Help for a Rietz Standard 12.5 slide rule


Hi everybody.

I own an old Rietz Standard 12.5 slide rule, manufactured by "Antica Fabbrica Vittorio Marini" (Italy), once owned by my father for his calculations during late high school days and early work days (mid Fifties up till Seventies, I believe).
It lacks the following items:

- the hairline

- the leather case

While I can supply for the leather case in some way, I'd like to complete it with a spare hairline. I think my father lost or broke it even before I was born.

Does anyone of you knows who can sell me such device? Or can you tell me how can I replace it?

Thanks in advance.

-- Antonio


I doubt you'll get spare hairlines from anybody still nowadays. So you have to do it yourself. The quick and dirty method is to

+ look for a sheet of transparent plastic ("Plexiglas" or similar),

+ take a needle and a straight edge and cut a fine line in the plastic (there is no need to color this line, the dust will do this for you while you use your slide rule),

+ cut out 2 equal rectangular pieces with the line approximately in their center and perpendicular to one of their edges - the height of the rectangle shall be 1cm more than the height of your slide rule,

+ look for material being as thick as your slide rule,

+ cut out 2 strips of this (5mm high, length = width of the rectangles),

+ take 1 rectangle and adjust it on your slide rule to have the line running *perpendicular* to the edge of your slide rule, then lock it in this position with approximately 5mm standing out on either side,

+ take your 2 strips and glue them on the rectangle next to the top and bottom edge of your slide rule using a liquid adhesive (place a piece of paper between one strip and the edge of your slide rule for proper distance and take care for the glue not touching your slide rule),

+ wait until everything is really fix,

+ place the second rectangle on your assembly, adjust as the first, lock and glue, then wait again.

Done! OK, not too quick - and this will just allow you to use the hair line on either side of the rule, not to transfer anything from one side to the other, but anyway! The glue lines shall take care of the necessary spacing to let the hair line assembly glide over your slide rule. Good luck!


I've restored hair lines on slide rule cursors by filling the line with a marker pen, such as a Sharpie, and then wiping off the excess ink with a piece of tissue paper.


Pardon, I'm not english mother-tongue:

I called it hairline, but I meant the whole transparent plastic containing the hairline and sliding onto the slide rule.

Thanks Walter B. for your instructrions

-- Antonio



Try the web site
you may get some leads on where to get a cursor. There is a nice example of your sliderule at the site. This will give you an idea of what the cursor should look like.


Chris Dean


Chris, Antonio,

Thanks for this link. I had a standard double sided slide rule in my mind with rectangular cross section when writing my instructions (I've got an Aristo Studio 0968 (35cm) here and my Aristo Rietz 89 at another place). Single sided cursors are trickier than double sided - you need a far stiffer "window" for obvious static reasons. Since in these so called pocket slide rules the cursor is shaped like a cylindrical lens, replacing it may easily exceed the DIY sector.

Good luck to you anyway!

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