Rowan Belt modding NEQ6 - Need help!

[teoria_del_big_bang]

4 hours ago, Ishan Mair said:

How did you check for  the "90  degree" movement  for axis-shaft mentioned by @teoria_del_big_bang in this sketch in topic earlier ?

Really I did this just by feel. If you try to move the axis in the direction shown you can feel if there is any movement. 

As you screw the nut up to the bearing you start to pull all the mechanical bits together (bearings, spindles etc). Even by hand it is very easy to do this, once they are all snugged up any extra pressure then puts preload on those taper bearings (you essentially start to wedge them in between the inner and outer races).

We require very little pre-load as the axis really does no work as such we just need enough to stop any slop in that direction, also enough to stop the nut loosening itself, and no more. The more preload we put on the tighter that axis will become and as these are not really precision machined we will start to see tight spots as it rotates, and we risk the stepper motor stalling or at least losing steps. Although if you do put everything back together and you have issues with motors stalling it is more likely to be the worm assemblies causing it as these also have cyclic tight spots.

So I think personally it is quite easy to tighten these enough only by hand. I think most tutorials show tightening with a C spanner or with some implement which is fine but lightly does it.

Steve

[newbie alert]

3 hours ago, teoria_del_big_bang said:

Really I did this just by feel. If you try to move the axis in the direction shown you can feel if there is any movement. 

As you screw the nut up to the bearing you start to pull all the mechanical bits together (bearings, spindles etc). Even by hand it is very easy to do this, once they are all snugged up any extra pressure then puts preload on those taper bearings (you essentially start to wedge them in between the inner and outer races).

We require very little pre-load as the axis really does no work as such we just need enough to stop any slop in that direction, also enough to stop the nut loosening itself, and no more. The more preload we put on the tighter that axis will become and as these are not really precision machined we will start to see tight spots as it rotates, and we risk the stepper motor stalling or at least losing steps. Although if you do put everything back together and you have issues with motors stalling it is more likely to be the worm assemblies causing it as these also have cyclic tight spots.

So I think personally it is quite easy to tighten these enough only by hand. I think most tutorials show tightening with a C spanner or with some implement which is fine but lightly does it.

Steve

Totally agree with you there Steve.. if you look at his first video, and compare it to the second it shows it clear as mud..

[masjstovel]

@Ishan Mair i did as @teoria_del_big_bang describes, by hand force. As i understand the construction it can be as loose as possible as long as it doesnt move in the 90degree angle. On my mount thats barely handtight. Meaning 25% of my strength perhaps. But i guess that differs from mount to mount. As @teoria_del_big_bang says, i experienced the grinding of the motors to be tight worm gear, not tight axies.

[masjstovel]

Update:

So, finally I had clear skies and eventually got to test the mount first time since supertuning it.

And the result:
It was a total disaster!

I almost had tears in my eyes after all that work with the mount.

 

So now i need some help diagnosing the problem.

The guiding was terrible as you could see from the attached pictures.
I am wondering what could be the issue.

What i am experiencing is as mentioned earlier, that the axis has some "tight" areas. a little bit on RA , but especially on DEC, so it makes the setup hard to balance, especially in DEC.

Other factors than the mount-supertuning that might have caused issues:

• I really dont know the reason for this, except the tightness in DEC, but i balanced my rig after fully equipped and after the "session" I saw that DEC was somewhere between slightly and moderately not in balance. More slightly than moderately. 
• At some times when slewing to targets the power light on the mount started blinking. Only at full speed, not in guiding. I used 12v 5A power supply plugged in the wall.I am in the process of rearranging cables - a power "hub" for everything and a pole with fuses. I did some tests just now with this new power supply (not the one i used yesterday) and i saw that the voltage dropped from 12.10V which its set to, down to 11.80V when slewing full speed. The light started flashing again after some time slewing. Ampere AC was steady-ish at 5A. and Ampere DC was going from 1.45 not slewing to 1.41-1.42 when slewing.
• I dont have vision south so i calibrated in PHD2 in a west, at maybe 30degrees height.

 

First photo is after calibrating (cleared calibration data before session)

 

 

Second photo: Running PHD2 guiding assistant. This is during uncorrected guiding. RA was dropping but going up and down like the tendensies you can see in the start. Dropped to -16" but bumping alot up and down.

 

 

3rd photo: Results after going through the guiding assistant. Note the DEC backlash. There is no noticable backlash physically in DEC. There is slight noticable in RA, but not in DEC and this number is huge. I watched several times for tangeled equipment, but didnt notice any.

 

4th photo: backlash-graph. Insane.

 

 

5th photo: Guiding after guiding assistant.

