# T8 lead screw Tr8×8 envelope, 100 to 400 mm

> What are the dimensions of a T8 lead screw?

- Category: Hardware › Motion
- Kind: Hardware
- Basis: Tr8×8(P2) trapezoidal lead screw, 4-start: Ø8 major, 2 mm pitch, 8 mm lead; envelope only
- Page: https://xemstudio.com/objects/t8-lead-screw/ · JSON: https://xemstudio.com/api/geometry?object=t8-lead-screw · Plain text: https://xemstudio.com/objects/t8-lead-screw/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses

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

## Notes

- Ø8 envelope, 100, 150, 200, 250, 300 and 400 long; the thread is not drawn.
- Tr8×8(P2): 2 mm pitch, four starts, 8 mm of travel per turn. Tr8×2 (single start, 2 mm per turn) has the same envelope; four thread ends visible on the screw's end face mean 8 mm lead.
- The end goes into a 5 → 8 mm coupler on a NEMA 17 or a bearing of 8 mm bore.

## 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 |
|---|---|---|---|---|
| screw | Ø8 | coupler bore or bearing | slide | t8-screw-* |

## Sizes

| file | Ø | length |
|---|---|---|
| t8-screw-100 | 8 | 100 |
| t8-screw-150 | 8 | 150 |
| t8-screw-200 | 8 | 200 |
| t8-screw-250 | 8 | 250 |
| t8-screw-300 | 8 | 300 |
| t8-screw-400 | 8 | 400 |

## Where the files are

- Wikipedia: [Leadscrew](https://en.wikipedia.org/wiki/Leadscrew) — web — CC BY-SA 4.0 (text)
- McMaster-Carr: [Lead screws and nuts (free STEP/IGES/STL per part, for your own design use; no redistribution)](https://www.mcmaster.com/products/lead-screws/) — STEP, IGES, STL, PDF — McMaster-Carr site terms: personal design use, no redistribution (verify at link)

## Free STEP/STL (6 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/t8-lead-screw/index.json

- t8-screw-100: [STEP](https://xemstudio.com/files/hardware/lead-screw-t8/t8-screw-100.step) · [STL](https://xemstudio.com/files/hardware/lead-screw-t8/t8-screw-100.stl) — T8 lead screw envelope Ø8 × 100 (thread not modeled)
- t8-screw-150: [STEP](https://xemstudio.com/files/hardware/lead-screw-t8/t8-screw-150.step) · [STL](https://xemstudio.com/files/hardware/lead-screw-t8/t8-screw-150.stl) — T8 lead screw envelope Ø8 × 150 (thread not modeled)
- t8-screw-200: [STEP](https://xemstudio.com/files/hardware/lead-screw-t8/t8-screw-200.step) · [STL](https://xemstudio.com/files/hardware/lead-screw-t8/t8-screw-200.stl) — T8 lead screw envelope Ø8 × 200 (thread not modeled)
- t8-screw-250: [STEP](https://xemstudio.com/files/hardware/lead-screw-t8/t8-screw-250.step) · [STL](https://xemstudio.com/files/hardware/lead-screw-t8/t8-screw-250.stl) — T8 lead screw envelope Ø8 × 250 (thread not modeled)
- t8-screw-300: [STEP](https://xemstudio.com/files/hardware/lead-screw-t8/t8-screw-300.step) · [STL](https://xemstudio.com/files/hardware/lead-screw-t8/t8-screw-300.stl) — T8 lead screw envelope Ø8 × 300 (thread not modeled)
- t8-screw-400: [STEP](https://xemstudio.com/files/hardware/lead-screw-t8/t8-screw-400.step) · [STL](https://xemstudio.com/files/hardware/lead-screw-t8/t8-screw-400.stl) — T8 lead screw envelope Ø8 × 400 (thread not modeled)

## How it fits

### Goes in or on
- [608 ball bearing](https://xemstudio.com/objects/608-bearing/): Ø8 end in a 608

### Connects to
- [T8 flange nut: Ø10.2 body, Ø22 flange, 4 × Ø3.5 on 16](https://xemstudio.com/objects/t8-nut/): Tr8×8 thread through the nut
- [Flexible shaft couplers, 5–10 mm bores](https://xemstudio.com/objects/shaft-couplers/): 5 → 8 coupler to the motor
- [NEMA 17 stepper motor](https://xemstudio.com/objects/nema-17-stepper/): drives the screw

## Questions

**Is T8 lead 2 mm or 8 mm?**

Both are sold as T8. Tr8×8 (4-start) moves 8 mm per turn; Tr8×2 moves 2 mm. Four thread ends on the screw end = 8 mm lead.

**What is the T8 pitch?**

2 mm between threads; with 4 starts the lead is 8 mm.

## Fits with

- [T8 flange nut: Ø10.2 body, Ø22 flange, 4 × Ø3.5 on 16](https://xemstudio.com/objects/t8-nut/)
- [NEMA 17 stepper motor](https://xemstudio.com/objects/nema-17-stepper/)
- [Flexible shaft couplers, 5–10 mm bores](https://xemstudio.com/objects/shaft-couplers/)
- [608 ball bearing](https://xemstudio.com/objects/608-bearing/)