# Thread-forming screws for plastic (EJOT PT type): screw hole diameter by plastic, M2.2–M4, boss hole rule, K sizes

> What hole diameter does a PT thread-forming screw need in ABS, nylon, polycarbonate or polypropylene?

- Category: Hardware › Fasteners
- Kind: Standard part
- Basis: EJOT's PT flyer (nominal diameters, hole rule, lengths) and a maker sheet of PT hole diameters by plastic, M2.2 to M4; numbers only
- Page: https://xemstudio.com/objects/plastic-thread-forming-screw-holes/ · JSON: https://xemstudio.com/api/geometry?object=plastic-thread-forming-screw-holes · Plain text: https://xemstudio.com/objects/plastic-thread-forming-screw-holes/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** Every file is drawn at true size with no tolerance added. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your process's clearance before making the part.

## Notes

- The hole table gives the recommended hole diameter in mm by plastic for M2.2, M2.5, M3, M3.5 and M4 PT-type screws, standard materials one row each. The sheet lists the high-strength group (glass-filled PA / PBT, PC, PC-GF30, PMMA, PPO, PEEK, PPS) with one value set; the layout did not show whether each material has its own values, so it is shown as one row (it matches the ABS row). For materials with high filler content or high internal strength the same sheet says the optimum hole diameter can be increased to 0.88 d, where d is the nominal screw diameter.
- EJOT's flyer prints the rule hole diameter dh = 0.7 to 0.8 × d1 depending on the material (d1 the nominal screw diameter); the table values equal 0.7 × d for PE-LD / PP, 0.75 × d for PA, POM, PE-HD, PBT, PET and 0.8 × d for ABS, PS, PVC and the glass-filled grades. The flyer also prints other design ratios (for example dT = 2 × d1, 0.3 to 0.5 × d1 and di = 2 × d1 near the drawing), but the text read did not say which dimension each belongs to, so they are not stated here. Boss outside diameter and engagement depth tables by PT size were not in the sources read (EJOT refers to its design recommendation or hotline).
- EJOT PT sizes by K designation (nominal diameter, mm): K10 1, K12 1.2, K14 1.4, K16 1.6, K18 1.8, K20 2, K22 2.2, K25 2.5, K30 3, K35 3.5, K40 4, K50 5, K60 6, K70 7, K80 8, K100 10. Screw lengths (mm, with the flyer's tolerance): 3, 3.5, 4, 4.5, 5, 6, 7, 8, 10, 12, 14, 16, 18, 20, 22, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100 (which lengths exist for which diameter is not clear from the text read). EJOT recommends DELTA PT for high-filler or high-strength materials and, to reduce boss shear stress when assembling, first reducing the outside boss diameter and then increasing the hole diameter (a larger hole lowers pull-out load; deeper engagement can offset it).
- Not on this page: other makers' screws for plastic (Stanley Plastite, PT-K families by other brands) and ASME Type B / AB plastic hole sizes (the hole tables read were not usable). No file: a PT thread (30° flank, trilobular-like profile) is not drawn from numbers here.
- Heat-set inserts for plastic bosses: heat-set-insert-holes; sheet metal pilot holes: sheet-metal-screw-pilot-holes.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| boss hole | M3 PT screw: 2.4 mm in ABS, 2.25 mm in PA 6 / POM / PBT, 2.1 mm in PP; rule 0.7 to 0.8 x d (up to 0.88 x d for filled / high-strength grades) | EJOT PT-type thread-forming screw of the nominal diameter (M2.2 to M4 tabulated) | designed | all |

