Wednesday, February 18, 2015

Building the DSLR sized CableCam - Part3 - The main body

This Blog post is one of an entire series
Motivation and Design

Assembling the main body

After building the two arms, the next step is to assemble the main body where the drive shaft, motor, gear etc will be located.

We start with the one part that has a shoulder for the ball bearing of the drive shaft. The shoulder is inside of the cablecam.

The ball bearing will be held in place by a cover. This cover has four M3 threads cut

And mounted using four M3x8 screws from the inner side.

To attach the arm with this main body part, the four rectangular shaped parts are put on the outside, like shown in the right lower part of the picture assembled, on the other side disassembled still.
As the screw goes through two 3mm parts, we use three M3x12mm screws on the outer sides and three M3x25 distance nut on the inside for each.

Complete the same task on the other side as well.

Now we can add the remaining seven 25mm distance nuts using seven M3x10 screws.

For easier handling we stop here and assemble the drive shaft. The shaft itself has a driving dog replacing the skate wheel's bearings. Hence the first step is to mount the wheel on it.
The other components needed in the next steps are

  • One 608 ball bearing for the second side plate, the one we have not touched yet
  • Then comes a 4mm spacer
  • The T2.5 6mm timing belt of length 285mm/114teeth
  • The matching belt pulley with 84 teeth and a d3.5 hole in its drive dog at the exact position
  • A 3mm spacer
  • A shaft locking clip

First we add the ball bearing onto the drive shaft
This ball bearing goes into the other plate, the one we have not used yet. Watchout for the side the wheel is. The wheel will be on the other side and the motor position has to match the second plate. Best is to simply lay the second plate on the distance nuts of the first so that the oval pocket is on the same side as the motor mounting point.
In the image below you would put the wheel this side into up into the plate.

Next the 4mm spacer and the belt pulley, which is secured with the drive shaft using a M3x25 screw, two small washers and a M3 lock nut.

Then the 3mm spacer

And finally the side plate is mounted and the shaft locking clip attached near the bearing cover to ensure the wheel cannot be pulled out anymore.
Before actually mounting the plate however, make sure the belt is in the proper position. It should not collide with any of the distance nuts once we mount the motor.
We use seven M3x10 screws for the inner holes.
The three outer most are six M3x12 screws holding the rectangular shaped parts in place as we did before.

To mount the gimbal there is a 8mm thick structure. Please note that the drilling holes are *not* centered. The idea is, the cablecam frame should be below the edge of the gimbal mounting surface.

Between the cablecam frame go 5 spacers with inner diameter 3mm and length 25mm, so we can push the M3 screws through. In the center comes a M3x50mm, all others are M3x45mm screws.

Just to be on the safe side, two of them get a lock nut in addition.

This can then be used to mount the gimbal, either directly or using the half sized or large adapter plate.

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