Skywatcher EQ5 regrease and latitude modification

Synchronicity · June 9, 2018

I've decided I need to 'refurbish' my Skywatcher EQ5 Synscan mount so here I am looking for advice.

Part 1, stripping down, cleaning and re-lubricating the RA and Dec drives bearings etc I am happy enough to just work through and see what I find but I'm looking for advice on what to use as a lubricant? I'm thinking a light silicone grease for the axis but I've got very little experience to go on. Any other advice or things to look out for is also welcome.

Part 2, the latitude adjustment bolts I am more concerned about. I replaced a bent bolt thanks to Paul (wookie1965) kindly sending me a spare he had but it's still not right. Looking at photos online it's clearly a design weakness so I'm trying to come up with a workaround. I tried contacting Gunnar about his NEQ6 mod on this thread but he's not replied. Does anyone know if there is a mod available for this or does anyone have any suggestions? I've looked at a few ideas like fixing a rotatable pin joint where the plate that the bolts push is located but I'm concerned that I limit the rotation angle too much - I'll know better when it is in bits and I can see and measure everything.

Thanks

Michael

Cosmic Geoff · June 9, 2018

5 hours ago, Synchronicity said:

Part 2, the latitude adjustment bolts I am more concerned about.

Plenty of people would like an answer to this. My view, wearing my mechanical engineer hat, is that the latitude adjustment should be via worm and sector gears rather than the actual rubbish arrangement which only works for mid-latitudes and not over a range of 90 degrees as it should. However this would probably be judged too expensive for the market.

As it is, one is stuck with the actual arrangement and has to work around it. One should take care when adjusting the latitude and not expect the push bolt to take the load of raising the whole weight of the OTA, counterweight, moving part of mount head plus friction. If you do, it is likely to bend.

Synchronicity · June 9, 2018

I'm shocked at what I have found when I stripped it down. My latitude was set for home which is 55 48' and the bolt had felt tight even though there was some play in the head. It turns out that the bolt was fully in and touching the other side of the mount base - the flap it is supposed to push was sitting on top of it! This means that it is physically impossible to set the angle any higher using these bolts.

Thinking cap on and turned up to stubborn ?

Michael

JamesF · June 9, 2018

Some people have removed the lobe that the bolt pushes against and replaced it with something larger and positioned more appropriately for their latitude. If you're comfortable with the engineering involved that's probably relatively straightforward. A few examples of such a mod have been posted here over the years.

I had a similar problem on my EQ3-2 and resolved it sufficiently for 51N by placing a brass cap over the end of the bolt. I think it might have been a brass stop end for 10mm water/gas pipe or something like that. The cap now "wobbles about" on the end of the bolt, pushing against the adjustment lobe and the bolt runs more true to the thread in the base of the mount. It's not ideal, but for me it does the job.

A few more ideas here and here

James

spillage · June 11, 2018

You can use a small steel plate and fix this to the main part of the mount (in front of the lug). I used expoy resin behind it, this will mean the bolt will not have to go in as far and lessen the angle of contact.

Mark.

cuivenion · June 11, 2018

As to the grease question I use Superlube:

https://www.zoro.co.uk/shop/lubricants-and-chemicals/greases/85g-super-lube-grease/p/ZT1036828X?utm_campaign=pla-Lubricants+%26+Chemicals+-+&utm_source=google&utm_medium=shopping-pla&utm_keyword=ZT1036828X&istCompanyId=6aa6787b-063e-4414-802d-129f235df603&istItemId=wtqixrrala&istBid=tztx&gclid=EAIaIQobChMIvNe-wYfM2wIV47ztCh0xJAs2EAQYAyABEgLkdfD_BwE

Or a variant of for things like the azimuth and altitude bolts, and any other bolts where you want to cut down on wear and tear on the bolt and threads on the mount.

For the internals such as the bearing's, shafts, worm and worm gear I use WS2 (Tungsten disulfide) suspended in Oil. It's a little messy and you have to be careful handling it (keep out of eyes/mouth etc). But its the grease I've has the best results with. I use Archoil 2600 but that has been discontinued, this by the same company looks like very similer stuff and is what I'll go for when I run out of my current batch:

https://www.amazon.co.uk/Archoil-AR4200-CLP-Firearms-20ml/dp/B00GGLJW0Q

Might want a bit more than 20ml just in case. Depends how liberal you are applying it.