Router Forums banner
1 - 20 of 24 Posts

·
Registered
Oliver (Prof. Henry)
Joined
·
2,237 Posts
Discussion Starter · #1 ·
When you work alone in a one man shop you often need an extra hand to help with a project. Most of us find work-arounds or jigs that help us move forward without calling for help. Those are fine as far as they go but there is one thing they can't provide. Encouragement.

I like to stop occasionally to admire my work and often wish there were someone in the shop to share it with and make sure it is looking okay. Now I can get instant, encouraging feedback from my recent automaton project. Introducing the important Extra Hand. A quick turn of the crank and I'm feeling great!



This project looks deceptively simple but in reality it took 25 days and 19 sketchbook pages to figure out a mechanism that could rotate the fingers 160º and the thumb 67º with a single turn of the crank. Many ideas fell by the wayside but the end result is simple and with fewer parts than some of my early sketches.

You can watch a video on YouTube here:
Thumbs Up - YouTube

Another satisfying Acme Product. :sarcastic:
 

Attachments

·
Retired Moderator
Joined
·
16,385 Posts
Good job Oliver. Now you need one that will pat you on the back when you do really well. But then you would also need a foot that kicks you in the rear end when you do really badly too. That would be the one I would probably get the most use of.
 

·
Registered
Joined
·
1,992 Posts
Oliver, That thing is really cool; but you have left-off something important - the fingers should be made of hot-dogs! Otherwise, this thing could get damaged badly when it uses a Saw-Stop Table Saw. <just kidding> Those gear teeth are truly well-executed. You have proven to me to be a man of vision and ingenuity! I am proud to be your friend!
Otis Guillebeau from Auburn, Georgia
 

·
Registered
Joined
·
238 Posts
Bravo!!! Your way or calculating and constructing this is outstanding !!!

I must admit though that I would never spend any time on something like this, but you succeeded very well, and your contraption taught me that an easy and very effective way to build DIY teeth for a gear is by using toothpicks - or kebab skewers - whatever needed. I find your idea fascinating. Until now, CNC guys looked down on us plebians as we could not design these gears by hand. Very well done !!!
 

·
Registered
Joined
·
23 Posts
Plans?

Do you have plans for the hand? I already have a real live one, but she only provides criticism,scorn,unusable advise, and the boot in the butt. seriously I would love to build one of the hand.
Lowell:yes4:
 

·
Registered
Oliver (Prof. Henry)
Joined
·
2,237 Posts
Discussion Starter · #15 ·
Bravo!!! Your way or calculating and constructing this is outstanding !!!

I must admit though that I would never spend any time on something like this, but you succeeded very well, and your contraption taught me that an easy and very effective way to build DIY teeth for a gear is by using toothpicks - or kebab skewers - whatever needed. I find your idea fascinating. Until now, CNC guys looked down on us plebians as we could not design these gears by hand. Very well done !!!
I'd like to take credit for inventing the pin gears Dimitri but they are commonly used in making automata. You are correct about using toothpick or kebab skewers, just about anything can work. One of my early versions used dowels but they were spaced improperly and locked up. When I remade them I switched to metal pins spaced closer together.
 

Attachments

·
Registered
Oliver (Prof. Henry)
Joined
·
2,237 Posts
Discussion Starter · #19 ·
Do you have plans for the hand? I already have a real live one, but she only provides criticism,scorn,unusable advise, and the boot in the butt. seriously I would love to build one of the hand.
Lowell:yes4:
I don't have any plans Lowell, but I can get you pretty close. The attached PDF has some of my sketchbook pages as well as actual diagrams for the hand and gears.

Most of the project is made from 1/2" stock. I used poplar and basswood. The only 3/4" material is the pillow block for the main shaft and the support for the rack gear.

The sides are 4" x 4"; the top is 12" long and made in two pieces 1" wide and 3" wide for ease of assembly. In the attached photos you can see everything is held together with 1/4" pegs. The peg assembly is important because you will be taking everything apart and putting it together many, many times as you fine tune it.

You'll see there is a pin that comes out the bottom of the fingers, goes through the slot in the top, and engages the gear underneath. When the gear rotates it pulls the fingers opened and closed. I used 3/32 rods and tubular material for the gear pins.

If you want more details send me a PM and I'll see what I can do to answer your questions.
 

Attachments

1 - 20 of 24 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top