My catalogue only shows two balance staffs for the 16s hampden. I have 3 new models and it should take the 2720 staff which is 5.51mm long.
the 3720 staff is 5.13 long. the 21j double roller that I have has a 5.50mm long staff that fits perfectly. I haven't been able to find any in that length. Does anyone have any info on the part number of the 5.51mm or have a source for some? Any help is appreciated. Bill Vaughan

How many are you looking for...I will look and see what I have...

Three would be great. But, what you can spare is great also. Do you have a part number for the 5.51mm? Thank you, Bill

Hi,
Here is some info I have for Hampden staffs


Hampden 16

5.60 1.27 .76 .71 .65 2720 OS, ¾ Pl, M1890
5.13 1.27 .75 .71 .57 3720 NS, ¾ Pl, M1902

This from a source that has proven very reliable.
I have 1 piece, 2720, which measures aprox 5.6mm long.
I have lots of 3720

William,
I have looked thru all my Hampden staffs and I don't have any of the #3720 Style 2 staffs all my 3720 staffs are the short ones...Sorry I can't help with this...I hope someone on the group has them...

This posting moved to appropriate forum.

Hi Bill,

Gary is right with regard to the 5.6mm on those staffs, they are the ones for the new 1902 Model which your 3 should be.

Cheers

Thanks for the info. All three that I have will not take the 5.13mm or 5.60mm. One has the 5.51mm which all three should take because you can see where someone has bent the cock to compensate for the longer staff. Why they used the same number for two different lengths is beyond my understanding. If anyone can solve this dilemma, I sure would like to know how. Bill

Hi,
First the measurement I made may be off, I am not proficient at holding the staff parallel with the jaws of the micrometer) so I guess at the dimension.just to distinguish one staff from another, not to be used as an absolute.
As far as the length of the staff verses the gap in the watch, most "good" watch makers either polish the staff, or shim the bridge, rather than do "PERMANENT DAMAGE" to the bridge.
Just my experience and opinion.
Mel

Might pay to check the balance jewels Bill, if someone has used a cock jewel for the foot jewel or vice-versa (as I think they are interchangeable to the uninitiated) or even used a comparative jewel from another manufacturer the clearance could be altered due to incorrect jewel heights. I have seen it many times.

Bila, I have tried that too. I have shimmed the cock on one and have it running fine but it shouldn't have to be that way. Brian C. said that there was a another 3720 that was for the later model which was 5.51mm. I had one that I bought and it measured 5.78mm. This is just a real confusing thing to me. I could polish them down shorter but I wonder how much before the taper starts hitting the jewel? Thank you, Bill