Saturday, December 17, 2011

Black Friday Computer Upgrade

I had an EXCELLENT Black Friday. I didn't want to distract myself for the last few weeks of school, so I shipped my amazing find home instead. In the end my Black Friday deal turned out to be a great "survived" the semester gift. This became one of my few impulse buys. I saw the deal on Newegg and couldn't resist. Who wouldn't want three monitors?

 They work great for CAD. Those wide format assemblies like my long board can be put 1:1 on the screens.

Ok... I'll admit they are somewhat ridiculous, but they finally gave me my "Command Center". I had been running two monitors for a few years before getting these new monitors. I found I have trouble using a computer with fewer than 2 monitors. I usually put whatever program I'm using on my main screen and something I need to use often on the other. When designing stuff I put my CAD on one display and the file browser on the other. I never have to minimize the CAD in order to open new files. With the three monitors I use the center and right monitors as I always have. The new left monitor gets used for "research". Research is usually Google for whatever information I might need for designs or homework.

Now I just need to figure out how to fit the monitors and my rather large speakers on my small desk at school... I'll probably have to hang a bit over onto my roommate's desk. Hopefully there won't be too many complaints =D

Saturday, December 3, 2011

Long Board Deck

After a long Friday with the CNC router I finally added the clear plastic deck to the chassis of the board. I hadn't worked with a CNC router before this, so it was an interesting experience. The setup was fairly different from what I do for milling. The 12"x40" sheet of polycarbonate was held on one edge by wood clamps, while the other was held down by a 2x4 screwed directly into the router's table. The setup took a few hours, but the cutting out of the board only took a few minutes. Hopefully I'll be a bit quicker with the next part I do on the router. Now I just need to finish the under glow and the board will be complete!

This was right after the cutout finished. The circle in the bottom of the board was a test cut. The default feed rates were a bit too quick on the machine. Although it cut out the circle just fine, the noise made by the router attracted a lot of attention. The high speed motion also risked the machine losing its position. Drilling the holes took forever because the router's spindle did not want to go below 6000RPM. At this speed the drill bit created a bunch of "stringies" as I call them. I had to pause the machine between every hole in order to remove them from the drill bit. Otherwise they would have melted large areas around the later holes in the deck.

I temporarily added some paper between the rails and the board in order to prevent scratches. I'll remove these once I get a clear protective film for the board. Until then the board will be covered in blue tape! The blue tape is kind of ugly, so I won't post a picture of it.

Wednesday, October 26, 2011

Long Board Mishap

I was bouncing on the board a bit..... I thought the 3/4" plywood would have been a bit stronger, but I guess I have a reason to finish the polycarbonate deck now.

Friday, October 21, 2011

Long Board Improvements

I decided it was time to add a few new features to the long board. I Threw on some EL wire for under glow. It isn't very bright, but it can be seen at night. I also had access to a CNC vinyl cutter. I stuck my test piece to the bottom of the board. The yellow looks kind of weird, but it's still better than the bland plywood.
Tape always seems to make a good kludge.

Saturday, August 13, 2011

Long Board Upgrade Parts

As it turns out, the polycarbonate side plates were not as strong as I had hoped. I hadn't realized this until now, but polycarbonate develops micro cracks that spread under small amounts of stress. Every machined surface has micro cracks, so a number of the parts showed signs of cracks developing around the bolt holds. In order to prevent me eating the ground again I decided to suck it up and machine the plates from aluminum as I had originally planned to do.
 As you can see I attempted to use my material as efficiently as possible, so I crammed the parts into the smallest piece of 1/4" aluminum plate I could. The 1/8" mill bit took as long as I expected it to take. It was around 2 hours a part... Painfully slow as usual in aluminum...

Sunday, July 31, 2011

Long Board Finished... not really...

I couldn't wait to get the board into a usable state, So I hacked together a wooden board from 3/4" plywood. I threw on some old skateboard trucks at first in order to see if the shape was what I wanted. I finished the remaining parts for the trucks. All of the pieces came together nicely and looked really clean.

Sadly I couldn't decide how to make the rubber bushings cleanly... As with all of my kludges I turned to my favorite tool in the shop: the 3 TON ARBOR PRESS!!!!!!!!
I had a 1/4" thick sheet of rubber, but I needed to cut somewhat clean circles out of it. I figured scissors couldn't do the job, so I looked around for somewhat sharp tubing. I couldn't find any so I turned to the next best thing... socket sets. The socket heads were round on the bottom so they can't cut you. Normally I wouldn't expect them to cut through a sheet of rubber, but 3 tons is enough force to cut nearly anything. The socket sets cut the rubber like it was butter.
The rubber was too soft.......
I succumbed to speed wobble and became a road pizza..... (there's no need for a picture of my leg... I'm pretty sure I'll have a large scar to remember the test of this long board.) I added more rubber to make the trucks tighter, but they're still alot looser than I hoped they would be. I guess I'll just have to learn how to ride better.

Saturday, July 9, 2011

Long Board Progress

After a week of spare time I popped out a few parts. I avoided using the CNC as much as possible because it removes material so slowly. None of the parts were particularly difficult to machine. All of the setups could be done in a vice and they had fairly sloppy tolerances... although I did aim to get them as tight as possible for the fun of it.

 I also started to polish the parts. This is the first time i had a polishing wheel, so I got a bit carried away and started to polish everything. I still need to improve my technique. Machined surfaces polished easily, but the machining marks still remained. Surfaces left unmachined look alot better, but they aren't perfect mirrors.
 I got lazy and decided to make the side plates from polycarbonate. I can cut it at more than 10 times the rate of aluminum and I don't have to baby the machine as much. It should be strong enough and it looks aesthetically pleasing, so it's a win - win situation!
The spherical bearings worked perfectly and aligned up as I hoped they would. The bearing seats were a bit tighter than I hoped they would be. It's not a problem as long as I don't need to replace them. The trucks have really started to take shape, but the whole board is still a long way from being completed.

