USB Microscope Stand

There are a number of low cost USB microscopes available these days. They're really just webcams with closeup lenses, but they do a fair job of providing magnified views. They all come with a stand, but the stand is barely adequate, and really does not allow for the full capabilities of the unit. For this reason, I built a custom microscope stand (picture to the left).

See more information about my particular microscope at the bottom of this page.

The USB camera I purchased magnifies an advertised 20X and 200X. Actually, it magnifies a range around 20X, but this requires adjusting both the distance from the specimen, as well as the focus. Adjusting the focus to the extreme end of the range provides 200X (advertised) magnification; at the highest magnification, distance from the specimen is critical and needs to be finely adjusted.

The stand I built enables the microscope to be moved up to 9 inches from the specimen, provides an improved focusing knob, as well as a fine distance adjustment.

This web page provides a build log for the stand.

For comparison, to the left is the stand provided with the microscope (the microscope itself is not in the picture). While it is serviceable, it is not very sturdy, does not hold position well, and is difficult to adjust at the higher magnification.

The build starts with cutting up some aluminum plate. I don't have a metal cutting bandsaw, so I use a hacksaw to cut the pieces slightly oversize, and then true them up on a mill.

After truing up the pieces on the mill, I use layout die and a scribe to mark up for further machining.

To reduce the amount of milling required, the pieces are rough cut with a hacksaw. The "center holes" are drilled in both pieces.

The "ears" on the pieces are milled to size.

The rounded portions are milled by mounting the center hole on a rod (held in the mill vise), and rotating the piece against the milling cutter.

Note: The piece should be rotated so that convention milling is being done. If you attempt to do climb milling while rotating the piece, the cutter will "grab" the stock and attempt to pull it around. This can result in injury to you, breakage of the cutter, or messing up the stock. Even though it takes longer, stick to conventional milling!

At this stage, milling of the "outside" is complete.

The center hole is enlarged by mounting in the lathe, drilling successively larger holes, and then finishing with a boring tool.

This photo shows a completed piece, after boring. Also shown is a "spacer" (essentially a thick ring cut from aluminum) which I used to raise the pieces off the chuck jaws to enable the boring tool to work without running into the chuck jaws.

Here are the two microscope clamp pieces, essentially complete. The final step was to file a slight chamfer on all of the sharp corners and edges.

Note also that in this picture the tightening screws have not yet been cut to length. While not strictly necessary, I shortened the screws for cosmetic appearance, so that they do not protrude after tightening.

This picture shows the completed mounting rings in use.

Note that the holes drilled for the focusing knob were "moved" closer to the microscope after initial testing. The holes drilled initially (to the left of the focusing knob) are no longer used.

A piece of drill rod, threaded on one end, provides the main upright for the stand. Note that a thin washer and thin nut are used on the lower end; the nut was thinned by facing in the lathe.

Here, a brass rod is turned down in preparation for making a knurled thumb screw. The small diameter is threaded with a die, and the larger diameter is knurled prior to parting off.

The completed thumb screw.

Making the two bracket pieces which go on the drill rod is fairly straightforward. Note the thumbscrew in the lower piece.

Note that the corners have been milled off (see next photo) - this was primarily for appearance sake, but also to remove sharp corners.

Milling off the corners: This was done by setting up the pieces in the mill vise with a 45 degree angle plate.

This photo shows the completed brackets in use on the stand. Note that additional holes were drilled (not seen in earlier photos) and a "stiffening rod" was added (see just in front of and to the right of the main rod).

After initial setup and testing, I found that the microscope "wobbled" when adjusting the distance knob. Addition of the stiffening rod eliminated this wobble.

Note: The empty threaded hole seen in the top bracket was an error, and is not needed.

Here is another view of the bracket assembly. In this view, the stiffening rod can be more clearly seen.

In use, the microscope is moved up and down the main rod by loosening the thumbscrew, and sliding the bracket up or down the rod. Turning the knulred knob on the top allows for fine adjustment of the distance between microscope and specimen.

This view shows the focus knob and focus mechanism. The brass rod lifts the focus knob well above the microscope; the large diameter of the knob provides "leverage" to enable easy focusing. The o-rings (seen between the two clamping rings) press against the focusing thumb-wheel built into the microscope so that the microscope thumb-wheel turns when the upper focusing knob is used.

Note also the knurled brass round nut (seen between the microscope and the rod brackets). This nut tightens the microscope on the horizontal rod, and also allows the microscope to be tilted for oblique views of a specimen. The microscope can even be turned horizontally when necessary.

A repeat view of the completed stand.