View Full Version : Newbie Advice about machine and used vacuum pump for holddown


Ping
03-14-2009, 10:11 AM
In this my first post, I must start with saying: Thanks a million to all you contributors to this forum. So much help in the decision process. Have finally decided to equip my small 1 person shop with a CNC router for mainly cabinet work and built-in's.
I am to import from USA to Sweden (in Europe) either a 5x10 EZ-router std with spindle or a 4x8 Shopbot std with spindle. The Shopbot cost slightly more. I can have both without table and legs which makes shipping less costly.
Will build a vacuum table and had planned for using four vacuum cleaner engines (from these central units sitting in the basement).

But now i stumbled upon a vacuum pump. The guy sent me a picture and he will sell it for the equivalent of $ 500. He didn't know more than it had been used for lifting some heavy materials. Only that it runs on 380 V 3-phase (std here in Sweden for heavier machines).
Does anyone know if this a good deal and if it will work for me as a single vacuum unit? If you think its worth it, I will take a trip and examine it. What should I look for, in that case?

I am grateful for any comments on this and of course also on my CNC choises.

Geof
03-14-2009, 06:12 PM
I cannot comment on your choice of machine but I can say I think you will find vacuum cleaners inadequate for a vacuum table and looking at the pump in the picture it may be inadequate because it looks like a centrifugal pump.

For effective vacuum holding you need to be able to pull a vacuum equal to at least 0.75 atm and this is impossible with vacuum cleaner motors and a real strain for a multistage centrifugal pump. You really need a positive displacement pump such as a vane pump. I converted an old compressor into a vacuum pump and it worked very well.