HELP!! Creaking screeching Feathertouch focuser

[AlistairHowie]

So today I took delivery of my secondhand FLT98 with Feathertouch focuser. All in excellent condition but for the Feathertouch which feels far from silky smooth. As the drawtube goes in and out there are moments of what feels like rubbing/grinding between it and the casing that it slides in and out of. There's also squeaking/screeching - see here http://www.youtube.com/watch?v=7XiqSsDjAyo&feature=youtu.be . Ignore the doorbell ringing in the middle of my production!

I have made sure that the silver focuser locking screw underneath is completely loose, and that the gold tension adjustment screw on the top of the focuser is also very loose. Is there something else that I'm missing? I have also noticed that I don't really detect much change in ease of movement of the drawtube from when the tension knob was screwed all the way down versus when it was slack per my video. It seems quite stiff, but that of course could be normal for a refractor focuser - I wouldn't know, it's my first one.

I'm hoping this doesn't require a return to the US for fixing.

All advice gratefully received - am feeling a bit down at the moment!

[Bizibilder]

Sounds like its dry/dirty - just try a dismantle and clean with a clean cloth. You may just need a tiny touch of white lithium grease on any sliding bearing surfaces.

[steppenwolf]

The Feathertouch does not move as 'freely' as a Crayford but it should be very smooth with some small resistance giving it a very solid 'feel'. There should be next to no noise at all except for a barely perceptible sound of the grease in the gearing - more a feeling than a sound. Yours is clearly not right! I get the impression that your drawtube is vibrating within its housing as it moves in and out - is there any lateral movement in the drawtube? This could be a simple adjustment (can't remember off hand if there are adjustable screws to retain the drawtube laterally within the casing I'm afraid) or a lubrication issue.

[Brian Nordstrom]

It might be the knobs are hard up against the housing ( body ) , try lossening the small allen head screws that hold the single knob off first and pull it back off the shaft 1/2 a mmm and retighten . If that does not make any differance try the same with first the 10 to 1 focus knob , if its still the same try the main knob on that side last .

It sounds like dry alloy against alloy ? . I would try the knobs first 1 at a time before going any deeper .

I say this because my GSO 10 to 1 focuser I have on my ED80 made the same noise from new , it had been dropped and one knob was binding slightly on the main body .It does not take much to sound this horrible .

Good luck .

Brian.

[Brian Nordstrom]

Oh one more thing , your focuser aint a Crayrord , its a Rack and Pinion . I have one on my 127mm triplet and its just awsome .

Good luck again .

Brian.

[Tom Habaj]

I suggest to remove focuser from the telescope an see what happens with the drawtube when you move it in/out. That way you have a bigger chance to find a source of the problem. It may be that the drawtube is not in the axis with the focuser body (maybe one of the internal bearings is broken). Anyway you should contact Wayne at Feathertouch and show him link to your video. I'm sure he will know where the problem is. If you will have to send your FT back to the States you will not pay for any repair, but the shipping costs may be quite high.

[AlistairHowie]

It might be the knobs are hard up against the housing ( body ) , try lossening the small allen head screws that hold the single knob off first and pull it back off the shaft 1/2 a mmm and retighten . If that does not make any differance try the same with first the 10 to 1 focus knob , if its still the same try the main knob on that side last .

It sounds like dry alloy against alloy ? . I would try the knobs first 1 at a time before going any deeper .

I say this because my GSO 10 to 1 focuser I have on my ED80 made the same noise from new , it had been dropped and one knob was binding slightly on the main body .It does not take much to sound this horrible .

Good luck .

Brian.

Thanks, Brian - I'll give all that a go.

I suggest to remove focuser from the telescope an see what happens with the drawtube when you move it in/out. That way you have a bigger chance to find a source of the problem. It may be that the drawtube is not in the axis with the focuser body (maybe one of the internal bearings is broken). Anyway you should contact Wayne at Feathertouch and show him link to your video. I'm sure he will know where the problem is. If you will have to send your FT back to the States you will not pay for any repair, but the shipping costs may be quite high.

Thanks, Tom. I've already emailed the link to them but they're out til Monday on 4th July celebrations. I was just hoping for a quick resolution to make me feel better about a secondhand purchase! How do I remove the Feathertouch - do I just unscrew the focuser rotator knobs completely and it slides out?

