Mirror clipsPosted By Ron Oehlert |
For any size mirror, the simplest & easiest to construct is an over-sized flat triangle of wood under the mirror. The cut-off *points* of the triangle are the mounting points & can be supported parallel to the optical axis by bolts & nuts (like *legs* protruding behind & attched to rear of mirror box). Springs over the bolts under the board work well with smaller mirrors or nuts on each side of board with bolt passing thru allows mechanical push-pull alignment that remains aligned when screwed down snug despite travel vibration (use washers under the nuts to spread load across more wood). Anchor the bolts to either the mirror box or cell board with adjustment provided at the other ends of bolts; which end depends on what is convenient to your situation/arrangement. Size the wood thickness & bolts to the mirror; if they look flimsy they are & likewise if they look sturdy enough. An index mark on the mirrors' side (or back, if view holes are cut into mirror board & mirror box) along with a corresponding mark on the cell allows returning to collimated position if travel rotates the mirror in it's cell. Heavy-duty felt furnature pads may be used to support the mirror (underneath) & inverted L-shaped blocks of wood standing on the *point* ends serve as both retaining clip & side supports (padded with pieces of furnature pads). Precision construction is un-neccessary since the mirror should Not be clamped tight to cell, but remain loose-fitting. The larger the mirror, the more underneath support pads used. I used such a home-made push-pull cell for decades & never needed to re-collimate unless the mirror was removed.