Drilling lugholes experience

[vortx]

This is an old post I found while browsing archives for info on my resurrected 1665 project.

Originally posted by davethecat on thereplicacollector.com

Thanks to davethecat for helping me on my way! Hope you guys will find this as helpful as I did.

The post:

OK. I survived. After reading all of the tutorials on this subject over the past year, I decided to mod my own MBW DRSD. Afterward, I thought that it might be valuable to the group to post some practical tips that I learned along the way. Call this "through the eyes of a naive but fearless novice".

1. Don't start this project unless you have AMPLE time to commit to the project. Don't do what I did. I had a two-hour window prior to a social commitment. I found myself having to disengage and then pick it up later only to spend my Father's Day eve awake until 3a. I woke back up at 6a and finished everything by noon. I can see how this project can go very easy, and how it can get very hard. I suspect that every attempt is different based on the material you are working with and the impact of a millimeter here and a millimeter there.

2. Two words: Proper tools. Just because you have a Dremel, it doesn't mean you have all of the tools you need. I used practically everything I had.

3. Use a power drill, not a Dremel. Save the Dremel for polishing the finished product. Any garden-variety drill will work. The Dremel simply spins too fast to do the job well. A power drill also has enough mass to add leverage to the job. I found that to be a big help.

4. Buy lots of drill bits. Specifically, buy lots of cobolt (or better) drill bits. You never know when one will break or dull along the way. As much as you will want to work this project to completion in one sitting, don't create a hard stop by running out of bits.

5. Don't be cheap. Pay attention to how your bit is cutting. If drilling starts to get slow, there is a good chance that the bit is getting dull. If you even remotely suspect that you have a dull bit, change it. Worst-case scenario, you waste a $3 bit. Better to waste a $3 bit than a $400 MBW case.

6. Cobolt bits hurt. If you are holding the case in your hand as you drill, make sure that your finger is safely away from the exit hole when you break through. Otherwise, well..... If you think cobolt slices though SS like butter, just wait till you see what it does with flesh. :-(

7. Use the right oil. For the first half of the project, I used some old Slick50 PTFE-filled spray lube. I thought it was a decent (perhaps better) substitute for 3 in 1 or WD40. It worked OK, but not great. I switched to WD40 when I started on the bracelet. It worked 2x better. Make sure you lube both the hole and the bit.

8. While drilling, remove metal a little at a time. Counter synch the bit back out of the hole regularly. This "excavates" the metal out of the hole.

9. Drill on a perfect axis. Entering at an angle will oval the outer hole and will ultimately freeze the bit. Even when you are at a perfect 90-degree angle, don't become complacent. Too much pressure on the bit will bend the bit as it turns, creating an ovaling of your outer hole. I can't stress this enough

10. If you oval a hole, don't over compensate, don't try to fix it. Let it be - it adds character & makes the watch look more age-appropriate. Maybe a blessing in disguise? When you polish up everything at the end, it ends up looking much better & much less like a mistake. Furthermore, almost any tool mark adds to the believability of the age of the watch. Keep that in mind as you work. At the end, there are very few tool marks that can't be recovered with a little Simichrome or a Scotchbrite pad.

11. When you have successfully drilled the case, don't become complacent or overjoyed. I assure you that the hard part is yet to come. Drilling the bracelet was 2x harder than the case, and then adapting the end links was 2x harder than drilling the bracelet. Finally assembling it all back together was 5x harder than anything else I attempted.

12. End links. What can I say? If someone out there has a secret to what works, I'd love to hear it before I attempt to do this next on my 6541. The fold-over end links have a metal loop that appears to be tacked welded to the larger piece. On one of my links it was tacked at the top and loose on the bottom. The other rings were tacked both at the top and the bottom. It's too thin to drill out. I tired to bend and enlarge the ring as much as I could. There was solder material inside the ring, so I had to use a Swiss file to smooth the path out. I reamed the inside of the rings with the drill and that seemed to help too. I also used a circular and triangular Swiss file to bend and ream the metal at the same time. This part took me forever. I sincerely thought at more than one point that this was going to be the part of the project that ruined everything. I even went as far as doing a mid-project eBay search for replacement end links. No luck.... back to work

13. The end links get bent very easily. I assure you, if you bend an end link in an odd place, this whole project can turn into a nightmare. I bent one along the center-bottom cross bar. Afterward, re-bending it to fit, while still ensuring a straight axis though the spring bar path was quite a task. Also, watch out when you are reassembling the watch. The bottom corner-bend on the end link can bend easily as you try to pry the spring bars into place. If that happens, you need to observe the movement of the bracelet against the bent out portion of the end link. If it wears against each other, you have a big problem. End links aren't easy to source, so don't screw yours up.

