In the pop-up window, enter the thread type, size, designation, class, and direction of your screw.

If you haven’t already, create your design and use the Thread tool to model your threads. Now that you have the values for the thread pitch and pitch diameter offset, head over to Fusion 360. And just like that, you have your pitch diameter offset value! It’ll look like this:Įnter the values for the major and minor diameter of your screw, the cutting diameter of the tool you’re using (you can easily find these on the manufacturer’s website), and the flat (or crest) into the spreadsheet. Once you’ve downloaded and opened the calculator, click the “Internal - Simple” tab. Download the pitch diameter offset calculator.John gives an in-depth explanation in his thread milling video. John Saunders from NYC CNC has created a calculator that takes the geometry of your tool into account and generates the pitch diameter offset for you-saving you time and ensuring accuracy. To ensure precision, you don’t want to randomly input values for the pitch diameter offset, but rather calculate it. The pitch diameter offset is crucial because the tool you’re using may not always come to a fine point-like the Harvey Tool 60º double-angle shank cutter we’re using for this threading operation. In other words, the pitch diameter offset is the difference between the major and minor diameters. Every machine screw has a major diameter (D) and a minor diameter (d), marking the respective crest and root of the threads. However, calculating the pitch diameter offset is a little more involved. Finding the thread pitch for a screw is straightforward-you can take it directly from the fastener that you’re using (see common metric thread pitches and imperial threads per inch). When programming a thread milling operation in Fusion 360, there are two important numbers you need: the thread pitch and the pitch diameter offset. This video features the Bantam Tools Desktop CNC Milling Machine milling threads in aluminum 6061. We often get asked if our Bantam Tools Milling Machines support rigid tapping, and while it doesn’t, there are other strategies you can use to machine threads into your part, such as thread milling. In this brief how-to, we walk you through the steps for programming thread milling operations in Fusion 360.

Fusion 360 milling