dazzystar

Ah yes!

Also, not sure if this is important but the coupler is a 6mm to 5mm version as the gear has a 5mm bore whereas the DEC axis has a 6mm bore. Don't ask me why it's like that as this was included in the kit supplied by George Cushing.

6 minutes ago, fozzybear said:

is the steel rod that's attached to the coupling (is is a ridgid one or a flexible coupling) is the rod keyed (ie a flat on it) or cylindrical. if cylindrical and on the coupling there are 2 grub screws the rod might not be centralised if you understand. And throw it of balance ideally you would mount the large gear directly onto the RA shaft can you not turn the RA gear the other way round of does this provide enough room to attach the belt? also on the motor rotate the pinion gear as well

The 5mm steel rod isn't keyed and it's a rigid coupler. I can't mount the gear directly to the RA shaft as it won't clear the locking handle when in motion (known issue with all EQ3 mounts).  The coupler is 20mm in length if that helps. Not sure what else to try as you can see it's hard getting the belt lined up straight.  I'm not sure what you mean by 'can you not turn the RA gear the other way round'

Cheers
Daz

But the DEC axis is quiet....also, I've noticed that when the RA pulley is moving it looks like something is bent but the small steel rod is straight...any clues?

On its way!

No idea. All I've done is drag it to the post. I've tried again but no good. I'll do a Wetransfer link if you PM me your email address.

On 26/02/2022 at 21:27, fozzybear said:

maybe use your phone and record the noise and post here to determine if motor or mount noise as In Dec as only move in that axis as the worm gear has a little backlash movement if the same as an EQ5 but the EQ3 I am not OK with it's configuration 

Here's a short movie of the noise from the RA axis. Any clues as to what it can be? Please excuse the dog barking!

The noise is definitely coming from the RA axis area. This has the 6mm to 5mm coupler, pulley and small 5mm rod. I'll record a short video this evening and post it here so you can see / hear for yourself. I'll also try it without the OTA on the mount to see if it's anything to do with the weight.

How did you guys work out which type of pulleys you needed?

Hi All,

Having completed my OnStep EQ3 upgrade I'm not happy with the stepper mounting on the RA axis as there's only one mounting hole on the body of the mount and although the 3D printed mounting bracket seems to hold I can't see it holding well for long. Has anyone any thoughts on something that would be better?

Cheers
Daz

Any good @fozzybear Appears to be a little simpler than OnStep and works with EQMOD which is a huge bonus for me.

Not heard of Astroeq before.

I'll do that tomorrow. Is there any kind of test program I can use with OnStep to move the axis?

Thanks @fozzybear. My DEC axis belt is much tighter than the RA and I'm getting some noise when slewing but not sure which axis but do have a feeling it's the DEC. Would too tight a belt give a noise do you think? Also, as we  have to extend the RA axis using a coupler to clear the brake arm I can see a little wobble when the pulley is moving. Need to check this as I'm not sure if it's the small rod of metal I have or something else!

Guys. How tight should the belts be?

No. The sides.

I remember those. I'm probably older than you Malcolm!

Thanks Malcolm. Already a member there but the .io interface is not as user friendly as here!

Transpires that once a motor and belt are added, this backlash, disappears or rather I can't detect the same feeling as without.

The 150mm belt arrived this morning but I've had to raise the DEC bracket up to get it tighter. Here's a couple of pictures. Even with the bracket raised up by this amount the belt is still a little loose so think I'll have to modify the bracket.

The 158mm fits perfectly. I've ordered a 150mm belt off of ebay and hopefully will get it tomorrow. We'll see if it fits ok but there's virtually no movement on the bracket for the DEC axis.

Hi All,

I've removed the stock motors in readiness to replace them with new steppers as part of my OnStep upgrade but have noticed that on both the DEC and RA axis when I turn the worm shaft by hand I can feel backlash. It needs around 1.5mm - 2.0mm of travel before it starts to move (in either direction). What can I do to improve this?

Cheers
Daz

Nice!

I want all my 'kit' mounted on the OTA, hence the dovetail clamps but your version looks great.

Brilliant. Well, one of the belts should fit!

I've got a small selection coming from Amazon tomorrow. https://www.amazon.co.uk/gp/product/B098JBFMGL/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

But my main concern is not finding one of the correct length.

This is going to be a potential PITA I think. I've measured the RA axis with string and it's around 155mm. I have some movement to play with but not on the DEC axis (which I've not measure yet but will be shorter due to the 12T pulley). 

No I meant if you know the distance between centres and you know the specs on the two pulleys I thought you'd be able to enter that into a calculator. Think the string is the best thing for now though.