Anti-foam agent for oil ?

[Bandit]

Another thing I thought about was perhaps some of the heat could be caused by pumping to much oil and the pressure relief dumping it. This maybe only happening with the smaller bores, the simple fact that a small hole can only flow so much, and of course a larger hole can flow more. This will depend on there being a pressure relief in the circuit. The flow is adequate for a large bore of .400 plus, but that same flow will be over twice as much as a .220 bore can flow or may need. The problem here maybe getting the needed pressure to clear chips and lube bit and shank.
A pressure relief is to prevent stalling pump and blowing components/causing damage etc. Is there a way the relief can be checked (if used)?

 

[cuslog]

Another thing I thought about was perhaps some of the heat could be caused by pumping to much oil and the pressure relief dumping it. This maybe only happening with the smaller bores, the simple fact that a small hole can only flow so much, and of course a larger hole can flow more. This will depend on there being a pressure relief in the circuit. The flow is adequate for a large bore of .400 plus, but that same flow will be over twice as much as a .220 bore can flow or may need. The problem here maybe getting the needed pressure to clear chips and lube bit and shank.
A pressure relief is to prevent stalling pump and blowing components/causing damage etc. Is there a way the relief can be checked (if used)?

Yes, there is an in-line relief valve, set @ 1600 ~ 2000 psi (Princess auto analog setting with no gauge on it, so no easy way to check it.). I "think" I would see it as a reduction in flow across the window on top of the chip box (picture). At full flow, it spreads out and pretty much covers the entire window. If it were by-passing, I think I would notice a change in that "picture" (which I haven't noticed).

 

[Bandit]

In hand with the above, I take it the smaller bit is turning faster then the larger ones, (general machining practice), may be causing a shearing and a cavitation effect at the drill bit head (as per others above). A worn pump or restricted inlet will also cause cavitation, this can cause foam and heat also at the pump, to be pumped through system.
Can the smaller bit be turned slower, chip load reduced some, (slower feed), maybe both, without drill problems? Yes it may take a bit longer to drill.
Many questions, only a few workable answers, and maybe 1 answer that will work!
I would like to see the machine, and good work with that little runout over the distance.
I missed the chance to see one a friend had near Kamloops. He passed before I ever got there.

 

[cuslog]

Follow-up for those that took an interest / commented;
Chatted this past week with my mentor / deep hole driller with decades more experience than me. I mentioned .0002 per rev feed and that it took me ~ an hour to drill a 28.5" deep hole. His response: way too slow, he would do that in about 20 minutes. So, today, I tried doubling the feed rate to ~ .0004 per rev. He was right, same hole took ~ 25 minutes and the bonus was: still had foam but not nearly as much and the heat was down too. Still ran pressure @~ 1200 PSI but it simply had less time to develop foam or heat.
Sometimes a man can be too cautious, sometimes its better to just "make 'em eat", just gotta know when the time is right.
Its really nice to have a mentor to guide you !

 

[Bandit]

That is good to hear! Sometimes what seems to be the obvious, is not the way but the opposite is.

A mentor is a great thing, sometimes a world and a life time of experience, and to be able tell of mistakes and success can be a major learning experience for others.​

I do not know whats with this phone!??$%@××+?​

 

[140mower]

That is good to hear! Sometimes what seems to be the obvious, is not the way but the opposite is.

A mentor is a great thing, sometimes a world and a life time of experience, and to be able tell of mistakes and success can be a major learning experience for others.​

I do not know whats with this phone!??$%@××+?​

Don't you love getting older, and after a lifetime of having too many thumbs, and a guy still can't control one.......

 

[Bandit]

Yeah, the mentor for this phone is likely 4 years old! And thinks it's old, out of date garbage.
NOW, the dam thing is printing proper again! Would be great if I knew what I touched to do it, and then why it changed back.
Wait, what you got more then 1 thumb?! Why does " thumb" have a "b" on the end of it?
Oops, it is now time to sign off.

 

[140mower]

I think that you accidentally hit the B next to the Italics I.....