Stand For Iris Plotting Compass

I used PLA+, 0.2mm layers, 0.4mm nozzle, no adhesion or support, full speed (on my printer) 60mm/s, 15% infill.

Settings not critical, unlike the main model which has very specific layer and base layer thicknesses.

The edges are all filleted apart from the bottom and sides of the centre-marking groove so this can remain well defined. I used an initial layer line width of 100% instead of the usual 125% to make sure there was no material poking out at the bottom of the groove. If you use 125% you might have to file/sand the notch to clean it up. Or you can use the stand with the flat side up (so the centre-marking point is the filleted one) it's up to you. 

Accuracy of the centre point rather depends rather on your pencil tip and what angle you hold it at! To see how it's doing, mark the centre with the guide in one position and then rotate the guide around inside the dial and see if the mark you made is central in the guide in different positions. If not, then try angling the pencil to correct it. Once you have the knack you should be able to centre your circles ok.  

It works the other way around too - if you have a point already that you want as your centre, line up the guide and iris with the centre point, take out the guide, select your diameter on the iris and draw your circle.

If you didn't add the rubber feet to your iris, the guide will be flush with the dial. If you have the feet, the guide will sit slightly below the edge of the dial. Basically because I forgot to add the thickness of the feet when designing the guide, hehehehe, shoot me now :o)

My favourite propelling pencil is a Rotring Tikky, but for some reason such as the angle of the head it draws wibbly circles with this iris especially on the mid-range sizes. So I tried a Bic disposable propelling pencil and that drew really nice ones! 

I tried a print with the slot slightly loose so the iris can be picked up without the stand, and then one with the slot snug so it stands dead straight and when you pick up the iris the guide comes with it, and I preferred the latter as I'm likely to want the guide as well when I'm using it. So I kept the snug version (which also has a bigger better guide channel) and that's what's on here.

Just the addition of a stand / centre-finder for this iris. Follow the original model link for the nice dial that has the graduations next to the outer ring index mark, and then follow the original model link in that posting to find the rest of the parts for the complete model.