Crown and Hands for a PRS-53

Does anyone know what size crown is required for a PRS-53? I am slowly acquiring the bits to rebuild a PRS-53 having started with a case I found on eBay.

I now have a dial and movement with some help from the forum and from Eddie.

I think the stem will have tap size 10 for a 2801. Will the tube therefore be 1.00mm?

I could just buy crown, hands and a movement spacer from Zeno but I am loathe too: partly because they want quite a high markup and partly because of the cloning of the '53 and selling them under their own brand.

I have got the hand measurements but I am also struggling to find the hour hand with the slight taper.

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Finally to the crown. The Precista is fitted with a non-screw down, ‘O’ ring protected crown. This measures 3.9mm in width and 6mm in diameter with coarse enough splines to allow for easy manual winding. It is not as large in diameter as those crowns fitted to the likes of the Omega 53 though features a bevel to the case side which is very attractive and assists in pulling the crown out for time setting. The tube is some 2mm in diameter and there is absolutely no wobble from the crown in either winding or setting positions.

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from the excellent review at http://www.watcharama.com/precista-prs-53/

Well, after lots of searching for hands and a crown elsewhere I eventually sucked it up and paid Zeno what they wanted for the parts.

Installed the dial and hands, installed them in the watch then realised I'd buggered the keyless works while removing the stem. One rebuild of the keyless works later and I finally have a working PRS 53 with a non hacking movement.

https://sites.google.com/site/alexnh...725_204109.jpg

A couple of questions. What should I have lubricated the hour wheel with when I installed it and what lube for the keyless works?

Get onto the cousins website, find the technical service sheet for the ETA 2824 and 2801, that'll tell you what lubricants to use and (most important) where to apply them. Look on Cousins website under watch parts/ branded/ ETA.

Remember the old adage: any oil is better than no oil!

I use Moebius HP1300 for the keyless work and on the hr wheel,, D5 will also suffice.

The service sheet doesn`t mention this, but it's sensible to oil orgrease the flat face of the winding pinion because it rubs against the mainplate when the watch is hand-wound. I also lubricate the teeth of the winding pinion lightly.

As for the crown, I think it'll be tap 9, standard ETA 2801/2824 stems are tap 9 and I can`t see why this should differ.

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Originally Posted by walkerwek1958

Get onto the cousins website, find the technical service sheet for the ETA 2824 and 2801, that'll tell you what lubricants to use and (most important) where to apply them. Look on Cousins website under watch parts/ branded/ ETA.

Remember the old adage: any oil is better than no oil!

I use Moebius HP1300 for the keyless work and on the hr wheel,, D5 will also suffice.

The service sheet doesn`t mention this, but it's sensible to oil orgrease the flat face of the winding pinion because it rubs against the mainplate when the watch is hand-wound. I also lubricate the teeth of the winding pinion lightly.

As for the crown, I think it'll be tap 9, standard ETA 2801/2824 stems are tap 9 and I can`t see why this should differ.

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Thank you, I have followed the old adage and put some coconut oil on it because I had run out of WD40 ;)

I think I will buy 2ml of HP1300 once I get over the sticker shock.

I thought I need a #10 tap stem, but anyway the stem on the movement was long enough to cut down and Zeno kindly included one too.

I think I'll need some crystal glue, I mistook it for dirt and cleaned it off and the watch steamed up badly this morning. Or maybe I coudl fit a gasket instead??

Can I rest fairly secure in the future availability of acrylic crystals or should I buy one now just in case?

I've never handled one of these, but usually a generic acrylic crystal can be fitted to a watch that had an acrylic fitted originally. Adhesives should not be needed, only as a last resort where the case is pitted and the crystal struggles to seal.

Deciding what to fit, and obtaining a crystal that will do the job, can be tricky. If the correct one is still available that's fine, but if not you need to use some judgement, it's all about finding something that looks OK and keeps the water out.

Are you sure the crystal's the cause of leakage? Unless they're cracked they usually stay right for many years. A mineral or sapphire crystal sealing against a seal can leak if the seal cracks or degrades, but acrylics seal by tension of the plastic against the case and they don`t usually give problems.

There are 4 places a watch will leak, leakage where the pendant tube fits into the case is the least common one, the other 3 (caseback seal, crown seal, glass seal) are more obvious.

It could be any of those really. Crown is new and feels like it makes a good seal. Probably either case back or crystal. The caseback gasket is old and I hadn't added any silicone grease. The crystal is quite an easy push fit.

If an acrylic crystal can be pushed in using thumb pressure its usually too loose. Acrylic tension ring crystals are available increments of 0.1 mm so it should always be possible to get the right fit. They need pressing in with a crystal press if they’re the correct size.

As for caseback seals, silicone grease is used to overcome friction when the caseback is tightened against the seal, its role is not to improve sealing. If the seal gas list elasticity or is showing signs of perishing it should be replaced.

Strongly recommend you get the movement out and address the leakage problem.

Ok, it is off the wrist for now and I'll look for a gasket and either glue or a new crystal.

I am more confident that it is the crystal seal. It may have been a mistake to remove the glue and crystal but I mistook it for dirt buildup! I think it's a simple curved crystal (i.e. near constant radius), rather than a 'boxed dome' with a tight radius at the edges and flatter on top (like the PRS-29).

Do you think with a tight crystal I can avoid glue?

suggest you clean everything up, inspect the crystal for damage that might prevent it sealing, and assess how tight a fit the crystal is in the case. As stated previously, if it presses in easily with finger pressure it won’t be tight enough. If it isn’t a tight fit, measure the diameter and try a replacement that’s 0.1mm bigger. Does the crystal have a tension ring? Most waterproof acrylic crystals do, but there are some designs that use a thick acrylic with no ring and a generic replacement isn’t easy to find.

Its difficult to advise without seeing the thing.

I don't recall a tension ring when I had it out, and it was fairly easy to replace by thumb pressure with the dried glue removed from the case. I'm not convinced it's the original crystal as various reviews and disassembly threads say it had a tension ring crystal.

Nearly done. Second hand just needs a nudge to got the marks better. I ended up putting an ISA 1198 movement in it.

https://i.ibb.co/c3TpRKh/16557527333...2289424457.jpg

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Originally Posted by ernestrome

Nearly done. Second hand just needs a nudge to got the marks better. I ended up putting an ISA 1198 movement in it.

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Wow, this has been a long project.

Quite interesting that you replaced the manual(?) movement with a quartz!

Yes, it took a while. I bought the case many years ago on eBay, without movement dial etc. I bought the hands and crown from Zeno. Eddie put me in touch with a kind member here who had a dial.
I bought a used ETA 2801 and built it up but couldn't get it to keep good time. It was at that point that i thought I'd do the movement swap. Unfortunately i then broke a dial foot removing it from the 2801! I ended up using a dial dot to get it finally done.