Digital Microscope Mount for Heavy-Duty Desktop Stand

I didn't like the stand that my digital microscope came with, so I designed my own. I built this mount with this in mind. It is designed so that you can print just the microscope mount, relying on the stand adjustability, or with the fine-adjustment mechanism.

Note: This model only contains the microscope mount accessory. It also requires the stand to be printed. The accessory screws onto an accessory adapter (part included in the stand model files) and requires an adapter for this mount (one adapter per accessory).

Features

• 40mm diameter tightening ring to hold the microscope (the stand the microscope came with required special screws that pressed into the microscope body to hold it in place).
• Can be printed with fine-adjustment mechanism, or just as a single-piece mount (relying on stand adjustment).
• 3D parts available for editing in my Onshape project

Non-Printable Parts

There are a few non-printable parts needed

• Two (2) M3x10 socket head screws for attaching accessory to adapter
• (Adjustable Version Only) One (1) M6-1.0 x 50mm hex head bolt for adjustment knob
• (Adjustable Version Only) One (1) M3 x 3mm grub screw for locking pinion onto adjustment knob
• (Adjustable Version Only)  Two (2) M3x10mm socket head screw for attaching microscope mount to accessory base
• (Adjustable Version Only)  One (1) M3x10mm socket head screw for tightening ring
• (Adjustable Version Only) One (1) M3 socket head screw for applying pressure to rack and tightening assembly. Minimum length for this is 6mm, but I use a 10mm screw.

Print Instructions

All parts can be printed in PLA with 0.4 nozzle. All parts use a layer height of 0.2mm with 15% infill and 2 walls loops. I've included the 3mf file.

Microscope Mount

• Print the adjustable version if you want the fine-adjustment mechanism, or the non-adjustable version if you want to rely on the stand adjustment only
• Print with tightening ring in the air
• I've printed without support, and it came out OK, with just a bit of roughness on the underside of the top of the ring, but you can add support there to be safe

Accessory Base

• Only print if you want the fine-adjustment mechanism
• Print with dovetail facing upwards
• No support needed

Rack

• Only print if you want the fine-adjustment mechanism
• Print with rack gearing facing upwards
• No support needed

Pinion

• Only print if you want the fine-adjustment mechanism
• Print on side with centerbore hole vertical
• No support needed

Pressure Block

• Only print if you want the fine-adjustment mechanism
• Print with hole cutout facing upwards
• No support needed

Knob

• Print with larger face on printer bed
• No support needed

Assembly Instructions for Non-Adjustable Version

Just screw mount to accessory adapter using the two M3 screws from the dovetail side of the adapter. The screw heads should recess into the adapter. The mount should be attached so that the tightening ring is towards the bottom of the adapter.

After this, you should be able to mount the accessory onto the stand as described in the stand instructions.

Assembly Instructions for Adjustable Version

1. Assemble Pinion Gear

The pinion gear fits into the rear of the accessory base and is rotated using a knob. The pinion gear is locked onto the knob using a grub screw.

Assemble a knob by pressing a hex bolt onto the 3D printed knob head and making sure the hex head is fitted into the cutout firmly. It should be a tight fit to prevent movement.

Start screwing the M3 grub screw into the pinion gear before installing the pinion gear (will be harder once it's inside the base). The hole is sized so that the screw should be self-tapping. Screw part way into the pinion gear without starting to come out on the inside of the pinion centerbore hole.

Pass the pinion through the cutout in the rear of the base while pushing the adjustment knob though the side of the base. You want the knob on the right side of the base (the side with only one hole). You might be able to have the knob of the opposite side (maybe for left-handed people) but it might interfere with the pressure screw.

Pass the knob through the pinion ceterbore hole, and push on as far as it will go (knob base face touching the accessory base part). Now tighten the pinion grub screw to lock the pinion to the adjustment knob. Be careful not to over-tighten to prevent stripping of the threads. It might be easier to temporarily install the rack into the base to help hold the pinion gear in place while you do this.

2. Assemble Rack and Pressure Block

The rack slides into the base and meshes with the pinion. You can test to make sure this meshing works properly by temporarily installing the rack and turning the knob to make sure the rack moves smoothly.

To prevent looseness in the rack assembly, there's a pressure screw in the final assembly that can be adjusted to apply tightening force on the rack. To prevent the screw damaging the rack, a pressure block is used to distribute the force a bit.

We need to install this pressure block before installing the rack. It's a pretty small part, so it can be a bit tricky. The size tolerances should be adequate so that is just drops in though. To install, place the pressure block in the corresponding hole in the base dovetail. The screw cutout on the pressure block should go into the hole (not visible after installing) and the profile should match the dovetail so that it lies flat (see picture below).

Once the pressure block is installed (be careful not to tip the base or the pressure block will fall out), install the rack by inserting it from the open end of the dovetail. You might need to press down on the pressure block so that the rack can move over it. Once the rack is installed, it will hold the pressure block in place.

3. Attach Microscope Mount

The microscope mount screws into the rack using two M3x10 socket head screws. The screw heads should recess into the part so that they are flush with the outer face. The tightening ring should be closer to the bottom, near the adjustment knob.

There are also grooves on the underside of the mount face that interact with guides on the base part, which prevent the rack from moving too far down and unmeshing with the pinion gear.

At this point, you can also attach the M3 screw to the tightening ring. It passes through the counter-bored side and self-taps into the other side. Install this screw, but leave it loose for now so that you can install the microscope later.

4. Attach the Pressure Screw and Adjust Pressure

On the side opposite the adjustment knob, there is a hole for an M3 screw. This interacts with the pressure block inside the base. The hole is sized so that the screw will self-tap.

While installing the screw, keep checking the looseness of the rack and microscope mount. Once the pressure screw starts interacting with the pressure block, it should start pressing the pressure block into the side of the rack, adding some pressure and tightening the assembly. Be careful not to over tighten since with could strip the thread or tighten the assembly too much. Adjust the pressure screw until the assembly is as tight as you would like it. It shouldn't wobble or fall down under its own weight, but shouldn't be too hard to adjust with the knob.

5. Mount to Accessory Adapter

Use two M3x10mm screws to attach the microscope mount assembly to the accessory adapter. You may need to print an additional adapter (part included in the stand model) if you are already using the adapter that was printed in the stand assembly. The screws recess into the adapter part and self-tap into the base part.

6. Attach to Stand and Install Microscope

The mounting accessory can not be mounted onto the stand as described in the stand instructions. You can also install the microscope into the tightening ring and screw in the M3 screw to tighten the ring around the microscope body.

Future

There are a few changes I may make in the future

• Redesign the pressure mechanism to make it easier to install and to get better control of the tightness
• Add microscope mount options with different ring diameters to support other microscope models
• Find some way of reducing the dependency on self-tapping screws, since I'm always afraid of over-tightening and damaging a part.