[John]

I recently bought an older Moonlite focuser for a refractor. It was not as smooth as I'd been expecting and the drawtube was not square with the body of the focuser but I only noticed this when looking at the focuser from the scope end and noticed that the end of the drawtube was not concentric with the main body of the focuser. To investigate further I removed the drawtube and then found that one of the four ring bearings that the top of the drawtube presses against had split and was just dragging against the drawtube the rather than rolling smoothly with its movement. I e.mailed Moonlite in the USA and got a prompt response. for around $20 they sent be a set of four new bearings and now the focuser is silky smooth even when tensioned up for heavy accessories.

Could this be your problem perhaps ?

[johninderby]

The FT R&P focusers should not not need any major adjustment or lubricatrion and should last a lifetime. They simply never wear out. As it's second hand I would think it most likely that the scope has been dropped and the focuser damaged. Another possibility is that someone has taken it apart and not been able to put it back together again properly.

I think it will probably need returning to Starlight Instruments for repair.

John

[AlistairHowie]

Thanks, John. I agree with your first two sentences. The scope categorically hasn;t been dropped - it's in mint condition and well looked after. It was perfectly packed in its travel case such that it took me 10 minutes to get it all unwrapped. The focuser also shows absolutely no signs of damage, no scratches, etc. I know that doesn't mean it hasn't been dropped, but when I consider the scope's history and who the vendor was, I'm very confident it hasn't been abused in any way. But clearly something doesn't add up. I've emailed Feathertouch the link to the video and I'll see what they recommend when they get back from 4th July celebrations on Monday.

In the meantime, I might try Ian King. I'm just about to order an iEQ45, mounting plate, diagonal and EPs from him, so I'm hopefull he might offer to take a look at it.

[Steve 1962]

Hi Alistair

Have you tried loosening off the single brass nurled bolt on the top of the focusser??

Steve

[Tom Habaj]

Thanks, Brian - I'll give all that a go.

Thanks, Tom. I've already emailed the link to them but they're out til Monday on 4th July celebrations. I was just hoping for a quick resolution to make me feel better about a secondhand purchase! How do I remove the Feathertouch - do I just unscrew the focuser rotator knobs completely and it slides out?

Yes, to remove the focuser from telescope unscrew (not compleatly) 3 knobs on the rotator.

[AlistairHowie]

Hi Alistair

Have you tried loosening off the single brass nurled bolt on the top of the focusser??

Steve

Hi Steve - yes, I've completely slackened the gold focuser tension screw on top, and the silver focuser lock screw on the bottom.

[perfrej]

Hi all!

It used to be my focuser... Since it has hardly been used and I feel that it has been perfect all along, I can only think of one thing. First of all, there is no way that it can be:

1. Dirty

2. Faulty

3. Damaged in transit

So, the one thing that hits me now is that the black knob is probably in a tad too far on its axis. It was off because I had a Lakeside motor unit on that side and I put it back as the very last thing before closing the case for shipping to Alistair. In other words, I tested the focuser without the knob and it felt normal (which for a feathertouch is close to sexy). I must have pushed it too far in so that it has made contact with the body.

So, Alistair, just loosen the hex nut , ease the black knob out 1mm and tighten it. It must be that, and I am sorry that I didn't check it after putting the knob back on.

All in all, the Feathertouch is a really nice piece of equipment and it doesn't sag one bit with pounds and pounds of load.

All the best,

Per

[AlistairHowie]

Thanks, Per. Phew, Smooth as butter now! Many thanks.

[perfrej]

Wonderful! That was clumsy of me...

I am 100% confident that you will enjoy it - I've had great success with it

/per

[ollypenrice]

Ah, a happy thread and fine intervention from Per, there. I love the Feathertouch on my TEC. As stated above it is not the lightest or silkiest action I've felt, it is the most secure and the most precise. That's why it's so darned good.

Olly

[Moonshane]

how good is this forum? top result guys.

[steppenwolf]

Great result, if I'd known it was Per's, I could have assured you that it wasn't a major issue! Delighted that the wonderful FT' honour has been restored!

[JohnC]

Yes.......Still the best astro forum in the world!!

[AlistairHowie]

Thanks again, all. Now ... if those clouds would just clear ....

[Hankk]

OK, it's an 11-year-old thread. But I just came back from an eclipse trip where I checked two telescopes for flights around the world, and the Crawford focusers for both ended up apparently damaged. Both had the same symptoms of rough motion and the feeling that something was badly broken inside. I figured they'd been bashed in with the axles bent and needed to be sent for repair.

But thanks to this thread, I tried backing out the low-speed knob, to see if it was rubbing on the inner 1x knob. Loosened it and moved it out 1 mm. Problem fixed on the Featherlight focuser, and on the GSO.  Thank you!!