A printed hole comes out small and a printed peg comes out fat, by an amount that belongs to your machine, your nozzle and the spool in front of it. Guessing that amount is why a first print is usually wrong. Print this plate once and you never have to guess it again.
Every station wears its own number, in seven segment digits you can read at arm's length. On the comb and the collars the number is hundredths of a millimetre, so 25 means 0.25 mm. On the arms it is tenths of a percent of strain, so 25 means 2.5 percent.
Push a pin into each hole in turn, smallest first. Two answers come out of one bar: the tightest hole it enters and stays put in, and the first hole it slides into without wobble.
Push each arm sideways until it touches its rail, then let go. Every rail sits the same distance away, so the arms differ only in how hard that bend is on the plastic. Note the thinnest one that springs all the way back.
Drop each collar over the shaft. The tightest one that still spins freely is your running fit, and it will be looser than either number the comb gives.
Kept in this browser and nowhere else. Other generators on this site read the same four numbers, so you only ever answer these questions once per printer and spool.
Two sums, and they are the only two you need. Both run on whichever profile is ticked above.
Add the clearance to the diameter, not the radius. Deep holes want the looser end of the range, and a hole shallower than a millimetre or two barely needs any clearance at all.
A cantilever strains its root by 3 y t / 2 L², where y is the bend, t the thickness and L the free length. Everything else follows: double the length and the same arm takes four times the bend.
| Layer height | Whatever you usually use |
| Walls | 3 or more |
| Infill | 20 percent or more |
| Supports | None, nothing overhangs |
| Orientation | As downloaded |
| Brim | On the shaft, if it wobbles |
The answer belongs to the settings that made it, so print this the way you print everything else. A kit sliced at 0.1 mm will not describe a part sliced at 0.3 mm, and a new spool of a different brand is a new measurement.
Holes and pegs both print standing, because a hole lying on its side is a different hole. The comb's holes start on the bed with their first layer squashed, which is exactly how holes usually arrive, so the number you read includes that.
Circles are really polygons here. A pin's corners sit on its circle, so it is never fatter than nominal; a hole's flats sit on its circle, so it always passes a nominal pin. Skip that and every hole comes out a few hundredths small, which is most of a step.
Once a profile is saved, the other tools here pick it up on their own: the Adapter Maker offers your three fits at the top of its list, the Bracket Maker works out the hole each screw really wants, and the Keychain Maker cuts its ring hole over size by what your printer loses.
A saved profile lives in this browser under printfit, as the active entry of a small list. Anything else served from this site can read it:
JSON.parse(localStorage.printfit)
The share button on a profile puts the same four numbers in a link, which is the only copy that survives clearing a browser. The geometry is a small Javascript module that runs in node as happily as here.