Two pieces of stainless steel billtes will be used to make the watch.
I've sliced a thin piece to create the case, the bezel will be turned from another piece of 316L stainless.
The case body is being faced off.
The case is to within .25mn of final thicnkess (case will be ca. 4.6mm thick).
Boring out the center hole, to an intermediate diameter.
Turning stainless steel requires many stops, as the stainless steel gums up on the tool bit and needs to be removed often.
Turned initial shape opening.
This now needs to be marked for squareness.
The case center is placed on a dividing head, and marked at 90 degree intervals.
These marks are then scratched on the lathe.
The case is squared and from these marks the case sides will be etched to be cut at another point.
The interior is opened to within .25mm of final smallest diameter.
Here I am turning the glass back seating.
Glass back seating turned.
Turning the front area that seats the movement.
The area that is to threaded is turned to size.
Installing the change gears on the lathe, and spindle handle to hand cut the threading.
The area to be threaded is painted black so that the cutting of the thread can be easily seen.
First cuts of the thread on the case body.
The threads are cut for the case body to accept the bezel.
The bezel is worked on. The excess steel has to be removed to be able to cut off the bezel.
Turnign the area that is to be threaded so that it attaches to the case body.
The area to be threaded is painted blac, and the threading started.
Mating the case body to the bezel. There are some adjustments to be made, but it is a good fit.
Detail of the bezel thread.
Next, turnin the dial seating on the bezel.
Marking the case sides.
Squaring the case, these lines are inscribed on the front of the case.
Further turning of bezel area to be able to part off the bezel.
When turning I have to stop ofgten to remove the material as stainless tends to cut into long threads.
I choose to saw off the bezel, while it takes much longer, it allows me to reduce waste, as the remaining stainless part will be used for the buckle.
Stainless bezel to be dressed.
Turning the front flat.
Turning a bevel on the bezel.
Fitting the bezel to the case.
After testing with the movement, the bezel will be reduced by .6mm in thickness.
The case is marked out again and ready to be cut.
I score a guide cut on the case with a slitting saw.
Then I proceed to cut the case with an end mill.
Milling of the side of the case.
Further fine milling will be carried out after the other sides are cut.
The other side is started
Near to final dimensions.
Two sides have been milled off.
Here I have started the 3rd side, the area of the lugs.
It is placed with some brackets to give it more rigidity as there was some chatter resulting from the thinness of the case sides.
Milling away the last side of the case.
Bottom of case finished.
Temporary case shape.
Since the case sides are off final measurement by about 0.3-0.5mm I use a fine diamond grinding stone to bring them to size.
This also corrects any unevenness during the cutting of the stainless steel, as the vintage milling machine I use was originally designed for softer steels.
The finishing from the grinding wheel. This will be removed with a straight line brushed finish.
The case is measured and adjusted to be rectangular, as there are slight inaccuracies in the squareness of the case.A
A look at the back, before being finished, and before milling out the hidden lug area.
A first tentative view of the watch (these images were taken before the case sides were worked on.
Another initial view, the strap is simply placed near the case.
The area for the hidden lug attachments is marked out on the rear of the case.
The case is placed in a vice, and supported so that it is not marred be vice body or jaws. Guide holes are drilled on each end of the strap slot.
One side of the lug area is milled.
Marking out the first corner of the lug area. A guide hole is drilled so that the corner can be sharp, as the diameter of the milling cutter would not permit such a close angle at the corner.
Second guide hole is drilled.
Other lug are milled.
Hidden lug area milled, and will be finely finished.
This is how the watch looked as a square piece, and I wasn't happy with its wrist presence. Too large and not comfortable.
Drawing a test profile with markers and strap to get a sense of what the case would feel like when machined.
So the sides were tapered, as an aesthetic touch to the Royal Oak case.
The rotary table was centered.
Then the vice is trammed - so that its jaws are parallel to the X axis movement of the jig borer table.
Then, using a projecting microscope the case I measure the angle of the case taper.
