I have used this method of alignment and since it worked great I thought it is worth be shared here.
I have used some temporary MDF guides which centered in the laser tube brackets, helping me determine the nylon screw position using the smaller diameter.
The disks in the center I cut on the PCB cnc machine at work. The hole is 0.5mm so it will force the beam to stay sharp and centered.
These guides worked so well that I used them to align all the mirrors and when I put the tube in place and fired for the first time it burned a nice round shape 4-5 mm diam in the wood on the table (the lens is not installed yet).
The red dot is not very visible on the mirrors, so I temporarily used small pieces of masking tape.
- First guide holds a small red pointer laser
- The pcb material (fiberglass + copper) has a hole 0.5mm
- Second guide. The beam passes through the second disc and can be seen on the cardboard box behind (where the first mirror sits).
- Both guides seen here