C = parts.insert.heatset ('data') returns every insert in the catalogue as a table, one row for each insert and maker that sells it, sorted by thread, length and outside diameter. C = parts.insert.heatset ('data', NAME) returns those of the thread NAME, as 'M4', and C = parts.insert.heatset ('data', NAME, L) those L millimetres long, each with the hole it needs. Nothing is built.

S = parts.insert.heatset ('solid', NAME, L) builds the insert as a solid.Shape: its top face, where the screw enters, on the xy plane, the insert below it to z = -L, its axis on the z axis. Placed at the mouth of a hole drilled along -z, it sits flush with the surface, as it is set. S.Name holds the designation, as 'Heat-set insert M4 x 8.1'. Only inserts in the catalogue are built, to ruthex’s dimensions where ruthex sells the insert, else to CNC Kitchen’s.

No function cuts or sizes the hole, here or in drafting: a printed hole comes out a different size with each printer, material and setting, so the designer makes it. A row’s d3 is its maker’s recommendation to start from; its t and w are the depth and wall the part must leave for the insert.

Name/Value pairs:

'Maker'

For 'data': only that maker’s rows, 'ruthex' or 'CNC Kitchen', in any case.

'Diameter'

Only the insert of that outside diameter d1. Two inserts are M3 x 4, one 4.6 and one 5 across, the second made for the Voron printers, and a solid of either needs it.

'Detailed'

For 'solid': true knurls the two bands, chamfers the end of the pilot and cuts the thread through by solid.Shape.thread. By default (false) the insert has its outline, the bands plain at d1, a groove after each and the pilot, with a bore of the thread’s nominal diameter.

The table has these variables, each with its unit and its description, which summary (C) lists; lengths are in millimetres:

The form

The makers’ inserts differ only in their knurls, which no fit depends on, so every insert is built to one form from its own L, d1 and d2, in proportions read from the makers’ models. This form is a modelling choice; no maker dimensions it. Where no maker gives d2, the pilot is 0.1 smaller than the hole, as ruthex’s are. With h = (d1 - d2) / 2, from the top down:

The bands are knurled only when detailed. The knurls have the teeth of 90 degrees of DIN 82, cut to full depth with their roots at d2: a pitch of 2 h, fitted by solid.Shape.knurl to a whole number of teeth.

The catalogue

Every insert ruthex or CNC Kitchen sells with a metric thread, a row for each maker with its own values. Where both sell an insert they agree, except that CNC Kitchen recommends holes 0.1 larger from M4 to M8, gives M8 x 12.7 an outside diameter of 10.2 against 10.1, and gives the M3 x 5 x 4 a wall of 1.6 against 1.3.

ruthex: the RX series product data sheet, metric ISO thread, status 15.08.2022, page 1, dimensions and order numbers, for every insert but two sold since, read from the drawings and item numbers on their packets as ruthex.de shows them: M6 x 6.8 (RX-M6Sx6.8) and M10 x 12.7 (RX-M10x12.7).

CNC Kitchen: Dimensions & Design Guidelines, metric inserts, June 2025. It gives no pilot diameter and no article numbers.

The depth of a blind hole, L + 1, is drawn by both. The proportions of the form come from the makers’ own published STEP models, measured: ruthex’s ten metric models and CNC Kitchen’s twelve.

See also: parts.screw.cap, parts.nut.hex

Source Code: parts.insert.heatset