Recently I upgraded my Ryobi 10″ compound miter saw to a Dewalt DW17 (Type 3) 12″ saw. As I don’t have dust management system in my garage, I always hooked up my Craftsman 6HP shop vac directly to saw’s exhaust. Shop Vac’s hose is 2″ ID so it fit nicely my Ryobi miter saw (it would fall off all the time tho, so I had to duct tape it) as well as my Dewalt table saw. For some strange reason new Dewalt Miter saw had much smaller port (42mm or 1.66 inch OD).

Curse you Dewalt for screwing with people like that! I have another shop vac with 1.5″ hose and it didn’t fit either! Googling I discovered I wasn’t the only one pissed at them for using non-standard diameter, as other people tried and failed to find suitable adapter. I ordered on on Amazon which by the specs should’ve worked. It was made by Dewalt (D279053) but didn’t fit saw or vac hose! WTF? 🙂

Finally I just decided to 3D print one myself. And after several attempts I finally made an adapter that fits nicely, if a little tight. I used ABS plastic for durability and heat resistance and made walls pretty thick. It took me almost 1.5 hours to print, and came out a little short, but seems to be working. No layer separation this time either! 🙂 I always got it with tall prints in winter, so I’m guessing hot summer temperatures helped.
Feel free to print one or modify to your needs. There’s room for improvement.  For example you can make large tube thinner and slope it towards smaller one if your printer is good with overhangs. It will reduce material and time needed.

Here’s link to the design on Thingiverse.