Is the rolex 3156 more anti-magnetic compared to 3186?

[timuS]

Hi everyone,

I encountered upon some rolex part-sheets online and found something interesting. The day-date caliber 3156's pallet fork no. is 3131-421, which is the same as the pallet fork no. of milgauss caliber 3131. And we know the milgauss pallet fork is made from an non-magnetic amorphous nickel-phosphorous alloy.

When you look at the GMT 2C 3186 caliber's pallet fork, it has a part no. 3135-421. Clearly this is not the same as the milgauss pallet fork.

Thus, does this mean that the 3156 day-date is more anti-magnetic compared to the 3186 GMT 2C?

How important is the pallet fork when trying to make the watch anti-magnetic? (I always thought an amagnetic hair-spring was enough )

Thanks in advance!

sumit

[padi56]

Now Rolex watches are made mainly from S.steel or precious metals and in conjunction with nickel, brass or beryllium, bronze or Glucydur balance wheels and pallet forks so they are very anti-magnetic to begin with, not 100% sure if the screws used are ferrous metal.Sure the older Nivourax hairsprings are very very very slightly magnetic but you would have to come in contact with a quite a strong magnetic field to fully magnetise them.

[dsio]

It would make some sense for them to take additional steps to improve the resistance of the Day-Date movements to magnetic fields due to the fact that while GMT and Submariner watches are for the very most part Stainless Steel (iron alloy, and thus offering considerable magnetic shielding in the case) the Day-Date watches are not made in steel, but rather in Gold and Platinum only, both of which are non-ferrous metals which would offer less protection than Stainless Steel.

As an engineer that makes a fair bit of sense to me, that given the movement is exclusively used in those precious metal cases, and will invariably be exposed to a greater degree than other movements, that you would choose anti-magnetic movement parts, if available.

[timuS]

Originally Posted by dsio

It would make some sense for them to take additional steps to improve the resistance of the Day-Date movements to magnetic fields due to the fact that while GMT and Submariner watches are for the very most part Stainless Steel (iron alloy, and thus offering considerable magnetic shielding in the case) the Day-Date watches are not made in steel, but rather in Gold and Platinum only, both of which are non-ferrous metals which would offer less protection than Stainless Steel.

As an engineer that makes a fair bit of sense to me, that given the movement is exclusively used in those precious metal cases, and will invariably be exposed to a greater degree than other movements, that you would choose anti-magnetic movement parts, if available.

Hi Ashley! That could be true, but rolex puts this same 3131-421 milgauss pallet fork in the the Explorer 1's caliber 3232 - which is cased in stainless steel!

An interesting fact is that rolex uses this 3131-421 milgauss pallet fork in all paraflex equipped calibers (dunno about the new explorer 2's 3187 though)!! I still wonder why?

Does this mean that the newer calibers more anti-magnetic?

[timuS]

Originally Posted by padi56

Now Rolex watches are made mainly from S.steel or precious metals and in conjunction with nickel, brass or beryllium, bronze or Glucydur balance wheels and pallet forks so they are very anti-magnetic to begin with, not 100% sure if the screws used are ferrous metal.Sure the older Nivourax hairsprings are very very very slightly magnetic but you would have to come in contact with a quite a strong magnetic field to fully magnetise them.

Hey Padi! Thanks for the reply!

do you feel that the pallet fork is as important compared to the escape wheel or the hair-spring when it comes to making a movement anti-magnetic?

[Tools]

I don't think that you could leap to such a conclusion..

The Pallet fork part number is 421.. the same for all of them. The first 4 numbers... 3131 or 3135, etc is likely only a size differentiation since most movements are based on only a couple of different base platforms..

[tomchicago]

When did they start putting Paracrhom Blu's in the regular Day-Date (not the II)?

[padi56]

Originally Posted by Tools

I don't think that you could leap to such a conclusion..

The Pallet fork part number is 421.. the same for all of them. The first 4 numbers... 3131 or 3135, etc is likely only a size differentiation since most movements are based on only a couple of different base platforms..

Have to agree Larry basically they are all based on the cal 3135

[timuS]

Originally Posted by Tools

I don't think that you could leap to such a conclusion..

The Pallet fork part number is 421.. the same for all of them. The first 4 numbers... 3131 or 3135, etc is likely only a size differentiation since most movements are based on only a couple of different base platforms..

Originally Posted by padi56

Have to agree Larry basically they are all based on the cal 3135

Yes guys, that does make sense. But does that also mean rolex uses the non-magnetic amorphous nickel-phosphorous alloy only for the 3131-421 pallet fork used in millgauss, but some standard alloy for the 3131-421 pallet fork used in the 3156 day-date II ?

[Tools]

Originally Posted by timuS

Yes guys, that does make sense. But does that also mean rolex uses the non-magnetic amorphous nickel-phosphorous alloy only for the 3131-421 pallet fork used in millgauss, but some standard alloy for the 3131-421 pallet fork used in the 3156 day-date II ?

I can't speak to the composition..

However, if they have the identical part number, they are the identical part... If they are the same part, but of different composition, there will be a modifier prefix or suffix (usually) to be able to tell the difference when ordering..