- Joined
- Jan 26, 2013
- Messages
- 200
At the risk of getting myself in trouble here but... I cringe when I read about using various filler materials embedded in magical compounds to produce bearing surfaces. The idea that two materials bearing on each other, regardless of their lubricious properties is completely antithetical to what should be accomplished. To wit, creating as large as possible parallel (congruent for cylinders) planes which glide on a thin film of lubricant. The solution to that has historically been scraping to produce a flat plane as well as the numerous pockets to retain oil. Only when the parts cease to move should they settle into contact. The instant they move, those pockets should deliver oil between the surfaces and NO contact should exist.
That being said, the hardness of the surface, ie: cast iron, epoxy, etc, should be such to resist embedding of particulates, resulting in a lapping surface. If you examine the various formulations of Turcite or Rulon, or even Moglice, these are relatively soft materials but resist embedding. Many claims are made for various products but I've seldom seen thorough engineering studies (the kind with real numbers) on their long term functionality. Moglice is probably the best in terms of publishing some hard data on their product's characteristics.
Moglice also suggests a minimum thickness to be applied. This makes sense to me as a varied surface of different materials seems problematic to me, but I conjecture. I would think spot applications of some product may suffice to prevent loss of lubrication through some gouge or clearance, but would not likely produce a bearing surface of desirable quality.
I have rebuilt a number of small machine ways, and taken Richard King's class. Having only used turcite once on a grinder bed I'm certainly no expert. But what experience I have has shown me that the old rules are not ameliorated by modern magic elixirs and synthetics. Those rules, as stated earlier, are simple. Scraped parallel planes, lots of little contact points and oil retention pockets. Preventing surface to surface contact is paramount!
Mark S.
That being said, the hardness of the surface, ie: cast iron, epoxy, etc, should be such to resist embedding of particulates, resulting in a lapping surface. If you examine the various formulations of Turcite or Rulon, or even Moglice, these are relatively soft materials but resist embedding. Many claims are made for various products but I've seldom seen thorough engineering studies (the kind with real numbers) on their long term functionality. Moglice is probably the best in terms of publishing some hard data on their product's characteristics.
Moglice also suggests a minimum thickness to be applied. This makes sense to me as a varied surface of different materials seems problematic to me, but I conjecture. I would think spot applications of some product may suffice to prevent loss of lubrication through some gouge or clearance, but would not likely produce a bearing surface of desirable quality.
I have rebuilt a number of small machine ways, and taken Richard King's class. Having only used turcite once on a grinder bed I'm certainly no expert. But what experience I have has shown me that the old rules are not ameliorated by modern magic elixirs and synthetics. Those rules, as stated earlier, are simple. Scraped parallel planes, lots of little contact points and oil retention pockets. Preventing surface to surface contact is paramount!
Mark S.