Is there an easier way to retain an oil film then scraping?
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    Default Is there an easier way to retain an oil film then scraping?

    After reading and watching videos on scraping I was wanting to ask why go through all the work of scraping if your main goal is oil retention. Could similar results be made by grinding small grooves into the surface and then grinding or machining to remove any irregularities caused by grooving? Please enlighten me......Rick.

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    I have seen ways screwed up by someone using a hand grinder. UGLY! and Idiotic to ruin a machine doing that!!

    I hate to dignify your question inside this famous Machine Forum Practical Machinist. You should ask this in Hobby machine forums.

    My advice is Learn how to hand scrape or 1/2 moon flake and do it that way so the machine looks original, not something some hobbyist would do.

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    Quote Originally Posted by rickyroadrunner View Post
    After reading and watching videos on scraping I was wanting to ask why go through all the work of scraping if your main goal is oil retention. Could similar results be made by grinding small grooves into the surface and then grinding or machining to remove any irregularities caused by grooving? Please enlighten me......Rick.
    In theory and practice, yes, however, scraping is not about creating oil retention. Scraping is about precise, minute manipulation of geometry to create proper motion, alignment, fit, and load bearing. Oil retention is one of the secondary advantages, not the main goal. You usually find milled or ground grooves accompanying scraping as a way to get oil into those small pockets, way wipers to keep the crap out. The pockets made by scraping are pretty shallow tho, so if your main goal is oil retention, you'd flake that surface. Flaking being the pretty looking bird shaped, half moons. Those marks are generally 10 or so times deeper, with their sole purpose to be oil retention. While making "proper", "nice looking" flaking takes practice, a couple flaking passes to give you some .001" or so deep oil pockets is much less work/time consuming than scraping a surface to desired geometry.

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    Ricky;

    To add a little bit to that, the furrow that is cut into a machine way is to provide a distribution channel for the lubricating oil. When the oiling system is working well, the movement of the ways pushes/distributes the oil into the pockets of the scraped surfaces.

    p.s. Don't be afraid to ask questions. You may also want to look over some of the threads in this subforum. There is a wealth of info on the hows and whys of scraping/restoration. Some people here have been inspired to "take it up", and try for themselves.

    regards,
    Jon P.

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    Quote Originally Posted by rickyroadrunner View Post
    After reading and watching videos on scraping I was wanting to ask why go through all the work of scraping if your main goal is oil retention. Could similar results be made by grinding small grooves into the surface and then grinding or machining to remove any irregularities caused by grooving? Please enlighten me......Rick.
    For starters, "oil retention" is not the only, nor even "main" goal.

    As to alternatives - a good deal of expensive professional research has been done to find automatable / lower labour-content, and as important - more easily and highly repeatable results, yes.

    Photetching, and micro-machining have been compared to legacy hand scraping and flaking.

    So far.. the old methods have "won". That doesn't mean folks should cease looking for improvement.

    One of the more obvious approaches, though not cheap, has been to change the lubricant and provide constant positive pressure appropriate to it being a constant "flush" as well as lube. Another is to make different choices of materials, usually with one of them being sacrificial AND easily replaced as an assembly. Google "wear strips" and find miracle plastics and the Bronzes - some with graphite plugs

    One issue of the "old way" being that any flaked depressions good enough to retain oil well will also retain the particles of fretting corrosion. No surprise than a fair percentage of machine tools do NOT leave the factory with any hand-scraping nor flaking of any kind, and never did. For those, it is a field-repair technique, if-even.

    Not to forget, too, that whole generations of modern machine tools no longer use the traditional sliding vee, flat, or box "ways" throughout, or even "at all". Some are on rolling-element linear bearings.

    Hand scraping "may" still be on the menu. Their SUPPORTS have to be put into near-as-dammit perfect alignment and/or restored to it after corrosion and such have done the dirty. The class of grinding and lapping equipment that put them to rights at the factory is seldom portable to a field location, nor is the worn machine itself easily or economically transported.

    Hand, or power-assisted (Biax) scraping and flaking are VERY "portable", so live-on as a viable field repair technique.

    Ironically, it is "hobbyists" who flock to it and have become major supporters of keeping scraping alive and well as a skill. Hobbyists, retirees, and small-shop owners tend to be "the ones" who see value in restoring "old iron" for fun - or simply earning a crust with the best they can afford.

    Major companies are as like to simply scrap a worn machine and buy a new one because the costs have been amortized several times over, and a new one is expected to be more productive and/or better suited to the changing workloads.

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    Hydrostatic ways were another style of machine tool way design that negated the need for scraping for oil retention. A very effective system but quite expensive to equip machines with.

    Trying to reproduce scraping style effects with an angle grinder won't bring you much success, the depressions will be too deep for starters.

    Regards Tyrone.

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    I have had a few students from New Mexico and if you private message you email address and where you live I could ask them if they are close to you and show you how to 1/2 moon flake.

    Many times if the machine us running accurately you can just 1/2 moon flake it (like the ways and top of Bridgeport) and it would help retain and distribute the oil so the machine could last longer. If it is wore out then it would be a waste of time IMHO.

    20150609_104448.jpg3180.jpg

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    All the previous replies were correct !
    Including the sometimes blunt, maybe less polite, replies from people who are truly expert at it.

    Endless solutions for machine tools exist.
    Powered oil (hydrostatic ways), powered air (air bearings (=hydrostatic)), oil, powered oil, air, exotic plastics (like iglidur from Igus), linear ways, roller guideways, etc.

    My point:

    Your "main goal" is never oil retention.
    Scraping, via manual, biax, pneumatic discs, etc., whatever, is *never* about oil retention as such as a primary goal.



