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Third Hand ++
3a. Drilling and Tapping
I managed to bring my base board into the ECET Projects lab. They have a few very convenient drill presses there and ever so handy 3/8" drill bits that I was fortunate enough to borrow for a bit.
It was pretty straightforward to use the drill press to drill nice neat holes. I was actually surprised at how soft polypropylene is under a drill. I was even more surprised that it held up to the heat generated from friction. In my past experience with plastics and Dremels, plastic is very hard until it melts from heat and there's a huge mess. Granted, the drill press is a lot slower than the Dremel, but there's still plenty of heat and material to move through.
I started washing off my Sharpie grid with a convenient bottle of alcohol in the lab when I realized that I needed to peel off all the tape strips I had put on.
Everything all clean and nice. The drill press couldn't reach the middle hole so I decided to forgo it.
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5. Fabricating the Hands
This little post will be about making some hands and extra attachments for my third hand ++. As you can see from the picture above, I'm trying to make two different kinds of hands. The top one has its teeth bent inwards so that they don't bit into whatever I'm working on. I also soldered a banana jack onto the head of a 1/4"-20 bolt. The reason for this is that the mounting screw hole on the bottom of most cameras, including mine, is a 1/4"-20 threaded hole (this means 1/4" diameter, 20 turns of threading per inch). This little addon will allow me to put my camera on an arm for recording videos or whatnot. |
4. Fabricating the Arms
Putting the arms together was fairly simple and straightforward. After I decided how long I wanted to make each arm I used the Loc-Line Pliers to put them together. The base end is a 1/8"-27 NPT Connector that will screw into a grid of tapped holes in the base board. The 'hand' end is a straight nozzle that has been tapped to allow the attachment of a threaded banana jack. Here's a video of me tapping the end of the Loc-Line nozzle. I originally used pliers to hold the other end of the nozzle while I tapped it, but I realized that the pliers were biting into the plastic too much and messing up the socket joint on the nozzle. So I switched to using tape to keep the nozzle from rotating. (Still have two messed up nozzles that dont stay on as well as they should though. =/ ) |
1b. Objectives
(Third Hand from Thinkgeek) Basic concept:
Improvements:
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2a. Finding Components: The Base
The base for this helping hands set up is extremely important. The base provides the stability for the arms. Without a strong base, the arms will be useless. rstraugh at Instructables used a 1/2" thick aluminum base for his helping hands. He recommends OnlineMetals.com for getting the materials. However, after browsing the aluminum selection, it was obvious that aluminum was way too expensive. Instead, I bought a sheet of 1/2" thick, 12"x12" Polypropylene sheet. I also bought a 1 foot 1/2" diameter plastic rod to make into a PCB holder. As you can see, the materials were pretty cheap, but the cost of shipping more than doubled the total cost. My plan is to drill a grid of holes into the polypropylene sheet so that I can reposition the arms around on the sheet. I expect that the polypropylene will not be as dense as aluminum, but it should be offset by the sheer size of the sheet. I think it should be heavy enough to provide a stable base for the arms. |
1a. Flexible and Modular
Some other attachments and miscellany for the third hand. A PCB holder attached to the arms. |
1. Inspiration
I saw and article on Instructables.com about building a more useful set of helping hands with segmented industrial coolant hose. Looks pretty useful, so I'm going to make myself a set of these bad boys. |
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