CNC Hold Down System

Background:

This is a completely free and open source system for CNC’s and workshop jigs called the “BiT FiT System” (a combination of my woodturning business “Beauty in Trees”, partial inspiration from the MatchFit System and the idea that I hope you will customize and “FiT” it to your unique needs). 

It can be used with T-tracks or dovetail channels similar to the MatchFit system.  However, unlike the MatchFit system, this design utilizes larger keys that can accommodate ¼-20 nuts and bolts and will hold up a little longer as the spoilboard gets resurfaced.

There is nothing groundbreaking about the designs, and it is inspired by the MatchFit system, Carbide 3D’s Essential Clamps and various other designs I’ve seen over the years. I simply wanted a standardized, cohesive system that encompassed my needs but was flexible enough to be expanded for and by, others.

I’ve included documents outlining the specs as well as my source files from Fusion 360 and Vectric.  Note: MakerWorld would not accept the Vectric file, but it is availble on my page on Printables). The Fusion files are fully parametric, and the most-commonly-adjusted parameters are marked as favorites.  Many of the STL’s are also included for those not comfortable with Fusion 360 and simply want to print.

All Fusion 360 files are in Millimeters while CAM files are in inches – sorry, but I typically 3D model in millimeters and mill in inches, but everything is compatible.

I will update this project as accessories are added and for any other fixes or tweaks as they arise.  I encourage you to run with it and “FiT” it to your needs!

Components:

The system comprises the following areas so far, and the included PDF contains details and specs for each component:

• Spoilboard with dog holes and channels (either dovetailed or square for t-tracks)
• Bench Dogs for aligning stock
• Keys, Clamps and Knobs for securing stock

Required Hardware:

• ¼-20 Bolts: one for each clamp and key combination.  The length will depend on your project and which clamp you are using (standard, medium, thin or tall).  I use 1-1/2” – 2-1/2” most often.
• M3x4x5 Heatset Inserts: one for every standard knob.  You would use a ¼-20 nut for the “Nut” version or simply tap your own threads with the “Tap” version.

Printing Details:

I typically print components using a 0.4mm nozzle and 0.2 mm layer.  Supports are not required for any components at this time, but I recommend an outer brim for the knobs.  Other component-specific concerns are noted in the supporting documentation.