(20mm) Expandable Bench Dogs

➡️ ⚙️ ⚒️ 📏 Checkout the entire 20mm Ultimate MFT Bench Dogs collection

Update 2025-04-18: Added an extended version to stack two boards (for jigs for example), the only part to re-print is the ‘top bushing’), and the bolt must be 20mm more

Update 2024-10-27: Updated version, now with 9 diameters to find the perfect fit. Also some minor improvements and rubber O-Ring compability

Expanding/expandable bench dog

Insert in a MFT hole, turn, and you'll be suprised that you can't remove it!

By rotating clockwise, the O Rings are compressed and expand to lock the bench dog into the hole. Turn counterclockwise and the bench dog will release.

The Locking Knob (above the table part) is available in 14mm, 20mm, 40mm, 60mm, 80mm and 100mm height. Choose the length you prefer (you will need an hex bolt 20mm taller, ex: a 80mm locking knob requires a 100mm bolt).

The Bushing parts need accuracy, depending your MFT table holes you should use one of the 9 provided sizes. Find the best fit for your holes, a good starting point would be to check with the ¾" MFT holes gauge to know the size.

The O-Rings, you can buy it (easy way), size: 20mm OD, 13mm ID, 3mm CS (Amazon), or you can print it with TPU. I optimized the TPU profile for 90A / 95A, but result can vary depending the brand or the shore hardness, you may need some tries to get a good behavior from the O Ring.

You will need two O-Rings, one M6 hex bolt (lenght depends of the locking knob) and one M6 nut.

Enjoy!