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.
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.
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!
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.
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.
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!
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.
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).
@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.
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.
@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.
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.
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?
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.
Rubber would very quickly perish in the extremes of temperature and moist environments telescopes get used in, also the crayford design is well tested and widely used and there are probably a dozen other reasons why it is as it is.
Flatten the surface that the bar runs on and put electrical tape there. I did and all it took is 3 layers and works far better than metal to metal and is easy to replace. Metal to metal is a very poor idea and will become uneven with time, and takes just to much pressure to move smoothly. This way pressure is easy to reduce or increase. Easy fix and super cheap.
Silicon would have been a great choice. I'm also into RC planes, which often use rubber bands to hold break-away parts (from hard landings) held on by them. I've converted to silicon and found they last for years (in fact, I've never had to replace one yet!). The old rubber bands would wear out in 6 months max!
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.
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
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.
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.
wow you are alive what happened to you people that just disappear off here usually end up in the bereavement list i do apologize my friend no harm intended how are you why no activity for so long or is that a private matter nice to see you are ALIVE :)))
net voyager2017 i gave up on astronomy some time ago, since then had to put myself in the garage with a case of sepsis and now struggling with post sepsis syndrome, so keep those clicks coming please folks.
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:-)
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.
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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.
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. 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.
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!
The mod makes a HUGE difference, well worth doing.
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.
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.
Good point... I didn't think of that. I do know some tension screws have plastic tips but have no idea if the skywatcher does.
@@gregors1422 They do on the Evostar's
I think it's a machining artifact due to the thin tube. Other Crayfords have flat drawtube flats.
Thank you. Very useful. I have used some fine pelicula of rubber glue (poliadex) which once is dry, it makes the friction higher
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!
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.
Nice mod! No backslash due to the elasticity of rubber?
Thanks for getting straight to the point on this
@astronomyshed You're probably right. Ideally, a cylinder-shaped focuser and flattened surface of the tube touch only at one point - tangent.
Can a ZWO AF be added to this focused
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).
@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.
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.
@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.
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.
my focuser suddenly become slack and count easy move it in and out by hand. Had to increase the tension.
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?
so when does this new space rocket your building take it's maiden flight ? :P :)
Nice video, very helpful!
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.
Rubber would very quickly perish in the extremes of temperature and moist environments telescopes get used in, also the crayford design is well tested and widely used and there are probably a dozen other reasons why it is as it is.
astronomyshed An excellent point that I did not consider.
Flatten the surface that the bar runs on and put electrical tape there. I did and all it took is 3 layers and works far better than metal to metal and is easy to replace. Metal to metal is a very poor idea and will become uneven with time, and takes just to much pressure to move smoothly. This way pressure is easy to reduce or increase. Easy fix and super cheap.
Silicon would have been a great choice. I'm also into RC planes, which often use rubber bands to hold break-away parts (from hard landings) held on by them. I've converted to silicon and found they last for years (in fact, I've never had to replace one yet!). The old rubber bands would wear out in 6 months max!
Very well video. Thanks.What is the sliding distance that the focuser can do?
Mine is 38 mm (SW Dual focuser) I guess it's pretty standard for a 1000mm focal length.
Cheers for the video great mod..nice to here a familiar accent on youtube .
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.
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
Guys the focuser does not move just move by itself
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.
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.
I think this guy has passed away not seen him on here in years these are all reruns no new material for years now
net voyager2017 the reports of my death are greatly exaggerated
the reports of my passing are greatly exaggerated!
wow you are alive what happened to you people that just disappear off here usually end up in the bereavement list i do apologize my friend no harm intended how are you why no activity for so long or is that a private matter nice to see you are ALIVE :)))
well nearly quarter of a million views not bad i think my comment might have something to do with that sorry again !
net voyager2017 i gave up on astronomy some time ago, since then had to put myself in the garage with a case of sepsis and now struggling with post sepsis syndrome, so keep those clicks coming please folks.
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:-)
why dont you write a book :) !
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...
Too much talk but very very very good vids
fookus
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.