Hi I can get a good deal on a bunch of smaller vac pumps. they are Barnant Model 400-1901. they are just little 1.2 amp 120v deals. they should be able to pull around 20hg each at 18 psi. have any of you made hold downs with arrays of small pumps like this or would I be wasting my time?
I did some vacuum fixtures here:
Thanks. These type of fixtures are what I want to make. What I am asking here is if you can use multiple small vac pumps in parallel or series or however ? or do they just work against each other? I don’t know anything about vacuum pressure
I don’t know about those specific pumps to be honest, I use one that’s pretty similar to this one:
The principal of these things is that when you put the part on the fixture it makes a perfect seal. That means as long as your vacuum can pull a near perfect vacuum it just has to be able to do that with little to no air moving.
If you have leaks (and you’ll always have at least a tiny leak) the vacuum pump needs to be big enough to overcome those leaks.
Anecdotally I can tell you that the pump I linked can handle a fair bit of leakage before the vacuum is lost.
Sorry that’s not more scientific!
I use a Venturi vacuum pump on my 18x24 Pierson Workholding chuck. No moving parts, oil or things that wear out. Flawless operation for years. Just keep it clean and you are good!
I made a configureable vacuum hold down fixture from HDPE. I pull the vacuum with an oilless pump. I had an inexpensive oil one but after running continuously for several hours is started to spit oil out the vent. Might have been a lemon but I upgrade since I use vacuum hold down fixtures all the time.
This one is specifically for cribbage boards.