# Screw (fly) press: Tr16×4 screw in a C-frame nut

> How does a screw press work?

- Category: Mechanisms › Screws
- Kind: Hardware
- Basis: Xem Studio design following Brown No. 105 (1868)
- Page: https://xemstudio.com/objects/screw-press-mechanism/ · JSON: https://xemstudio.com/api/geometry?object=screw-press-mechanism · Plain text: https://xemstudio.com/objects/screw-press-mechanism/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files Xem Studio Design License (free to use and sell from, not to redistribute as files: https://xemstudio.com/license/)
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** True size, with no printing tolerance added.

## Notes

- A coarse screw turns in a fixed nut at the top of a C-frame; its end comes down on the work. One turn = one lead (4 mm); the bar through the head gives the leverage: ideal force gain 2π × 40 / 4 ≈ 63, and in a fly press the weighted bar's momentum adds a blow.
- The catalog Tr16×4 jack screw is reused (basic ISO 2904 profile, drawn engaged in the frame's nut with no allowance); the frame is a Xem Studio design following Brown's figure. Drawn with the screw tip 10 mm above the foot.
- Brown's No. 105 (screw stamping press: rectilinear motion from circular).
- Parts (each has its own page): screw-jack-screw-tr16x4, screw-press-c-frame-tr16x4, tommy-bar-6x80.
- Brown's movement No. 105 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

## Sizes

| parameter | value |
|---|---|
| thread | Tr16×4 |
| travel per turn | 4 mm |
| lever | 80 mm bar |
| ideal gain | ≈ 63 |

## Where the files are

- Henry T. Brown (1868, public domain): [Five Hundred and Seven Mechanical Movements — scan on archive.org](https://archive.org/details/fivehundredseven00browiala) — web — Publisher's page; dimensions are facts
- 507movements.com: [Brown's movement No. 105: figure, his text and an animation](https://507movements.com/mm_105.html) — web — Publisher's page; dimensions are facts

## Free STEP/STL (1 parts, Xem Studio Design License, Xem Studio)

Index: https://xemstudio.com/files/hardware/screw-press-mechanism/index.json · license: https://xemstudio.com/files/hardware/screw-press-mechanism/LICENSE.md

- screw-press-mechanism-assembly: [STEP](https://xemstudio.com/files/hardware/screw-press-mechanism/screw-press-mechanism-assembly.step) · [STL](https://xemstudio.com/files/hardware/screw-press-mechanism/screw-press-mechanism-assembly.stl) — Assembled mechanism, all parts placed at one pose (STEP keeps each part separate)

## Questions

**How does a screw press work?**

A coarse screw turns in a fixed nut at the top of a C-frame; its end comes down on the work. One turn = one lead (4 mm); the bar through the head gives the leverage: ideal force gain 2π × 40 / 4 ≈ 63, and in a fly press the weighted bar's momentum adds a blow.

## Fits with

- [Screw-jack screw Tr16×4, 90 mm thread, Ø28 head with tommy-bar holes](https://xemstudio.com/objects/screw-jack-screw-tr16x4/)
- [Screw-press C-frame with a Tr16×4 nut boss, 70 × 60 foot](https://xemstudio.com/objects/screw-press-c-frame-tr16x4/)
- [Tommy bar Ø6 × 80](https://xemstudio.com/objects/tommy-bar-6x80/)