 

Other info: Did polaralignment with SharpCap and got excellent result (00.00.00 actually)

So what im trying to find out here; Does the issues i've mentioned about the power and balance effect guiding this way, or is it likely there is something with the supertuning?

 

Could anyone please help me troubleshooting on this? 

 

[spillage]

I will start with the tightness. Take just the RA back out and put an extra spacer on top of the brass gear (to early to rember it's name). This will remove any tightness around the top area. 

When putting the worm gear back together I ignore the tip on astrobaby's site and adjust the worm gear before fitting it back together. Take the play out of the RA by going to tight then back of a bit by bit.

Have you gone through the supertune setup?

Do the same with the DEC and do not over tighten the motors, just apply some pressure before tightening.

Even balance is I find crucial with the belt mod and of course good PA,.

[masjstovel]

56 minutes ago, spillage said:

I will start with the tightness. Take just the RA back out and put an extra spacer on top of the brass gear (to early to rember it's name). This will remove any tightness around the top area. 

When putting the worm gear back together I ignore the tip on astrobaby's site and adjust the worm gear before fitting it back together. Take the play out of the RA by going to tight then back of a bit by bit.

Have you gone through the supertune setup?

Do the same with the DEC and do not over tighten the motors, just apply some pressure before tightening.

Even balance is I find crucial with the belt mod and of course good PA,.

Thank you!!

I did astro-babys guide as backup to Martin Pyotts youtube videos on supertuning neq6, if thats what ypu mean by supertune setup?

What i didnt do was calculating spacers, as they were all in good shape and i left them where they were on disassembly. The result: ~1mm space between setting circles and mount on both RA and DEC. Didnt think too much about it since the axies were tight and had no play. Thoughts on this? In my head this space = too many/high spacers? 

When you say "on top of brass gear" you mean on the opposite side of the teeth?

Also i am not sure how you mean adjust the worm gear before assembly? You mean the lockrings for the worm? (I did that before assembly making sure the worm had no play and and not tightening more) or do you mean the adjustment of the worm distance to brass wheel with the 2 setting screws?

Edited March 4, 2020 by masjstovel

[spillage]

Mine was also tight but adding an exta spacer on the opposite side of the teeth on the gear improved it. The setting circle now has allot of clearance but this is fine for me.

The super tune measures the spacing below the teeth on the gear and makes sure that the worm and gear are aligned as well as can be.

The worm housing adjustment you did is the same as me and yes I meant taking sideways movement out of the worm gear before fixing into place.

I seem to find that when putting the RA back together having the mount sat upside down helps. When fitting the RA tapered bearing I like to rotate the bottom of the mount a few times and slightly undo and then redo up to make sure it is in evenly. I just normally do this up as tight as I can by hand.

 

Hope this makes a bit more sense.  

 

[alacant]

53 minutes ago, spillage said:

opposite side of the teeth on the gear improved it

Hi

Following @spillage's description. A plastic container washer on both sides works well and gives just the right clearance. However, any drag is almost always due to the conical bearing at the base of each axis.

HTH

Edited March 4, 2020 by alacant

[masjstovel]

11 minutes ago, spillage said:

Mine was also tight but adding an exta spacer on the opposite side of the teeth on the gear improved it. The setting circle now has allot of clearance but this is fine for me.

The super tune measures the spacing below the teeth on the gear and makes sure that the worm and gear are aligned as well as can be.

The worm housing adjustment you did is the same as me and yes I meant taking sideways movement out of the worm gear before fixing into place.

I seem to find that when putting the RA back together having the mount sat upside down helps. When fitting the RA tapered bearing I like to rotate the bottom of the mount a few times and slightly undo and then redo up to make sure it is in evenly. I just normally do this up as tight as I can by hand.

 

Hope this makes a bit more sense.  

 

Thanks alot! Ive been needing this help!

There is 1 or 2 (was 2 one place, but dont remember where) spacer on the top side already. You mean one extra on top of this/these?

And to clarify; the tightening of the motors. I am not sure how tight/lose you mean. Is it in relation to the belts? I kept the motors in tension on the belt with "moderate" strength with 2 fingers when tightening the screws for the motors. These i tighted pretty good. 

I struggled very much in reassembling the RA axis (read; plastic hammer, blood and tears). You mean the cone shaped bearing on the bottom? That could be the issue yes! Thanks again. And sorry for question-bombing:)

[spillage]

if you put the mount on the bench upside down and then place the bottom of the mount down onto to RA axis I find it easier to remove refit. If it gets tight just gently rock the mount to feel where it lose and then gently lift it up a few mm and then let it down again. You have to have the bearing very square to the axis or it binds going down. Hard to explain but a bit of a balancing act.