Thursday, June 30, 2011

Long Board - New Project

After a year of walking to class I decided I needed a long board to get to class. In my usual style I figured I should make one instead of buying one. I started by doing some research on the designs and standards for long boards and skate boards. I saw a number of different truck designs that seemed common. It seems that the rubber bushing style of truck is the most popular. In this design the truck is forced to straighten itself out by squished pieces of rubber. These pieces give the boarder more resistance as they attempt to steer the board. My personal favorite design used metal springs instead of the rubber bushings. I like to design things to last. I figured the springs would never deteriorate with time. Unfortunately I couldn't figure out how to make the trucks small and use the springs. Eventually I decided to go with the standard design for long board trucks. The one thing that really bugged me about this truck design was there wasn't a defined mechanism that caused the truck to turn. The pins in the trucks relied on a loose fit in order to actually turn. I started to look for an improvement when I stumbled upon spherical bearings on Mcmaster. These bearings gave freedom in all directions, which was the exact motion I needed. I designed the trucks around these bearings.  The spherical bearings give the trucks fully defined motion.

After deciding on the components I immediately started up SolidWorks and started poking around with different designs. Eventually I settled with this design for the trucks.
This render of the entire board has an older design for the trucks. I spent a few days changing around the design to make it easier for me to machine. The best looking board in my opinion was one made from 1/2" polycarbonate. I figure this board will really stand out when around the regular long boards.
I split the truck into many different pieces to avoid material removal. The biggest limiting factor when I'm machining is removing material. Splitting up pieces meant a large portion of the parts were extruded aluminum with holes drilled in them. Parts like that are really easy to produce with a manual machine. The design also meant that I only needed CNC work for the bearing seats and the side plates for the trucks. I attempted to locate the parts by geometry instead of the bolt holes themselves. The most critical surfaces required parallel edges, which are very easy to produce in one setup on either the manual or CNC mill. The only new thing for me on these trucks was the use of spherical bearings. I hope they perform as well as I imagined them performing.

Saturday, January 8, 2011

Powered Desk Chair

This project had a lot of potential, but I kind of let it fail. Maybe I'll finish it one day, but it probably won't be any time in the near future.

I had an Ikea desk chair that didn't roll very well, so I figured I'd modify it into a powered desk chair. It would have "swerve modules" to give it the ability to strafe and turn just like a normal unpowered desk chair. The design was fairly simple stuff that I had basically done in robotics at my high school. The intended final chair would have looked like this, but the electronics required to make it run properly were a bit out of my budget range.

The continuous 40A motor controllers put the electronics out of my budget considering the ones I had used in the past cost around 90 dollars a piece. I made the three swerve modules before I decided to ditch the project.

 As with most of my projects I had to use the arbor press. It took apart that Ikea chair with ease.

Even though I bagged the project I learned a lot from its construction. In order to make the sprockets I wrote a program in python to generate the g-code for my CNC to cut any size sprocket. I also learned what tolerances are needed to make a chain drive without a chain tensioner and I also learned what tolerances work with bevel gears. Did I mention that I also have 3 very cool looking paper weights?

Monday, January 3, 2011

Phone Case Finished

Well I started the case in August... Now its January...

I was a bit of a klutz and in the middle of a bit change from the drill bit for a #2 screw through hole to an 1/8" mill bit I didn't realize that the screw on my CNC's drawbar had backed out. My CNC has a somewhat unique drawbar design that requires a spanner to tighten the collets in place. The collets are really small, only around a 1/2" at their largest dimension. I did some research one time and found out what they were, but I can't remember what they are. I vaguely remember them as ww collets, but I could be completely wrong. In any case my collets use outside threads. When the screw loosened on the drawbar it bottomed out on the collets threads. I didn't realize this and continued to turn the drawbar to tighten the mill bit into the spindle. Sadly the tiny amount of torque I put on the machine was enough to shear the 1/32" pin that slips into the collet's keyway. The collet became stuck in the spindle and the mill bit wouldn't hold in. I had to leave for school, so any machining in the Secret Underwater Base / Machine Shop had to be put off until December.

Surviving a semester of school took its toll on me and left me sleeping a lot over break. Therefore I didn't work on all of the projects I wanted to finish. The phone case turned out to take 3 days. I got lazy again and machined the center ring that surrounds the phone from polycarbonate. In my opinion it looks better than the aluminum anyways.
 This was the cursed part that I broke my spindle while making. Once I had my new spindle (which I got repaired and the bearings replaced for free) the part came out pretty quickly. I did discover that my mill bits were all fairly dull. I'll have to order a few more. Thankfully 1/8" mill bits are pretty cheap.

The case turned out exactly as awesome as I had imagined. It does have a few drawbacks...
-It is really heavy. I don't particularly mind, but I really doubt there are many other people that would want a phone that weighs as much as this one.
-It is really huge. This thing rivals a brick... enough said.
-It is sharp. I had to use cap head screws because the hex set I carry around doesn't have a key small enough to tighten a button head screw. So far I only cut my leg once. I attempted to climb over something and one of the screws dug into my leg. If I get cut again I'll replace the cap head screws with button heads.
-It needs a hex set. I'm screwed (hahaha its a pun) if I ever need to remove the battery and I don't have my hex set with me.

It may have a few drawbacks, but I love the case and will probably leave it on the phone until I replace the phone.