DrawSTL Open Editor

Mechanical

Bolt and nut: printable ISO metric threads in one file

This page opens the DrawSTL bolt template: a parametric bolt with a real ISO metric thread profile, optionally paired with a matching nut, downloaded as a print-ready STL. Sizes run from M3 to M10 using the standard coarse pitches, so M6 gets 1 mm and M8 gets 1.25 mm.

Head style is either a hex head or a socket cap with a hex key recess, with diameters from the matching ISO standard. The print tolerance is what makes a printed pair actually turn: half of it is removed from the bolt and half added to the nut.

Open in editor See the sizes

Free, no sign-up. Change the sizes in millimetres and download the STL.

DrawSTL bolt template: a hex head bolt with an ISO metric thread next to its matching hex nut lying flat on the print bed

Ready-made variants

Each variant is the same template with different settings. Follow the link and the editor opens with those values.

Adjustable sizes

These values are edited in the editor's template panel. A number outside the range is clamped to the nearest limit automatically.

SizeRangeDefault
SizeM3, M4, M5, M6, M8, M10M6
Length4–120 mm20 mm
Head typeHex, Socket capHex
Add nutOn / OffOn
Print tolerance0–0.6 mm0.2 mm

What it is used for

  • Plastic fasteners where metal screws are not wanted
  • Assembly mock-ups, prototypes and fit tests
  • Toys, furniture jigs and light fixtures
  • Teaching models that show how a thread works
  • Adjustable clamping on jigs, moulds and holders

Printing tips

Orientation
The bolt head sits on the bed and the thread runs upward. The nut lies flat beside it. No rotation needed.
Layer height
0.12 mm. The flanks are short overhangs, so thinner layers mean a cleaner thread; from M8 up, 0.16 mm is acceptable.
Infill
40-100% works. Do not go below 3 walls or the thread crests print hollow.
Supports
None. The hex head rests on the bed and the ISO 60 degree flanks are short overhangs.
Material
PETG resists splitting under clamping load better than PLA. ABS or ASA suits vibrating or impact-loaded spots.

Tips

  • Print the bolt and nut from the same file with the same settings if they have to work together.
  • If the thread will not turn, raise the tolerance by 0.05 mm; lower it by 0.05 mm if it feels sloppy.
  • Brush the thread after printing, since leftover stringing jams the first turn.

Print tolerance and M sizes

Print tolerance is the clearance that keeps the two threads from fusing. The template removes half of it from the bolt's external thread and adds the other half to the nut's internal thread, so both deviate symmetrically from nominal and the total clearance equals your value.

The 0.2 mm default gives a hand-tight, freely turning fit on a calibrated printer. At 0.3 mm the nut spins loosely and 0.1 mm is tight. Enter 0 for nominal ISO geometry, which is what you want when mating with a metal nut.

  • M3 and M4: the printed thread is very fine, best treated as visual
  • M5 and M6: usable threads at 0.12 mm layers
  • M8 and M10: the sizes where a printed thread really carries load
  • Tolerance 0: nominal ISO geometry for mating with metal hardware

Hex head or socket cap

The hex head follows ISO 4017 for across-flats and head height. It is easy to turn by hand or with a spanner, and its flat underside on the bed makes it the most trouble-free option to print.

The socket cap is dimensioned to ISO 4762 and carries a hex key recess on top. It looks tidier, but in plastic the recess corners round off quickly, so pick the hex head when real torque is involved.

Frequently asked questions

Will a printed bolt fit a metal nut?

Set tolerance to 0 and the geometry is nominal ISO, which usually fits. Expect to clean the thread, and remember a plastic thread cannot take steel torque.

Can I print the nut on its own?

Yes, turn the nut option off to get the bolt alone. For a standalone nut use the hex nut template, which goes to M12 and takes custom sizes.

Which layer height gives the cleanest thread?

Start at 0.12 mm. The flanks are built from small steps, so thinner layers flatten the flank and smooth the turning action.

Is there an M12 or larger size?

The bolt template stops at M10. The hex nut template covers M12 and custom sizes; for a larger bolt you would combine a threaded rod in the editor.

Similar templates

  • DrawSTL hex nut template: a plastic hex nut with 45 degree chamfers on both faces and an ISO metric internal thread

    Hex nut

    This page opens the DrawSTL hex nut template: a parametric ISO metric internally threaded nut that you size in millimetres and download as a print-ready STL. Pick a standard size from M3 to M12 and the across-flats, nut height and coarse pitch all come from the ISO table, so there is nothing to look up.

    Sizes and details
  • DrawSTL spacer template: a cylindrical plastic spacer with a central hole and 45 degree chamfers on the top and bottom edges

    Spacer / sleeve

    This page opens the DrawSTL spacer template: a parametric cylindrical spacer or standoff that sets the distance between two parts, sized in millimetres and downloaded as a print-ready STL. Three values are all it takes: outer diameter, inner diameter and length. Set the inner diameter to zero for a solid disc.

    Sizes and details
  • DrawSTL L bracket template: two arms meeting at a right angle with screw holes in each arm and a triangular rib in the corner

    L bracket

    This page opens the DrawSTL L bracket template: a parametric right-angle corner bracket with screw holes that you size in millimetres and download as a print-ready STL. You give the horizontal arm, the vertical arm, the width and the thickness, and the holes are spaced evenly along each arm.

    Sizes and details

Set the sizes to fit your part

Open the template in the editor, enter your values and download a print-ready STL. No account needed.

Open in editor