Setting Up Old Equatorial Mount - Help Needed

[Mandy D]

I was given this equatorial mount and pier a few years ago, but never got around to setting it up. I'm thinking about using it with my RC6. The RA and declination axes are free and seem fairly smooth, but it seems to have an awful lot of balance weights on it. From the height of the pier, I am guessing it was probably used with a Newt, so I will probably have to extend the pier height or buy a tripod. Can any of you nice people give me some advice and guidance on setting it up, please or tell me if I would be wasting my time and money with this, but I would prefer to get it working as it was given to me by someone who is no longer with us. It seems to have setting circles on one axis, but not the other.

I know I will need some Vixen dovetail mounts and will have to drill the mounting plate on the mount. Are these what I want in the link below?

Please keep in mind that I have never used an equatorial mount before, so I am a complete beginner. I understand the basic idea and know I will have to polar align it, but the rest is pretty much a mystery to me.

https://www.rothervalleyoptics.co.uk/adm-vixen-style-dovetail-plate-adaptor.html

Edited May 12, 2022 by Mandy D

[Carbon Brush]

Hi Mandy.

Interesting find. I have something similar, in pieces, in my garage. One day (maybe after retiring) I will get it sorted.

The dovetail adapter is sort of correct. It does the job, but you ought to get something longer, if you plan put a long tube scope on there.
I'm not suggesting a part just yet as I think there are other things to look at first.

The state of the outside suggests to me the first job is a strip down. You need to know whether the axes just need a bit of new grease or (worst case) they are completely rusted in.

If you look at the mount just in terms of ££ of value, there is little there. Recovering it will be time consuming.
You would be better off looking at buying a used EQ mount. For example, I think there is one in the sale section for £200 with motor drive.
However, if this has some sentimental attachment, your many hours are not chargeable and you will get a lot of pleasure from the 'fettling'.

David.

[Mandy D]

Hi David

Thanks for replying. The scope that may go on this is an RC6, so fairly short.

As stated in my original post, the axes move smoothly. I've just checked and cannot feel any play in either of them, so I am hopeful that they are OK. It feels like there is grease in there, i.e. no rubbing or scraping as you move it.

I totally agree that a new mount would be a better bet, but I don't really want to throw £200 at one right now, as I am saving for an HEQ5 Goto. As I mentioned, the mount belonged to someone who is no longer with us and I'd really like to put it into use. I would propose to strip it into it's component parts, have them shot blasted and then powder coated.

I'm just a little confused as to what exactly is there. For example, what is the bracket for above the setting circles? Is anything important missing?

Thanks again for your comments.

Mandy

[Carbon Brush]

Hi Mandy.

The large metal 'wheel' behind the setting circle is a gear.
It is probably intended that you fasten a motor & gearbox with a worm gear output on the bracket.
This gives you a 'clock' drive. That is 1 rev/24 hours. A tracking mount.
Or you can fasten a slow motion shaft/gear on there for fine control.

I'm sure someone on SGL will have seen (or maybe have pictures) this type of mount in a more complete state.

David.

[Mandy D]

Hi David

Thank you. Yes, now that I look at it I can see that it is wheel gear for driving with a worm. That would make sense as it came out of an observatory. It would also explain the odd bracket adjacent to it as a mount for the motor.

Hopefully, someone will turn up with said pics or more info.

Mandy

Edited May 12, 2022 by Mandy D

[doublevodka]

Reminds me of a fullerscope mount, maybe have a look here to start with? https://www.bcftelescopes.co.uk/about-broadhurst-clarkson-and-fuller-ltd/broadhurstclarksonandfullerltd/ it almost certainly had a long reflector on it at some point

[Mandy D]

35 minutes ago, doublevodka said:

Reminds me of a fullerscope mount, maybe have a look here to start with? https://www.bcftelescopes.co.uk/about-broadhurst-clarkson-and-fuller-ltd/broadhurstclarksonandfullerltd/ it almost certainly had a long reflector on it at some point

Interesting read. Thank you. I'm not sure mine is quite as professionally made ...

