I have just started to build a Core-XY printer ([http://www.thingiverse.com/thing:1003119](http://www.thingiverse.com/thing:1003119)) and one of the jobs I need to do is tap a 6mm thread into the end of a number of the 2020 extrusion pieces. Tapping is an easy task - as long as the thread is started straight and true.

To help with this task I designed this little guide. Just slip it over the end of the extrusion and use the guide hole to keep the tap upright and on-centre.

It was designed in OpenSCAD: the source file has various parameters that can be changed according to the exact dimensions of your 2020 extrusion and the hole you wish to tap. The design can easily be changed for other sizes of extrusion, but you will have to work out the position of the hole for yourself!

Apologies for not including a picture of the finished tapping guide - I made one in black PLA, and it's impossible to take a useful picture of it! The Thingiview viewer will give a very clear idea of its shape.

Print Settings

Rafts:

No

Supports:

Resolution:

0.3mm

Infill:

Notes:

This is a very simple item - just use your favourite slicer to rotate it 180 degrees so that the top flat surface is on the bed, and print away using whatever plastic you prefer.

If you look at the SCAD file you will see a variable called "fiddle_factor" - everybody's printer prints fractionally different sizes, so this factor allows the user to make sure that the tapping guide is an easy fit on the extrusion without being too loose. Don't get too hung up about the fit, as anything that gets the tap close to vertical will do the job.

Post-Printing

Using the tapping guide

Slip the guide over the end of the extrusion, insert the tap and create 3 or 4 turns of thread (remembering to cut a half-turn, then go back a quarter turn or so to clear the metal chips). Once you have made those threads you can take the guide away as the tap will run true from then on.

Category: Hand Tools