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Help! Heq5 making loud noises


cuivenion

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4 hours ago, cuivenion said:

One question, is the worm adjustment safe to do with the mount fully loaded?

Personally, I would make adjustments with the mount unloaded, it would make it easier to feel how much backlash is in the mesh without having to spin a lot of mass around. If the axis end float is adjusted correctly it shouldn’t really make any difference to the worm mesh whether the mount is loaded or unloaded. If you find that loading the mount causes the DEC worm to bind that would indicate that the DEC axis main bearings are not preloaded correctly.

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6 minutes ago, Oddsocks said:

Personally, I would make adjustments with the mount unloaded, it would make it easier to feel how much backlash is in the mesh without having to spin a lot of mass around. If the axis end float is adjusted correctly it shouldn’t really make any difference to the worm mesh whether the mount is loaded or unloaded. If you find that loading the mount causes the DEC worm to bind that would indicate that the DEC axis main bearings are not preloaded correctly.

Unloaded is I how I did it in the end. Much easier. Anyways success! Declination and RA worm both adjusted, and the I've had the mount slewing around for while now. Loaded and unloaded, with handset and with EQMOD. No problems, looks like I'm all set. I just need clear skies now.

Thanks for all the help everyone, very much appreciated.

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59 minutes ago, david_taurus83 said:

Good news. Hopefully it was just something simple as a minor adjustment. How old is the mount? As mentioned already, might be due for a strip down, clean and new grease.

It's a good few years, I can't remember the exact age. It was sold as a tuned mount. I'm hoping to get some good performance now as it does have the belt drive and it seems to be quite smooth once adjusted. I'll do a full strip down and regrease in June or July during the short nights.

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2 hours ago, Oddsocks said:

Personally, I would make adjustments with the mount unloaded, it would make it easier to feel how much backlash is in the mesh without having to spin a lot of mass around. If the axis end float is adjusted correctly it shouldn’t really make any difference to the worm mesh whether the mount is loaded or unloaded. If you find that loading the mount causes the DEC worm to bind that would indicate that the DEC axis main bearings are not preloaded correctly.

Hi Oddsocks, just for future reference do mind explaining what and where the main bearings are. Are they mentioned in Astrobaby's guide? Although the fault was there with no load it was more pronounced with a 200p on the mount, so I could probably do with checking that when I do a strip down.

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The main bearings (large ones) are the ones that go on either end of the RA and Dec shafts. The worm bearings (small ones) sit at either end of the worm shafts. The main bearing unless in a really bad way should just need cleaning in paraffin or petrol, left to dry and regreased. Check the guide but sure it would be like on the eq6, the Dec rotation is adjusted by screwing the the white collar that the weight bar sits inside and the RA is done using a ring that sits over the polar scope.

If you do strip it make sure when tightening these back up, as they start to get nearly there rotate the collar or ring a bit and rotate the shaft and then do up a bit more, this ensures that the bearings inside will sit correctly.

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13 hours ago, cuivenion said:

just for future reference do mind explaining what and where the main bearings are. Are they mentioned in Astrobaby's guide?

Spillage has answered the main question and yes, Astrobabys guide shows photographs of the various bearings in both axis.

http://www.astro-baby.com/heq5-rebuild/heq5-m1.htm

You will find that each axis contains a set of sealed main roller bearings and a taper bearing, the taper bearing sets the end float, or pre-load, in each axis.

All of the bearings are industrial standard and it is easy and relatively inexpensive to source good quality replacements from UK bearing suppliers if you find any of the bearings feel 'notchy' as you rotate them by hand once they are removed from the mount.

The main axis bearings are sealed and can't be cleaned and re-packed with fresh grease without some engineering know-how and tools to prize open the bearing dust seals for access to the ball races for cleaning and repacking.

Because the bearings used by Synta are not particularly high quality you might find simply replacing them is a quicker and simpler option.

The taper bearings used for pre-load are open and can be cleaned and re-greased easily but again, if you find they don't rotate smoothy replace them.

There is a good deal of debate on this forum, and elsewhere, over the need to replace the factory fitted main bearings, with some users fitting higher quality bearings during a strip-down whether they are needed or not. Ultimately this is something you have to decide when you inspect your own mount.

