Making a new wheel post

Making a new wheel post

The reverse minute wheel post had snapped, it happens.

The best way for this repair is to cut about 1/16th inch off the post and silver solder a piece of steel rod, using a scarf joint.

The reason for cutting the post is to allow a fresh portion of metal for the pinhole, if we were to use a butt joint; the pinhole would be drilled through an already weakened portion of the post and would soon fail.

The parts are silver soldered and roughly cleaned, set up in the lathe using a pin vice to protect the post threads. A jacot tool is used to support the post and the new metal is filed to match the taper.

The post is fitted to the clock and a scribe mark is placed for the taper pin. Cross drilling small parts such as these might present a problem, there are various ways to overcome this.

I used to normally do these jobs by eyeball methods but find that with age I have to use a jig of some sort. An easy way is to drill a hole in the edge of a piece of scrap metal, the same dia as the post. Place the repaired post on the metal surface and mark the location, using the scribe mark. Drill a hole of the required dia and then place the post in the hole, drill through the post and it should be near the middle. The last job is to round over the end of the post. That should have been the finished repair but the job went pair shaped. I typed the article before the repair, I knew exactly each step of the repair, I have done it many times. What I could not have foreseen was, the maker had riveted the post into the front plate, they are normally threaded.

I used a No1 centre drill to weaken the rivet on the inside of the plate but it still held fast, I had to use a dental type burr to remove enough metal for the post to be removed. Looking at the original post, it became clear why the maker had riveted, instead of threading, it had been turned with an eccentric foot (see picture), this allowed the maker to adjust the depth of the two wheels and then rivet when satisfied.

A new post was turned and threaded 6BA, it turns out he made the eccentric feature for nothing; I tapped the rivet hole and the wheels meshed ok.


Roughing out a post

New post-running in a 6ba fixing-forming the taper


New post in place and showing mark for the pinhole

Temporary drill jig-original post with eccentric
stud and a .6mm spade drill


New post with cross pin