The new Omega Speedmaster is a sweet watch, I have zero complains about it. All the improvements made to the movement, made the watch even more appealing to me. From the movement to the bracelet, the watch has treated me well. Now, if you are like me, you can’t leave things alone, even if you have zero complains about them you have to change something, here is where Uncle Seiko comes in.
I have been a fan of Uncle Seiko mostly for the Seiko straps and bracelet options he has provided, to us, the watch enthusiasts over the years. Uncle Seiko has a lot of options for the Speedmaster in general. But the new addition, his interpretation of the US1450, was not an option for the Speedy 3861, until some surgical modifications were discovered by @twisted_trad (Instagram). He was able to fit the US1450 on the 3861 Speedmaster by removing the small tabs located in the back of the bracelet’s end-links.
US1450 End-links, top: with tabs. Bottom: tabs removed. 
US1450 by Uncle Seiko end-links
Just to make things clear, I have ZERO complains about the new Speedmaster’s bracelet. It is pure quality, the taper makes it really wearable, the finishing is great, it is really comfortable and it has not been a hair puller. Ok, maybe I do have a complain, that would be the micro-adjustments. But as soon as you get the bracelet to fit the way you want it, at least in my case, I haven’t had to change it since.
Now, going back to our medical procedure, the tools needed for this procedure, were:
- Wire cutters.
- Sand paper ( 2500 Grit for finishing and lower for material removal)
- Isopropyl Alcohol
- Paper towels
The best way to remove the end-link tabs is by using wire cutters. Yes, the tabs are made out of the same solid part as the end-link but they are not hard enough to present an issue for regular wire cutters.
After using the wire cutters I used two types of sand paper to get the end-links as flat as possible without any sharp edges and give the smoothness back and avoid scratching the case. I don’t have the exact grit of the coarser sand paper I used, but the finer one was a 2500 grit.
One side of the end-link after tab removal. 
Fitment of the end-link in the case.
Isopropyl Alcohol was used to clean up any metal debris left over on the end-links. A quick waterfall-like pour on one of the ends will suffice to wash away any left over metal sheds. The paper towel as you might have guessed was to pat dry the end-links.
The end result is a brand new bracelet for the 3861. Yes, ideally you’d wait for the manufacturer (Uncle Seiko) to make one that fits, or hope that the original Omega version fits the watch. I didn’t want to do either one of these, and I am grateful for @twisted_trad for sharing the wealth.
Uncle Seiko US1450 
Uncle Seiko US1450 Stamped Clasp 
Speedmaster on the US1450
Finally, the fitment. The end-links fit, as you would expect, if not I would not have put you through this, right? But if I am going to be extremely honest, the shape of the end-links, does not completely match the shape of the case. There is probably half a millimeter of “excess”. This is nitpicking, just like with the original bracelet, but there might be people that will be bothered by this, not me.
The pictures don’t do justice to the bracelet’s end-links. The excess appears to be more than what it actually is, but in the metal, it is barely noticeable. I would really not get discouraged to get this bracelet as is, and make the modifications yourself. On the contrary, I definitely recommend this bracelet if you are aiming for a more old school look and feel, or want to have more variety for your Speedmaster.
I hope you find this brief article useful. Let me know if you’d like to see more about this process or anything I could have missed that you could use.
DL