Home made accelerated life tester for hall sensor based throttle.
Daniel K., a very close friend of mine got a new ski boat and needed video camera mount and tracker to follow the water skier while dragged behind the boat. There are such trackers you can buy for $300 but Daniel wanted to build it more than he actually needed it, so we did it. The whole project is made of machining grade Aluminum using my Sherline CNC Mill and Lathe and some manual work as well.
All the credit to Daniel, except for losing the photos we took at my workshop when we completed the work. The only one photo left is shown above.
As a result of struggling with backlash issues much longer than needed I built this probe and wrote a small VB procedure to help read backlash values within seconds. The probe is similar to edge finder which rises a bit on the parallel interface when grounded. The electrical connection is made between the probe and the spindle using two alligators and required an isolated base which is made of clear Polycarbonate. At the base are two rare earth magnets which holds the probe on the milling vise or alternatively between its jaws. The audio jack plugs into a connections box which leads it to the controller.
The script is self-explanatory, just notice the settings under “User Inputs” and make sure to select the correct values:
Resolution – If you need an immediate low-res (i.e. non-accurate) backlash reading you can run at 10 or 100 and the feed rate will be set respectively (the resolution will be low but the speed will be high). For final reading always use 1000.
Active Axis – Simply set to X, Y or Z and place the spindle (or tool or whatever is attached to the spindle) between probe’s brackets, somewhere in the middle, and in a way that will allow the brackets to touch the spindle when the axis moves in both directions.
Two Sides – This is useful for Z but can be used on any axis. When measuring backlash I always read it in two directions and set the average result as backlash compensation. With X and Y there should be no problem, but when doing Z, how do you set a tool to touch the two brackets of the probe? You can use any tool such as fly cutter, a bit with extended tip or a hex wrench attached to a drill chuck. Otherwise, you can set this parameter to False and the script will run the axis in one direction, which is going down to the table.
Number of loops – For some reason I initially wrote the script with an option to run multiple cycles and display the average reading but I never used it and always run once. It is there in case you find it useful.
The code can be found here, open the VB editor and paste it there. Always remember to “SAVE AS” or else Mach 3 might use a previously stored file name and overwrite existing file you may need.
I guess every Sherline owner knows Luiz Ally (Tryally) and his videos on YouTube including the one about his slim vise which looks like an excellent solution for holding small and thin objects.
If you are interested in building such vise you may find the attached file useful.
it’s a SketchUp model I’ve designed with minor modifications from the original, what I was able to see on the video. I have not built it yet and not sure if I will go for the exact solution or to something similar based on a tool plate, we’ll see.
So for now you are welcome to download the file and feedback if you have any comments, and I repeat, I have not built it yet so it may contain errors.
Design credits to Luiz of course.
A KB emulator for CNC is a device built from and acts as standard keyboard with one major difference: it only has the keys necessary for basic operation of a mill or lathe and is packaged accordingly.
As shown in the pic below, I took the original interface electronics from a standard full size keyboard and added a larger PCB to avoid soldering all the wires in that small fragile board. Then I mapped the inputs and identified the connections I need in order to produce the characters (such as arrows, Atl, Ccontrol, letters and other keys).
The new keyboard goes in a much smaller box and what I made so far is the upper part while the lower one is pasted there (from SketchUp) just to show the layout. In the future I plan to replace the electronics with Bluetooth interface and place batteries in the package.
I assume that in due time I will change some of the keys as well and maybe add a joystick.