Captive Nut Redesign

After a lot of testing with the Z axis, i encountered a large amount of problems with motor stalling, especially when the dremel tool was mounted.  The problem was that the U-Screws weren't designed to take large amounts of load while maintaining low friction.  So, i went to a new design, which was simply a metal enclosure for a nut. It works much better, and allows for much smoother vertical movement!

Z axis mounting

 The mounting process for mounting the Y and Z axis onto the X gantry. Everything is starting to come together!

The Z axis in progress

The Z axis mounts on the Y axis, similarly to the way the Y gantry mounts on the X Gantry.  Controlled by the same motor setup, it works in similar ways.  This axis, the final one, gave me the most trouble, as the weight of the rotary tool put a lot more pressure on the motor.  Note the change in coupling materials- i went through the familiar re-design process moving to machined aluminum, which worked much better.

To keep the Dremel mount plate from moving, i have it secured with two rollers, which stay rotation on either side. They run in C Channel grooves along each side of the mount plate.

Here is a detail of the Z axis system. Here you see for the first time the captive screw method I use for the majority of the machine- U-bolts made of spring steel, with a mounting hole drilled into one side.  They have slightly more wobble than a regular captive nut, but have much more freedom, which works well with the imperfections in the threaded rod I bought!

Re Designed Bearings

 After Experiencing a good amount of wobble on the X axis, i decided to remedy the problem by adding more constraints to the bearings.  Since the wobble was along the Z axis, I needed to add horizontal bearings.  Since the movement would be fairly slow anyways, simple low friction pads worked fine.  They are on a variable distance, which is set with a screw!

The Y Gantry!

Finally finished the Y gantry linear bearing system! The assembly slides freely on the Y-axis, with minimal jitters and shaking.

Bearings

After doing some research, I found that a V shaped bearing system works much better than just the horizontal and vertical bearings I used on the X axis.  So, for the Y axis, I used aluminum L-bar for both the track and the bearing mount, with quite satisfying results.

Right-  A Finished bearing mount.

Bottom-  The mounts in place on the rails.

Mounting The Gantry

With the bearings mounted onto L brackets, I simply attached them to a flat piece of wood, which will later hold the Z-axis.  The bearings are tightened by a series of screws holding them in place.  To prevent jitter, I drilled another hole for a screw, but instead, my drill bit got stuck in the hole, and holds the two pieces together quite well!

Motor Controller!

After frustrations getting the Arduino to power my stepper motors directly (which was a big mistake), i decided to buy an Easy Driver to test out my motors while I was still building the gantries. It works incredibly well, and is very easy to set up! What you see here is an stand alone board that rotates the motor continuously, and can plug into an outlet, perfect for testing!

Childrens Book Illustrations

Being the nice person that I am, I agreed to do the illustrations for my friends Children's book, which she is writing for her senior project. All done in watercolor on paper, and there are 4 more panels left to illustrate. I'll post updates when they're finished, but in the meantime, enjoy!

Air-Powered Nerf Rifle

Made partially for fun and partially for a game I was playing with friends, this is an improved nerf rifle. Its powered by a simple bike pump, and air is released via a sprinkler valve.  With a sliding bolt on the barrel, it takes 1-2 seconds to load a nerf dart, then after 3-10 seconds after that to pump the chamber up. At 5 pumps, a nerf dart will fly faster and straighter than many commercial nerf guns, at 12 pumps, the rifle has a usable range of 160 ft, with an accuracy of 5 in. at 30 ft.

See below for construction details!