[doublevodka]

5 minutes ago, Mandy D said:

Interesting read. Thank you. I'm not sure mine is quite as professionally made ...

It looks quite similar to one of the earlier models, although, of course, it could be homemade https://www.google.com/search?q=fullerscope+mount&tbm=isch&ved=2ahUKEwjm9_LVo9r3AhVL5IUKHToqA10Q2-cCegQIABAA&oq=fullerscope+mount&gs_lcp=CgNpbWcQAzIECCMQJ1DmCFjmCGDvDWgAcAB4AIABOIgBaZIBATKYAQCgAQGqAQtnd3Mtd2l6LWltZ8ABAQ&sclient=img&ei=8Sd9Yqa7HsvIlwS61IzoBQ&bih=947&biw=1920&rlz=1C1DIMC_enGB871GB871

[Franklin]

Looks indeed like an old Fullerscopes MkIII mount head or maybe a MkII with a paint job. The feet on the pier look to be homemade, maybe the originals were removed at some point and misplaced!

[Mandy D]

@doublevodka It is quite similar, but like you say, I'm tempted to think that it may be home made. Looking at all of these pictures and comparing what I have, I'm begining to get a clearer picture of how equatorial mounts work. I have just agreed to buy a Starwatcher 200P, so that would be a better fit for this mount than my RC, so no need to increase the pier height.

I'm currently trying (and failing) to remove the counterbalance weights from the shaft. Once I have it stripped I'll assess the parts, then (hopefully!) get them professionally cleaned and finished. I can then return to here and see if someone can help me get it set up and working, initially as a hand guided EQ mount. I'd love to have a clock drive on it, but that would have to be much later.

[Mandy D]

18 minutes ago, Franklin said:

Looks indeed like an old Fullerscopes MkIII mount head or maybe a MkII with a paint job. The feet on the pier look to be homemade, maybe the originals were removed at some point and misplaced!

Yes, the feet definitely seem homemade. I've just had a close look at them and they are steel box-section with some small bolts in the underside, presumably for levelling. So, a Fullerscope MkII or III, then?

It looks like it is going to be a lot of work to restore this beast, but it seems very solidly made, with the obvious exception of the feet. The welding looks sub-par on all parts of the mount, but I don't think it is going to let go. I inherited an old SIP stick welder with it. I wonder if that was an encrypted message?

[doublevodka]

16 hours ago, Mandy D said:

@doublevodka It is quite similar, but like you say, I'm tempted to think that it may be home made. Looking at all of these pictures and comparing what I have, I'm begining to get a clearer picture of how equatorial mounts work. I have just agreed to buy a Starwatcher 200P, so that would be a better fit for this mount than my RC, so no need to increase the pier height.

I'm currently trying (and failing) to remove the counterbalance weights from the shaft. Once I have it stripped I'll assess the parts, then (hopefully!) get them professionally cleaned and finished. I can then return to here and see if someone can help me get it set up and working, initially as a hand guided EQ mount. I'd love to have a clock drive on it, but that would have to be much later.

It could well be a diy one, although there still something "fullerscope" about it, the earlier models didn't have the brand cast into it, so it could still be one of those potentially. The 200p will be a good choice for it I'm sure.

As for getting it apart, sounds like a liberal dose of WD40 is needed  

As for clock drive etc, maybe look into OnStep? - https://onstep.groups.io/g/main/wiki/3860

Looking forward to seeing how this turns out, I definitely have a soft spot for old kit like this, I will own a Tal or something similar one day 😂

[Cosmic Geoff]

Looking at the photos, it appears that any RA drive is entirely missing, while the gear (?) on the other axis is for a declination drive.  It looks like a significant amount of work would be needed to provide hand slow-motions or motorized drives.

