PRS-29AM Larger Crown

[jason.humphrey.180]

No watch is perfect right?
The Air Ministry has been in my collection for 2 years now and as a modern recreation of the 6b/159 it's pretty well perfect and in my humble opinion beats Longines' modern effort in it's purity.

With a manual wind ETA 2801-2 inside, I couldn't ask for more when it comes to a functional and robust movement.
My experience with this movement is limited to the PRS-29AM and a Hamilton Khaki Field Mechanical before they reduced the beat rate and upped the power reserve.
The only thing I've found while owning the watch is that the winding action could be more pleasurable (like on the Hamilton with it's larger diameter crown).
A quick conversation with The Horological Underground in Bristol and they said yes....no problem.... it's a common tap size, we'll see what we can do.
Pic 1&2 show the crowns side by side before any fettling.
The new crown is only ½-¾mm larger in diameter but it makes for a more pleasurable winding experience.

It was originally polished but they applied a circular brushing on the lathe and also reshaped the underside similar to the OEM crown.

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[TheGent]

Fantastic mod!


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[Mr Curta]

An excellent example of a small change making a big difference. Nice one

[Wallasey Runner]

Looks good and clearly practical on a watch that needs winding daily. Nothing worse than small fiddly crowns.

[brummie64]

Nice work, that looks like an ideal fix for greater enjoyment .

[jason.humphrey.180]

An excellent example of a small change making a big difference. Nice one

I'm able to put more torque through the crown with less effort now with the added benefit that the new one is brushed and seems more in-keeping with the fully brushed case.

[2012]

That does look good, but do you have a picture with it face on?

I have many manual wind watches, and most are pleasing to wind, but when I tried on a Hamilton Khaki over Christmas, I was surprised by how large the winding crown was. And yes, it was a pleasure to wind too.

[TaketheCannoli]

A huge improvement from such a small part.

[forpetesake]

Bravo!
I completely understand why you did this. The tactile properties of watches are rarely mentioned here. It either feels right or it doesn't.

[Ghost Chilli]

Definitely a fan of a slightly larger crown here. Think that is a great upgrade.

[walkerwek1958]

OK, it looks nicer and I agree it’s easier to use, but this is a different type of crown!

Have a look at the original, it has a longer pipe with a rubber D ring seal, that provides secondary sealing but it also helps align the crown and stem with the movement. The movement and movement ring don’t clamp into the case with case clamps, the clamping action relies on the caseback squeezing against the movement ring as its tightened down, this makes it harder to align the crown/ stem with the movement and there’s a risk of the watch going together with stress on the stem.

The lack of secondary seal wouldn’t worry me too much, lots of watches rely on a single O ring in the crown, but the D ring seal on the crown is part of the original design and as I’ve stated it does play a role in aligning the stem. The design would be better if case clamps were fitted to secure the movement and movement ring into the case, but its not uncommon to see this design in the less expensive watches.

The original crown is loosely described as ‘Japanese style’, Seiko and Citizen favour this design with a longer pipe on the crown that incorporates a D ring seal.

[jason.humphrey.180]

OK, it looks nicer and I agree it’s easier to use, but this is a different type of crown!

Have a look at the original, it has a longer pipe with a rubber D ring seal, that provides secondary sealing but it also helps align the crown and stem with the movement. The movement and movement ring don’t clamp into the case with case clamps, the clamping action relies on the caseback squeezing against the movement ring as its tightened down, this makes it harder to align the crown/ stem with the movement and there’s a risk of the watch going together with stress on the stem.

The lack of secondary seal wouldn’t worry me too much, lots of watches rely on a single O ring in the crown, but the D ring seal on the crown is part of the original design and as I’ve stated it does play a role in aligning the stem. The design would be better if case clamps were fitted to secure the movement and movement ring into the case, but its not uncommon to see this design in the less expensive watches.

The original crown is loosely described as ‘Japanese style’, Seiko and Citizen favour this design with a longer pipe on the crown that incorporates a D ring seal.

I see what you mean. They did do a pressure test before I had it back but if it means i'll get more pleasure from the watch I think I will live with the compromise.
BTW....I've been trying to access the forum with tapatalk which used to work quite well for me but in the last few months it has become slow to unresponsive. What are people using these days to access the forum from their phones?

[jason.humphrey.180]

That does look good, but do you have a picture with it face on?

I have many manual wind watches, and most are pleasing to wind, but when I tried on a Hamilton Khaki over Christmas, I was surprised by how large the winding crown was. And yes, it was a pleasure to wind too.

Here we go

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[TomGW]

I totally understand the satisfaction of a larger crown. I have a Tutima 1941 chrono with the oversized crown and it is such a pleasant experience to wind.