OnStep Dobsonian with Zero Woodworking

thingiverse

Applies to GSO 10" Dobsonians with premium Altitude bearing tension adjustment mechanism Apretura AD10, Zhummel Z10, Orion Sky Line 10" 8" and 12" telescope models of the same lineup will require a different belt and mild redesign of the motor-clamp block. Advantages of this design: * minimum printed parts * no woodworking ** no drilling holes ** no cutting oppeneings * quick removal or drive disengagement ** your scope will keep its original look Design CAD if you need to modify anything (create free OnShape account): * https://cad.onshape.com/documents/f11693570747630f33117fb4 Video links of assembly and installation isntructions. * Part 1: https://youtu.be/fOAaE_Po2ws * Part 2: https://youtu.be/KCvG_8NTk9I * Part 3: https://youtu.be/c0LmdYlJm8Y Big thanks to Bryan Pryor (https://www.youtube.com/user/bryanpryor). His implementation of friction drive inspired me to design this project. Big Big Thanks to OnStep comunity! * https://onstep.groups.io/g/main/wiki/3860 BOM: * Precision geared steppers with 8 mm shaft output ** https://www.omc-stepperonline.com/nema-17-stepper-motor-l-40mm-gear-ratio-100-1-plm-series-planetary-gearbox-17hs15-1584s-plmg100 ** 17HS15-1584S-PLMG100 ** 17HS15-1584S-HG100 * HTD 3M Timinig Belt ** https://www.ebay.com/itm/174757509790 ** 3mm pitch and 15 mm wide ** 1569 mm long (523 teeth) ** Belt length calculator (to use for 8" or 12" adaptation): https://www.technobotsonline.com/timing-pulley-distance-between-centres-calculator.html * Small HTD 3M pulley 20T 8 mm bore * O-rings for friction pulley ID: 22..23 mm with 3 mm crossection * M4 nuts and bolts (6 and 10 mm long) * 2x M6 Knob/knurl screws with a 40 mm long thread for clamping (with washers) * 2x M6x16 bolts to mount timing wheel * 4x M6 nuts, preferable 10 mm high (M6x10x10) ** https://www.ebay.com/itm/154889217949 ###WARNING Timing wheel and motor block tolerances are calculated to 0.8 mm nozzle using low-shrinkage material: * PETG (recommended) * PLA (if you keep your scope in a car on hot weather - you will have a problem) ###AND ANOTHER WARNING To put mounting nuts for altitude wheel into the channel of the bearing base you must unscrew 4 bolts form the inside with a Philips screwdriver. I strongly recommend to remove the mirror cell - this way it will be easier to reach these bolts from the back side of the tube. Also it will keep mirror safe from accidental damages during assembly. you will ha assembly from the scope - take out mirror cell for its own safety