Pen ink sac sizes?

[6thformpennutuk]

Hi all,

 

I have about 10 pens that need new ink sacs, but I can't work out what sizes of sac to buy. Can anyone tell me what the number of the sac relates to, so I can buy the right sized sacs for these pens. For example, I have a sheaffer jr, a WASP clipper, a parker moderne, and a conway stewart no 55, all of which need new sacs, plus a few more too!

Any help with this would be much appreciated.

 

Max

[Oxonian]

Hi Max,

 

There are various threads dealing with this in depth but the short explanations is roughly thus,

The ink sacs are sized in number, the number being the diameter of the section nipple in sixty fourths of an inch, so a quarter inch nipple uses a size 16 sac etc.

 

It is basically that simple but there are various authorities, reference sources and repairers, amateur and professional who feel that it is a good idea to take the measurement and drop one number so that a pen that has a quarter inch nipple should use a size 15 sac to ensure a good tight fit to the nipple and ensure that the sac is far enough away from the wall of the barrel to avoid it being heated by contact with the hand whilst writing and drop a blot on the page but that is a matter of choice.

 

Most sacs when supplied are over long and need to be trimmed to size, easy way is hold sac alongside barrel, lay section over the sac in the position it will be in the pen mark it and cut the sac about a quarter to maybe a half inch shorter than the mark.

 

In UK sacs can be obtained from various places most of mine come from Peter Twydle at the Pen Museum or Ian Williamson at Cathedral pens, both of these have silicone and latex sacs and charge about the same, silicone sacs are in general a little thicker than latex ones and there are some pens where the clearances are a little tight, there are others mainly things like Jade or pale coloured vintage celluloids where a silicone sac is a good idea to lessen the chance of ambering or staining due to sulphur in the latex sacs.

 

Measure your pens and away you go, have fun, best of luck,

 

Cheers, John

[laburlisque]

Another great source of info is the guide at pensacs.com - Lewis

[tipstricks]

With a caliper I measure the diameter where the ink sac has to be fitted, and then I use the sac with the nearest little diameter, e.g. if I have 6.5mm I use a #16 size sac, with a drop of shellac.

 

Pen sac diameters are measured in 64ths of an inch.

#10 size pen sac is 10/64 inch = 3.97 mm.

#12 size pen sac is 12/64 inch = 4.76 mm.

#14 size pen sac is 14/64 inch = 5.55 mm.

#16 size pen sac is 16/64 inch = 6.35 mm.

#18 size pen sac is 18/64 inch = 7.14 mm.

#20 size pen sac is 20/64 inch = 7.93 mm.

#22 size pen sac is 22/64 inch = 8.73 mm.

#24 size pen sac is 14/64 inch = 9.52 mm.

 

All straight sacs are made long and can be easily trimmed with scissors to proper length.

[pe2dave]

  On 6/24/2007 at 7:15 PM, tipstricks said:

With a caliper I measure the diameter where the ink sac has to be fitted, and then I use the sac with the nearest little diameter, e.g. if I have 6.5mm I use a #16 size sac, with a drop of shellac.

 

Pen sac diameters are measured in 64ths of an inch.

#10 size pen sac is 10/64 inch = 3.97 mm.

#12 size pen sac is 12/64 inch = 4.76 mm.

#14 size pen sac is 14/64 inch = 5.55 mm.

#16 size pen sac is 16/64 inch = 6.35 mm.

#18 size pen sac is 18/64 inch = 7.14 mm.

#20 size pen sac is 20/64 inch = 7.93 mm.

#22 size pen sac is 22/64 inch = 8.73 mm.

#24 size pen sac is 14/64 inch = 9.52 mm.

 

All straight sacs are made long and can be easily trimmed with scissors to proper length.

 

Very useful, thanks. So I'm looking for #18 (slack)

or #19 (seems to exist on some places, not many),

or #20, tight, only if I want to max out on ink. Not bothered.

 

Except I've read the leverless 'needs' the necked sac?

Hence cutting a larger one down to size seems sub-optimal?

 

Also found 'latex' or 'silicon'? I'd guess for this pen,

with the lever mangling it every few days, latex would be

a better match?

 

Dave (learning quickly - thanks peeps)

[dasmarians]

  On 6/24/2007 at 4:30 PM, 6thformpennutuk said:

Hi all,

 

I have about 10 pens that need new ink sacs, but I can't work out what sizes of sac to buy. Can anyone tell me what the number of the sac relates to, so I can buy the right sized sacs for these pens. For example, I have a sheaffer jr, a WASP clipper, a parker moderne, and a conway stewart no 55, all of which need new sacs, plus a few more too!

Any help with this would be much appreciated.

 

Max

 

 

HI, I make my own sacs, if you want some I can trade with you (not money, not commercial)

works very well, I used with:

 

wearever

parker 21

eversharp skyline

and no brand vintage pens

 

regards

Dasmarians

[waterman1924]

CLICK HERE---->PEN SAC CHART.... from Pendemonium...

Edited March 27, 2011 by waterman1924

[PDW]

  On 3/27/2011 at 6:50 PM, dasmarians said:

 

 

 

HI, I make my own sacs, if you want some I can trade with you (not money, not commercial)

works very well, I used with:

 

wearever

parker 21

eversharp skyline

and no brand vintage pens

 

regards

Dasmarians

 

Are you willing to let us into the secret of how you make them? They look good!

Edited March 27, 2011 by PDW

[dasmarians]

It's not difficoult PDW, but it's dirty, a lot of patience and the right components to do it.

