PTFE (plumber) tape for focuser slop?

[jschusterman]

Hey all, doesn't anyone have a link to something that shows how to fix focuser slop/play using ptfe tape? Specifically something that includes pictures or diagrams? I see people here on SGL mention using this method to help, but no one actually explains how it's done. Thanks!

- Josh

[Paul73]

Wonderful stuff! Cheaper than chips!

 I do have a fair bit of it firming up annoyingly mismatched joints. You could use it to expand the moving tube, but it is a botch that will need redoing of it is between two moving  interfaces. Try adjusting the adjustable parts of the focused first. Then bite the bullet and buy a quality focuser. It is worth it.

What are you using at the moment?

Paul

[Alien 13]

I prefer making shims out of strips of cut up coke or beer cans, you do need to cut out some tabs to hold it in place though..

Alan

[John]

Depends on your focuser type but it is possible to adjust most of them to reduce most of the slop / play in them.

What type of scope / focuser are you having this issue with ?

 

[Dave In Vermont]

I, too, suggest a quality focuser. I put GSO Crayford Dual-Fucuser 10:1 Focuser's on all my scopes. Inexpensive and excellent and NO SLOP!

Dave

[jschusterman]

Thanks for chiming in guys. The plan of course is to eventually get a moonlite focuser, but for the next several months I need to work with my current focuser. Just spent a pretty penny on coma corrector, lp filter, and a modded camera!

So the scope is a Celestron C8N purchased this year, stock focuser, which I guess is r&p. Quite a bit of slop when changing focus direction. So I basically just wrap a layer or two (or five) of the tape around the focuser tube? Any particular part of it, like closer to the bottom when extended, or closer to the threading that the adapters attach to? Or evenly throughout?

[jschusterman]

Forgot to mention... I did manage to tighten up some of the slop with those tiny adjustments built into the body of the focuser. But I still feel like I can get it cleaner and the focuser tube more evenly seated within the tube housing.

[Geoff Lister]

PTFE plumbing tape works well to seal gaps in permanent pipe joints. It is soft and fragile and not very good at staying in place between moving parts. I have tried it, on the helical focuser of my Skywatcher Heritage 130P Newtonian, and after a few in-out movements, I found little bits were braking off and falling out at each end of the joint. I would not want the bits floating about inside a refractor, or MCT/SCT. I also tried some linseed oil based plumber's putty, but this set too hard.

The shims mentioned earlier may be more suitable for your application.

Geoff

[Waldemar]

Totally agree with Geoff. The best material to use is thin copper sheet, available in different thickness as of 0,05 mm.

If you can measure the play on one side with callipers and devide the outcome by two, you will know the needed thickness. 
Lubricate one side with SuperLube grease and secure the other side with a very small amount of superglue, it will stay in place.

Prevent overlaps

[jschusterman]

Really great to have these suggestions, thanks everyone! If I accomplish one of these ideas, I'll post pics. Thanks again!