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Third Hand ++

3a. Drilling and Tapping

posted Feb 15, 2010, 9:31 PM by Bill Bai   [ updated Feb 16, 2010, 8:57 AM ]

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.

It is surprisingly difficult to peel Scotch tape in one piece.

Everything all clean and nice.  The drill press couldn't reach the middle hole so I decided to forgo it.

Isometric view!

3/8" exactly.  Yeah.  I'm just THAT good. =D

1/8"-27 NPT Tap.  Time to do work.

Tapping the Base Board


Tappin' that hole!

Perfect fit. 

Turned out pretty good if I do say so myself.

6. Final Assembly

posted Feb 15, 2010, 9:29 PM by Bill Bai   [ updated Feb 20, 2010, 10:20 PM ]

So everything has finally come together and the assembly is complete!  I now have a fully functional four arm 12"x12" helping hands station.  Awesome.

This looks like the same picture as above, but the top right arm has the camera mount attached to it.

The camera's view, mounted on the arm.

5. Fabricating the Hands

posted Feb 15, 2010, 9:27 PM by Bill Bai   [ updated Feb 20, 2010, 10:25 PM ]

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

posted Feb 13, 2010, 5:00 PM by Bill Bai   [ updated Feb 14, 2010, 7:15 PM ]

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.

Loc-Line Pliers


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. =/ )

Tapping the Nozzle


1b. Objectives

posted Feb 3, 2010, 11:50 PM by Bill Bai   [ updated Feb 11, 2010, 8:03 PM ]

(Third Hand from Thinkgeek)

I'm not planning to build exactly the same thing that the original article lays out.  Instead, I want to improve and expand upon the basic concepts of what it does.

Basic concept:
  • More flexible arms compared to standard third hand
Improvements:
  • Improved adaptability
  • Larger base w/ grid of holes
  • More arms
  • Longer arms
  • More interchangeable attachments

2a. Finding Components: The Base

posted Feb 2, 2010, 2:48 AM by Bill Bai   [ updated Feb 11, 2010, 8:02 PM ]

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

posted Feb 1, 2010, 9:42 PM by Bill Bai   [ updated Feb 11, 2010, 8:03 PM ]

Some other attachments and miscellany for the third hand.

A PCB holder attached to the arms.

Fume extractor to suck smoke away when soldering.

LCD holder for microcontroller circuit

Clamp arm.

Another guy utilized magnetic bases and a 1/4" steel plate to make his helping hands.

All images belong to their authors on Instructables.

1. Inspiration

posted Feb 1, 2010, 9:02 PM by Bill Bai   [ updated Feb 3, 2010, 11:49 PM ]


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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