Vixen Porta

[Alan64]

7 hours ago, dave34 said:

Cant wait to see the finished item, metallic candy apple would look a treat, great thread.

Thank you, and indeed it would, but just a tad darker.  I can't wait either.  

The mount is wonderfully compact, small, fixed, and will not require much paint.  I've been browsing over the 5 oz. spray-cans here; two cans will do...

https://parts.gmparts.com/search?searchTerm=red metallic spray paint

Those are of a true automotive formulation, quite Sun-resistant I hope; compared to the decorative, and usually oil-based types, which tend to fade and turn orange more rapidly , for example...

https://www.amazon.com/Rust-Oleum-331200-Universal-Spray-Cherry/dp/B0876GJBRY/ref=sr_1_1?crid=187CUKK3GRTDM&dib=eyJ2IjoiMSJ9.XYwzsbE1d2uPec7KOJNxOXJOxHxI4zQiFzOQ8PXGca2HemD7ybNYpS23aB1RCy844cL317Vt7cSwnhnqZ6tfgGbkdL-6NFLAJHvxR_Jjbt8YkW4Z8LJOwtk_KvST6Bt7ACZpR88S_x57sN9z8uByuh1-7aNb3IvT_p957h_t4vvJJui7SG-9zOUScNfiYOc9IbRkUkHITkeCx0IYHY_sxu3v815OAv1gxEHOp6DTHuL--cKm9Wd0YOgcvndqH9wpUKMvWZbWOT0uWUTr4NrYG9EnB17ZusdbVJijahRWDsc.Q8cRkqOPTMMOV21MKYW1A9OLUVgcZZfvhjiLmKxUAns&dib_tag=se&keywords=rustoleum+dark+cherry&qid=1721317649&sprefix=rustoleum+dark+cherry%2Caps%2C101&sr=8-1

There is this, but again, it would require several coats of a clear-gloss...

https://www.amazon.com/Krylon-K03806A00-Glitter-Blast-Cherry/dp/B005574K22/ref=sr_1_1?crid=HNAH9OG1ZPLO&dib=eyJ2IjoiMSJ9.FFJQBLF82iU9gUq4pPCk5f94Cf6uHM-JRU7yvr48elBQKtIVwbhiWncj2jBfEp6hpKXxTuwnMhmYXHvzNNSJIYafbG7JMU97gDRCOF7QHC2llv1xsN58Py_LLWzag7ESauNHPfr2trky6YB6A-los-2ECd8C-8vLcltOQT9oFS5ruNPjg-4Y7DF99m02iH_oUk7RwHlVqVzBTETiNv41W27xxmqhJ46dZ1e0-wnaYO51dofdBFLbR8U_kd8u8xZUv_3TVlSLzUO8eAgzs7qV0utUNnTO-LHUzFSswFsoTHU.kV02cJeix-lVBljd-1nQMdH71P32QrAE-iuo48m6ClI&dib_tag=se&keywords=krylon+glitter+bomb&qid=1721318282&sprefix=krylon+glitter+bomb%2Caps%2C103&sr=8-1

However, I know nothing about its fading resistance.

In the end, this is my wee-widdle astro conveyance, so it should have an automotive finish.

[Alan64]

3 hours ago, Mr Spock said:

Dug it out this afternoon. It's actually a mini Porta  I might try the 60mm on it.

That's great news.  Don't be distraught over its being a Mini-Porta, not at all.  It should be every bit well-made as a Porta, only a little smaller, and the alt-azimuthal equivalent to an EQ1-class mount-head.  This is another one that I had gotten with my full-127mm f/15 Maksutov a few years ago...

However, there's a 50mm f/12 achromat riding it, a Towa.  

But your Mini-Porta is leagues ahead of that re-branded Bresser.  The Vixen friction-fit knobs with chromed-plastic extensions...

...can break, certainly.  The Vixen friction-fit knobs, only, without the stalks, are best.

The Porta I and II mounts are about the same equivalent to an EQ2-class mount, or slightly larger.  

I'm at the point where slow-motion controls are a must, no matter how small the mount.

 

[Alan64]

Fresh out of the bag...

After pulling and scraping...

 

The clamp out of its bag...

After removing what I could from the clamp, I transferred both the arm and clamp to a tub and reapplied more of the old remover...

 

After that had sat for a while, I got a brass brush and went over both forms, removing more of the old paint, then rinsed with water...

 

You can see that extra-thick layer of paint within the arm still.

Next, I will putting them back in the tub overnight, and with the new, fresh pail of remover applied this time.

Edited July 19 by Alan64

[Alan64]

For a third time's a charm, I used the new pail of remover...

It appears much more appetising, and clings a lot better, too.

I've enclosed the tub in a plastic bag and stored the lot in the shed overnight.

[Alan64]

 

I may not have to apply more remover.

I should've used that fresher from the beginning, but waste not, want not.

I will be using the old stuff for the axes's two-piece housings, first.

[Paz]

This thread has been a very interesting read. I've had a Porta 2 for many years and have used it loads in that time with an ST80, ST120, 127mm Mak, 72mm f6 refractor, and a 102mm f7 refractor. It's a great combination of being sturdy for its weight and having slow motion controls. Here's an action shot of a Porta 2 from years ago with an ST120 (on this holiday on the south coast I got some of the the very best views of the sun in white light I have ever had in any scope due to great conditions).

