Jump to content

Low dome acrylic crystal problem


Russell

Recommended Posts

Hello,

I'm new to this forum and I heard a lot of good things about this forum, so I hope I can learn new things.

I have a watch with a low dome acrylic crystal, I have never work with low dome crystals before, so I find this quite confusing. The diameter of the crystal is about 20mm and the diameter inside of the bezel is 19.2mm. When I pop out the crystal I notice some tiny cracks around the crystal's edge that meets the bezel, I thought it wasn't a big of a deal, something that I can just polish off later on, but turns out it wasn't. Any ways, I tried to put the crystal back into the watch, but it's very hard I tried using the crystal lift but it didn't work and damage the crystal even further. I did some research and found out that low dome crystals are meant to fit into the bezel easily and secured with glue or cement, is this right? I do find the measurements of the crystal and inside of the bezel to be very odd. 

I also need to find new crystals for this watch, what size crystal should I get? the smallest one I can find is 19.4mm

Thank you very much for your help and advice.

Best,

Russell

Edited by Russell
incomplete title
Link to comment
Share on other sites

  • Russell changed the title to Low dome acrylic crystal problem

Hi  The first thing we need is the make and caliber of the watch and a few pictures of the movement, case / front and back and of the old crystal, Armed with that information we can proceed. There is little point in guessing or aproximating sizes  as it will lead to mistakes.  You say the dis of the crystal is "about" 20mm,  best to measure it exactly with a vernier gauge and have some hard facts to go on..  A good web site to look at is Esslingers .com in America  they have various tutorial pages to do with watch repair and one which deals with measuring and fitting of crystals.

Link to comment
Share on other sites

2 hours ago, Russell said:

Any ways, I tried to put the crystal back into the watch, but it's very hard I tried using the crystal lift but it didn't work and damage the crystal even further.

Avoid clamping crystal lifts, acrylic crystal are best removed and refit with a crystal press and the correct dies. The STK catalog has a brief section on that.

Link to comment
Share on other sites

3 hours ago, Russell said:

low dome crystals are meant to fit into the bezel easily and secured with glue or cement, is this right?

No, not if they are round actylic crystals., you shouldn't need any glue at all.

Crystal lift type tools are not very good at all with low domed crystals, and not the best for fitting any crystals. As @jdm mentioned above a crystal press with the correct dies is your best bet.

Have a search of the forum on how to use a crystal press.

Link to comment
Share on other sites

2 minutes ago, Russell said:

.And I do not have access to a crystal press, is there any other option other than using a crystal press??

A crystal /  caseback press is indispensable tool. Some decent ones are not bery expensive, check pinned topic below. That being said most often on acrylic crystals a bit of filing around and GS Hypocement is all it takes to fit by hand and have them stay there.

 

Link to comment
Share on other sites

I bought a crystal press a while back for 20-25 bucks from Amazon and the thread that connects the dies to the tool are slightly bent, not visible at first but once I attach it to the tool it's pretty obvious the die face isn't parallel to the ground.

@jdm @watchweasolthanks for the advices. I'll try sanding the crystal

Link to comment
Share on other sites

One of the issues with the common modern presses is that they do only that - press the crystal. 
 

What you often need for acrylic crystals without tension ring is a set which allows you to deform the crystal by using a cup and a corresponding dome to compress the crystal over. 

  • Like 2
Link to comment
Share on other sites



  • Recently Browsing

    • No registered users viewing this page.
  • Topics

  • Posts

    • Yeah ive watched that a few times before,  i couldnt find my old school dividers to scribe it up 😅 Yep thats the guy i bought a roll from .
    • Yes, "Sold out" is difficult to understand. There doesn't seem to be a lot going on. It's been nine months since any new video was published on the Watch Repair Channel. The Level 4 course on watchfix.com has been in progress for what feels like forever (several years!?). Maybe Mark's enterprises aren't doing well or perhaps already so profitable there's nothing much to motivate him for more material. Or, perhaps these days he's more into crochet. The real reason is probably something entirely different but it would be nice/interesting to know. I don't mean to sound gloomy or pessimistic, but I wouldn't be surprised to be met by an HTTP 404. Every day feels like a gift. Speaking of watchfix.com I've been postponing the "Level 5: Servicing Chronograph Watches" course for a very, very long time. Anyway, I just enrolled on it so it's going to be very interesting to see the videos. I must say, IMO there's nothing really that can compete with Mark's courses when it comes to presentation and video quality. It's simply world-class and makes me associate with some really expensive BBC productions.
    • Steel has some funny properties, or at least counterintuitive. The modulus of elasticity is effectively (not exactly, but close enough) the same for steel that is annealed and hardened. What changes is the point of plastic deformation* . If the movement of your spring doesn't pass that, it should work fine. It looks a little thick, I would thin it a bit maybe from the main body out about halfway, maybe 10-20% thinner (not in thickness, along its form). But if it works it works!   *So- if you have two bars of the same steel, one annealed, one at 600 Vickers (general hardness watch arbors might be), clamp them to a table so the same length is hanging out, and put a weight on the ends, they will bend the same amount. But if you continue to add weight, then remove it, at a point the annealed bar won't return to its original straightness. That's the point of plastic deformation. But up to that point, as springs, they are the same. However- their wear characteristics will be very very different. And getting the hardened bar past its point of plastic deformation takes a lot more effort.
    • @JohnR725 now that you've mentioned it. This is actually the second aftermarket spring (same place and brand) I ordered as the first one broke. The eye on which the arbor pulls on, broke off on the first spring after the first wind, and also it was a bit to large for the arbor. Looked like on one the second picture in the 2nd group. The second one was exactly the same, I had to bend it a bit, to give it a more prominent curve to the end of the spring so that the arbor catches the eye.  Also I believe both were 5-10mm shorter. Not that I writing that, I feel a bit dumb, as the spring might actually been the problem all along, although its advertised as a substitute to the original...     
    • The CS70 is the only one they show as annealed.  A further search on ebay, I found CS75 and CS100 annealed carbon steel strips  e.g. https://www.ebay.co.uk/itm/314072784422
×
×
  • Create New...