I just use a screwdriver between the motor and housing and just apply a small amount of pressure.

The cone shaped bearing need to be carefully tightened. So take up the slack rotate a few times, tighten a bit more rotate and repeat until hand tight.

[masjstovel]

20 minutes ago, spillage said:

if you put the mount on the bench upside down and then place the bottom of the mount down onto to RA axis I find it easier to remove refit. If it gets tight just gently rock the mount to feel where it lose and then gently lift it up a few mm and then let it down again. You have to have the bearing very square to the axis or it binds going down. Hard to explain but a bit of a balancing act.

I just use a screwdriver between the motor and housing and just apply a small amount of pressure.

The cone shaped bearing need to be carefully tightened. So take up the slack rotate a few times, tighten a bit more rotate and repeat until hand tight.

The picture starts to get clearer for me now. So tightening the coneshaped bearing; you screw the holding ring on polarscope to tighten it in place, right? So screw, rotate, screw and so on? And as it is tight and in place for sure, then slacken a bit? 

Also for DEC; screw, rotate , screw rotate on the weight-shaft end?

Smart tip with the screwdriver. So the motor is screwed not too tight in place, but the belts are as tight as possible?

And again the extra washer/spacer is needed even when there are spacer there already?:) 

There are some slight "braking" sounds when the axies go tighter so a misialigned coneshaped bearibg sounds plausible.

@alacant that washer really works well?:)

Edited March 4, 2020 by masjstovel

[alacant]

7 hours ago, masjstovel said:

that washer really works well?:)

Hi. Yes. We use an eq6 to take astro images.

The -ones we used- teflon spacer washers are thin and you need more than one of them. They then distort and snap. This is an image we took last night. The guiding is usually below unity RMS. But of course, look at the images, not the numbers. It is the the atmosphere which plays the biggest part in, and ultimately decides, the RMS, not the mount;)

HTH and good luck.

 

 

Edited March 4, 2020 by alacant
Punctuation

[spillage]

Bearing:

Yes this will help the bearing sit correctly in place.

Spacer:

I found that adding a bit extra made the axis rotate more free. 

 

[1parsec]

6 hours ago, masjstovel said:

Smart tip with the screwdriver. So the motor is screwed not too tight in place, but the belts are as tight as possible?

The belt does not need to be very tight.  Apply just enough tension to remove any slack from the belt.  Usually light finger pressure pushing on the motor is enough.

If using a screwdriver it is easy to apply too high tension. Be careful if using a screw driver as a lever.

 

[masjstovel]

2 hours ago, 1parsec said:

The belt does not need to be very tight.  Apply just enough tension to remove any slack from the belt.  Usually light finger pressure pushing on the motor is enough.

If using a screwdriver it is easy to apply too high tension. Be careful if using a screw driver as a lever.

 

Then i think the belt tension is as it is. But the motors arent supposed to be very tightly screwed down? I dont understand why this is

Edited March 4, 2020 by masjstovel

[1parsec]

1 hour ago, masjstovel said:

Then i think the belt tension is as it is. But the motors arent supposed to be very tightly screwed down? I dont understand why this is

Apply the belt tension and then tighten the screws holding the motor sufficiently so the motor doesn't move.

 

[masjstovel]

Ok. Desembled DEC again. Worked alot on the coned bearing on the weightshaft end. Couldnt really see any wrong there so just reassembled again. Had the weightshaft even looser than last time before i tightened the 3 lockingscrews.  Both axis is much smoother now. 

 

But.. guiding still sucks. Basically the same as yesterday.

I dont understand this. Guiding also is everywhere. 
Is there supposed to be new/other ASCOM drivers for belt modded mount? Its like the guiding and motor movement (from phd2-graph) are so radical and steep. 

Also I dont feel any backlash in DEC physically still. When i loosened the weight-bar nut a bit and the 2 set screws, theres still no backlash. This makes it hard to adjust the setscrews for the worm placement correctly. It's like i get no feedback from what i do except feeling the set-screw tighten when the worm meets the brass wheel. Where do i go from here?

Edited March 5, 2020 by masjstovel

[alacant]

9 hours ago, masjstovel said:

Where do i go from here?

Hi

- Slotted nut to take up the worm endfloat (remove the round cover with the two holes to reveal it): make sure it's not too tight. With the clutch tight, rotate dec and with the cover off, loosen the nut until you can feel movement. Now tighten until the enfloat just disappears.

- You may now have the worm too close to the brass gear causing it to bind. Slacken the north grub 1/8 of a turn, tighten the south by the same amount.

- phd2: do a ga run of at least 2 minutes, then guide somewhere high in the sky for as long as you can bear it.

- post the guide log

[spillage]

sorry if I have read this wrong.

