Fitting a replica case back on a genuine DJ 1601?

[Timelord]

Greetings to all! 
 

This question may be a long shot but  I won’t know if I won’t ask?

 

I have a genuine date just case (reference 1601 made for 1570 mvt) without a back and was wondering if anyone knows if the thread on a replica case is the same pitch and measure so I can buy a replica  to close it until I find the genuine? Has anyone ever tried measuring it as I don’t have one to try ?  
 

Also,  if I recall correctly, the same thread dimensions were also used on the 18k day/date presidential as were on the SS date just!  I just can’t find the post on any of the other forums to confirm this?

thanks for any input 

[Ben]

I think somewhere like startime supply probably sell a 1:1 case back that would fit..

If not you've got phong, ruby watches that would be able to supply.

 

Or even a genuine - https://www.ebay.co.uk/itm/Vintage-Rolex-Datejust-1601-Caseback-Year-70-Part-/154536726876?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l6249&mkrid=711-127632-2357-0

 

 

 

 

http://www.customwatchconcepts.com/product_info.php?products_id=17

https://www.ebay.co.uk/itm/383145658971

[Nanuq]

I know the rep casebacks won't fit a genuine 1680, if that helps.

 

[automatico]

"I know the rep casebacks won't fit a genuine 1680, if that helps."

 

Yep, and I tried 8 or 10 replica DJ case backs on a 1601 case and every one had threads smaller than the 1601 case.  Even tried a couple repsub case backs and the threads were also too small.

Tried a rep 'tooter' case back for a 36mm toot and it was same as the rep DJ except for the writing on the back.

Found a tutone DJ look-alike with 'Bubbles' on the dial and the back will screw down on the 1601 case but the threads seem to be a hair small so I did not try to tighten it.  If you want it, send a mailing address...USA only.

 

Btw...I always lightly lubricate case back threads after I had a 16xxx DJ case back seize up solid on a case many years ago.  Finally got it to turn loose in a Bergeon 5700 case back remover but the threads stripped.  Hard to believe how tight it was stuck, it screwed down like normal except for about half a turn.

I use Chemours Krytox 205 on the threads and gasket.  You can find it reasonably priced on eBay, Amazon etc.

 

 

Product Description

Size:0.5 oz | Style:Krytox GPL205 Performance Lubricant Grease Krytox GPL205 Grease features an effective temperature range of -36C thru 204C. Base oil viscosity, 18cSt @ 100 C / 160cSt @ 40 C. Oil separation from grease, wt loss, % per 30hr @ 99C = 4. NLG1 Grade 2. Krytox GPL205 contains no additives and can be used on components that may come in contact with all chemicals including acids, bases, solvents and other reactive chemicals. Typical applications include valves, bearings, seal barrier fluids, instruments and oxygen systems. Additionally, Krytox Grease is compatible with all elastomeric seal materials and engineering plastics. See Krytox Greases GPL202 through GPL207 for applications that require higher temperature ranges and high viscosity needs. See Krytox Greases GPL215 and GPL217 for slow speeds or extreme pressure applications that require molybdenum disulfide additives. See Krytox Greases GPL224 through GPL227 for high pressure, highly corrosive environments such as automotive bearings, sealed pump bearings, and electric motors bearings that require anti- corrosion/anti-wear inhibitor additives. Krytox Grease provides exceptional performance, stability, and reliability in the toughest conditions – to maximize productivity and equipment life. Krytox Grease is undamaged by, and non-reactive with, acidic or caustic cleaners and disinfectants, steam, moisture or high temps. Krytox Grease is non-toxic, has no chlorine content or hazardous VOC materials, is odorless and silicone-free in formulation.

[horologist]

2 hours ago, automatico said:

, it screwed down like normal except for about half a turn.

 

did it screw down all the way up to half a turn before fully  tightening or only screwed down for half a turn? 
 

This is a great post, which is a very important part of horological but seldom discussed!  Thanks to the OP for asking as I was about to attempt to straighten dud threads on my gold 1601 using the case back of a replica!  I could have made it worse!  
 

years ago I purchased an 18k gold DJ 1601 (head only) with dud threads from a now banned member on rolexforums.com, but the case back threads were squeaking and chattering upon the last few turns!  My guess is that it is @#$& and I never attempted to open it again in case i would never be able to close it! I was thinking of sending it to the RSC but never did as they would most likely tell me that I need a new case!

[automatico]

"did it screw down all the way up to half a turn before fully  tightening or only screwed down for half a turn?"

 

It went on most of the way same as usual but got harder to turn just before sealing the gasket. 

[Timelord]

Thanks guys!  That was very helpful as I could have damaged my mid case if I had bought a replica case back!  Thanks Ben for the link! I also found a couple more !

 

7 hours ago, automatico said:

"did it screw down all the way up to half a turn before fully  tightening or only screwed down for half a turn?"

 

It went on most of the way same as usual but got harder to turn just before sealing the gasket. 

 Thanks for clarifying! 

seems like your case was galled where the threads cold weld which is a typical property prone for metals like stainless steel,titanium, platinum and worst of them is aluminium!

 

if the threads got stripped, it is surprising that it screwed down at all at any stage of closing as there would be little left on the walls of the case!  Maybe it wasn’t as bad as you could have chased the threads if you had a tap and die!  A spare case back (sacrificial) could be made into a tap& die by cutting a couple of lines at right angles to the thread and hardened by heat !  Thanks for sharing this experience!