Here on the projection screen you can almost make out the ca 27-degree angle around the perimeter of the projection screen.
Here is a detail.
Cutting the first angle on the case.
Placing a gauge block to measure the depth of cut against a known quantum.
Side of case is finished from machining marks
The case is then rough sanded to get rid of machining marks.
It has to be flat before further finishing can be done.
After the surface is comparatively flat, then I started to test a matte finish on the zinc plate with diamond compound.
Initial results of grinding the stainless case against low grit diamond paste.
Initial test with bezel.
Another view of case.
The edges of the case are beveled at a particular angle using a jig, and a diamond cup grinder so that the grinding cut acts as the finishing satined finish.
Views of the beveled edges on the case.
Another view.
Now the case tube hole, for the stem is drilled. Here I am locating where the hole is to be drilled with the centering microscope on the jig borer.
Drilling of hole.
View of hole drilled.
The stem tube to support the crown when winding is then turned from raw stainless stock
The hole is drilled.
Then further drilled, in order to maintain concentricity of the hole to outer diameter.
Outer diameter checked with a dial gauge caliper.
The final shape of the part is given and then parted off the rod.
The stem tube previous to insertion.
The stem tube is then pressure fitted to the case.
A special cutter is shaped in order to cut the sapphire gasket ring.
The idea was to have a gasket that was hidden inside the bezel so that the white material of the Hytrel is not seen.
Gasket inserted into the bezel.
Sapphire press fitted into the bezel. The gasket is not discernible to the naked eye.
The root of the bezel threads needed to be cleared away, so that the screw on bezel can be tightened properly.
This was done both with a hand graver, but also with specially ground fine tiped cutters.
The spring bar holes were marked out and center punched.
The hole is started by hand and then finished with a handheld drill.
Positioning the spring bar.
I chose to engrave the case inside the hidden lug area.
First I made a template at the correct ratio to be able to engrave the interior of the lugs.
This was placed on the pantograph and the case engraved.
On one lug it is written 'Coggiola'.
On the other the watch number, being the 8th I started work on.
Further finishing of the case to get each surface perfectly flat is carried out.
I did this by lapping the case flat on a lapping disc.
Then by grinding the face flat with diamond past on a glass plate.
The challenge is to get an entirely uniform surface, even a micron difference shows up when matte grinding. The challenge are the sides and interior areas of the case center.
Testing the view with the bezel.
Further grinding on a zinc block continued for many many hours.
Now I move to show the start of the crown. A piece of stainless steel silver soldered to a brass bar.
The weld is very strong and allows me to use a cut off from the same piece of 316L steel used for the case.
This is then turned on the lathe like a normal rod.
Giving the initial rough round shape.
Center drilling.
Drawing near to the final diameter.
This part is then placed in the optical dividing head on the jig borer to mill out the grip.
The piece is located with the centering microscope.
A test crown was made (one of 4) with double dimples, but I was not happy with this as it did not relate to the case in any meaningful way.
The process was repeated four times with different styles.
Here knurling the grip on the lathe.
The result.
Parted off the lathe and ready to be examined on the watch.
Crown 2 with fine knurling.
Crown 3 with thicker knurling grip.
The fourth crown that I liked best. The single dots relate to the dial.
The crown parts: Here case stem tube, then crown exterior and interior thread where stem screws on.
The two parts of the crown were silver soldered together, and cleaning and refinishing of the crown was necessary.
Outer part is being refinished on the lathe.
The interior groove, where the stem tube goes in has to be cleaned of soldering flux which becomes hard when heated.
To get a matte finish on the crown, it is rolled with a piece of soft wood onto the correct grit sandpaper, to mimic the finish of the case.
The crown given a matte finish.
Further finishing on the lathe, here the center convex area polished.
The outer side of the crown is ground on the zinc plate with diamond paste.
The finished crown.
After cleaning testing on the watch is done for correct depth of fit and eccentricity of its movement on the stem tube.
