O-ring size?

[SteelCity]

I've dismantled A Sheaffer touchdown and removed the O ring and want to purchase a replacement, but there seems to be 2 sizes (small and large) My old o ring is 5/16' or 7mm in diameter. Is this "small"?

And could someone recommend a reliable inexpensive (oxymoron?) source? Is it something can purchase from my local Home Depot?

Thanks.

[OldGriz]

I've dismantled A Sheaffer touchdown and removed the O ring and want to purchase a replacement, but there seems to be 2 sizes (small and large) My old o ring is 5/16' or 7mm in diameter. Is this "small"?

And could someone recommend a reliable inexpensive (oxymoron?) source? Is it something can purchase from my local Home Depot?

Thanks.

 

I, and most of the restorers I know, purchase our Snorkel and Touchdown rings and supplies from Martin Ferguson

They are the best match for the original parts that Sheaffer used....

[Gerry]

Yes, those are the small O-Rings. The Large are 8mm.

 

Regards,

 

Gerry

[Ron Z]

No, you reall can't go out and buy the 0 rings from Home Despot.

 

The 0 rings are a very specific buna-N rubber, of a very specific size and durometer (hardness). I have some from Sheaffer, along with the order sheet that was in with them, and I can tell you that they are nothing like what you will find in any home center or hardware store.

 

The best source for them is indeed Martin Ferguson. Martin has been ordering the right stuff from the same manufacturer that Sheaffer used.

[fountainbel]

Buna N is a nitrile NBR70 compound, known as the "standard" compound for O rings

Its standard hardness is 70 shore. The dimension used in a snorkel or touchdown is 7x1mm.

On few pens - where the barrel wall is somewhat bulged out - I use a 7x1.2mm.

At least in Europe these O rings are easily findable, the major European manufacturer is Eriks.

The link to their American subsidiary is : http://eriksusa.com/en/products/o-rings/

Francis

[Richard]

Buna N is a nitrile NBR70 compound, known as the "standard" compound for O rings

Its standard hardness is 70 shore. The dimension used in a snorkel or touchdown is 7x1mm.

Sheaffer's O-rings are not the standard compound; 70 durometer is almost correct.

Sheaffer's O-rings are not a standard size; 7x1 is almost correct.

 

I have just placed an order for several thousand O-rings of the correct size and material.

Edited January 3, 2009 by Richard

[yu_bh]

Hi I wonder what is the color of original sheaffer oring?

 

Isnt it grey? or white turned into grey?

Edited July 24, 2009 by yu_bh

[Possum Hill]

Buna N is a nitrile NBR70 compound, known as the "standard" compound for O rings

Its standard hardness is 70 shore. The dimension used in a snorkel or touchdown is 7x1mm.

Sheaffer's O-rings are not the standard compound; 70 durometer is almost correct.

Sheaffer's O-rings are not a standard size; 7x1 is almost correct.

 

I have just placed an order for several thousand O-rings of the correct size and material.

So what are the correct dimensions, compound and hardness? Does anyone actually know?