Bergeon 4266 maintenance?

[MartinOfPrague]

Hello, I bought a used Bergeon 4266 crystal lift, and there is a problem - it looks that the jaws do not grip the acrylic crystals sufficiently and in most cases, they slip even at the lightest attempt to tighten. I examined the brass jaws under a loupe, they seem worn to me. Is it possible they need to be sharpened (shaped), like screwdrivers? Is it even realistic to do so without special tools? Or was it downright bad idea, to buy this kind of tool used?

[RichardHarris123]

Photos would help. 

[MartinOfPrague]

All right, I'll be back with photos.

[Geotex]

Are you certain you are using the tool in the right circumstances? Many (most?) crystals are not shaped appropriately and should just be pushed out manually for removal and inserted using a press tool rather than a lift. Front-loading movements that specifically require a lift will use crystals that have sufficient flat surface on the side of the dome to accomodate the lift. Another point is that if you are using a lift for insertion, the lift must engage part way up the side of the crystal rather than flush with the base. The lifts are initially sold with shims or jigs in order to accomplish this, but those may not be included when you purchase a used lift.

[JohnR725]

in addition to the photos the tool photo of the crystal your trying to work with would be also helpful

[mikepilk]

1 hour ago, MartinOfPrague said:

Hello, I bought a used Bergeon 4266 crystal lift, and there is a problem - it looks that the jaws do not grip the acrylic crystals sufficiently and in most cases, they slip even at the lightest attempt to tighten. I examined the brass jaws under a loupe, they seem worn to me. Is it possible they need to be sharpened (shaped), like screwdrivers? Is it even realistic to do so without special tools? Or was it downright bad idea, to buy this kind of tool used?

The internal rubber gasket has perished. I had the same problem. Cheap and easy to replace

[tomh207]

It’s not a big problem to strip it, clean, lube and replace the ring. It’s the cheapest bergeon thing I’ve bought so far.

 

worth doing, mine works really well now

 

Tom

 

[mikepilk]

25 minutes ago, Geotex said:

Are you certain you are using the tool in the right circumstances? Many (most?) crystals are not shaped appropriately and should just be pushed out manually for removal and inserted using a press tool rather than a lift. Front-loading movements that specifically require a lift will use crystals that have sufficient flat surface on the side of the dome to accomodate the lift. Another point is that if you are using a lift for insertion, the lift must engage part way up the side of the crystal rather than flush with the base. The lifts are initially sold with shims or jigs in order to accomplish this, but those may not be included when you purchase a used lift.

I use the crystal lift to fit all my acrylic glasses. You need to use the base to make sure you grip the acrylic in the right place, to avoid damage. I would try fitting with a press tool as shown in the Sternkreuz catalogue.  I could use my cheap caseback press for the top plate, but I don't see anywhere to buy the lower convex rubbers pressure plates. It says it should be about half the size of the upper plate, but Cousins only show convex sizes of 38mm +.

 

 

[MartinOfPrague]

46 minutes ago, Geotex said:

Are you certain you are using the tool in the right circumstances? 

Thanks @Geotex! My tool came with a shim/jig (even with the adaptor for oval-shaped crystals), but I did not know the crystals for front-loaders Are shaped differently.

So, is there a common view among watchmakers that crystal lifts should be used for front-loaded watches only? As a newbie in watchmaking, I thought crystal lift could be the easiest way to replace a crystal which is cracked of scratched beyond polishing - without the need of taking movement out of the case.

37 minutes ago, mikepilk said:

The internal rubber gasket has perished. I had the same problem. Cheap and easy to replace

Thanks. I disassembled the tool and indeed I noticed the gasket is very tired, I just wasn't sure how big is the impact to the usability of the tool. I will order a new gasket, then.

Edited January 28 by MartinOfPrague

[tomh207]

Whether front loader or not this tool is for acrylic crystals without a tension ring. You also want the jig that will hold the crystal correctly so you can pick up the new crystal correctly using the crystal lift.

 

one of these

Tom

 

 

[MartinOfPrague]

2 hours ago, RichardHarris123 said:

Photos would help. 

Here are the pictures. I hope you can judge something from them. The last one is the poor old beater I am practicing with – not the best crystal shape for a crystal lift indeed, I reckon.

I also noticed these notches in the aluminium body of the tool, they look like an excessive wear rather than design feature to me, but I am not sure. Could they be a part of the problem?

[Yani365]

The tooth edges look ok. You don't want them so sharp that they actually cut into the crystal. Rather, the force these apply is inward towards the center point of the crystal.

The jig that #Tomh207 shown above is used to allow a space below the lift when using the lift to install the crystal. This ensures that the crystal edge will have enough exposed edge to enter the case edge. 

Some crystals will have too much of a slope to allow the jig to put force towards the center without slipping off. Those crystals will usually be able to be removed by hand, pressing them out from below. If needed, a press could be used, gently, to remove the crystal. Reinstalling those crystals may require a different tool than the lift you have. #Mikepilk shows that tool above.

Let us know how it works out!