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Look at that! A new toy :) DIY pivot drill


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To many watches are waiting the wonder (somehow getting new pivots or staffs) disassembled in the shelf in small boxes. So i decided to put every other projects aside and make a pivot drill. 

First, the dimensions of the tool were determined after measuring pictures found on google :) Damn is it tiny! 50x40x10mm brass was drilled through with 3mm drill on a table drill press. 

2016-06-04 17.48.30.jpeg

The middle was sawed out to leave 10mm and 12mm wide headstocks. The hole on the 12mm side was reamed to 3.175mm for the carbide microdrill shank diameter. 

Female cones from 3mm blue steel with 0.4mm hole at the end and from 5mm steel with 0.5mm hole were turned on the Dremel and ER20 "lathe" respectively. These holes are for the current gear staff to be drilled but i will need a series of cones later. 

Well, its ugly yet, i know :) 

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But the drill cought right the center. 

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And now you can guess if i have big collets to turn the pulley wheel  :/ 

 

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To many watches are waiting the wonder (somehow getting new pivots or staffs) disassembled in the shelf in small boxes. So i decided to put every other projects aside and make a pivot drill.  Fir

Here we go... The set comprises the tail stock attachment, an alignment tool, the drill holder, and 2 collets. This is the drill plate with a variety of different hole sizes, all with

I hav bought a Stowa pocket watch 11 months ago with both balance pivots broken. Now i had repivoted both and of the staff.   

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you really struck on a great idea here. and it's well executed. tell me: how is the wheel held to the center? i missed that part. is it held by the bit? how can you tell if the drill runs true without any runout?

you did an excellent job on this!

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19 hours ago, ramrod said:

you really struck on a great idea here. and it's well executed. tell me: how is the wheel held to the center? i missed that part. is it held by the bit? how can you tell if the drill runs true without any runout?

you did an excellent job on this!

The wheel is held between centers, like on professional watchmaker turns :) The first picture shows that both holes were drilled with one drill, so both are centered.

The right side hole is then reamed with the 1/8 drill (for the drill stock diameter). And the female cone on this side is turned down to this exact diamater. So the drill put in the hole is aligned exactly to the center of the female cone. 

The book says that the center should be found on the workpiece to lead the drill so a tiny untrue of the drill is not an issue. In this case however, the drill found its center. 

My 13mm collet still not arrived, but the tool ordered later is already here ... arrrgh...

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And one more important thing. The right female turn most sit ona completely flat face and square to the tool side. This was chieved by sanding on a sheet of glass with wet sandpaper while holding it with a perfectly squared aluminium piece.

Edited by szbalogh
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Added the pinion-end polishing feature to the tool :)

2016-06-07 22.05.10.jpeg

After finishing the plate (0.4mm thick) with 0.1, 0.15 and 0.2mm holes quickly mounted one balance with one broken pinion. The broken end is on the left side. Recognized that the healthy pinion is barely sticking out of the hole so cones with small drills were made in the plate sinc the picture was taken. Now a decent part of the pinion is sticking out on the other side of the plate. 

I can change the hole size by adjusting the plate height :) Yes i have to make the plate narrower and those screws are from a watch so need to make some screws here. And some nice looking M3 screws with good looking heads for tightening the cone rods. 

 

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  • 2 weeks later...

Using it as a staking tool :D 

Driving the 0.4mm pinion turned in the Dremel "lathe" from a 1.5mm HSS drill bit into the predrilled 3rd wheel staff. The pinion succeded for the 3rd try. The first one flew on Earth's orbit. The next one was caught with a nylon bag but it was too thin. 

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The first repivoting in my life :)

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Now i need runners for pinion burnishing. This is the back of a broken 1/8 carbide drill. Tapered, drilled with 0.4mm and i will grind it down to half. The final pinion will be 0.27mm. 

2016-06-16 21.35.52.jpeg

 

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You may have been better using a piece of tool steel dressed as a burnisher.  The idea is to work harden the the surface to a very hard smooth finish.  Polishing only will look great and work OK for a shorter period of time than if you had burnished the pivots.

Great job you've done though!

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  • 2 weeks later...

Would it be possible to drill a escape wheel with this drill? Have an Alpina pocket watch 355 that needs a new pivot in one end. It has been here so long. I can't find any parts for it? 

HELP !!!!

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Would it be possible to drill a escape wheel with this drill? Have an Alpina pocket watch 355 that needs a new pivot in one end. It has been here so long. I can't find any parts for it? 

HELP !!!!