So far as load carrying, the factory fitted bearings could support a car easily and would barely notice the kind of loads we would put on them but when we calibrate a mount for guiding we want the mount to move smoothly in any orientation, otherwise we find that we need to recalibrate for guiding every time we point the telescope at a different part of the sky, and during a long sequence on a single target we might find the guiding calibration we began with is not so effective as the session progresses.

Have a good read through of Astrobabys guide and take the time to inspect the bearings carefully for smoothness of rotation once you remove them from the mount, any doubt then replace those that don't perform well.

 

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42 minutes ago, Oddsocks said:

Spillage has answered the main question and yes, Astrobabys guide shows photographs of the various bearings in both axis.

http://www.astro-baby.com/heq5-rebuild/heq5-m1.htm

You will find that each axis contains a set of sealed main roller bearings and a taper bearing, the taper bearing sets the end float, or pre-load, in each axis.

All of the bearings are industrial standard and it is easy and relatively inexpensive to source good quality replacements from UK bearing suppliers if you find any of the bearings feel 'notchy' as you rotate them by hand once they are removed from the mount.

The main axis bearings are sealed and can't be cleaned and re-packed with fresh grease without some engineering know-how and tools to prize open the bearing dust seals for access to the ball races for cleaning and repacking.

Because the bearings used by Synta are not particularly high quality you might find simply replacing them is a quicker and simpler option.

The taper bearings used for pre-load are open and can be cleaned and re-greased easily but again, if you find they don't rotate smoothy replace them.

There is a good deal of debate on this forum, and elsewhere, over the need to replace the factory fitted main bearings, with some users fitting higher quality bearings during a strip-down whether they are needed or not. Ultimately this is something you have to decide when you inspect your own mount.

So far as load carrying, the factory fitted bearings could support a car easily and would barely notice the kind of loads we would put on them but when we calibrate a mount for guiding we want the mount to move smoothly in any orientation, otherwise we find that we need to recalibrate for guiding every time we point the telescope at a different part of the sky, and during a long sequence on a single target we might find the guiding calibration we began with is not so effective as the session progresses.

Have a good read through of Astrobabys guide and take the time to inspect the bearings carefully for smoothness of rotation once you remove them from the mount, any doubt then replace those that don't perform well.

 

Thanks, I understand this a lot better now. When I first got the mount the counterweight collar was loose, so it's really no surprise that the Dec was binding. I did eventually rectify this but obviously it was still not quite right. I did adjust the end float again while adjusting the worm as I could detect slight movement in it. One more question (sorry), can you adjust the end float (for the axis) at any time or does the worm has to be loosened first? Astro baby's guide is very good, I'll be giving it several read throughs.

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2 hours ago, cuivenion said:

One more question (sorry), can you adjust the end float (for the axis) at any time or does the worm has to be loosened first?

No problem.

The axis end-float, (or preload) should be adjusted with the worm mesh loosened because sideways pressure exerted on the axis by the worm may prevent the axis from straightening as the preload is increased.

The two adjustments, worm mesh and axis preload, are mutually interdependent, as you adjust one the other will be affected.

If an axis preload is too low, (loose) and the worm mesh is already adjusted tightly against the axis gear, when you try and increase the axis preload to pull the axis straight it will increase the forces acting on the worm-gear mesh and possibly bend and damage the worm.

It also makes it hard to judge how much the preload has to be increased/decreased to prevent binding but take up all the slack movement (end-float) in the axis.

So always slacken the worm mesh before adjusting axis pre-load then readjust worm mesh once axis preload is adjusted correctly.

 

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Ok I thought I'd post this here as it's a continuation of the similer problem but in the RA axis. I had noticed recently that the tracking was extremely jumpy near the horizon, and when I checked sure enough the RA axis end float was loose and unsecured too. Following the advice above I set about rectifying this. I've got to the point of setting the worm and I can't get the axis to move without binding or having to much play. I realise from reading Astrobabys guide that the RA is tricker than the dec but I have a feeling I'm doing something wrong.

