Please download this model from the Printables 3d model repository: Print 137790

Update 16Apr22
The lever can be hard to grip to open and close the blast gate, so I've designed a pair of alternatives that have lugs to help with their operation. One consequence is that they need to be printed with support under the square drive recess. The arrow-lugged lever retains the concept of the arrow to indicate air flow. Download the new levers from here Print 137790

See this YouTube video by Nils Rasmusson ([https://www.thingiverse.com/the3dprintingzone/designs]) for a performance comparison of this blast gate with other commercially available designs [https://www.youtube.com/watch?v=epJ929kZzc4&t=8s&ab_channel=LRN2DIY]

Update 28Mar22
Please download this model from the Printables 3d model repository: Print 137790

My 100mm ball valve type blast gate (thing:4585570) works well, but is big! This redesign aims to keep the functionality but make it a little more compact.

This still suits 100mm tubing.

In addition to printing filament you'll need 4 short M4 set screws to fasten the two halves of the case together, and another M4 x 8mm screw, with an M4 hex nut, to fasten the lever on its bearing (I used M4 x 8mm socket head button screws). If you want to make use of the bracket to mount the blast gate to a wall, you need to replace two of the M4 x 8mm screws with M4 x 18mm (or longer) and a pair of M4 hex nuts. The holes in the case / housing may need to be eased with a suitable drill bit - 4mm on one half of the case and 3.3mm (for tapping to M4) on the other.

You need to print 2 cases, 1 rotator, 1 bearing, 1 lever bearing and 1 lever for each gate, and the bracket if you want to use it. It's useful to use a different colour for the lever from that used to print the case so that the position of the ball (open or closed) can be seen easily.

Update 05 Feb 21
Please see the comments with a post from George (zhushengliang) with regard to the .step files.