The dec cone adjustment it to take up the slack of the axix bar and stop movement up and down (between the weight bar and dovetail clamp).

The worm gear will need the four bolts slackening on the worm housing then you can move the grub screws, re-tighten the worm housing bolts and test for back lash and run the mount to check for binding. As you have already taken out the slack on the actual worm before assembly you should not really need to play with the ring bolt (inside the black cap).

Getting the scope balanced is really important with the belt mod and I run PHD with the target to help me with this. If RA keeps hitting west then I adjust the weights and check the target again. This is just my way and may not be right.

[masjstovel]

2 hours ago, alacant said:

Hi

- Slotted nut to take up the worm endfloat (remove the round cover with the two holes to reveal it): make sure it's not too tight. With the clutch tight, rotate dec and with the cover off, loosen the nut until you can feel movement. Now tighten until the enfloat just disappears.

- You may now have the worm too close to the brass gear causing it to bind. Slacken the north grub 1/8 of a turn, tighten the south by the same amount.

- phd2: do a ga run of at least 2 minutes, then guide somewhere high in the sky for as long as you can bear it.

- post the guide log

Thanks, I will post my phd-log. 

Yes, I've done the procedure,  but in RA axis i easily feel the backlash when working with the set-screws, so  its much easier to know when im on the right spot as the backlash disappears. In DEC i dont feel any backlash when working with the setscrews, thats the problem. So my only reference in DEC is when the setscrew meets resistance. 

 

1 hour ago, spillage said:

sorry if I have read this wrong.

The dec cone adjustment it to take up the slack of the axix bar and stop movement up and down (between the weight bar and dovetail clamp).

The worm gear will need the four bolts slackening on the worm housing then you can move the grub screws, re-tighten the worm housing bolts and test for back lash and run the mount to check for binding. As you have already taken out the slack on the actual worm before assembly you should not really need to play with the ring bolt (inside the black cap).

Getting the scope balanced is really important with the belt mod and I run PHD with the target to help me with this. If RA keeps hitting west then I adjust the weights and check the target again. This is just my way and may not be right.

Thx @spillage. Yes i am aware that it takes up slack. My DEC is easier to spin around the more loose it is so i worked with this too as it was too tight. I did the deassembly to check my bearings in relation to the slight braking sound when DEC tightens.

 

The easiness in the axies now is close to perfect. And i was happy with my balancing yesterday. 

But guiding is far from perfect. I get 31000ms on DEC backlash even if DEC is no backlash i can feel physically. 

This i dont understand. Also the phd2-graph is oscillating heavily on bot axies. Dec wants to stay on the bottom side of the graph.

This is why i start wondering if theres something i need to program. Like in phd2 or in ascom, regarding tracking speed or something. I dont know?

Worth mentioning is whst i told @alacant is that i "never" feel backlash in DEC, so that its hard to know how the worm is on my brassgear

 

2nd picture was before guiding assistant yesterday and a bot strange. Havent seen RA and DEC acting with identic trends before

[masjstovel]

Neat trick on checking balance in PHD btw, i will try that:)

[spillage]

In PHD if you click on the brain the first page will show you the location of the stored file. Normally users/user-name/PHD2. This file will give everyone the info they need to check you guiding. A new one is created each time you start PHD2 and guide.

If you slacken off the dec worm housing you really should be feeling some backlash. What if you slacken off the four bolts and wind out both grub screws?

 

[alacant]

57 minutes ago, spillage said:

slacken off the four bolts

I wonder if the OP is adjusting the grub screws without first loosening these?

¿?

[masjstovel]

32 minutes ago, alacant said:

I wonder if the OP is adjusting the grub screws without first loosening these?

¿?

No their loosened slightly before playing with the setscrews if thats what you mean? The 4 screws on dec housing

Edited March 5, 2020 by masjstovel

[masjstovel]

1 hour ago, spillage said:

In PHD if you click on the brain the first page will show you the location of the stored file. Normally users/user-name/PHD2. This file will give everyone the info they need to check you guiding. A new one is created each time you start PHD2 and guide.

If you slacken off the dec worm housing you really should be feeling some backlash. What if you slacken off the four bolts and wind out both grub screws?

 

I can check again tonight but with both screws all the way out plus housing bolts slightly loosened there are a couple of millimeters backlash tops if any and with alot of force, if i recall correctly.

I was going to remove the housing as well yesterday, but i couldnt get the DEC motor out because it was stuck in the belt like the belt. There was tight space to get the cog in there so i dont think theres anything wrong with the belt. Slewing works and everything, but i cant get off the dec housing with the belt in place on the motor. 

Edited March 5, 2020 by masjstovel