This is for my Gemini 4 Cal. 1861. I ordered the 3570.50 model with the spacer ring. With or without the ring, there is too big of a gap even when the caseback is screwed in as far as it can go. Is this the correct back and spacer for my model? Compared to the OEM sapphire back, the thread lip seems like it's too steep!
I have had three of these installed, and all were fine. I'm sure Priek will make it right if you contact him.
The problem is you are trying to fit this to a model which already has a display back, the Gemini4 back is a display back with a graphic inside the crystal. The display back models have a different movement ring than the metal case back models, you'll need to order a standard movement ring for a 3570.50. Once you fit the movement ring you should be fine.
Thanks! That makes sense now. So I should ask for a ring with which model ref? BTW, the display back that got for my Sub looks great:
I think you will have to replace the movement ring (enlargement ring) with a movement ring for the standard 145.022 model. The movement ring is the ring around the outside of the movement which holds it in place against the inside of the case. All the 861/1861 Speedmaster cases and movements are the same size and fitment Part number is 079LC0861C and can be ordered from Ofrei or Cousinsuk. http://www.ofrei.com/page670.html its here near the bottom of the page. There are normally a few on ebay too. It is relatively straight forward to replace but you will need watchmakers screwdriver and magnifying glass, unless you have a watch maker to do it for you. But if you have already removed the case back then I assume you must have some watch makers tools?
This is a very simple swap - just remove the case back, remove the 2 movement screws, lift out the enlargement ring, drop in the new one, install the 2 screws, and then install your case back.
Thanks for all of your responses. I'm glad that I asked here before contacting Thomas --I was pretty sure that the error was mine.