Like most of us making our own pumps and or tubes for pumping, I did so out of cost. Here was my solution:
I went to TAP plastics. They sell all sorts of plastics supplies, and you can order from them online, but if you have one nearby it is worth the time to visit. They have a scrap bin and so I purchased a piece of 1/4” clear acrylic sheet for less than $1. Got a tube of Acrylic glue, medium body, and then bought a 10” length of clear acrylic tube, 3” clear acrylic tube 1/8” wall. Cost me $12 with a cut. I cut the sheet to fit one end of the tube, sanded it smooth and made sure I have a tight fit then glued it on. The end I inserted into I shaped the edges round and smooth on my bench grinder and buffer then used a propane torch to flame edge it smooth. While I was flame edging it I flared the tube open as well, which made it way more comfortable.
I bought a brand new tire inflator valve for a car rim, the type you use to inflate your car tires when they are low. They let air in one way and then self seal when you take the inflator hose away. Have a pin head in the middle you have to depress to let the air out. Pick one up at any tire/wheel shop. Less than $1. I measured the end of the tire inflator with the thread on it so that I could use it as a one way air valve for my tube. With the pin head air release part inside the tube. Drilled a hole in the end of the tube and screwed and glued the tire inflator valve into the hole. Once the glue dried, I simply stuck a 24” piece of clear vinyl tubing over the valve and lubed up my cock and stuck the pump on and started sucking the air out with my mouth! I know.. The self-blow-job comments will follow. This worked for years and I was able to draw a pretty impressive vacuum using this method. Even worked in the tub with hot water.
Upgraded to a commercial cheap unit about a year ago but have outgrown the tube. Time to make a new tube and use the hand pump of the commercial unit
Will try to post pics and share.