EQ6 belt drive modification

[nightvision]

Thanks Malcolm, after reading the thread and recent updates I picked up on the improved PE handling that the 4:1 provided but I was left with the impression that I needed to have the pulley set machined to fit the shafts, it was this that put me off. Have I got that right?

Hmmm, just been checking out the BO site, it seems you can specify bore size and grub screw etc...

http://www.beltingonline.com/60-tooth-t5-pulley-al21t5-4915

Edited April 18, 2013 by nightvision

[malc-c]

Both pulleys need re-working. The smaller one need the 3mm bore opening up to 5mm, the larger need re-boring to 9mm, and in the case of the HEQ5 reducing in thickness. I believe the EQ6 conversion needs less work with just re-boring of the pulleys - I would need to read through the EQ6 belt drive conversion threads, or you could PM George to get the specifications. If you drop a mail to Ted at belting on line with the details of what you need he'll drop you a quote including the machining costs so you'll be able to drop the parts straight in.

[nightvision]

Thanks for the info Malcolm.

[Gina]

Both pulleys need re-working. The smaller one need the 3mm bore opening up to 5mm, the larger need re-boring to 9mm, and in the case of the HEQ5 reducing in thickness. I believe the EQ6 conversion needs less work with just re-boring of the pulleys - I would need to read through the EQ6 belt drive conversion threads, or you could PM George to get the specifications. If you drop a mail to Ted at belting on line with the details of what you need he'll drop you a quote including the machining costs so you'll be able to drop the parts straight in.

Now that sounds a good idea Malcolm I have some of the motionco small MXL pulleys and one of them has an inner part that isn't concentric with the pulley teeth or bore. It's out enough that reboring to 5mm would break out of the inner bit - nasty

I've been considering buying a lathe as there are several uses I have for one but OTOH I don't know how many things I'll have to turn in the future and as I get older I'm feeling less and less like making everything myself. To buy the bits ready made and just "drop them in" sounds pretty tempting Another point is finding a suitable place to put the lathe. I can clear space in our big shed but it would need a bench making up. Sounds nothing compared with that observatory I know but my OH is showings signs of his age now and is shortly coming home from hospital having suffered a broken hip. I think I need to draw my horns in a bit. I just can't do it all - much as I'd like to.

As for the benefits of doing the mount mod, I had guiding working really well last night with the OAG on my MN190 with a pretty flat graph interrupted by regular spikes in both RA and dec which I believe may be due to PE from the gearing. Unfortunately imaging was a no-no for other reasons and I don't actually know yet how good my guiding is.

[Zakalwe]

Thanks for the update Malcolm, just read most of the thread and it looks like it's worth doing. I think I will go for the Austrian kit (about £120 delivered), I counted the teeth in the image and there looks to be 47 on the larger cog. I use EQMod via the handset so everything should remain the same.

You will have to modify the mount to make them fit.

[nightvision]

Thanks for that Zakalwe, have you done your mount?

[malc-c]

You will have to modify the mount to make them fit.

In the very first post in this thread George states that no modifications to the mount are required, and that the machined pulleys drop straight in - Confusing !

[chrisshillito]

In the very first post in this thread George states that no modifications to the mount are required, and that the machined pulleys drop straight in - Confusing !

If you set everything up perfectly no modifications are required. However, I think that anyone considering doing an internal belt mod should also be prepared to make a few minor alterations whilst they've got the mount in pieces. They may not be essential but they can ease the setup process.

It certainly doesn't hurt to widen our those slots as this gives you a little more lattitude in positioning the motor pulley on the shaft.

On my EQ6Pro I've also drilled/filed two slots in the rear face of the motor compartment which really does make the fitting and tensioning of the belts much, much easier. These slots naturally have a simple cover plate.

Chris.

[Armando]

Hi @all,

I just found this interesting thread and now I'm really tempted to mod my EQ6 too.

I've no access to a lathe; so I need a ready to use solution...

I think I'll be obliged to get the parts from HPC Gears: I can't modify the bore of the small pulley.

I see the following dimensions about the big pulley:

1. pulley outside diameter = 39mm

2. boss diameter = 20mm

3. width = 11mm

Anyway George opted for a 48T pulley that has a width reduced to 15mm and the outside diameter (according to the specs) is 30.53mm

I'm tempted to think that an outside diameter of 39mm together with a 15mm width is possible with no need to modify the mount (maybe the only need is enlarging the slot required by the belt but I think it's feasible).

So the question...

I see that 60T pulley (60W A60W by HPC Gears for 6.35mm wide belt) outside diameter is 38.30mm and its width is 15mm.

Will the 60T pulley fit without issues?