 

Yes, but not by me. I have not enough experience with the tool. Till now i could succesfully repivot only one 3rd wheel which has 0.37mm pivot. Two drills were broken in two balances, but leesson learned. Dont wanted to remove the roller table and i couldnt anneal the balance becouse the roller jewel shellac. Since the balance was to hard the 0.2 drill could not drill itt so i had to predrill it with 0.1mm drill. All went fine untill i took the 0.2 drill and pushed it to hard. It was sticcking into the hole and snapped the tip of the drill. And made the same mistake in another balance when i realized the problem. 

However, the other end of one balance was succesfully drilled thereafter. The wider drill has to be really slowly pushed forward. So it is possible to drill not-annealed staffs with carbide drills.

Edited by szbalogh
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There is a tool which is specifically made for this job. I have seen them on the bay & I have always been outbid. I think I see a post where a guy made one but can not find it on the net just now, In theory you could do this with a watch makers lathe but i have not tried it.

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57 minutes ago, clockboy said:

In theory you could do this with a watch makers lathe 

Yes, but You need to make an initial cone or hole that is leading the drill and the staff to be drilled must be perfectly centered in the collet or the drill will break. The drilling tool solving both problems. 

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Lorch (and no doubt others) made a tailstock arrangement for their lathes which comprised a plate with a circle of varying sized conical holes which could be brought into alignment with the axis of the lathe,  mounted onto a hollow shaft into which a drill holder could be inserted, specifically for re-pivoting work. I have one somewhere, will post a pic later.

 

 

 

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Unfortunately my lathe (Star) has a very slight mis-alignment between the tailstock & collet end so drilling is difficult.

I guess at some stage it must have be abused or dropped but I still manage with this minor fault.

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Here we go...

100_9263.JPG

The set comprises the tail stock attachment, an alignment tool, the drill holder, and 2 collets.100_9262.JPG

This is the drill plate with a variety of different hole sizes, all with a conical profile so that the staff to be drilled stays aligned.

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a 0.42mm spade drill in the drilling rod.

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and how it fits through the back of the drill plate.

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All together on my 6mm Lorch Triumph with the alignment tool in place.

I have not actually used this in anger as yet so I don't know how well things align between the head stock and the tail stock, but I would imagine that this set up is probably better used with a safety pulley type set up which would mean that you would be working between centres. I do have a safety pulley but it is for my BTM 8mm lathe, and this kit doesn't fit that. My lathe bits and pieces are somewhat eclectic as they have gradually been accuculated from a variety of sources and although the BTM is up and running, both lathes still need parts to get the best from them.

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And an assortment of drills which I think go down to 0.1mm and up to 1.1mm, although above 0.5mm they don't fit this rig.

 

This is my other pivot drill.

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Almost exactly what SZB has built.

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Sadly I have no drills to fit this.

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I'm always amazed by peoples creativeness. A watchmaker/repairer thinks to himself/herself you know what I need to drill holes in a staff to fit a new pivot what shall I use. Oh damn there isn't a tool I know ill draw one up and have it made incredible :D

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This balance was drilled but the bit was broken so o had to grind down the staff. Now it is drilled with 0.3mm drill and the pinion wire grinded from hss bit is fitted. 

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The tool is motorized and fancy screws were made.

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With the adjustable puley wheel distance it is now totally safe for the drills. 

Now my question is how to measure the two endstonesdistance?

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Oh boy took it long to grind down the pinion to correct length... But finally it has basicly no endshake and spinning freely. Quickly added the hairspring and watched it swinging and swingigng.... :)

https://www.dropbox.com/s/1ejz57v9cv2j3cm/2016-07-14 15.11.36.mp4?dl=0

The wheel is not true. This is becouse i was not carefull and started drilling without shaping a proper cone end on the staff after grinding down the broken drill. So the second hole was not centered. Since the video i have trued it to some extent. 

The roller jewel however broke off when the balance fell off once from the tool accidentally :( It has oval impulse pin so it will be hard to replace. maybe a new jewel grinding job... we will se :)

The left pinion is the new one. 

2016-07-14 17.14.24.jpeg

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If when you spin the balance you find that it always stops in the same spot then adjustments will have to be made to the balance screws via tiny weights (tiny washers) to get the balance true. Getting a balance truly balanced is a difficult job & requires patience. 

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7 hours ago, clockboy said:

If when you spin the balance you find that it always stops in the same spot then adjustments will have to be made to the balance screws via tiny weights (tiny washers) to get the balance true. Getting a balance truly balanced is a difficult job & requires patience. 

Yes yes, thank You! It has to be trued and balanced. Movement side it always stops with the impulse pin hole up. If i get the required jewel (Ellipsenstein in german) i will balance it for sure. 

Meanwhile i could not resist to try it, so glued a square pallet stone with nail polish and reassembled partially. It will work!!! :) 

 

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