Are you kidding me? Huge Kuddo's to Dave for his tolerance and patience with me this weekend. He found a staff for my 16s DR Adj8p South Bend... and coached me through my second restaff...

This is the second time I've watched him turn down a pivot, free hand in a collet with his miniature stone, burnishing steel and polishing paste...

Regrettably, I dropped the assembly on it's head doing the free spin checks and sheared the upper pivot he had just nursed to a perfect fit.

Since we were fresh out of staffs, and I was rather deflated... I chose to head home and lick my wounds.

I dug through my recent purchases and came up with three staffs in my cache. Of course, all three had the same over-sized pivots. I studied my tools and found that I had everything I needed to burnish my own pivots... so, armed with all this knowledge, I went to work.

Then I got in to the "Are You Kidding Me" phase... How in the **** do you even see this damned thing... and once you can see it, how do you know if the tool is square on the surface... and when I'm finally comfortable that I'm on target, how do I know when to stop...

So, being afraid of just how fragile these things are and not wanting to over do it, I tried sneaking up on the pivot, one gazzilionth of an inch at a time.

Round one, no love
Round two, no love
Round three, still too big
Round four, leaned on it too hard and sheared the pivot... This is round two of "Are You Kidding Me?"

Fast forward to Second Staff, round six
Round seven, finally got comfortable with the lighting, selection of glasses and visual aids, position at the lathe, how to hold and see the tool...
Round eight, finally got the staff to stand up in the jewels.

Riveted the wheel on and attempted the spin test. The spin test was fine with the screw not quite torqued.. but that last 1/4 turn on the screw would bind the staff...

So, now I get to learn how to use a balloon chuck... At least the visual is a lot better and the chuck gave me a "fence" to ride the tool against to help me square up to the pivot.

On round five with the balloon chuck, I finally got a happy free spin test.

I think I gained about ten watches worth of experience in one lesson.

Paul, I must commend you for thinking and remembering how you installed a staff under my watchful eye.

The free spin of the balance wheel is the most critical part of a proper running watch and must be respected at all times. There are no short-cuts.

When the staff tightens up during the last 1/4 turn of the Balance cock screw, there can be two simple causes;

A. The Balance Cock/Plate interface has been "adjusted" with a centerpunch to compensate for the last "too short" staff.

When the wheel stops at the last 1/4 turn of the screw that means there could be punch marks at the outer end of the Balance cock or the surface it rests on. If there are marks there carefully flat file them smooth with a Flat face jewelers file.

B. The staff is too long or the pivot is tapered.

With the wheel "free spinning" when the Cock screw is short of tight, turn the assembly over. If the wheel continues to free spin, the staff is too long, if the wheel stops spinning, the pivot is tapered.

The "too long" pivot us easily shortened with a light touch of an Arkansas stone to the longest end of the spinning staff end (when in a lathe) followed by by a radius dress of the end, a polish, and re-test for free spin.

If the pivot is tapered where it should be straight, that takes a very careful fine stone at the thicker inner radius followed by a "steel"* burnish to the outside diameter of the tip end with repeated re-testing until it is free spinnning.

I must add here that this is what I do, as there are other reasons why a balance wheel jams, I have addressed only the two most common ones I experience and how I deal with them. There are surely other ways to do this, but sobeit.

*A polishing "steel" is a (usually rectangular) steel bar about 3/16 x 3/8 x 2-1/2 inches long held in a wooden handle that allows you to burnish pivot tips (using a loupe). It is a most important tool for most staff and pivot work.

Paul. Your Lathe experience sounds just like mine. I could put a nail in it and screw it up trying to turn the head down.... Now I have a selection of stones and Gravers that I use and a tad bit of experience and it's a little easier. Dave has forgotten more about watches than I will ever know. We are lucky to have members like him in the club. My latest project was turning down a roller table shaft without doing anything to the pivot or hub.

Thanks for sharing the info, it is very instructive guys. It seems that punch marks are a common way (for some)to fix a short staff issue. I don't think it is a correct way to go about it though. I have a movement that had these marks under the balance cock and assumed it was because of a possible short staff.