[Alan64]

This factory pit of the clamp or saddle was never filled, except by the paint...

"The paint will fill it.  Next!"

This, after the first application of the new, fresh remover, overall, then rinsing and picking it as clean as I could, and before the second, hopefully the final application...

The surfaces of the aluminium forms are somewhat coarse overall, a lack of finishing; let alone polishing.

I allowed the neodymium magnets to bathe in an L-shaped river of acetone.  Note the large round pool, the source, at right...

Fat lot of good that was.  I'll have to chisel, crack them out, if and when I want.

Given the somewhat rough finish of these forms, it is reminding of when I was bronzing my Meade LX70, an EQ5-class manual mount. 

The innards of what is in reality my Suzhou Synta EQ-5 were polished, however those of earlier years were not, the interiors rough, unpolished.  This Porta I head is also rough and unfinished.  So that helps date it a bit more accurately, as being an earlier one.  It could very well be that round 2008 was the debut of the Vixen Porta I.  But in the end, it's of no real consequence as to its actual age, or is it? 

What is precisely the difference(s) between a Porta and a Porta II?

The joint, where the arm joins the base or compartment, becoming one piece...

My decrepit Minolta has done it again.

Right afterwards, I attempted to pull the two pieces apart, what the heck, however not actually knowing it to be in two pieces, and...

The arm and base are truly separate.  I did not know for certain until that happened.

What a weak joint.  Are these welding marks or spots, a kiss and a promise, a slap and a dab...  

Ha!

I'd have to guess TIG or MIG welding.

Instead, before any priming or painting is done, the two mating surfaces of that joint will be sanded, scored, glued, the bolts returned, and with the glue added to their threads.

It will then be even more as one piece, apparently stronger than what was done overseas.  It will never separate again.

I will not be painting the tool compartment, the interior with its magnets, with its rubber cover over it.  It will be sanded here and there, then polished with very-fine steel-wool saturated with lemon-oil, instead.  I may even felt it, eventually, in red, naturally.

I will need to remove the final remnants of the old paint before re-joining the two pieces permanently.

Edited July 20 by Alan64

[globular]

This thread is a joy. Thank you. Keep it coming. 

[Alan64]

41 minutes ago, globular said:

This thread is a joy. Thank you. Keep it coming. 

Thank you.  It will be the most fully-featured mount of the apocalypse.

[Mr Spock]

Nice project. Looks like it's going well 👍

[bosun21]

I'm following this thread with interest. I have just obtained a Vixen Porta myself and the only thing I have done was to clean and regrease the azimuth bearing which is now much smoother. It's functioning just fine so I will be leaving it as is. I will still be following your thread to its conclusion though.

[Alan64]

I ordered a couple of things yesterday, for the axes...

Amazon...

AliExpress...

I'll be chomping at the bit just before I open the 2mm-thick phosphor-bronze sheet-let, and to make certain that it is phosphor-bronze in fact. 

I have 0.20mm and 0.51mm thick sheeting in that already, for washers and other.

I'm now going out to completely disassemble the axes, photographing everything of importance along the way. 

I will also be removing the factory grease with a higher or highest grade of kerosene.  It cuts right through it all.

[Alan64]

The first thing to remove from the axes, in order to renovate same, are the lock-nuts...

Here, the fender-washers have been removed, and exposing the wave-washers...

Note the plastic washer at left; at right, underneath its steel washer.  Those plastic washers will be eliminated, and replaced with other.

This is the first time that I've encountered wave-washers, at top, which will be replaced with the needle thrust-bearings on order...

We now begin to see the form of the large central bolt.

The wave-washers up close... 

I could make those of phosphor-bronze.  Wouldn't they be lovely?

The axis is then separated...

We now see the worm-gear.

Here we see the first of the main plastic washers, at left, top, two of them stacked together...

Then, that on right is shown further, with the third of the main plastic washers, and the largest...

Also seen is the worm itself.

A flash shot of the three main plastic washers...

Edited Monday at 03:07 by Alan64

[Alan64]

The next thing to do was to pry up the worm-cover, but it actually serves to hide the two other set-screws...

By removing those, I discovered that what I had thought were cam-nuts, that screw in and out,

were in reality, sleeves, only sleeves, cam-sleeves.  The two pairs of set-screws had been securing

the alignment of the worm-shaft, thereby the worm, in relation to the gear.

I already have the stainless-steel set-screws, to replace those that are of black-oxide steel, but I

haven't received the ones of brass, yet.

The altitudinal axis sorted out and the factory grease removed utterly...

After removing the last pair of set-screws, the worm-shaft with its cam-sleeves pulled right out.

That in the little bag at upper-left are history.  The fender-washer and nuts of the azimuthal axis are also

present within the image.

The worm-shaft with its cam-sleeves...

The two plastic washers are history.

The worm-shaft's cam-sleeves removed and displayed alongside...

This curved metal tab bears against the worm-gear's shaft and locks it in place...

At left we can see where the tip of the historic 8mm set-screw dug into the surface.  At right, there's wear and tear visible.

That tab will be duplicated in phosphor-bronze, as steel(iron) should never bear against aluminium; nor stainless-steel against aluminium,

the lesser of the two evils.

Here, the tab is in its position of the housing...

An 8mm clamping-knob with its buffering slug of phosphor-bronze will one day be pushing a tab of the same

metal against the worm-gear's shaft.