I'm thinking about the following solutions:

12T (or 15T) pulley from HPC Gears with 5mm bore

60T pulley from HPC Gears with 12mm bore

I'll greatly appreciate your help.

Thank you and Clear Skies!

Armando Beneduce

[George]

The 60t pulley won't fit unless you enlarge the slot, you would also have to machine out the worm housing too using a mill or possibly a stand drill.

Sent from my GT-I9300 using Tapatalk 2

[Armando]

Hi George,

I just read your answer, thank you.

I'm still tempted to opt for a 60T pulley: I should be able to enlarge the worm housing.

Could you suggest me the right (MXL) belt length?

Thank you again and Clear Skies!

Armando Beneduce

[Armando]

Ok,

according to the centre distance corresponding to 12:48 reduction required by 80T belt, I think I should opt for 86 tooth to fit a 60T pulley.

CS

Armando

[George]

Hi George,

I just read your answer, thank you.

I'm still tempted to opt for a 60T pulley: I should be able to enlarge the worm housing.

Could you suggest me the right (MXL) belt length?

Thank you again and Clear Skies!

Armando Beneduce

I think this link has been posted somewhere in this discussion, it will be trial and error until you actually get the pulleys fitted as being a few mm out in your calculations can mean the difference between a few teeth. I think originally to save on postage I opted to get a size either side of my calculations.

[Armando]

Hi George,

I think this link has been posted somewhere in this discussion, it will be trial and error until you actually get the pulleys fitted as being a few mm out in your calculations can mean the difference between a few teeth. I think originally to save on postage I opted to get a size either side of my calculations.

I used that link. What I found was that 87T should be the best choice. But I also read that you had to enlarge one of the motors plates holes to properly tighten one of the belts.

So I evaluated the 86T solution...

I see no 86T belt offered by HPCGears. So I'll be obliged to buy a pair of (Polyurethane) 87T belts.

Anyway what I'm not sure about refers to the number of tooth in mesh: only 4 on the small pulley. Do you think I can ignore this issue? I think no great torque is required but I still didn't give a look at belts technical specs... Pretty the same issue should occurs with 48:12 reduction if it really exists...

Thank you and Clear Skies!

Armando Beneduce

[George]

4 in mesh sounds about right for the small pulley, I also had to make the motor plate slot a few mm larger for adjustment, it takes a minute or two with a jewellers file.

[Gina]

Yes, the aluminium these mounts are made of is very soft and easily worked.  I found that when I was modifying the PA altitude adjuster.

[miralem]

Hope all of the members in this thread are doing great!

I recently bought a black EQ6 with pulse motors made in Japan, with an old external controller Boxdörfer MTS-3 SLP, so no goto functions.

I wanted to upgrade it to Onstep using this Roman's board

https://oshwlab.com/hujer.roman/onstep-for-eq6

But before that, I want to convert it to BELT driven pulleys, but since kits are over 150€/200€ I wanted to buy 48:12 that can exactly match the case so I don't change anything on pulleys nor case. I know that the axis diameter of wormgear is 12mm so the Bore Diameter of the pulley must be 12mm, and the maximum width is about 9mm in this case, so the maximum width of the pulley can be 6mm for the same belt of 6mm.  The OEM pulley diameter is 39mm, so the one that will fit with the belt must be about 36mm if I am not wrong. And max-width of all pulley must not be over 15mm with is reserved on worm for the pulley.

But having searched on the net, I cannot find any pulley that will be straight plug and play...

Can someone help me with the pulleys and belts, where to buy them? Thanks in advance...

p.s. I have read all the thread more than once...

[malc-c]

whilst not exact, a quick google came up with a supplier I've used in the past called Beltingonline - they have a T2.5 pitch pully that may fit with a little aftermarket machining link here

[malc-c]

25 minutes ago, miralem said:

 

But before that, I want to convert it to BELT driven pulleys, but since kits are over 150€/200€ I wanted to buy 48:12 that can exactly match the case so I don't change anything on pulleys nor case.

You have two choices - pay the 150 euro for the custom CNC machined parts, or obtain parts discussed in this thread and undertake the machining and fettling required to fit them.  You won't be able to pick up a set of pulleys that just drop in.  The Rowan belt drive kits include special CNC machined pulleys, and its that process that you are paying the money for.

[miralem]

I have bought Rowan's kit, payed extra customs fee, and I also bought 0.9 Degree Nema17 Stepper Motor 11Ncm(15.6oz.in) 20mm Nema 17 Stepping Motor 1.2A 400 steps, as well as 4x SKF 608 2RS BEARING 8 X 22 X 7 BRAND NEW and now I am choosing right PCB for onstep upgrade... Hope it will turn up to be nice astro set