I set the worm adjustment in the home position, everything seems fine worm turns easily, no play. When I run the motor the RA binds always at the same point. When the counterweight bar is pointing to about 2 o clock in the air, just past the opposite of the home position. If I slacken the worm to stop the binding I get play in other parts of the axis.

Here's the thing. If I set the worm as above in the home position and then unlock the clutch and turn the RA to the position where it binds and reengage the clutch then the worm becomes tight and hard to turn. That suggests to me that its not worm/wheel that's the problem.

I'm at a bit of a loss, I've tried having the end float slightly looser/tighter and it doen't seem to make a difference, and also reinserting the tapered bearing. Any help appreciated on this one.

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If you load up the mount and rotate the RA with the clutch released will it spin freely or can you feel any binding when rotating it around. I had to redo the tightening up of the RA on my eq6 a few times till it sat right. You should have it tight enough so that there is not movement and the axis in and out (if that makes sense). 

Could it be that you need to tighten the worm rather than loosen it? When you mean the counter bar is at 2 o'clock is this without any weight?

I may be really wrong here so anyone feel free to put me right, but the mount in normal use should not put your counter weights above the horizontal so if you mount is putting your scope East to West then it should be okay.

It might be a bad tooth on the gear. If you put the scope back to home using the motors and then release the clutch putting the mount back into this 2 o'clock position what happens.

How tight is the worm and if you remove both caps and view this when it happens can you see any movement on the end of the worm?

My mount needed some very sympathetic adjustments.

sorry this is probably not in order but just me thinking aloud.

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From the description of the problem there could be several possibilities.

A bit of foundry swarf or grit in the taper bearing, or the taper bearing is of poor quality, or the taper bearing outer cup-shell is not pressed into the casting squarely, or one of the sealed main bearings is of questionable quality with too much side-play, or just bad manufacturing QA on the main axis ring gear (eccentric instead of concentric).

Releasing and tightening the clutch in any orientation should not have a great influence on the end-float in the main axis bearings unless they are too loose to begin with, the taper bearing has insufficient pre-load or the shim washer is missing or incorrectly sized.

With the worm gear removed entirely the main axis pre-load should be adjusted and freedom of movement checked around a full rotation with and without the clutch engaged, if you find any point(s) where the axis binds as it turns, or you find that it binds when the clutch is engaged then I would probably strip both axis and thoroughly clean the foundry castings plus inspect/regrease/replace any bearings that show excessive slop or 'notchy/gritty movement.

To determine if poor manufacturing QA is the problem you really need access to a few engineering instruments such as a dial gauge and stand to determine how accurately machined are the main axis shaft and ring gear. 

William.

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18 minutes ago, spillage said:

If you load up the mount and rotate the RA with the clutch released will it spin freely or can you feel any binding when rotating it around. I had to redo the tightening up of the RA on my eq6 a few times till it sat right. You should have it tight enough so that there is not movement and the axis in and out (if that makes sense). 

Could it be that you need to tighten the worm rather than loosen it? When you mean the counter bar is at 2 o'clock is this without any weight?

I may be really wrong here so anyone feel free to put me right, but the mount in normal use should not put your counter weights above the horizontal so if you mount is putting your scope East to West then it should be okay.

It might be a bad tooth on the gear. If you put the scope back to home using the motors and then release the clutch putting the mount back into this 2 o'clock position what happens.

How tight is the worm and if you remove both caps and view this when it happens can you see any movement on the end of the worm?

My mount needed some very sympathetic adjustments.

sorry this is probably not in order but just me thinking aloud.

Hi, the mount was unloaded, I was trying to get a full revolution of the axis and the 2 o clock position was where it started to bind, you're right that I wouldn't be using the mount in that position anyway but I'd rather get it sorted. Tightening the worm made the problem worse. The Ra is rotating freely with the clutch disengaged.

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42 minutes ago, Oddsocks said:

From the description of the problem there could be several possibilities.

A bit of foundry swarf or grit in the taper bearing, or the taper bearing is of poor quality, or the taper bearing outer cup-shell is not pressed into the casting squarely, or one of the sealed main bearings is of questionable quality with too much side-play, or just bad manufacturing QA on the main axis ring gear (eccentric instead of concentric).

