Skywatcher Evoguide 50ED, issues

[Stuart1971]

Hello,

I recently bought a second hand SW Evoguide 50ED, and it’s in mint condition and was happy with it, but I noticed that with the helical focuser when I change direction from in to out or vice versa, there is backlash, in fact the green focusing ring will focus one way, and as soon as I swap direction the same ring will move approx 1/4 of a turn before it starts moving focus the opposite way. Yo can actually feel the backlash as it goes really loose for a 1/4 turn before it picks up and starts to move..

So my question to any owners of this little scope, is this normal or do I have an issue and can it be taken apart and looked at..?

[OK Apricot]

Mine was the same when I had one. Never an issue for me as much as a little build quality/design niggle. 

[Budgie1]

Mine is the same, I put it down to a manufacturing feature which doesn't really have any effect on the operation of the scope.

As I use mine as a guide scope then I rarely change focus on it anyway.

[happy-kat]

I just make sure when focusing to always end in a decent amount of upward focusing direction to make sure there's no slush then do up the focusing screw, all's then good.

[Stuart1971]

Thanks guys, a couple of wraps of Plumbers PTFE take around the thread of the helical under the green wheel, has done the trick..👍🏻

[MrJHD]

How well does the plumbers tape work. I have just bought an eaf to use with it and I am worried about backlash. I use the evoguide as my main scope. 

[Stuart1971]

1 hour ago, MrJHD said:

How well does the plumbers tape work. I have just bought an eaf to use with it and I am worried about backlash. I use the evoguide as my main scope. 

It took out around 50% of the backlash.

I may 3D print a new focus knob with a tighter pitch to try and eliminate it all

[Backyardscope]

Mine has that issue, i suppose if you know where the focus point is there is not much to fuss about.

I have also created a cradle and clasps similar to the Starizona design.

It is so much better and holds the scope well.

 

[happy-kat]

Following reading this approach elsewhere when I'm using mine for focusing I always make focusing finish with a decent amount of upward focus travel then the lock screw, if I then move the focus in a backward direction it doesn't to me actually effect focus even if it moves. I'm manually focusing.

Edited June 7 by happy-kat

[Stuart1971]

Yes I use 3D printed tube rings for mine too, much more stable