Astro Baby Guide to Rebuiling the TAL-1
6 - Rebuilding/Restoring the TAL 6x30 Finder

The TAL 6x30 Finder is relatively straightforward to strip down. You will need some precision/jewellers cross head screwdrivers though as most of the
screws on this are very small.

As ever with optical components exercise extreme care. One slip of a screwdriver can ruin an otherwise perfectly sound optical assembly.

This unit was stripped as it was suffering a host of problems including a sticky focuser that made a nasty grinding sound when adjusted, dirt inside tube, lens
components were very grubby and the exterior finish was ruined.

Stage 1 - Stripping down the 6x30 finder
removing the finderscopes collimating rings Removing the finderscopes primary lens 1 Removing the finder scope primary lens 2
Remove the finders rings if desired. You need not do this unless you are planning refinishing the finder scope tube. The rings are held on with three small set screws around each ring. These need to be slackened off. To remove the front lens you will need to slacken off the small set screw at the front of the finder scope tube. The primary optic should be easy to move once the set screw in the previous step has been loosened. Using a small screwdriver you can gently push the lens holder around to unscrew it using the small slots in the lens holder.
The primary lens being removed The TAL 6x30 Primary Lens The rear optical assembly grub screw removal
One enough of the lens holder is showing its easy to unscrew this with your fingers. This unit showed signs of wear and broken paint inside the finder tube. The lens was also very dirty. The primary optic is removed and cleaned with an isopropyl alcohol and water mix (1 part IPA and 10 parts water). The lens on this unit was absolutely filthy. The rear optical elements are held in place with a small set screw located just in front of the rear element. Loosen this screw.
The rear optical assembly being removed The rear plate of the TAL finder grub screw The TAL 6x30 finder reap plate being removed
The rear optical assembly is removed by simply unscrewing it. This will be stripped down later to fix its rather 'gritty' feel. If desired the rear plate of the finder scope tube can also be removed by slackening off the small set screw at the rear of the tube....  ...and simply unscrewing the rear plate.
Stage 2 - Stripping and Repainting the Finders Optical Tube
The finder scope at the start of paint stripping The finder scope stripped of paint The finder masked ready for painting
Like the main tube the finder paintwork was very yellowed and showing signs of distress. This is the finder at the start of stripping. The finder scope stripped down. Note that the end plate that holds the rear optical assembly is brass. The main tube is aluminium. It was hard to mask the finder as it was tough to get masking paper inside over the threads. In the end I settled for rolling up a newspaper, putting masking tape over it and inserting it into the finder. This also made a convenient handle to hold the finder by during painting.
The finder was repainted with three coats of Rustoleum enamel paint to provide a hard, durable finish. Note: Enamel paints take a long time to cure and fully harden. You need to allow at least 7 days and mnore like 21 days before the paint is hard enough to accept rough handling. This will depend on ambient temperature and humidity of your location. Note: before repainting the exterior of the finderscope tube you may wish to apply some blackboard paint to the inner part of the tube. If you do this do not paint over any threads inside the tube.
Stage 3 - Stripping and Rebuilding the Finders Rear Optical Assembly
The TAL 6x30 rear optical assembly Removing the eye guard Lossening the set screws that retain the focus ring
The finders rear optical group/eyepiece is placed on a soft surface. Remove the eyeguard by unscrewing it from the main unit. This can be cleaned with soap and water. On this type of plastic you can also use a small amount of toothpaste to bring it back to a shiny condition. Loosen off the three small set screws around the knurled section/focuser grip of the eyepiece assembly.
The focus ring being removed from the finder The two compnents of the TAL 6x30 rear optical group The two elemnets from the finder cleaned of grease and dirt
With the three small set screws slackened off sufficiently the knurled section of the eyepiece will come away easily. The two components left are the main lens group to the left (brass coloured) and the reticule assembly to the right (black coloured). The brass sections simply unscrews. You can see that there is almost no grease left in this assembly plus there was a sharp piece of brass in the threads which was causing the focuser to feel and sound terrible. The main lens element and the reticule element were thoroughly cleaned with a lint free cloth and isopropyl alcohol to remove the remaining grease and to clean the lenses before being flushed with distilled water and left to dry. As ever Isopropyl Alcohol and distilled water are your friends.
Relubricating the rear optical assembly The two rear elements reassembled The focus ring being replaced
Once completely dry and with the lenses checked the brass part containing the lens elements was smeared with lithium grease and any excess grease removed with a paper towel.. It was then carefully assembled. The lens element and reticule element reassembled. Now the knurled component/focus grip is slipped over the assembly and....
The focus ring grub screws replaced Eyeguard being replaced The completed rear optical asssembly
The three set screw tightened. You need to work around these in turn with a bit of tension added to each one to keep the assembly square to the optical elements. Finally the eye guard is replaced. The finished assembly is now stored safely pending completion of the stripping and repainting of the optical tube. The unit now works smoothly.
Stage 4 - Rebuilding the 6x30 Finder
Replacing the collimation rings Replacing the rear of the finder scope tube tightening down the rear set screw
Once the enamel paint is fully dry and cured the finder scope can be reassembled. First re-attach the finders collimation rings. Be careful because the thread in these rings can be easily stripped and make sure the grub screws are located into the indentations in the finder scope tube. Now replace the rear plate to the finder scope. This should screw in easily. Tighten down the small grub screw that retains the rear plate. Do not overtighten.
The finder scope rear optical assembly refitting the rear optical assembly tighetning down the optical assembly grub screw
Here is the rear optical assembly ready to be reinstalled. Gently screw the rear optical assembly into the rear plate of the finder scope.  Tighten down the rear assembly gruub screw on the rear plate of the finderscope. Do not overtighten.
Replacing the primary optic The primary optic grub screw The completed finder scope
Carefully replace the primary optical element to the front of the finder scope. This needs to seat a little way down the tube. Now tighten down the main optical element grub screw. Do not overtighten. The finished finderscope looking (and working) as good as new.