Sky-Watcher Dual Speed Focusser Fitting Problem

[PaulG]

4 years after buying a Sky-Watcher dual speed Crayford focusser, I decided to fit it to my Evostar refractor tonight.

I got a bit of a shock when the new focusser would not fit inside the Evostar white collar.

I ended up sanding the white paint away from the inside of the collar with some wet & dry sand paper.

It now fits like a glove but is this normal to have to do this?

[xtreemchaos]

yes had to do the same with my 120mm, but as the undertaker said to the plummer "its better tight than slack"?. charl.

[Davey-T]

Is that what they call manufacturing tolerance 

Dave

[DRT]

1 hour ago, PaulG said:

4 years after buying a Sky-Watcher dual speed Crayford focusser, I decided to fit it to my Evostar refractor tonight.

I got a bit of a shock when the new focusser would not fit inside the Evostar white collar.

I ended up sanding the white paint away from the inside of the collar with some wet & dry sand paper.

It now fits like a glove but is this normal to have to do this?

I've swapped focusers on lots of SW refractors and this is perfectly normal. I've even bashed one in with a rubber mallet to make it fit and then removed it by dripping WD40 down the join between the collar and the focuser.

The stock SW (Synta) bits are more than likely made by multiple suppliers at the cheapest cost to a rather wide tolerance so it's not unsurprising that this happens. The upside is that we can buy very good optics reasonably cheaply  

[johninderby]

Oddy enough have fitted a couple of Skywatcher crayfords to Orion equivalents to the Evostar / Startravel refractors and not had to sand anything. Fit was just right. But then the Orions are more expensive but seem to be that bit better finished. 

[Paz]

Yes this sounds familiar. I have one fitted to my st120 and it was a very tight fit.

[PaulG]

17 hours ago, DRT said:

I've swapped focusers on lots of SW refractors and this is perfectly normal. I've even bashed one in with a rubber mallet to make it fit and then removed it by dripping WD40 down the join between the collar and the focuser.

The stock SW (Synta) bits are more than likely made by multiple suppliers at the cheapest cost to a rather wide tolerance so it's not unsurprising that this happens. The upside is that we can buy very good optics reasonably cheaply  

Bashed one in, crikey me and I was worried about using a firm push lol.

Cant wait to heave the 150mm Evostar back on to the mount again soon.

[PaulG]

Thanks for the replies guys.

Nice to know that I'm not the only one to make minor adjustments to allow a snug fit.

[PaulG]

17 hours ago, johninderby said:

Oddy enough have fitted a couple of Skywatcher crayfords to Orion equivalents to the Evostar / Startravel refractors and not had to sand anything. Fit was just right. But then the Orions are more expensive but seem to be that bit better finished. 

I guess quality speaks for itself John but unfortunately my pockets aren't very deep.