Releasing and tightening the clutch in any orientation should not have a great influence on the end-float in the main axis bearings unless they are too loose to begin with, the taper bearing has insufficient pre-load or the shim washer is missing or incorrectly sized.

With the worm gear removed entirely the main axis pre-load should be adjusted and freedom of movement checked around a full rotation with and without the clutch engaged, if you find any point(s) where the axis binds as it turns, or you find that it binds when the clutch is engaged then I would probably strip both axis and thoroughly clean the foundry castings plus inspect/regrease/replace any bearings that show excessive slop or 'notchy/gritty movement.

To determine if poor manufacturing QA is the problem you really need access to a few engineering instruments such as a dial gauge and stand to determine how accurately machined are the main axis shaft and ring gear. 

William.

I have taken apart the axis and the worm and worm gear look ok. The two main bearings in the worm gear I wasn't able to remove but the the inner parts seemed ok. I wasn't able to remove the other main bearing from the housing either. The tapered bearing seems ok but the three main bearings seem to have a caulky grey white substance on them. Are the three main bearings ok to clean, or do I have to worry about water or detergent getting into them.

I dont know what the shim washer is or where it goes so that could be a problem. Is it the red washer that goes on top of the bearing in the ring/wheel worm gear?

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10 minutes ago, spillage said:

If you can get hold of a digital micrometer then it might be worth following astrobaby's hypertune guide.

Just had a quick look, that's interesting reading. I'll go with a strip down and regrease first I think, but if that doesn't help I'll definitely go in this direction, thanks. I was wondering what the best way to remove the main bearings was for cleaning, as they deem very tightly fitted to the worm wheel and the main housing and I don't want to damage them.

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59 minutes ago, cuivenion said:

The tapered bearing seems ok but the three main bearings seem to have a caulky grey white substance on them. Are the three main bearings ok to clean, or do I have to worry about water or detergent getting into them.

I dont know what the shim washer is or where it goes so that could be a problem. Is it the red washer that goes on top of the bearing in the ring/wheel worm gear?

TBH the sealed main bearings won't benefit much from cleaning other than removing the foundry dust and grit from the outsides to aid reassembly and look pretty!

The outsides of the bearings do not move relative to the foundry castings and axis shaft, the important parts are the ball races inside the bearing, under the dust covers, which you can't reach.

I would never use water and detergent for cleaning bearings as in AstroBabys guide since water and grease don't mix too well if it should seep under the bearing seals. As an engineer I would use paraffin with an old toothbrush and lint-free cloth but paraffin is not so easy to find in small quantities. White Spirit, available in small quantities from most DIY stores in the decorating section is a good substitute but do keep White Spirit away from sources of ignition while using as it is highly flammable, minimise contact with the skin to avoid drying out and chapping and don't let it stay wet on painted surfaces for too long as it may stain.

The chalky grey substance on the outside of the bearings is most likely just overspray from the foundry spray-paint booths on top of an anti-corrosion coating applied by the bearing manufacturer and White Spirit should soften and remove it.

The red washer is one of the shims, there may also be one or two clear plastic shim-washers used on either axis to take up excess play in the axis assemblies, depending how well the foundry castings were made and finished, you may have the washers and you may not, you just need to be observant as you strip the mount, keep a camera handy and photograph everything as you take it apart. 

I used to use a video camera when I still worked as an engineer and just left it running for the duration of a strip down on any piece of machinery that didn't have a workshop manual available.

William.

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And it was all going so well....

IMG_0412.thumb.JPG.13707066842a11b516548c4e37d8d430.JPGIMG_0413.thumb.JPG.6cf918b1dc678098861f12367810ef66.JPG

No idea how this happened, I didn't force the nut on and it was only hand tight. I sure had a hard time getting it off though and it's knackered the thread. Is this even fixable? 

The irony is I had stripped and regreased and the binding issue was sorted. I was just trying different adjustments of the axis end float as the RA was still tight in the same orientation as before. The sets screws were definitely loosened, so annoyed right now.

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