Judging by the number of counterweights, assuming they are all solid steel, the scope originally fitted must have been unusually heavy. My 8" Newtonian required two 5Kg counterweights IIRC.

[DaveL59]

A penetrating oil would be better than WD40, at least more effective.

Also if you are going to have the bits powder coated, make sure the innards/threads are covered off else you'd be needing to re-bore for the bearings etc. I was tempted to do this for the wee TAL-M when I refurb'd it but in the end I spray painted in white hammerite instead. Came out pretty well but perhaps not as durable.

Not the same mount but astrobaby did a writeup when she overhauled a TAL some time back, which might help with ideas

TAL-1 Telescope Restoration Project (astro-baby.com)

[Mandy D]

On 13/05/2022 at 09:58, Cosmic Geoff said:

Looking at the photos, it appears that any RA drive is entirely missing, while the gear (?) on the other axis is for a declination drive.  It looks like a significant amount of work would be needed to provide hand slow-motions or motorized drives.

Judging by the number of counterweights, assuming they are all solid steel, the scope originally fitted must have been unusually heavy. My 8" Newtonian required two 5Kg counterweights IIRC.

The counterweight is in three pieces all welded together for some reason. It measures 114 dia x 200, so weighs in the order of 15 kg! The appearance of lots of small weights is given by self-adhesive foil tape stuck around the big chunks of steel!

Given that the RA drive is missing, am I wasting my time on this?

[Cosmic Geoff]

9 hours ago, Mandy D said:

Given that the RA drive is missing, am I wasting my time on this?

Depends on how much you want it to work and how much time and money you are prepared to invest. To bring it up to the standard of a manual equatorial mount, it will need a RA drive & slow motions designed and fabricated, part of the DEC drive to be designed and fabricated,  the weights cut down to size and paintwork done.  If you have to hire someone to do the work, the costs could be significant.

If it's a Project to restore a loved mount, carry on.

If you just want a mount for your 8" Newtonian, order a new one and get it by next week.

[Carbon Brush]

As a 'no cost' start. I'm guessing the weights are welded together by two or thre short welds. Not all the way around.
Carefully run a hacksaw on the welds. With any luck you won't significantly damge the metal.
Even if you don't cut all the way through the welds, by weakening them, a soft hammer might finish them off.
A soft hammer, or hammer with a bit of scrap wood, avoids putting dents in the weights. Apologies if you already know about this.
After that either a file or bench grinder will get rid of the remaining weld.

Even if you keep it as a manual mount, it has uses. That comes down to time and a can of paint - OK a bit more you get my drift.

As @Cosmic Geoff has said. Is it a 'project' or do you want a working mount next week?

[Mandy D]

@Carbon Brush Thanks. You are correct about the welds, but I think I'll just run a slitting disc on a small angle grinder through the welds. Hacksaw is too much like hard work for my taste! I'm not bothered about a bit of damage to the weights, as I'll pop them in the lathe and put a bevel on them all, anyway, to tidy them up. The biggest problem at the moment is getting them off the shaft, as I'm not sure what is securing them. There appear to be no discernable threads in the hole and nothing I can get a hexagon key into. Bizarre!

I don't really want to make a huge project out of this, but would like to have it working. Next week is not the aim, but perhaps the week after?

A manual mount sounds OK to me. I'm used to pushing the big Dob around, anyway and an HEQ5 is planned for.

[Mandy D]

@Carbon Brush I've just taken the first weight off by cutting the welds. The shaft does not go right through the other weights and the space is filled with lead! I've had another go at the grub screw, but no joy. There are definitely no threads at the top of the hole, so maybe that is clearance? I've tried metric and imperial hex keys and a flat screwdriver, but nothing. I'm reluctant to drill it, but that may be all that is left. Photos of progress are attached.

[Cosmic Geoff]

If you think the lead is holding the weights in place, then applying sufficient heat from a gas burner etc will melt it and free the weights.

