Making Stems

[rauld]

Hi Folks, I recently had to make a stem for a pocket watch and lacking and cutting tools I just filed it out of 2mm stock. I was thinking of looking into some cutting tools so I could turn it which would produce a far better product. Can someone point me in the direction of the tools, not a lathe but the cutting tools? I would really like to produce something like user Horlogerie did in his post. Here are a couple pics of my failures and the finished stem.

 

Thanks, Raul

 

[Ishima]

How on earth do you go about making a stem that way without a lathe? 

[rauld]

I filed it down while holding it in a pin vise then threaded it with the Anchor tap and die set. It did take 3 tries to get it right and half a day. The top one was the one that made it. The bottom 2 were failures for one reason or another.

[oldhippy]

Without a lathe or in the old days turns would have been used, it would be a hopeless task , you might get it to fit but it will not fit shoulder to shoulder, the square won't fit properly. In other words it will be a poor fit, causing wear on some sides and none on the other. back in the 70's and 80's you could buy stems partly finished, the way of finishing to get the correct fit would be to use your watchmakers lathe.     

[szbalogh]

Do You have a Dremel? Everyone has a Dremel

Or two bearings and an ER collet.

 

[Ishima]

Ah yes, I've seen that before, was quite impressed, i have a hobby motor, but the collet/item shakes way too much, because it's a cheap silverline motor. 

Edited July 26, 2016 by Ishima

[rauld]

I was actually looking for some info on cutting tools used when making a stem on a lathe if any know where to get them.

Rauld

[oldhippy]

Here you go all that you need to know and tools needed.

http://great-british-watch.co.uk/how-to-make-a-windingstem/

[szbalogh]

In addition to the link above. For cutting You need a graver. I got mine from a local machine tool shop. Unfortunately it is a rod, a square one is the proper one. It is 3mm HSS Co10 rod. There is a video of "perplxr" on Youtube how to shape the graver with grinder or whetstone. 

An alternative can be tungsten gravers which are much harder to find. On e-bay You can get round ones for cheap from China 3-4 USD for a 3mm round rod in 100mm length. Or for small parts i use vinyl cutters. You need a fine diamond file or cutting blade to shape these gravers. 

But the hardest part is to file the perfect squares. In my video for the HMT stem my workpiece was mounted in the Dremel and its collet was aligned vertically or horizontally with a square ruler.

I shaped my file from a small flat file. First, made a perfect square edge with a grinder, than scraped the flat side with diamond file in two angles to get diamond shaped irregular "teeth". 

[rauld]

That's what I was looking for! Thanks guys!

[anilv]

This is for a Patek?

You could sell it as is and buy a lathe and some other goodies for your workshop.!

 

Anil 

[anilv]

Ooops...my bad, Patek was in the link!

[Brian3]

I agree with oldhippy here, you've spent a lot of time on that stem and considering you did it by hand it's an awesome job........but it really won't work, please don't use it as it will grind it's way into the mainplate and cause so many problems going forward. Only way you can make a stem is with a lathe as the centricity of the component is critical to proper operation.

Here's a pic of a stem I made at home on my little lathe, I filed the square while on the lathe too by using the locking pin, filing flat and rotating 90 degrees each time.

Graver I use is an HHS one, 4mm square that I grind to my preference and to suit the job in hand, real inexpensive too.

End result was good with both inner and outer hubs perfectly round and fitting the mainplate well.

Look for Boley lathes on eBay, not usually all that expensive and really worth the investment.

[oldhippy]

That look a good job Brian3 it has a good finish.

[Brian3]

Thank you oldhippy, takes as I'm sure you know a well maintained sharp graver as any imperfections on that will be transferred to your work piece.

[Geo]

Tidy work Brian, thanks for posting.