Fountain pen sac size converter · Free · No account
Fountain pen sac sizes in millimetres, with a slip for your measurements.
Fountain pen sac sizes count the diameter in 64ths of an inch, so size 16 is 16/64 inch, or 6.35 mm. Type any size to convert it. The free PDF adds a table of sizes 12 to 24 in half sizes and two slips for measuring a pen.
- A4 and US Letter
- Prints at actual size
- Goes with The Fountain Pen Restoration Ledger
- Type the sizeEnter a fountain pen sac size, such as 16 or 18.5. The millimetre and inch figures appear as you type.
- Name the penOptionally type the pen’s make and model. It is printed on both measurement slips.
- Print and measureDownload the PDF, cut out a slip and write in the section, nipple and barrel measurements in millimetres.
Make your card
The page beside the form changes as you type. The PDF is made in your browser and is sized for A4 or US Letter.
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File details
- What it works out
- It converts a fountain pen sac size number to millimetres and inches.
- Using the result
- Measure the pen on the slip before choosing a sac.
- Calculation
- Sac sizes count 64ths of an inch, so millimetres are size times 25.4 divided by 64.
- A guide
- Suppliers measure in different ways; treat the figure as a guide and check their listing.
Questions
How is a fountain pen sac size converted to millimetres?
Multiply the size by 25.4 and divide by 64. Size 16 is 16 times 25.4 divided by 64, which is 6.35 mm.
Is the millimetre figure exact?
The result is shown to 0.01 mm. Suppliers measure sacs in different ways, so compare it with their listing.
Does it say which sac fits my pen?
No. It converts the nominal size and prints a slip for the pen’s section, nipple and barrel measurements.
Do I need to print at actual size?
No. The figures are text, so any scale reads correctly. Print at 100% to give the slips their full writing space.
Related Due Form edition
DF.028 The Fountain Pen Restoration Ledger
In production
A workshop ledger for recording fountain pen condition, intervention, parts and testing.
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