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What's on my Bench: Bearings

 

Good morning...
I've got two automata projects on my bench right now, Inclined Slide and Electric Chair.  Each of these automata will use bearings.
In the image below you see five bearings:
  • The top 3 are linear bearings.  Inside the outer sleeve are four races of small bearing balls.  I will be using these bearings in the Inclined Slide automata...there will be four of them that hold the seat that the biped will be sliding back and forth.  As these bearings slide/roll along the 6mm shaft they make more noise than I was expecting.  It will be interesting to see if they quiet down over time. I source these from ServoCity.com.
  • The lower 2 bearings are one way bearings.  I will be using these in both the Inclined Slide and Electric Chair automata.  I use them as clutches.  This enables me to operate automata with both a hand crank and a motor.  The two clutches isolate the crank and the motor from each other.  I source these from VXB.com.
I maintain a stock of stainless steel precision shafting in sizes 1/8, 3/16, and 1/4".  These are ordered in 12" lengths.  I would prefer to use precision hardwood shafting...but it is not available.  None of the wood dowels that I use fit properly into the bearings.
And I maintain a stock of ball bearing assemblies (1/8" ID-1/4" OD, 3/16" ID -3/8" OD , and 1/4" ID-1/2" OD  ) in both flanged and unflanged configurations.
The motors that I use are 60 rpm gear motors. I personally think that a hand crank speed of 60-90 rpm is desirable.  Using a motor of 60 rpm permits the use of one input shaft.
IMG_20191120_071600-1000.jpg
Cheers
-Jim Coffee-
one of the Automata Group Moderators
I create automata near San Diego, California


Mike
 

Jim, curious as to the cost. Do you incorporate the metal shafts in with the wood or do something entirely different?
--

Thanks!
Mike

Wooden Curiosities

 

Hi Mike...
Regarding costs: 
Regarding incorporation into the automata:  In the past I have:
  • Forced bearing assemblies over wood dowels.  While this does work, maintenance and removal are not easy.  The precision shafting is not expensive and is very precise.  
  • Used stainless shafting and ball bearing assemblies.  This works well.
In the future I will be copper plating at least some of the precision shafts.  The copper plating 'takes the the shafts back in time', it's a nice effect.  And the bearings still slide on and off easily.

Another type of bearing that I use are nylon spacers.  I source them from ServoCity.  When I have a shaft that does full rotation I use ball bearings.  But when I have a shaft that does partial rotation, and that has a relatively light load, I use nylon spacers.

All of us have our own building standards and objectives and goals.  In my case I like "quiet", "smooth", and "longevity".  I maintain an inventory of bearings and spacers that allows me to create without running out.  It's taken me time and money to build the inventory...but at the end of the day I really appreciate not having to slow down and wait for something to arrive in the mail.  And speaking of arriving in the mail...I should mention that I source virtually everything that I use online.  I get sick and tired of driving to somewhere only to find no stock, or out of stock.  
Cheers
-Jim Coffee-
San Diego, CA


On Sat, 23 Nov 2019 at 17:41, Mike <smc5910@...> wrote:
Jim, curious as to the cost. Do you incorporate the metal shafts in with the wood or do something entirely different?
--

Thanks!
Mike

Wooden Curiosities