Rotary Pen laser etch holder

thingiverse

This is to hold a standard lathe finished pen for laser etching using awesome T2Lasers rotary tool profiles and a standard eleksmaker A3 laser etcher. Parts needed to make this one as pictured, 2 x 250mm 3/8 steel rod, 6mm x 270mm threaded rod, motor and connectors to attach to Mana SE and I used a 22mm x 7mm bearing. You do not need anything like 250mm, I just used that as I had 500mm length sitting around and figured I may want to repurpose it later to something larger. Uses a cheap 28BYJ-48 motor plugged in to a Y axis plug with the other Y axis motor disconnected, IMPORTANT .. the motor is bipolar modified, pop off the blue plastic cover, cut the centre track connecting the two poles and remove the red centre tap wire. easy to google .. eg http://www.electronicsmayhem.com/?p=13 I used a 12V version so I had no need to drop motor currents on the stepper driver, resistance is far too high to overheat. The motor gearbox has some endplay which this rack removes by clamping however gearbox backlash is another issue, this is fine if you want to raster burn but if you want to use vector then you may get some unwanted artifacts. I set it up in T2laser's Rotary axis setup as 32768 steps/rotation (other models of the motor have different gearing ymmv) and set diameter of work piece, Due to such high number of steps you will likely need to perform a $111=100 to drop Y step rate to something the little motor can handle. Attached designspark files as usual for remodelling, the little handle is pretty much a joke, might want to add a base. The end support is to stop the weight of the rods pulling the end down if more than half closed, not needed for correct length rods. I also needed a 6mm tap to get a nice thread and a 3mm drill/tap for the motor mount holes. I ended up drilling the slider holes out to 10.2mm to make it slide easily. Was just the drill bit I had to hand. Drill 3d printed plastic with the drill running backwards to stop it being torn to pieces by big drills. If you want to use it to hold something else then create a suitable spindle_pen and bearing_pen to suit your item.