Sunday, 28 June 2015

Making a balance staff

Making a balance staff is one of the most demanding jobs in watch repair. This is because the balance pivots can be as small as 0.1 mm in diameter. Also, there are numerous clearances and tolerances to be taken care off. Over the years I have made and collected the tools required for this delicate operation. Last week I decided to take the plunge.

In the picture below you can see the balance with the balance spring and roller table removed. The old staff is on the balance and you can also see a balance staff blank. One can start with a blued steel rod but a blank saves a bit of time.

The old staff is removed. I did this on the turns because it is slower and offers more control. Care should be taken that the balance is not touched while cutting the rivet, nor should it be distorted during removal of the old staff.

Below you can see the blank mounted on the special runners I made for my turns. First, the seat for the balance is turned and then the arbor for the balance spring. The balance should be a perfect fit. Too tight and it will get distorted, too loose and it will be out of round. 

Here is the partially turned staff ready to be mounted on the balance. Mounting the staff at this stage eliminates the need of a dog.

And here is the staff riveted to the balance.

 Next, the arbor for the roller table is turned. Finally, the two pivots are turned. One can safely reduce these only to about 0.3-0.2 mm on the special runners. Beyond this the pivots are reduced on the Jacot tool. This is a special turns made specifically for reducing and rounding off fine pivots.

Below you can see the finished staff with the correct diameter and lengths of the two pivots. There is scope for improvement, particularly in the shape of the pivots and polishing. All the same, it feels nice to be able to make something so tiny and delicate.

The proof of the pudding is in the eating. So, here is the staff during a test assembly-

Kind regards


Monday, 25 May 2015

No.6 Skeleton Wristwatch

It gives me great pleasure to present the No.6 skeleton wristwatch. This is a new direction for A D Sambhare watches, Big and bold!

No.6 has a fully skeletonised Swiss ETA-6498 movement with hours and minutes. 

The Swiss made 316L stainless steel case is 44mm in diameter (excluding the crown), 11mm thick and has sapphire crystals front and back.

'Big and Bold'  also describes this rendition of the blued steel 'Sambhare' hands.

ADS logo at the 12 O'clock position.

The escapement.
Kind regards


Monday, 30 March 2015

No.4 on a bracelet

I put No.4-00 on a 20mm bracelet I had and I am very pleased with the result. Over the past year this bracelet has adorned 4 or 5 of my watches but I think it belongs here :-)

Wednesday, 21 January 2015

Uprighting tool

I bought this tool off ebay a while ago. An un-jeweled hole can sometimes be worn to an oval shape by it's pivot. This tool allows one to centre the worn hole of a wheel with respect to the other, unworn, hole.

Unfortunately, it only came with the centering runner. So, I made a runner that can carry reamers of various diameters. Below, you can see what I made, a runner, a grub screw and a reamer. The reamer is a bit rough but I shall make another one. This is because now I know what dimensions are required.

And here is how the the whole thing looks assembled.

I tried this on a junk movement. Below you can see how the unworn hole is centered and the movement is secured.

After this the bridge with the worn hole is fixed to the plate and the reamer is passed through it.

The reamed hole will need a bush and the hole in the bush will need to be opened up to the correct diameter. Altogether, I am pleased that this works!