retractaWDT - a retractable WDT Tool for Baristas

I love espresso. I love making espresso. 

But I hate needles!

What is this thing?

A WDT tool is used to stir freshly ground coffee. By distributing the powder evenly you reduce the chance of channelling and your espresso is always perfect (no guarantee!).

Many WDT tools use acupuncture needles because they are very fine and work great. BUT I HATE NEEDLES!

My take with this tool was to hide the pointy end of the needles when the tool is not in use.

What do you need?

• Some 3d-printed parts
  • retractaWDT_upper
  • retractaWDT_middle
  • retractaWDT_lower
  • retractaWDT_shaft
  • retractaWDT_cap (optional for extra safety)
  • retractaWDT_sleeve (optional for extreme safety)
• a very short piece of extra filament
• 2x magnets (6mm diameter/ 2mm height) (only needed if you want the cap or the sleeve)
• 8 acupuncture needles* 

*I am using the same needles that come with some 3d-printers to unclog nozzles. You can buy them all over the net. Watch out for the following sizes:

• 0.35x75mm or 0.4x75mm
• I got a whole bunch of them here: https://www.aliexpress.com/item/1005001467649993.html 

How do you print it?

I used my Original Prusa MK3S with MMU2S and some modifications.

0.2mm layers, standard profile.

You have to orient some of the parts for easiest printing (look at the picture).

How do you assemble it?

	Insert the shaft into the middle piece.
	Click the shaft into the lower piece. Watch out: There is a wrong an a right direction to do this. If it clicks in, you did it right!
	Insert a short piece of filament (1cm is enough) in the hole in the bottom of the lower part. It blocks the shaft from coming of.
	This step is only needed if you want to use a cap or the sleeve: Insert magnets in the lower part an in the cap/sleeve.
	Insert the needles. This step may be traumatic or satisfying. Please be patient!
	Push the needles all the way in and move the middle part up.
	Screw the top part on. If you use PETG this is gonna be really tight. PETG on PETG produces a lot of friction. It may help to warm the threads of the middle part with a lighter. Update: Use the version with bigger tolerances and it will screw in without any problems.
	You did it! Go make an amazing espresso!