Weight of bp knee + table

[Himse]

Hello everybody
i am planing to cnc convert my bp serie 1 and i intend to use the knee as z axis ..
i will mount 2 gas springs on the knee to overcome the weight problem ..

but how heavy is the knee + table (9"x40") ????
hope someone can help....

Rasmus

[chich2]

Hello Rasmus,
Welcome to CNCZone. I don't know what your knee and table would weigh. I converted my knee mill to cnc and made the Z axis the knee. To overcome the weight of the knee, I used a pneumatic cylinder. You can see my conersion at http://www.cnczone.com/forums/showthread.php?t=25895
If you read through the thread you will see what I did. A vented air regulator supplies air pressure to the cylinder at an always constant pressure. The knee is almost weightless. 52psi is all that is needed on a 100mm dia cylinder.

Chich

[HimyKabibble]

"52psi is all that is needed on a 100mm dia cylinder" - Which suggests the knee and table weigh in the neighborhood of 600 pounds...

Regards,
Ray L.

[Himse]

thanks ... i have bought 2 63mm cylinders and a pressurreg. i will post some pic along the way....
rasmus

[chich2]

Excellent. Make sure the regulator has to be a vented one. When the ram goes down it will compress the air in the cylinder so the regulator has to vent the rise in pressure. From memory mine will maintain the set pressure to + and - 0.5 PSI

Chich

P.S. Ray, My mill is not a Bridgeport. It is a knee mill however.