## Sizes

| group | plastic | M2.2 hole (mm) | M2.5 hole (mm) | M3 hole (mm) | M3.5 hole (mm) | M4 hole (mm) |
|---|---|---|---|---|---|---|
| standard materials | ABS | 1.76 | 2 | 2.4 | 2.8 | 3.2 |
| standard materials | ABS/PC blend (incl. regrind) | 1.76 | 2 | 2.4 | 2.8 | 3.2 |
| standard materials | ASA | 1.716 | 1.95 | 2.34 | 2.73 | 3.12 |
| standard materials | PA 4.6 | 1.606 | 1.825 | 2.19 | 2.555 | 2.92 |
| standard materials | PA 6 | 1.65 | 1.875 | 2.25 | 2.625 | 3 |
| standard materials | PA 6.6 | 1.65 | 1.875 | 2.25 | 2.625 | 3 |
| standard materials | PBT | 1.65 | 1.875 | 2.25 | 2.625 | 3 |
| standard materials | PE-LD | 1.54 | 1.75 | 2.1 | 2.45 | 2.8 |
| standard materials | PE-HD | 1.65 | 1.875 | 2.25 | 2.625 | 3 |
| standard materials | PET | 1.65 | 1.875 | 2.25 | 2.625 | 3 |
| standard materials | PET-GF30 | 1.76 | 2 | 2.4 | 2.8 | 3.2 |
| standard materials | POM | 1.65 | 1.875 | 2.25 | 2.625 | 3 |
| standard materials | POM-GF30 | 1.76 | 2 | 2.4 | 2.8 | 3.2 |
| standard materials | PP | 1.54 | 1.75 | 2.1 | 2.45 | 2.8 |
| standard materials | PP-GF30 | 1.584 | 1.8 | 2.16 | 2.52 | 2.88 |
| standard materials | PP-TV20 (20% reclaimed) | 1.584 | 1.8 | 2.16 | 2.52 | 2.88 |
| standard materials | PS | 1.76 | 2 | 2.4 | 2.8 | 3.2 |
| standard materials | PVC | 1.76 | 2 | 2.4 | 2.8 | 3.2 |
| standard materials | SAN | 1.694 | 1.925 | 2.31 | 2.695 | 3.08 |
| high-strength group (as read: one value set for the whole group) | PA 4.6-GF30, PA 6-GF30, PA 6.6-GF30, PBT-GF30, PC, PC-GF30, PMMA, PPO, PEEK, PPS | 1.76 | 2 | 2.4 | 2.8 | 3.2 |

## Where the files are

- EJOT: [PT screw for thermoplastics (flyer 08.23): nominal diameters K10 to K100, hole diameter rule dh = 0.7 to 0.8 x d1, lengths 3 to 100 mm](https://www.ejot.de/medias/sys_master/Industry_Flyer/Industry_Flyer/h54/h3c/9331729760286/EJOT-PT-Flyer-08.23-en.pdf) — web — Maker flyer; numbers only
- Cold-forged fastener maker sheet (hosted on a Shopify CDN; PT hole sizes by plastic): [Recommended hole diameter for PT-type screws by material, M2.2 to M4, standard and high-strength groups; note: high filler content up to 0.88 d](https://cdn.shopify.com/s/files/1/0056/7856/3437/files/MetPTholesize.pdf) — web — Maker datasheet; numbers only
- EJOT: [PT screws for thermoplastics (product page; CAD and design recommendations on request)](https://www.ejot.se/pt) — web — Publisher's page; dimensions are facts

## Questions

**What hole for an M3 PT screw in ABS?**

2.4 mm (0.8 × d); 2.25 mm in PA 6 / POM / PBT and 2.1 mm in PP and PE-LD, from the PT hole-size sheet.

**What is the hole rule for PT screws?**

EJOT's flyer: hole diameter 0.7 to 0.8 × the nominal screw diameter depending on the material; up to 0.88 × d for high-filler or high-strength materials per the hole-size sheet.

**What does K30 mean on an EJOT PT screw?**

K30 is the 3.0 mm nominal diameter (K25 is 2.5 mm, K40 4.0 mm).

## Fits with

- [Heat-set insert holes: hole cutters and test bosses for every insert size](https://xemstudio.com/objects/heat-set-insert-holes/)
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- [Sheet metal screw pilot holes: drill size and hole diameter for Types AB, A and 1/23/F, by sheet thickness (#2 to 1/2)](https://xemstudio.com/objects/sheet-metal-screw-pilot-holes/)
- [Self-tapping (sheet metal) screws: ISO 7049 pan head ST2.2–ST6.3 and ASME B18.6.4 Type AB thread #2 to 3/8](https://xemstudio.com/objects/self-tapping-screws-iso-7049-pan-head/)
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- [Helical wire thread inserts (Helicoil style, DIN 8140): M3–M16 drill size, tapped hole, insert length 1D–3D](https://xemstudio.com/objects/helical-thread-inserts-din-8140/)