 

regards

DasMarians

[pe2dave]

  On 3/27/2011 at 6:50 PM, dasmarians said:

 

 

 

HI, I make my own sacs, if you want some I can trade with you (not money, not commercial)

works very well, I used with:

 

wearever

parker 21

eversharp skyline

and no brand vintage pens

 

regards

 

 

I'm intrigued! How .... I can't even imagine.

Look forward to more detail? Please?

 

 

Dave

[MYU]

  On 3/27/2011 at 8:09 PM, waterman1924 said:

CLICK HERE---->PEN SAC CHART.... from Pendemonium...

They moved it to a different page now.

 

Pendemonium Pen Sac Chart.

 

 

#10 -- 10/64" = 3.97 mm.

#12 -- 12/64" = 4.76 mm. (3/16")

#13 -- 13/64" = 5.16 mm.

#14 -- 14/64" = 5.55 mm.

#15 -- 15/64" = 5.95 mm.

#16 -- 16/64" = 6.35 mm. (1/4")

#17 -- 17/64" = 6.75 mm.

#18 -- 18/64" = 7.14 mm.

#19 -- 19/64" = 7.54 mm.

#20 -- 20/64" = 7.93 mm. (5/16")

#22 -- 22/64" = 8.73 mm.

#24 -- 24/64" = 9.52 mm. (3/8")

Edited April 25, 2017 by MYU

[MYU]

By the way... why are there so many incremental ink sac sizes? Doesn't latex stretch enough? I've been measuring a couple of pens to try figuring out the proper size, and this level of precision (by 1/64th inch) is so small... is a "best guess" good enough?

[ac12]

 

 

  On 4/27/2017 at 1:37 AM, MYU said:

By the way... why are there so many incremental ink sac sizes? Doesn't latex stretch enough? I've been measuring a couple of pens to try figuring out the proper size, and this level of precision (by 1/64th inch) is so small... is a "best guess" good enough?

 

Being a hobby guy and not a pro, I just use the even number sacs, and skip the odd number sacs. This reduces the inventory of sac that I have buy and keep.

 

As for sizing the sac, I do not match to the nipple.

My method is to drop a sac into the pen and see how the sac fits into the body,

• If it is tight, I go down a size (in my case 2 sizes since I only have even number sacs), until I get a loose fit.
• If it is too loose/sloppy fit, I go up a size.

The fit of the sac can be different from a published size for the pen, because the J-bar or pressure bar may be bent/shaped and taking up more space in the barrel, leaving less space for the ink sac.

[FarmBoy]

  On 4/27/2017 at 4:45 AM, ac12 said:

 

 

Being a hobby guy and not a pro, I just use the even number sacs, and skip the odd number sacs. This reduces the inventory of sac that I have buy and keep.

 

As for sizing the sac, I do not match to the nipple.

My method is to drop a sac into the pen and see how the sac fits into the body,

• If it is tight, I go down a size (in my case 2 sizes since I only have even number sacs), until I get a loose fit.
• If it is too loose/sloppy fit, I go up a size.

The fit of the sac can be different from a published size for the pen, because the J-bar or pressure bar may be bent/shaped and taking up more space in the barrel, leaving less space for the ink sac.

I am starting a petition to force you to stock the odd sizes and the available half-sizes. For now I will not include the necked and tapered sizes.

 

OR you could commit to dealing with yellow pens...

[Ron Z]

I used to use the "even number sizes only" model until I found that the odd number sizes can be just right for a pen, even numbers on either side just wrong. A touchdown Sheaffer for instance uses a 15 1/2. You don't need the 1/2, but you do need a 15. A 14 is too small, a 16 won't fit in the sac guard. For the PFM a 16 is too small, 18 too big - you need a #17 unless you insist on the 1/2 size.

 

I've encountered many pens where the sac installed was way too small for the pen. The reason? It was what fit down the barrel. But the person installing the sac (I balk at using the term restorer) failed to clean all of the bits of dead sac out of the barrel and off of the barrel wall which made the ID smaller.

 

If in doubt, measure the sac nipple and go down one size - 16 to 15, 17 to 16 etc. You will find that the middle of the bell curve for most lever fill pens is in the 16-18 range.

[ac12]

Ron,

For the Snorkel and Touchdown, I used a different method. I buy the kit (sac+O-ring) from David.

I suppose I could have gone individual sac + O-ring, but for some reason I decided on the kit.

 

I agree about the 16. I think I used more 16s than all the other sizes combined.

Maybe I should get some 17s.

[danielfalgerho]

I'm trying to revive a nice sterling Eversharp slimline Ventura but it seems that a #10 ink sac fits very tightly in the squeeze mechanism and gets mangled pretty quickly as the bar chews up the ink sac. The neck is about 4mm which seems right for a #10 but does this pen require a smaller sac? Is there such a sac available? I doubt it. Any advice from Eversharp scholars - or anyone more knowledgeable than me would be welcome. Happy writing!

Edited November 6, 2019 by danielfalgerho

[Vintagepens]

I'm not usually one to respond to ancient threads, but since this one seems to come up when searching on sac selection, some correction is appropriate.
 

Choosing sac size by reference to the size of the sac nipple (peg) is not best practice. There is not a constant fixed relationship between the size of the nipple and the size of the barrel interior, so if you work from the nipple size you could easily end up with a sac too large to fit the barrel or so small that it can bounce around inside it. 

Reference video here with further explication: