Improving A Skywatcher Crayford Focuser 

I really like the way you blacked out the bottom if the draw tube. I'm going to try and smooth out mine this weekend. Great videos, thanks!

Thanks for your excellent videos, Dion -- I am a Skywatcher owner and noted the very same issues on my ED120. Looking forward to getting a whetstone and sorting that out soon.

Clear explanations and straight to the point result. Your video is exactly what I needed. My dual-focuser on a SW200/1000 had a tendency to be stuck up at a certain point, I guess my camera is a bit heavy for it. A nice clean up did the job for me, but I'll be sure to enhance that flat surface when I feel it to be necessary. Thank you!

I see you've got a skillful hand - very often such filing will result in a convex surface no matter how well one tries to control the file. I admire your skill!

On my Orion XT10 focuser drawtube I used 800 grit sand paper wrapped around a file and sanded that area totally flat and used electrical tape to give a friction surface. It took 3 layers. The focuser is super smooth and the 11:1 control is silky smooth. All that is needed is enough pressure to move and hold the draw tube. They used aluminum screws ( stupid) to hold the control bar, replaced those with 8/32 steel screws. The fine focus is greatly improved. Use with caution. take your time! the friction area is huge compared to the sharp ridges used that will wear down in time and make fine adjustments harder and harder. This way one can always replace the electrical tape to make up for wear.

Thank you. Very useful. I have used some fine pelicula of rubber glue (poliadex) which once is dry, it makes the friction higher

Thanks. My small refractor's crayford was driving me nuts with focus creep. Now I see why. First, I overloaded it with 2" eyepieces. Second, the flat on the focuser is painted with black enamel like the rest of the scope. Three, the tension screw is teflon tipped. So the two cosmetic details defeated the requisite friction. I cleaned the teflon and tube with alcohol and that did the trick for 1.25 eyepieces. To add heavier optics I will have to take stronger measures to increase friction.

Thanks for getting straight to the point on this

Thanks for this it's amazing how more accurate the focuser travel is by doing this simple mod. I can now get the dot from my Howie Glatter Laser to stay in the centre of the donut instead of wandering all over the place as the focuser is moved in and out. Why oh why can't Skywatcher mill this level in the first place.Surely it would only cost them a few pence extra per unit to have it done properly. Shockingly poor!

Nice video, very helpful!

I wish the Skywatcher refractors (like the Black Diamond series) came with the "improved" Crayford design which is found on the Quattro. Although this mod does help improve traction a lot on the older Skywatcher focusers, on my particular OTA the focuser was never truly centered to the objective and I resorted to replacing the whole thing with a Moonlite 2.5" motorized focuser. You mentioned in another video that although Skywatcher telescopes are mass produced they can be improved with some simple modifications once you get them home. A lot of people shake their head when they hear this but let me say from my own experience that this is absolutely 100% true and if done properly, you really can improve both the performance and value of your telescope without having to spend extra on a more expensive brand of OTA. The quartz mirrors and BK glass lenses in Skywatcher telescopes are high grade and most performance issues with these scopes are caused by user error, camera issues or parts of the telescope other than the objective (focuser, mount, etc).

I glued into this place a piece of latex rubber from glove (bought at a pharmacy) using a double sided tape and works the same. Some cleaning glove are made from thick rubber and this rubber is even better.

Cheers for the video great mod..nice to here a familiar accent on youtube .

Hello, very good video. I did that kind of work with my William Optics Crayford focuser and when i took the rod out, there was a spring and two white circular washers(plastic or teflon)on it. I reassembled everything not really knowing where the washers and spring has to go. so far it works well except for some slipping at the close to maximum extension of the draw tube. Anyone has clues or links that could help me?

Hey, I'm the first to comment. This is a great tutorial. I'm having problems with a brand new telescope with a 2.7 inch crayford. I cannot believe I spent 3000.00 on a telescope and the focuser doesn't function properly. I've only had the scope for 4 days and already the focuser has given me problems. I should have gone with a rack in pinion system. I'm very disappointed. On the other hand, you've done a great job with this tutorial.

I have a feeling that the concave in the surface was engineered in to the design, as you need a smooth focus, but the locking screw will inevitably leave small burs where it contacts the tube. to correct this issue I might recommend after flattening the surface, mill a channel .010 to .020in deep so any induced imperfections are clear of operation.

@astronomyshed You're probably right. Ideally, a cylinder-shaped focuser and flattened surface of the tube touch only at one point - tangent.

Very well video. Thanks.What is the sliding distance that the focuser can do?

Hi. Does making this upgrade have any possible negative side-effect on additional load to focuser when using a camera? My camera weighs some 800 grams.

@redfivemansell This is the thing, you'll find the flattened surface isn't flat, a result of it just being cast. As in the beginning of the video, a used focuser will show the contact points and it isn't across the whole, (supposedly) flat surface.

@redfivemansell No, it fact it improves it. Think about the logic, it works on friction, the round bar rubbing on the flat surface, so, the more of the bar in contact with that surface, the more efficient and positive the focuser actually is.

Can a ZWO AF be added to this focused

my focuser suddenly become slack and count easy move it in and out by hand. Had to increase the tension.

so when does this new space rocket your building take it's maiden flight ? :P :)

Have to say I dont agree with the adding of gun oil, the crayford system works and depends on friction, in fact technically it's a friction drive system. Also if you polish the contact surface too much this may also create slip.

It would have been nice if Skywatcher had fitted the bar which goes across the flat edge of the focusing tube with a rubber sleeve -- inexpensive and would have provided much better traction at practically no cost.

Maybe it's like that for a reason pretty sure someone would have noticed this in there tech department isn't it for breaking in it would eventually were down flat

@helsfury The crayford system is WAY better than rack & pinion, crayfords just take a little tuning

At 9,335 views and yours being the only criticism, from someone who has never uploaded a video to someone whos channel has had well over 600,000 views I wonder if you got up on the wrong side of the bed this morning :-) Anyway, thanks for commenting.

Hi friend. Please don't take offence.My criticism perhaps comes because a no motherlanguage people might have some trouble on trying to understand all the words you are speeching while the essential matter could be treated in some 20 seconds or so. Thanks for the quotation about "the wrong side of the be". It's little different on regard that we say in Italy which is "You get out of the bed with the wrong foot", anyway the meaning is the same. Ahaha. Thanks for your attention. Have a nice day:-)

Guys the focuser does not move just move by itself

I think this guy has passed away not seen him on here in years these are all reruns no new material for years now

Hello. The idea is great, only I wonder why nearly 8 minutes chatting while the mandatory action about "how to" lasts about a few seconds? :-) Anyway thanks for sharing.

why dont you write a book :) !

fookus

Too much talk but very very very good vids

You would think that for the ridiculous prices those instruments cost they would have taken some care and machine those tubes (in mass production there is 0 cost involved) instead of having thousand of people taking apart brand new equipment so they can fix them out of the box... Someone said astronomy and AP has gone a long way but i think it has just gone a long way into making some companies rich fast. If you see the parts internally of an AVX mount (1000USD) you will laugh, i opened mine to find sand, dirt and rust (brand new). Someone else opened his to do the DEC bearing mod and he found stones in it... (not sand - STONES)... laughable quality on those things. And please don't tell me 'what do you expect for 1000 USD' cause i expect a heck a lot more than a bag of stones and sand...

worse ever focuser...is unable to keep the focus and falls backwards from the gravity...the worse ever design...it is actually very simple and cheap to build working just by friction.

i´m very sure that those 2 contact edges were there engineered on purpose - they incerase pressure between shaft and tube and prevent tube rotation and slippage...