BB58 Clasp Hack
How to add the missing fourth Micro Adjustment.
The Black Bay 58 is one of the best watches for value you can get today. There’s not much to criticize.
Except for two things, an on-demand adjustable metal bracelet and no half-links.
In a quest for perfection, fellow watch enthusiast Ironcastle drilled a 4th micro adjustment into his Black Bay 58 clasp and agreed to share more details from his WatchUSeek Forum Post.
Note, this is a permanent change to your clasp, but does not require an extra part. You will need to alter one BB58 link by filing off its rivet.
If you want a reversible approach, the BB58 Retrofit with Rolex EasyLink allows for tool-less micro adjustment (5mm) while also acting as a form of half-link.
Manufactured Solution
I’m pleased to have found Steel Reef has a simple manufactured Extension Link. Their solution solves not only for the Black Bay58, but also, Black Bay GMT, Chrono, 36, 41, Harrods, Heritage Ranger and more.
The Steel Reef solution is way simpler, reversible and much more cost-effective than a retrofit.
Can I Just Buy from Ironcastle?
Ironcastle and I corresponded about this, and it comes down to the person asking and the eventual expectations. Reach via WatchUSeek or Klocksnack (Swedith forum)
Similarly, to the reversible Rolex EasyLink approach this is truly open to only fellow watch enthusiasts with an established history. IronCastle frequents WatchUSeek and Klocksnack.
Tools
Extra BB58 removable link from your set.
Alternatively, purchase extras from eBay. Get better pricing knowing that all the links from the Heritage M79230N in 16mm also works.
Pillar Drilling Machine or Drill Press, Wire Gauge Drill Bits and Cutting Oil.
Specialized Micro Drill Bits 0.9mm.
Hand Dremel Rotary Tool with Diamond Ball for Deburring and Felt Wool Wheels with Mandrel for polishing.
Water Sharpening Stone.
Sliding Callipers.
Gauge (an aluminium square profile).
Here’s the End Result
Once installed, you’ll have a 4th microhole resulting in a “half-link” or custom measurement you had chosen to drill for your needs.
Unless you only did a very minor level of micro-adjustment (which will look quite strange with microhole spacing), you’ll also end up with a modified BB58 link where the rivet is filed away.
4th Microhole
If your wrists tends to expand and contract make sure to measure somewhere in between.
Pictured on the Wrist
Wrist size shown is 17.6cm.
Prepping Your Clasp
Measure Thrice
Ironcastle measured the distance between the holes to be 2mm and the diameter of the microholes to be 0.9mm. This gives the center distance of 2.9mm.
In this approach, the microholes 4th microhole is uniform and the same distance apart as the other three.
Also, take into consideration between hot and cold temperatures. Some folks wrist size may fluctuate more than others, so measure in between, or consider your environment where you wear your watch the most.
Polymide Tape
Normally used to mask selected watch case surface areas during polishing and buffing.
Modify Your BB58 Link
Progressively enlarge using wire guauge drill bits.
Protect the Clasp and Mark
Cover the Clasp with Polymide Protection Tape to,
- Protects and allow you to mark the tape for drilling.
- Protect the clasp from scratches when handling.
The Polymide Tape is heat resistant and leaves no residue after removal.
Triple Check Before Starting
Drilling in the right position is the tricky part, and this comes down to three things,
Making the First Mark on the Right Spot – in the protective tape (which I did with the sliding calipers).
Punching in the Exact Spot – carefully line up to what you marked out. Take your time as we´re talking tenths of the millimeter here.
Drill to Exact Mark – line up your drill to the punch stroke and make sure to wear safety glasses.
Drilling the Microhole
Machine Drill
Ironcastle used a pillar drilling machine; an ordinary green Bosch with adjustable RPMs. The micro drills are from HSS-E steel which makes them suitable for cutting stainless steel among other materials. The RPM was set to 500 rpm.
Both sides of the holes were then deburred. This was done with a Hand Dremel Rotary Tool fitted with a 7105 Diamond Ball Point, 1/8″ Shank, for the inside of the clasp. The outside of the clasp, was done by hand using a slightly bigger drill bit.
Filing Off the BB58 Rivet
Wet Stone Hand File
With the fourth microhole position, in almost all cases, we will need to file off the closest BB58 rivet.
And keep in mind, it will be hidden within the clasp.
This is because the width of the clasp does not fit.
Initially, Ironcastle tried a hand file, but does not recommend this.
He found the best method, to be a water sharpening stones from Naniwa.
Ironcastle also used a gauge (an aluminium square profile), to create a perfect perpendicular surface to lean the link piece against, while filing.
After the rivet is filed away, you’ll want to polish the link.
For polishing of the modified BB58 link, Ironcastle turned to his dremel and fitted on a Felt Wool Polishing Wheels (with Mandrel) applied with Dailux Blue Jeweller’s Polishing Compound.
Rivet Filed Off
The rivet needs to be filed off to fit between the clasp. Keep in mind it will be hidden inside the clasp.
Assembling
The final moment of truth! Provided you measured correctly, you now have a custom size watch that fits perfectly.
As a reminder, when taking into an AD (Authorized Dealer), make sure to swap out the bracelet. Rolex may give you a hard time with it, or commend you for your ingenuity.
Some Caveats
Black Bay 58 Assembed
And the final product with a 4th microhole for that custom.
Ironcastle and I had a really great discussion on this topic, as we compared to the BB58 Retrofit with Rolex EasyLink.
Every solution has some caveats to consider.
Not Reversible – You get one shot at this, so measure thrice. Formally, Rolex will only give you a part if you trade in your old part and bring a full watch.
Servicing Bracelet in Future – Along these line, we are unsure if Rolex will service or polish your bracelet.
No Tool-Less Micro Adjustment – This impact those whose wrists significantly change between hot and cold while like preferring the tailoured fit.
Having said that, this approach does not require extra parts.
Special Mention
Photo – All photos were taken by Ironcastle in his garage.
Content – The majority of content of this article came from Ironcastle. I just did the editorial.
Banner Photo – courtesy of Jimkar from WatchUSeek.
Wheels and Watches – Has a nice video on how the 4th micro adjustment works.
What an amazing job! Are you will to take on my bracelet for a price? Please email me back if you are interested or if you can point me in the right direction.
Hi Anthony, I’ve also emailed you below.
For those also having trouble, sign-up to WatchuSeek and then go to Ironcastle’s profile and click Start a Conversation.