Focusser
There was an article by Michael Hart back in 1998 which gave details of a modification to the LX200 focus assembly, replacing nylon thrust washers with roller bearings and thrust washers. The article can be found at:
http://www.mapug-astronomy.net/AstroDesigns/MAPUG/ImgShift.htm#anchor1166419
Peterson engineering developed a kit for this modification see:
http://www.petersonengineering.com/SkyDiv/ez_focus_kit.htm>
I saw several postings referring to the ez-focus kit, and also to the original by Michael Hart. After a bit of reading I thought that this would be a good upgrade to apply to my 8 inch LX200 classic, which was bought in 1997. One of my other interests is in metalwork and I have a small home workshop, it was during a browse of one of the suppliers that I use that I noticed that they stock roller thrust bearings, and some of the type numbers looked familiar. Checking up, I found that the bearings were the same as mentioned in Michael's article. I ordered a couple of bearing sets and made a start on the modification.
The bearings can be obtained here in the UK from
Goto their bearings section, and select needle roller thrust bearings.
I did a little more research on the upgrade, and found two points about it, one I did not like and the other was a cure, again which I did not like, (not for the cure, but rather that it modified the focusser assembly, and it would not be possible to restore it to the original state)
The part that I did not like, was that in doing the modification, the main focus knob would have to be locked in place by it's grub screws, by screwing them down onto the threaded part of the inner focus assembly - sounds a mouthful, but the pictures explain this better. The solution is to remove a few mm of metal from the rear of the focus housing. As I did the modification, I made a photographic record which others may find useful. So here goes...
The first sequence starts with the original. focus knob view (on a very dusty scope I might add!) There are three pan head socket screws that need to be undone using a 3/32 hex key. BEFORE these screws are undone turn the focusser so that the mirror is in the fully forward position. Undo the screws and put somewhere safe, then pull the focus assembly back, moving the mirror to the rear position at the same time. Doing things this way will give you a long length of threaded rod to play with which makes removing the rod from the pin on the mirror cell much easier. The remaining images in the sequence show several views of the rod, and finally one of the pin (after a lot of mucky grease had been removed)
