Dividers and Calipers

[pmace]

I want to lay out 1 mm divisions along a curved line. Shouldn't be a big deal. Pick a starting point, set your dividers to 1 mm and march your way around the line. I've got digital calipers, spring dividers and a drafting compass with points in both legs. The problem is that the spring calipers and the drafting compass flex all over the place and make it difficult to keep things accurate. The digital calipers are nice because you can set the dimension easily and they don't flex. The problem is the jaws are so big you can't scribe accurately. Has anybody modified a digital caliper to scribe properly? Are there attachments to do this? How about some decent spring dividers that don't flex all over the place?

 

[Dave London]

Steve Lindsay makes the scriber it does not flex . I have no connection with the company at all just like his products

 

[Chujybear]

You want the dividers.. just need some that are more robust. Shorter legs can help.. the ones that have the bar run right through its legs are often better quality.. there is a set that is expensive, but looks outstanding with carbide inserts at Otto Frei right now.

Side tips.. if the points of your dividers are just ever so slightly rounded, they will not catch on the metal which could lead to some flexion .. the point just (just!) rounded will burnish your line in rather than scrape it, and so slide over the metal easier.
The other way is you can Mackie a micro, radiused knifes edge so it will “slice” more of a groove, but still slide freely without sticking..

I do feel your frustration.. do, if you can, splurge on a nice pair of dividers.

 

[papart1]

You want the dividers.. just need some that are more robust. Shorter legs can help.. the ones that have the bar run right through its legs are often better quality.. there is a set that is expensive, but looks outstanding with carbide inserts at Otto Frei right now.

Side tips.. if the points of your dividers are just ever so slightly rounded, they will not catch on the metal which could lead to some flexion .. the point just (just!) rounded will burnish your line in rather than scrape it, and so slide over the metal easier.
The other way is you can Mackie a micro, radiused knifes edge so it will “slice” more of a groove, but still slide freely without sticking..

I do feel your frustration.. do, if you can, splurge on a nice pair of dividers.

go to miro-mark and get the "miniture tool" set, has everything you need including the dividers. $34..+/_

 

[tolesh]

micromark has just the dividers for $10.45 4 1/2" long

 

[rweigel]

My favorite for small divisions is the Riefler 13c. No longer made, but still kicking arround at ebay, german flea markets (like mine) and some internet sellers. A little less than 4“ long (9.5cm), very light and precise as the legs are essentially one piece. Perhaps a tool maker takes the design up and makes something similiar. I use it mostly for stone setting.

Ralf

 

[tdelewis]

I have the same problem. Relax and don't use too much pressure.

 

[mitch]

i use a very small pair of draftsman calipers with the replaceable points. then i crank the arms completely closed, hard against each other and adjust the 'gap' by moving the points in or out. by slightly tightening the point clamp knobs- so they can move, but not too easily- you can push them against the gradations of a ruler/scale until they're the exact distance apart you need, then fully tighten the knobs. do it under a microscope and you can get dead on spacing.

i started doing this so long ago i almost forgot filing away small flats on opposing sides of the split jaws, so when they're closed they engage laterally, too, for some resistance against twisting. this is what i use for laying out checkering.

 

[pmace]

Thanks everyone. Who would think that something so simple would wind up being so complicated.

 

[Chujybear]

i use a very small pair of draftsman calipers with the replaceable points. then i crank the arms completely closed, hard against each other and adjust the 'gap' by moving the points in or out. by slightly tightening the point clamp knobs- so they can move, but not too easily- you can push them against the gradations of a ruler/scale until they're the exact distance apart you need, then fully tighten the knobs. do it under a microscope and you can get dead on spacing.

i started doing this so long ago i almost forgot filing away small flats on opposing sides of the split jaws, so when they're closed they engage laterally, too, for some resistance against twisting. this is what i use for laying out checkering.
View attachment 47203 View attachment 47204

That’s pretty tricky!

 

[mitch]

That’s pretty tricky!

cheap, too. my guiding principle in many aspects of life is 'crude, but effective'.

 

[jerrywh]

Any time you think something is simple you just don't know much about it.

 

[silvermon]

I want to lay out 1 mm divisions along a curved line. Shouldn't be a big deal. Pick a starting point, set your dividers to 1 mm and march your way around the line. I've got digital calipers, spring dividers and a drafting compass with points in both legs. The problem is that the spring calipers and the drafting compass flex all over the place and make it difficult to keep things accurate. The digital calipers are nice because you can set the dimension easily and they don't flex. The problem is the jaws are so big you can't scribe accurately. Has anybody modified a digital caliper to scribe properly? Are there attachments to do this? How about some decent spring dividers that don't flex all over the place?

Lots of good replies, but even for a one time use, grab a small piece of scrap sheet metal (.065" or thicker), hand shears, and a file. Trim one edge down to a couple mm, file in/out your two notches with the spacing. Save your one off scribe if you think you will do 1mm spacing again.

 

[Leland Davis]

pmace, I have modified a digital caliper to scribe with and it worked but it was kind of unhandy to use. I was going to send a pic but I can't find it that's how unhandy it was. If I ever find it I'm going to cut it down to about a 2 inch leg I think it may make it more user friendly.

 

[pmace]

pmace, I have modified a digital caliper to scribe with and it worked but it was kind of unhandy to use. I was going to send a pic but I can't find it that's how unhandy it was. If I ever find it I'm going to cut it down to about a 2 inch leg I think it may make it more user friendly.

I too have given up on the calipers as too big and cumbersome. I hardened the points on my cheap spring dividers and stoned them to a better point. Other than the side-to-side flexing they are behaving better. We'll see if a pair of good (or at least more expensive) round leg dividers is any better.

 

[Leland Davis]

The holy grail calipers on the cafe are the 2in Starrett. I have those and a 1 3/4 Browne and Sharp square leg I use which ever 1 is closest most of the time but for parallel lines I use the Browne and Sharp the square legs seem more ridged. I am trying mitch's trick. Chujyear was right about the rounded tips it works better for me too.

 

[mitch]

The holy grail calipers on the cafe are the 2in Starrett.

yep, and i have 4, count 'em, four, pairs. just wanted to brag...

 

[Leland Davis]

4 pairs no wonder they are hard to find

 

[Leland Davis]

ebay has a set of 2in brown and sharp round leg dividers right now

 

[dhall]

A European stone setter/engraver, named Jura, has a number of interesting tools and equipment he's designed. www.juratools.com (insert standard non-affiliation disclaimer, etc. here). Currently 148 euros ( just under $180) for a very stubby digital caliper with some pretty sexy-looking hardened chrome steel tips. Here's a YouTube video that highlights Jura's caliper and a ceramic pen (scribe).

For the chronic DIY crowd, the advantage of digital calipers makes it easy to braze some carbide on to the tips, grind and polish to whatever works for you, and use the zero button to re calibrate to make your own O.D. jaw stubby caliper. Obviously a lot more tricky to convert I.D. jaws and depth probe to carbide, but for most of us, carbide tips on the O.D. legs is all we need for this application. Jura's calipers look pretty sweet; I've lusted after a pair for a while, but never pulled the trigger.

Best regards,
Doug