Orion Optics UK altitude bearing

[dark star]

I have recently bought an Orion Optics UK VX12  dobsonian second hand. It is really great. I have finally got my Nexus DSC to work-I have a home made 14 inch truss dobsonian and it would not work properly on this, no doubt because the dobsonian mount was not square. The dobsonian came with Sky Commander DSC, which I also like, it is very simple compared to the Nexus DSC but works well.

The problem I have is that the moount has 4 curved teflon pads that the altitude bearings sit on. The telfon pads seem to come off sometimes when I lift the telescope  on and off the mount. Has anyone else had this problem and does anyone have any idea how to fix this.? The teflon pads have to be banged back in to place to get them back on the mount so it seems strange that they come off. Tonight I have lost one of the pads in the garden, hopefully I will manage to find it tomorrow when it is light.

I have some teflon but do not think it would be easy to cut the curved shape needed to fit it back on to the mount if I needed to make one.

David

 

[johninderby]

Never had the pads come off my 14” OO dob when I had it. Wonder what the original owner did to the pads. 🤔

Edited November 23, 2021 by johninderby

[scarp15]

Quite a while ago, I vaguely recall losing one of these on a dark sky trip with my VX14 dob. It just came off when clumsily due to a bit of fatigue or numbness when seating (or maybe removing) the rather hefty tube after a long winter session. I contacted OOUK and purchased a new set. Ended up replacing them all as they were a tighter fit, but kept hold of the old ones as they are still in good enough condition. They will for a cost send out spares for various parts, if it continues to be troublesome. Would also direct this matter with them as they will likely provide advice.

[NGC 1502]

The Teflon bearings on earlier OO UK Dob mounts had a habit of coming adrift.  That’s happened on both of mine. They are formed from flat Teflon strips forced into the curved cutouts in the aluminium mount, so the flat Teflon takes on the curved shape.  If the Teflon strip is fractionally too short it’s not quite tight enough and with use can slide out.

It might be possible to wedge it in place by forcing it back in with a packing piece on the end, effectively making the strip a fraction longer. Trial and error needed to be effective.

The problem was fixed on later mounts with a completely different shaped cutout in the aluminium mount.  The original cutout in the aluminium was curved in the same direction as the altitude bearings.  The updated cutout is curved in the opposite direction, that maybe counterintuitive but actually is much more secure.

Edited November 24, 2021 by NGC 1502
Added info