Modding my LinkMicro digital microscope

Jun 22

In this video, I show you how I modified my LinkMicro LM246MS digital microscope. I originally got this microscope from LinkMicro in exchange for reviewing it and I am very satisfied with it. I’ve been using it quite often, especially for my projects where I used a lot of SMD components and had to reflow the PCB. However, I was sometimes bothered by the Z-axis. So, this article will discuss my modification of the Z-axis.

Modding the Z-axis

So, the original Z-axis has several features. The most obvious one is setting the height of the whole microscope which determines the working distance. I found it sometimes cumbersome to set the proper height because the piece that holds the microscope on the Z-column can also rotate. So, I have to be careful to keep the microscope centred.

Another thing is that there is a fine adjustment of the Z-height. However, I don’t understand its purpose, because there’s also a focusing ring on the optics of the microscope. They both do the exact same thing with the same fine adjustability. Maybe they have a different range, I haven’t checked it thoroughly.

Then, one can adjust the microscope’s position along the Y-axis (direction perpendicular to the monitor’s surface) of the observed surface. This is a nice feature if the observed object cannot be placed directly on the centre of the base plate of the microscope. However, I also got rid of this feature, because I don’t need it.

Finally, there is another feature that was a bit cumbersome on my microscope. I mentioned this in my review video as well. There is a hinge-like mechanism at the bottom of the Z-column that allows the whole microscope to be tilted backwards. In my case, this feature did not really work. I tried to loosen the screw in this mechanism, I even disassembled it, but it did not work. However, it was somewhat loose, so the microscope was not super stable because it could move a bit at this point.

So, my modding is about removing the Z-column and replacing it with my DIY Z-column. My mechanism is a bit inspired by the Z-axis of the 3d printers. I made the whole Z-column adjustable by using a 30 cm long T8 lead screw. In the centre of the mechanism, there is a lead screw sitting and it is supported by two 8 mm diameter rods. I designed and printed a custom crosshead that connects the support rods to the lead screw and holds the microscope. The support rods are connected to the crosshead via a SCU88 linear bearing platform. The support rods are pushed and glued in the 3d printed end pieces. I designed the holes tight enough that they hold the rods tightly, but to avoid any unwanted movements, I added a dab of glue to fix them firmly. The lead screw is supported by two KFL08 bearing blocks. These blocks are screwed onto the 3d printed end pieces. The lead screw slightly sticks out from the end piece at the top which allows adding a handwheel to it. This wheel rotates the lead screw which then moves the crosshead (thus the microscope) up or down. There is no need for a lock screw on the Z-axis because of the friction between the lead screw and the nut attached to it. The crosshead can only move when the lead screw is rotated, but it won’t move under the weight of the microscope.

The pitch of the lead screw is 8 mm which means that 1 turn of it will move the microscope up or down by 8 mm. So 10-20 full turns can move the microscope enough to drastically change its working distance while it stays perfectly centered.