Crystal Press

[pcuk]

Hi,

I'm a newby, so please be gentle!  I have an early Accutron into which I need to fit a new crystal.  I have a NOS crystal.  I understand the principle of fitting a tension ring crystal with a press, but need to make a die to fit the crystal.  Does anyone know (or can estimate) the optimum internal angle of the top die please?

Secondly, on a slightly different subject, I have seen on this site discussions about recessed crystals and non-recessed crystal, but from what has been said I still don't really understand the difference.  Could someone enlighten me further please?

Thanks in anticipation. 

pcuk

[Chopin]

Why do you need to make a die to fit the crystal ?

[transporter]

If its a tension ring crystal should you not be using a crystal tool, not a crystal press, these tools grip all round the edge of the crystal squeezing it to a slightly smaller size allowing you to first lift the old crystal out and secondary allow you to fit the new crystal.

[ro63rto]

This is the style of tool you need with an acrylic crystal that uses a tension ring.

http://www.ebay.co.uk/itm/like/111995196774

[Alaskamick]

This style is not used with a crystal that has a tension ring. I guarantee you will break the crystal with it.

You need to use a press.

[Chopin]

1 hour ago, Alaskamick said:

This style is not used with a crystal that has a tension ring. I guarantee you will break the crystal with it.

You need to use a press.

Yep, this is true. Acrylic crystals WITHOUT a tension ring can be used with the claw tool. The ones WITH a tension ring will need a press.

It won't damage the crystal as it's basically a press fit crystal.

[ro63rto]

Pay attention people [emoji37]
This is why you should read all the post and NOT while you're about to fall asleep like me. [emoji4]

Apologies for my mistake [emoji20]

[transporter]

Plus one on that, my apologies, and yet another reason for me think about a BHI distance course, so if it's tensioned ringed will it require a gasket, or is the fit so tight on tolerances that it doesn't require a gasket?

[jdm]

I don't think that BHI training is ever relevant to replace a crystal 

I understand that tension ring crystal predates gaskets. So in most cases, you have one, or the other.

[vinn3]

welcome to the forum.  the "claw tool"  works on  the proper crystal.   after market crystals are a different story.  vin

[Ishima]

13 hours ago, transporter said:

 or is the fit so tight on tolerances that it doesn't require a gasket?

 

That's right, you'll find plenty of non tension ring acrylics without gaskets as well, but the tension ring was designed in order to make a better, tighter seal between case and crystal.

[Andyclient]

Mark has done a video on replacing a crystal fitted with a tension ring (armoured crystal)

 

Edited October 2, 2017 by Andyclient

[pcuk]

Hi 

Thanks for all of the responses.  I'm glad we clarified the difference  usage of a claw tool and a crystal press, but I never really had an answer to my request for information on the internal angle of the top die.  I need to make a die with the correct internal angle to press the new crystal into the watch case. 

Thanks

pcuk

[ro63rto]

Can't you take a mold of the new crystal, protected with cling film (ceran wrap) using JB weld or similar?

[Watchtime]

On 5-10-2017 at 12:26 AM, ro63rto said:

Can't you take a mold of the new crystal, protected with cling film (ceran wrap) using JB weld or similar?

+1, I think making such a die would be the best with a mold.

[jdm]

On 9/29/2017 at 6:38 PM, pcuk said:

Does anyone know (or can estimate) the optimum internal angle of the top die please?

I think you're worrying too much. A convex die of the right size will work just fine. 

[mikepilk]

I'm having problems trying to fit an acrylic tension ring glass to an Omega.

It's 'Omega Generic Acrylic' from Cousins - the same diameter as the 'proper' part, 31.6 mm 

I don't want to press too hard and damage the case, but it just won't go all the way in.

Any suggestions - maybe chill the glass in the freezer ?

 

[fjseal]

Mike,

Your idea of chilling the glass may be worth a try, but in the refridgerator, not the freezer. I think the freezer may crack the glass, so try the fridge overnight. I did have success using this method once when a watch glass was not quite seated, and chilling it did the trick. Good luck.

[mikepilk]

With my attempts the metal ring fell out. It's easy to fit without the ring, and it looks OK.

As I don't need to make the watch waterproof, I may just use it without the ring.

[Andyclient]

On 10/7/2017 at 6:51 PM, mikepilk said:

With my attempts the metal ring fell out. It's easy to fit without the ring, and it looks OK.

As I don't need to make the watch waterproof, I may just use it without the ring.

They can sometimes need quite a bit of pressure , i have broken an original Omega one in the past though (costly mistake) 

Could you try using the original tension ring ? if it fits without the new tension ring could be worth trying the old one