14. Like the end links, there needs to be more discussion on how to drill out the bracelet. If you try to hold it in your hand and drill in a similar fashion as you drilled the case, you will quickly learn that you need a new approach. The bit will freeze in the hole and then the bracelet will spin violently until you stop the drill. It doesn't matter how strong you are, you wont be able to overpower the drill by hand. A quick search pointed to a tip that made the difference: Using a long nosed pliers, camp the bracelet lengthwise along the bracelet's center link. When it starts to work, see point #1 "Take your time!" Oh yeah, an ancillary & implied tip is "keep your computer close in case you need to search for tips." :-)

15. A set of Swiss files is absolutely critical. Go to Ofrei's and buy the real deal. If that's too steep, Home Depot sells a decent hobbyist set for about $15. I used these at several points along the way.

16. The second hardest thing I encountered is getting the thing back together. You've drilled, bent, reamed, etc. and now the tolerances of all of the changes compound on themselves. Trying to get the re-assembled end link and bracelet back on is a [censored]. By the time you get to this point, you will be inpatient. Resist cutting corners because any slip of the spring bar tool or screwdriver will mar your case.

17. Before you try to assemble everything, use your Swiss files to smooth out any drill entrance or exit. Pay very careful attention to the inside of the case holes and the bracelet middle link. If you ignore this, expect a terrible time trying to assemble the bracelet. In effect, the rough dilled-out lip left on the case and bracelet holes adds a few millimeters to the width. The tolerances are too tight to assemble everything smoothly. If you do happen to get everything back together with these exposed rough spots, you will in effect have a grinding pattern where the rough spot hits other pieces of metal. That cant be good over time. Be smart, clean up/file-down your mess.

18. When you finally get to the point of polishing up everything with your Dremel, soften the edges of the case and the bracelet to add to the faux aging of the case.

19. Simichrome is OK, but a rouge cream works better.

20. Now I know why they say "Do it yourself, you will get much more enjoyment when it is YOUR work." What they are really saying is: "If you manage to take this on by yourself, expect to go to the depths of hell in depression as you narrowly miss screwing up your pride and joy. When you manage to salvage everything and start back down the right path, you will be elated. It is quite a rush when you get to the moment that you realize that you can stop dictating in your mind your "Help Joe/The Zigmeister/Palp/Tommy !!! I screwed up big-time...." email.

[vortx]

2mm SPRINGS BARS:

Geniune or very good aftermarket Spring Bars for the models we most covet,

1665,1680,1675,16800,16610 will measure:

center section: 2mm x 19.7mm*

depressable ends: 1.2mm in dia.*

extended overall length: 25.25/25.57mm (.994/1.006")*

You will, no doubt, see them advertised in all sizes and dimensions,

claiming to be what they are not. Use good judgement before making

your purchase and avoid dissapointment. There is plenty of good

information to be gleaned on this board as to where to acquire them

from the many capable and talented members.

Please keep in mind, the advertised dimensions are meant to show

relationship to an application. These dimensions may seem

cut and dry. In reality the spring bars do not have a true

2mm diameter main body, nor do the ends measure 1.2mm.

These measurements indicate the bore diameter in which they are to

be inserted, therefore, the true diameter of the respective part of

the spring bar will (should) measure:

ENDS-Diameter: 1.187/1.190mm (.0467/.0468")*

MAIN BODY-Diameter: 1.978/1.980mm (.0778/.0780")*

NOTE: *These dimensions acquired from 20 sample spring bars*

This differential allows for compliance in the bore,

just .0005" will make the difference between go and no-go.

[Cats]

Good tutorial this is very handy when i might consider doing it my self one time.

Do you have any experience with springbars that don't come out into the lugholes at the same depht.

I have a 1680 cases were one springbar end almost doesn't get into the hole.

A know for shure it's drilled properly at the good dimesnion and the springbar fit's properly without the bracelt atteched.

Thanks for sharing this info.

Carpe Diem

Cats

[Toadtorrent]

Very good write-up. I write-ieups like this are as important if not more so than the write-ups from the experts and professionals, as your experience is the one that most people would be entering in from.

It's very important and useful to have experts write-up how things should be done, but equally important to document the experience of somebody new to this kind of work, as the issues are quite different, and the things some folks take for granted (e.g. oil choice) are not things to be overlooked if you're new to the process and experience.

Great contribution!!