Replace G11 Altitude Lock Screws

I love my Losmandy mounts.

One of the small things that bugged me, however, was one of the four controls used in polar alignment.

  • There is a big, easy-to-grab knob for altitude adjustment, and an elegant two-sided knob for azimuth adjustment.
  • Separate clamps lock the mount against movement after adjustment.
    • To loosen these, there are two winged knobs for the azimuth clamp, but
    • the two screws that loosen the altitude clamp are hex-head screws, and require a hex tool to loosen and tighten.

Those two hex screws for the altitude clamp have always bugged me, because they require that I have a tool on hand to polar align the mount, leaving the possibility of forgetting the tool, or dropping it in the grass. I wanted completely tool-free adjustment, and those screws were the only part of the mount that prevented it.

Here is a nice solution:

These are the same type of lever you’ve seen holding the electronics drive panel or gemini control panel in place. You can turn the lever and, if it becomes obstructed, pull it out, freeing an internal lock, to rotate the handle without rotating the screw.

A quarter-turn locks and unlocks the altitude movement.

These parts are called “Adjustable Clamp Levers”, and manufacturers include Morton, Valtra, and Kipp. (The small control panel fasteners provided by Losmandy are Kipp.) Google will find distributors. You need 3/8-16 threads, and a threaded length of 1.25″

These specific ones are Morton, from the line called “Adjustable clamping levers with stud, zinc die-cast handle”. I bought mine from KBC Tools, part number 1-905-MH305 (Warning: this is not the part number on their catalogue page, which has an error on it; the correction is listed in their “corrections” page.) They were about $10 Canadian each.

One minor problem: the threaded length is 1.5″, which is too long. I cut 0.25″ off the end of each and now they fit fine. So you’ll need a hacksaw, Dremel, file, grinder, or milling machine (any one of these) to make this adjustment.

The same parts and dimensions work for the G11, and I’ve converted my G11 to the same system, but didn’t take photos.

Final note: someone on the Losmandy mailing list remarked that the levers might be natural places for cables to snag, and that the Losmandy mounts “have a lot of cables”. That’s very true. I can only say that it hasn’t been a problem for me yet, probably for two reasons:

  1. I leave the levers pointing “up” when not using them, so cables tend to slide over, not snag under, them; and
  2. I use a lot of little Velcro cable-ties to keep things neat.

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