Tuesday, 17 September 2013

One shot oiler plumbing

I bought a Taiwanese one-shot pump on e-bay for $50 - it seems to be pretty good quality. The out port is BSPP 1/8" I believe.



Reference chart for BSPP aka G thread sizing:
http://www.marylandmetrics.com/tech/bsppthreadspecs.htm

From there I want to use 10mm pipe to run to the manifolds because I have plenty of leftover tube kicking around. However all the Parker flow control valves and the other fittings are 1/4 NPT, so this ends up being a bit of a mishmash of standards!

Parts list from MettleAir for what I don't have:

Version 1 - using Parker flow control valves (of which I'm missing one and two are not as advertised on ebay)

1   - MTC 10-G01              10mm x 1/8 BSPP
5   - MTC 10-N02              10mm x 1/4 NPT
10 - 122-B                       1/4 NPT hex nipple
10 - MTM 1/4                   1/4x1/4 push-fit bulkhead
2  - 121-B                        1/4 NPT plug

Version 2 - using pneumatic flow control + check valves instead (I don't have to make the manifolds this way and I don't have to source more Parker valves)

1   - MTC 10-G01              10mm x 1/8 BSPP
1   - MTC 10-N04              10mm x 1/2 NPT
2   - AM30-250-5               2 x 1/2 NPT in 5 x 1/4 NPT out
1   -  122-D                      1/2 NPT hex nipple
1   -  121-D                      1/2 NPT plug
9   -  MSC 1/4-N02            1/4 x 1/4 NPT meter out flow control valve
9   -  MCVU 1/4                1/4 check valve

In addition, I will plan ahead for the air requirements. These are:

Air jet for the spindle
Fog coolant, also for the spindle
Power draw-bar
Line for a blower to clean off the table etc
One spare

So a 2 in 5 out manifold would be a good place to start.

Parts list for the missing stuff for this:

1   -  122-D                     1/2 NPT hex nipple
1   -  AM30-250-5             2 x 1/2 NPT in 5 x 1/4 NPT out
1   -  121-D                     1/2 NPT plug
10 -  MTPP 1/4                1/4 plug (I need five but they are cheap...)
10 -  MTPP 10                  10mm plug (don't strictly need these but...)




Here is the assembled manifold. The check valve plus the meter-out flow control valve are equivalent to the Parker flow-control valve but are significantly cheaper and far more compact. I plumbed in the X axis ways and ball-screw. Everything seems perfectly satisfactory. Having done this with NPT, I will be using BSPP G thread standard fittings for all future pneumatics projects. I think is it far superior to NPT. Firstly, the thread is parallel and therefore requires far less cutting force than the tapered NPT. Secondly, the seal is established by an o-ring not Teflon tape and just works. I have two (small but annoying) leaks in two recent projects using NPT which I will have to take time to fix and which just wouldn't have been an issue had I used BSPP. Live and learn :)




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