Removing focuser from SW80ED

[Grierson]

Good evening gentlemen and ladies. I wonder if anyone has replaced the focuser on SW 80ED DS Pro? I am currently faced with the task but the three Philips? headed screws securing the telescope tube to the focuser body are proving impossible to shift. I am currently at the stage of deciding to drill them out! but for obvious reasons I am reluctant to do so.

Has anyone come against the same or similar issue and managed to resolve it?

Any thoughts no matter how daft would be appreciated. - John

[nightfisher]

They should come out okay, make sure you use the correct screwdriver, and a little tip try tightening a fraction before undoing

[Knighty2112]

Yeah, a good quality screwdriver with correct size head should do the job. Just hope you haven't damaged any screw heads at all in trying before as that will cause more trouble for you. If still tight carefully let a small amount of WD40 soak into each screw to try to assist loosening it up a little. Go carefully and use small amounts, and leave to soak in for about 10 mins before wiping excess off and trying to losen the screws. Make sure no WD40 comes any where near the optics on the scope, and also wipe any away that might get inside the scope after soaking in to any screws near the focuser.

Edited June 1, 2017 by Knighty2112

[DRT]

You could try varying the temperature in which you are trying to remove the screws. If you have been trying when the scope is at ambient room temperature leave it somewhere cold for a while and try again, or vice versa.

[Skipper Billy]

Heat the area (hairdryer not blowtorch!) for a  good few mins - one screw at a time - the aluminium threads will expand more than the steel bolt.

The correct size screwdriver is essential - from  memory it is ph2.

Then as suggested above try tightening a fraction then undo.

Drilling out should be an absolute last resort and takes real skill and practise to avoid going down the side of the bolt into the alloy and potentially destroying a very nice scope - if you have to go down that route please PM me and i will give you some pointers on how to do it.

[Grierson]

Many thanks everyone for taking the trouble to respond. I actually shattered the end of my ph2 100mm driver as the wife held the 'scope and I tried turning the screw. I did manage to get one screw out before that happened but now I'll have to get down to B&Q to get another driver. The screw head took some of the metallic paint off my lovely telescope in the process.  I will have another go at the other two screws tomorrow taking on board your suggestions.  

I'm not at the drilling stage yet Billy but thanks for the offer - John

Edited June 1, 2017 by Grierson

[Skipper Billy]

Skywatcher appear to have started using some sort of very hard and very brittle threadlock compound.

The good news is that it is softened by heat.

Maybe that's what's giving  you trouble.

[SonnyE]

If you do have to resort to a drill, And I mean as a very last resort, find some left hand drill bits.

Often using a left-thanded drill set, the drilling will free the threads and the damaged screw will back out.

[Dave In Vermont]

I use a "Penetrant-Catalyst" called 'PB-Blaster'. And super-hard to remove screws, etc. - are covered in it. Wait an hour or so. Then try again. It's never failed me. Automotive-shops should be able to help you find this, if you have trouble locating it. Or it's sold under a different name over there.

Take your time & don't rush. You'll get it done.

Dave

[AdeKing]

A friend of mine had this problem and used a screw extractor bit which worked for him. I think this is what @SonnyE is referring to as they have left hand threads on them.

Screw Extractor Set

[KyleStoke]

I also had this problem, I think in the end one just turned to mush so I had to get a good grip with a pair of pliers did the trick, the suggestions above seem more delicate 

[Grierson]

Well another broken driver and a lot of heat I've finally got the screws out although I've managed to leave the shank of one of them still in the focuser when the head parted company. Looks as if I will still have to resort to drilling it out if and when I use the focuser again. I couldn't find 'P-B Blaster' Dave although my local Halfords suggested WD-40. At Gus' suggestion I had tried that last night with no luck. I was half expecting the focuser to be a tight fit to the 'scope tube but in fact it came away without difficulty. Again many thanks for all the helpful comments. - John

[Dave In Vermont]

I don't know how - leave alone why - WD40 got hyped as the 'be-all & fix-all' for everything from cleaning bicycle-chains to arthritis-pains! 10-Points to anyone who can even tell me what 'WD40' even stands for!

