowly and straight in a vise. Look from 2 angles to assure going in straight during tapping, or you will have to print another one. You will also need to print the front and rear frame supports from Leo_N to give support to your existing acrylic frame, if not already done so. If you don't, your stock frame will either bend or crack under increased belt tension. Hardware needed: - M8x1.25mmx30mm bolt (x1) All models printed at 0.2mm resolution and 100% infill, since somewhat structural. Support definitely needed for the Y-axis anchor and plate printing. The other models are positioned to not need support. Since 100% infill, make sure to use your best bed adhesion measures, as warping will be more a concern for the larger parts than if using some smaller infill values.