Quick/Easy Focus Of Any USB Microscope W Repeatable Results

Lighthouse makes a digital microscope stand that's pretty dang nice. I might try that. You do have a pretty ingenious set-up though. Well done.

This question can be taken two ways:

a) Does the rigidity of spiral tubing impede one's ability to easily focus anywhere in a 3D range of motion?

or

b) Does the intrinsic flexibility of the spiral tubing cause problems or movements when attempting to focus precisely?

A hybrid answer to both rephrased questions:

The primary reason for attaching a semi-rigid spiral tubing is to allow for larger (up to 3 inches) but more likely very small and incremental manual adjustments when required.

These inevitable last minute microscopic modifications, performed by simply tapping the tubing in any desired x, y, or z direction, for example, can actually be performed much quicker compared to raising and lowering the tripod arm.

Mounting the USB microscope 'directly' and 'rigidly' to the shaft of the tripod, on the other hand, severely restricts or even eliminates the possibility of implementing this jury rigged procedure consisting of only a quick finger tap.

One could conversely argue against the addition of this seven (7") tubing since the already-included ball joint connected to a mounting stand does allow for these small movements.

However, not including this seven (7") tubing extension prevents the user from making longer (up to approx. 3") manual adjustments which may come in handy some day if the measurement location needs to be located further away from the center of gravity of the tripod stand.

I personally would rather be prepared for any unanticipated measurement situation by designing a device that is more accommodating...

By the time one has reached this optional and final tapping stage the need to utilize the focus wheel or crank shaft should be extremely diminished assuming the same object is being photographed in the same area.

Also w/r/t the flexibility of spiral tubing causing problems such as unwanted movement when focusing, the degree of rigidity of the spiral tubing is great enough to prevent further movements once it has been set to a certain position.

I personally feel that designing the length of the tubing to be no more than seven (7) inches is paramount to avoid an inevitable 'drooping of the tubing' situation. The perceived innuendos of this phrase need not be elaborated upon.

A longer section of tubing inevitably results in an overall greater tubing weight and an increased moment arm producing more torque which naturally facilitates easier bending of the tubing from the natural and ever-present effects of gravity:

http://moon.ouhsc.edu/dthompso/namics/torque.htm

In layman's terms it is much easier to open a shut cellar door, for example, if one pushes upwards on the side farthest away from the door's hinges.

But just imagine being on a ladder looking upwards and trying to open this same cellar door by pushing upwards on this door at a point located just a few inches from the hinges: a daunting and almost impossible feat since the moment arm at this location is less.

I am sure these answers may have deviated to an extent from the original nature of the question but hopefully they have added some needed clarification to better understand the method to my madness.

I couldn't have asked for a better answer. It actually brought a smile to my face.

These following steps should be followed to ensure that the flexible arm does not collapse:

1) First stick a drill bit (separated from the drill) into the end of the opened spiral tubing with the intention to find the largest diameter drill bit that will snugly fit into this opening down to a depth of at least one (1") inch.

In this step let's assume you have chosen a 1/4" diameter bit.

2) Then use this specifically selected 1/4" diameter bit to penetrate into the closest aluminum side of the tripod's internal movable shaft. Going forward in this discussion let's refer to this side as the ‘near' side for simplicity.

a. On this step with the 1/4" diameter bit make sure to completely penetrate the first aluminum wall and just ‘barely' drill into the opposing internal ‘far' side of the other aluminum wall located 180 degrees away.

You just want to create a slight depression in the metal on the internal ‘far' side to only serve as an internal (inside the tubing) marker that you can later feel with a manually inserted smaller diameter drill bit.

6) Then once the sheet metal screw has been completely and tightly inserted into the hollow movable shaft, you must then saw off the head of the sheet metal screw.

7) If you were able to find a snugly fitting sheet metal screw, the open end of the hollow flexible tubing should screw snugly onto the extended portion of the sheet metal screw that now has its head sawed off.

Also note that the sheet metal screw should now tightly lodge into at least the ‘near' side of the hollow tube; this particular connection point will serve to stabilize the sheet metal screw sufficiently enough to allow you to screw on the flexible tubing by rotating it.

Only the tip of the sheet metal screw needs to slightly enter into the ‘far' side which is primarily used to prevent any upward force being generated from an externally positioned ‘drooping tubing' section that connects to the USB microscope.

NOTE: Be sure to avoid messing with the sheet metal screw too far past the ‘far' internal wall; this condition could prevent the upward/downward movement of the internal shaft if the screw is contacting the interior surface of the main exterior metal housing.

Yeah that makes sense, I don't have to worry about a dog.

To locate sources for the type of flexible tubing used in this project you might want to Google 'adjustable desk lamp manufacturers' for items such as:



These are the type of companies that wouldn't mind sending out a minimal amount of flexible tubing just as a sample.

The following photo came from the exact flexible tubing that I used in my project:



Keep in mind that the ID (inside diameter) and OD(outside diameter)of the requested sample from a manufacturer does not have to possess same exact same measurements as the ones I used in my project.

I would try to remain, however, within plus or minus 10% - 15% of the dimensions I used for my flexible tubing.

The above photographs showing the tubing dimensions used in my project assume that you are using a standard tripod with an outer diameter of 30 mm.

Remember that an excessively larger flexible tubing OD will require that you cut a correspondingly wider longitudinal channel which could potentially weaken the structural integrity of the primary outer tripod tubing.

Therefore, I would strongly recommend that you know the OD of the tripod's tubing before calling for samples. Then specify the OD of the flexible tubing samples so that they do not exceed 33% of the tripod tubing's OD etc.

Finally, never rule out first checking rummage sales or thrift shops since many used old adjustable desk lamps are always for sale at a heavily discounted price.

Good luck,
mdpmedia