Amazing!

It stands for "Water-Displacement - 40th compound tried." Boeing Aircraft wanted something that would displace water from electronics in the controls of jet-aircraft - should the pilot have been a clutz who accidently poured his coffee (or something) into the console of controls for the aircraft. And this compound was chosen because the lubricating-oil in it is "non-persistant" - meaning it will evaporate quickly and not leave much lubricating-oil behind in it's wake!

In non-technical terms = It won't work as an oil for very long as it's designed not to.

Yes - you read that right: It's not supposed to work as an oil or other lubricant.

The next time the genius at the hardware-shop hypes 'WD40' to you - ask him what WD40 actually is and stands for!

I had a similar problem removing the stock visual-back & focuser on my AR5 F9.3 Achromatic-Refractor from Meade. I had to resort to using a 5-pound rubber-mallet! I removed the lens-cell up front first. Then stood the OTA on end with the focuser/VB up top. And went "WUMP!!" around the tube until it slowly could be removed. AgenaAstro in Los Angeles wanted me to film my doing this - long story - and I decided "NO WAY!" I didn't want my smiling face associated with this guy who looks like he's beating the daylights out of an innocent telescope with a HUGE hammer!

I had an equal amount of 'fun' setting the new one Agena got from 'Antares' that also needed a mallet to seat it. But Agena did realize that Antares' new VB wasn't going to work for most people as most people wouldn't be mechanically skilled enough to do what I had to to get that monster on!!

So I have the only AR5 with a certain Antares Visual-Back fitted upon it. I see it's still marked 'OUT OF STOCK' on the Agena website.

Good Luck!

Dave

[Grierson]

4 hours ago, Dave In Vermont said:

I don't know how - leave alone why - WD40 got hyped as the 'be-all & fix-all' for everything from cleaning bicycle-chains to arthritis-pains! 10-Points to anyone who can even tell me what 'WD40' even stands for!

Amazing!

It stands for "Water-Displacement - 40th compound tried." Boeing Aircraft wanted something that would displace water from electronics in the controls of jet-aircraft - should the pilot have been a clutz who accidently poured his coffee (or something) into the console of controls for the aircraft. And this compound was chosen because the lubricating-oil in it is "non-persistant" - meaning it will evaporate quickly and not leave much lubricating-oil behind in it's wake!

In non-technical terms = It won't work as an oil for very long as it's designed not to.

Yes - you read that right: It's not supposed to work as an oil or other lubricant.

The next time the genius at the hardware-shop hypes 'WD40' to you - ask him what WD40 actually is and stands for!

I had a similar problem removing the stock visual-back & focuser on my AR5 F9.3 Achromatic-Refractor from Meade. I had to resort to using a 5-pound rubber-mallet! I removed the lens-cell up front first. Then stood the OTA on end with the focuser/VB up top. And went "WUMP!!" around the tube until it slowly could be removed. AgenaAstro in Los Angeles wanted me to film my doing this - long story - and I decided "NO WAY!" I didn't want my smiling face associated with this guy who looks like he's beating the daylights out of an innocent telescope with a HUGE hammer!

I had an equal amount of 'fun' setting the new one Agena got from 'Antares' that also needed a mallet to seat it. But Agena did realize that Antares' new VB wasn't going to work for most people as most people wouldn't be mechanically skilled enough to do what I had to to get that monster on!!

So I have the only AR5 with a certain Antares Visual-Back fitted upon it. I see it's still marked 'OUT OF STOCK' on the Agena website.

Good Luck!

Dave

  

[Mark Henthorne]

Just had the same issue with a recently acquired ED80 and replacing the stock focuser.

Skipper Billy's approach was spot on. All I would add to that is that when you get to the screw adjacent to the 'scope description label, I used a piece of metal as a heat shield to protect that from any melting or lifting of the label.