5 replies to this topic

[Paul Makinen]

The following topic shows a nice view of the inside of a cracked pier cap casting:

 

https://www.cloudyni...escope-problem/

 

My mount has the usual pair of set screws for locking the altitude adjustment, but one of the screws seems hopelessly frozen in place.  I would like to drill and thread a hole for a new screw. 

 

My questions are as follows: 

 

1) Are these aluminum castings?

 

2) How far away do I need to make the new hole to avoid cracking the casting (as in the topic referenced above)?

Edited by Paul Makinen, 10 October 2024 - 03:14 PM.

[GalaxyPiper]

The thing with these mounts is there is usually several metal washers that take up the gap in the main pivot area. This cental bolt should never be over tightened or it will lend itself to cracking one of the ears off.

 

There should be another screw, off center, that is used as a secondary pressure point to prevent movement, and also acts to counter and alleviate the central bolt from being overtightened.

 

Some versions of this mount have a RA turnbuckle mounted on the rear to further act as a stop as well as an adjustment to the RA. But once set for the location of the mount there should no longer be a need to adjust this.

 

The spacing washers (usually two) should be on the side that does not have the off set screw to help hold the pivot (This would be the bolt head side.). This is so the secondary locking screw does not "have-to-be" excessively long to gain purchase to provide a lockdown of movement (Usually a grub screw.) Acting as a rudimentary disk brake.

 

And yes...they are aluminum, so take heed, and take care.

Edited by GalaxyPiper, 16 October 2024 - 09:08 AM.

[deSitter]

The thing with these mounts is there is usually several metal washers that take up the gap in the main pivot area. This cental bolt should never be over tightened or it will lend itself to cracking one of the ears off.

 

 

Amen to that! Cast aluminum does not bend, it shatters. I have a probematic tripod hub ear that is going to need shimming. The impulse to brute force it must be resisted.

 

-drl

[GalaxyPiper]

If you have a grub screw on both ears, then the spacing washers need to be on both sides of the pivot.

One on each side.

 

I have seen three washers. It depends on when and on what model of the mount is made for.

In that case, one washer on the threaded hole side, and two on the bolt head side.

 

The washers are to fill in the gap of the lack of thought given in the design.

Always take a good look after placement to make sure where you have the washers make sense. 

 

If you have too much of a gap on the side with the grub screw, and have to much of the grub screw twisted in to reach the face side of RA Central pivot, then something is wrong.

 

Always test fit when proper instructions are not present.

 

All the best.

 

Bryan

Edited by GalaxyPiper, 16 October 2024 - 05:05 PM.

[Paul Makinen]

The thing with these mounts is there is usually several metal washers that take up the gap in the main pivot area. This cental bolt should never be over tightened or it will lend itself to cracking one of the ears off.

 

There should be another screw, off center, that is used as a secondary pressure point to prevent movement, and also acts to counter and alleviate the central bolt from being overtightened.

 

Some versions of this mount have a RA turnbuckle mounted on the rear to further act as a stop as well as an adjustment to the RA. But once set for the location of the mount there should no longer be a need to adjust this.

 

The spacing washers (usually two) should be on the side that does not have the off set screw to help hold the pivot (This would be the bolt head side.). This is so the secondary locking screw does not "have-to-be" excessively long to gain purchase to provide a lockdown of movement (Usually a grub screw.) Acting as a rudimentary disk brake.

 

And yes...they are aluminum, so take heed, and take care.

Thanks for all the detail here.
 

[bjkaras]

I have the same issue with my Parks mount. It has two grub screws; one on each side. That is the weakest link in the mount and I’m looking at other options. I’ll probably end up installing a turnbuckle or something similar.

Edited by bjkaras, 27 January 2025 - 07:11 PM.