On my Hammer A3-41 I have a homemade dust port adapter. It consists of 4 rings glued together. Two of the rings have an internal diameter sized to tightly slip over the 120mm dust port on the machine and two have an internal diameter sized so that the Rockler Dust Right handle slides in. Once the four rings were fitting individually I glued them together to make a 4 ring stack. I had to cut a notch out of two of the rings for the Dust Right handle.
My Hammer HS 950 also has a 120mm dust collection port. For this one I already had a schedule 40 PVC dust hose adapter on hand and after stretching it a bit over the port I got it to fit. This adapter is made specifically to adapt schedule 40 pipe to 4″ flex hose. I had to use another adapter in line with the first to get it to work with my Dust Right handle.
– Rockler Schedule 40 PVC to 4” Fitting Adapter – https://amzn.to/31tkirx
– Expandable 4″ Rockler hose – https://www.rockler.com/rockler-4-dia-dust-right-hose-4-l-compressed-extends-to-28-l
– Dust Right 4” Quick Change Tool Set – https://amzn.to/2DuhJgG
– Hammer HS 950 sander – https://us.feldershop.com/en-US/en-US/en-US/Sanding/Machines/Oscillating-Edge-Sander-Hammer-HS-950.html
– Hammer A3-41 jointer planer combo machine – https://us.feldershop.com/en-US/en-US/en-US/Planing/Machines/Hammer-A3-41-oxid.html