# Pololu Universal Aluminum Mounting Hub for 4mm Shaft, \#4-40 Holes (2-Pack)

**Type:** Product page · **SKU:** POLOLU-1081 · **Brand:** [Pololu](https://core-electronics.com.au/brands/pololu-australia)
**Page:** https://core-electronics.com.au/pololu-universal-aluminum-mounting-hub-for-4mm-shaft-4-40-holes-2-pack.html ([markdown](https://core-electronics.com.au/pololu-universal-aluminum-mounting-hub-for-4mm-shaft-4-40-holes-2-pack.html.md))

These universal aluminum mounting hubs allow you to mount custom wheels and mechanisms to 4 mm diameter motor shafts. The set includes two hubs, two #4-40 set screws for securing the hubs to motor shafts, and one 0.05″ Allen wrench for use with the set screws. Each hub has four threaded mounting holes for #4-40 screws (not included).

## Pricing

- **Price:** $18.35 (inc GST) — $16.68 AUD, exc GST
- **Quantity discounts:** 10+ $16.02 (exc GST) · 25+ $15.52 (exc GST)

## Availability & dispatch

- In stock, ships same business day if ordered before 2PM (Australia/Sydney).
- We can dispatch 2 today, and up to 450 more in 4–7 days.

## Description

These universal mounting hubs are designed to work with most [4 mm diameter shafts](https://core-electronics.com.au/#), including round shafts, and “D” shafts. Each of the two included hubs has four mounting holes for [\#4-40 screws](https://core-electronics.com.au/machine-screw-4-40-1-2-length-phillips-25-pack.html) (not included), letting you mount custom wheels or mechanisms to your motors. The two included #4-40 hex set screws (one for each hub) allow secure coupling of shaft to hub, and a [0.05" hex wrench](https://core-electronics.com.au/hex-allen-wrench-0-05.html) (often the smallest size in SAE Allen wrench sets) is included for use with the set screws. A dimension diagram of the hub is available under the resources tab.

The picture to the right shows a hub with Pololu’s [25:1 metal gearmotor 20Dx44L mm](https://core-electronics.com.au/catalog/product/view/sku/POLOLU-1092) and a [Pololu 20D mm metal gearmotor bracket](https://core-electronics.com.au/pololu-bracket-pair-for-discontinued-25-1-and-67-1-metal-gearmotors-20d-mm.html). These hubs will work with any Pololu 20D mm metal gearmotor or [25D mm metal gearmotor](https://core-electronics.com.au/#), and they also work with 60 mm, 70 mm, 80 mm, and 90 mm [Pololu wheels](https://core-electronics.com.au/#).

 | \| [![](https://core-electronics.com.au/media/remote_images/0J1194.250_MRavBp.jpg%3Fed4f2f8e73f1d28ec05b8e9ac82b0a9a)![](https://core-electronics.com.au/media/remote_images/zoom-d0cfc0fffa825c4654893ef42b77cee3_LUrqIJ.png)](https://core-electronics.com.au/#) \| \|---\| \| Pololu 20D mm gearmotor with bracket and hub. \| | \| [![](https://core-electronics.com.au/media/remote_images/0J2645.250_2igR8x.jpg%3F4bc75f8312ddb723b1f75beb484dfb38)![](https://core-electronics.com.au/media/remote_images/zoom-d0cfc0fffa825c4654893ef42b77cee3_LUrqIJ.png)](https://core-electronics.com.au/#) \| \|---\|---\| \| Pololu 60×8mm wheel on a Pololu 25D mm metal gearmotor. \| |
|---|

| [![](https://core-electronics.com.au/media/remote_images/0J2763.300_JltEXb.jpg%3F05b54bb3db229f67c35850795c461ea9)![](https://core-electronics.com.au/media/remote_images/zoom-d0cfc0fffa825c4654893ef42b77cee3_LUrqIJ.png)](https://core-electronics.com.au/#) |
|---|
| Pololu wheels with 90, 80, 70, and 60mm diameters in three colors: blue, red, and yellow. |

**Documents:**

- [Dimensional Drawing](https://core-electronics.com.au/attachments/localcontent/1081-4mm-4-40-hub-dimensions_33377918d55.pdf)

## Images

- [Product image 1](https://core-electronics.com.au/media/catalog/product/p/o/pololu_universal_aluminum_mounting_hub_for_4mm_shaft_4_40_holes__2_pack___pololu_1081__00.jpg)