I'm experimenting with motor geometery, and need a source
for a customizable template that I can print and wrap around
a cylinder, and then punch thru evenly located marks so I can
drill. I don't need a protractor/flexible garment tape measure...

Not this:



Imagine a paper tape measure, with customizable evenly spaced divisions.

I see all kinds of printable rulers, but that's not what I need, I don't need metric/sae etc.
I need to layout a customizable number of segments, print, and then wrap around
my cylinder so I can punch-mark and drill.

Anybody know of any online softwares that will let me do this? I searched but can't find anything...

 

I'd use a 2D CAD program for that. A9CAD for example.

 

As a machinist this is a problem that came up from time to time. How accurate do the hole spacing's need to be? I always used the data in my Machinery's Handbook, but now days this stuff is online and with no math involved. Put in your information and there it is. Just one of many online - https://planetcalc.com/1421/

If accuracy is needed a dividing head should be used.

 

What diameter is the cylinder? Will a standard sheet of paper be big enough for the template?

 

You could make your templates in any CAD software and scale them to match the correct diameter when printed.

 

For 11 holes, draw two lines with PowerPoint the exact distance apart you need. You can use the size/position feature to space them exactly (equal to the diameter of you cylinder).
Then draw 10 more lines in between them.
Then dray one horizontal line across all of them.
use the "align" vertical feature to align all the 12 segments and your horizontal line in the center.

Now select the 12 vertical lines and use the "evenly distribute" feature.
print, cut out, wrap the paper around your cylinder and overlap the first snd 12th to give 11 unique positions evenly spaced. The horizontal line keeps you accurate of all points in the same plane through your cylinder.

 

The print it out and wrap around idea is coming from engineers, I can tell.

Why not just lay it out on the cylinder?
1. Scribe a line around the cylinder at the point you want your holes to be. I'd use Dykem layout dye only because I have a couple of bottles of it, magicmarker works just as well, you would put this on the cylinder first before scribing, so you can see your marks.

2. Using one of the chord calculators find the chord for your diameter and angle. Angle found by dividing 360 by the number of spaces you want/need. The closer you can measure your diameter the more accurate your spacing will be. Then you would set a divider(like a compass but with a steel point on each leg) to the chord length (not the arc length) again the closer you measure the more accurate the result.

3. Make a mark on the line drawn in #1 where you want the first hole to be. Put one leg of the divider on that line and sribe a new line with the other divider leg. Repeat until you completely go around the cylinder ending up where you started.