In commercial mounts, the weights have a clearance hole and are held in place by a side screw with hand knob, backed up by a safety cap on the end of the rod.  If you can get these weights off, you could replace them with commercial weights - at a cost. Otherwise you will have to drill & tap a long side hole.  Or fix a common circlip on the shaft below the weights.

[Carbon Brush]

The lead is something I would never have guessed. I assumed there were fixings (as described by @Cosmic Geoff) hiding under the tape and rust.

I'm sure you will solve the mystery. In your first post you said "I am a complete beginner".
Then later you let on about the small angle grinder and lathe👍. So maybe you are new to an EQ mount, but not new to dealing with mechanical issues.

Do keep us posted on the project progress.

These days we look for an easily adjustable counterweight as we hang heavy cameras, jam jar size eyepieces or even different scopes on a mount.
When this mount was built, it was no doubt with one scope and limited eyepiece choice in mind.

 

[Mandy D]

@Carbon Brush You've nailed it: I'm a complete beginner with the EQ mounts, but do have mechanical experience! Sorry for the confusion.

The lead took me by surprise, too. I've felt for concealed holes for screws under the tape, but nothing. I think I'll end up drilling the screw out. I may need to get someone to heat the weights to get them off if the penetrating oil does not work, but I'll try twisting them off in a vice first.

I'm definitely planning on having easily adjustable counterweights. I've machined the small one up and bored for 3/4" to match the shaft. I have yet to drill and tap it for a grub screw.

Photo of first attempt at machining a counterweight. What size screw do you think? I'm tempted to go with M8.

[Mandy D]

6 hours ago, Cosmic Geoff said:

If you think the lead is holding the weights in place, then applying sufficient heat from a gas burner etc will melt it and free the weights.

In commercial mounts, the weights have a clearance hole and are held in place by a side screw with hand knob, backed up by a safety cap on the end of the rod.  If you can get these weights off, you could replace them with commercial weights - at a cost. Otherwise you will have to drill & tap a long side hole.  Or fix a common circlip on the shaft below the weights.

I don't think it is the lead holding the weights in place. It looks like they are rusted to the shaft and there is a single screw(?) in the side of the weights that is refusing to play. I may drill it out, yet! Heat, I think is likely to be deployed before too much longer.

Thanks for the info on commercial weights. I've looked at the price(!) and can certainly deal with drilling and tapping and finding a handwheel screw to work with the exisiting ones. I like the idea of a circlip on the end of the shaft to save my toes from possible injury!

[DaveL59]

it's not epoxy or chemical metal by chance?

Heat, the alternative when the FBH fails. Could well do the job with some assistance in turning the weights once you have the nice and hot - with care of course and using a suitable tool. Do you have anything like a metal band/chain clamp (oil filter removal type perhaps) that you could use to add leverage, maybe even with a tap from the FBH?

[Cosmic Geoff]

1 hour ago, Mandy D said:

@Carbon Brush You've nailed it: I'm a complete beginner with the EQ mounts, but do have mechanical experience! Sorry for the confusion.

The lead took me by surprise, too. I've felt for concealed holes for screws under the tape, but nothing. I think I'll end up drilling the screw out. I may need to get someone to heat the weights to get them off if the penetrating oil does not work, but I'll try twisting them off in a vice first.

I'm definitely planning on having easily adjustable counterweights. I've machined the small one up and bored for 3/4" to match the shaft. I have yet to drill and tap it for a grub screw.

Photo of first attempt at machining a counterweight. What size screw do you think? I'm tempted to go with M8.

The thumbscrew for an EQ-5 5Kg weight has a thread of 8mm diameter, but only the outer 20mm is threaded.  The end of the screw is plain and thinner (and the inner part of the hole appears smaller).  If you copy this, it should be easier to make, and you are less likely to break off your tap in the hole if you are only threading the first 20mm or so.