    Quote Originally Posted by rickyroadrunner View Post
    After reading and watching videos on scraping I was wanting to ask why go through all the work of scraping if your main goal is oil retention.
    Could similar results be made by grinding small grooves into the surface and then grinding or machining to remove any irregularities caused by grooving? Please enlighten me......Rick.

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    Quote Originally Posted by Richard King View Post
    I have seen ways screwed up by someone using a hand grinder. UGLY! and Idiotic to ruin a machine doing that!!

    I hate to dignify your question inside this famous Machine Forum Practical Machinist. You should ask this in Hobby machine forums.

    My advice is Learn how to hand scrape or 1/2 moon flake and do it that way so the machine looks original, not something some hobbyist would do.
    Thank you for your answer Mr. King. Actually I was hoping that you would respond. I have great respect for your knowledge and experience of machine repair and scraping. I didn't mean any disrespect by posting my question on this forum. I'm never afraid to ask questions when they are unsettled in my mind. As for asking the question on a hobby forum, I don't know of any not to mention it behooves me to seek out answers from the people most qualified to give them. That would be Practical Machinist. In lieu of the fact that I do not work in the field nor do I currently own any machines that could be discussed on this forum I do like to educate myself in things that interest me. Educating myself for now consists of reading and watching You Tube videos. This is how I have heard of you Mr. King. I do have an opportunity to buy a South Bend lathe for next to nothing and if I get it I plan on getting someone to survey it and explain to me what it will need to put it back to a good usable condition. By the way, by trade I am a automotive painter / bodyman. I have also worked as an auto mechanic. Restoring an old lathe sounds like something I will enjoy. If asking questions on this forum that would insult the intelligence of the members I can post them on a hobbyist forum.....Cheers.

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    Quote Originally Posted by Richard King View Post
    I have had a few students from New Mexico and if you private message you email address and where you live I could ask them if they are close to you and show you how to 1/2 moon flake.

    Many times if the machine us running accurately you can just 1/2 moon flake it (like the ways and top of Bridgeport) and it would help retain and distribute the oil so the machine could last longer. If it is wore out then it would be a waste of time IMHO.

    20150609_104448.jpg3180.jpg
    That is a very nice offer Mr. King. I will pm you later today!

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    Default Thanks to all that took time to answer.

    And BTW I have been on here quietly reading long enough to recognize some of your names. Thanks again I've got to tie my shoelaces and get working...LOL.

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    Quote Originally Posted by rickyroadrunner View Post
    Thank you for your answer Mr. King. Actually I was hoping that you would respond. I have great respect for your knowledge and experience of machine repair and scraping. I didn't mean any disrespect by posting my question on this forum. I'm never afraid to ask questions when they are unsettled in my mind. As for asking the question on a hobby forum, I don't know of any not to mention it behooves me to seek out answers from the people most qualified to give them. That would be Practical Machinist. In lieu of the fact that I do not work in the field nor do I currently own any machines that could be discussed on this forum I do like to educate myself in things that interest me. Educating myself for now consists of reading and watching You Tube videos. This is how I have heard of you Mr. King. I do have an opportunity to buy a South Bend lathe for next to nothing and if I get it I plan on getting someone to survey it and explain to me what it will need to put it back to a good usable condition. By the way, by trade I am a automotive painter / bodyman. I have also worked as an auto mechanic. Restoring an old lathe sounds like something I will enjoy. If asking questions on this forum that would insult the intelligence of the members I can post them on a hobbyist forum.....Cheers.
    I apologize for being such an ass on my first reply. I just get angry when I see machine ways screwed up that way. One never knows who's writing here and lately it seems we are seeing more and more Rung-Fo type machines or owners of them coming in here and asking about them.

    I can be a crab too...lol...my students have told me that too...LOL....As one of the guys I now have on ignore here who rubs me the wrong way (and others..lol) He always say's "Do no harm" And grinding lines or pockets with a die grinder and carbide burr IMHO looks like some "Primitive Pete" work. I remember watching him in JR High School in the 60's ....LOL
    The ABC of Hand Tools - Part 1 - YouTube
    Last edited by Richard King; 01-10-2018 at 02:26 PM.

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    Quote Originally Posted by rickyroadrunner View Post
    After reading and watching videos on scraping I was wanting to ask why go through all the work of scraping if your main goal is oil retention. Could similar results be made by grinding small grooves into the surface and then grinding or machining to remove any irregularities caused by grooving? Please enlighten me......Rick.
    Yep, done all the time for 100 years. Many ways to establish a pattern of valleys to "hold" ONTO oil, fine milling as done by Deckel and some lathe manufacturers was one of those. In the same time modern oil tackifiers are so good they may cause an over retention of oil and consequent loss of accuracy. You will NOT wipe off a good quality way oil - you'll need a solvent for that.

    In other words, when it comes to oil retention, scraping solves a problem which doesn't quite exist anymore.

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    [QUOTE=AlexO;3104159]Yep, done all the time for 100 years. Many ways to establish a pattern of valleys to "hold" ONTO oil, fine milling as done by Deckel and some lathe manufacturers was one of those. In the same time modern oil tackifiers are so good they may cause an over retention of oil and consequent loss of accuracy. You will NOT wipe off a good quality way oil - you'll need a solvent for that.

    In other words, when it comes to oil retention, scraping solves a problem which doesn't quite exist anymore.

    I am beginning to see that there are differences in modern machinery and vintage and the same goes for lubricants. Also it is becoming obvious to me that as mentioned by a few of you, location and access of machines are also a factor. I now know more than I did and thank all of you that took the time to answer....Rick.

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    I hope that Alex's comment is not being misunderstood: it pertains to the oil retention aspect. I think I'm preaching to the choir, but let's not forget that another very important function of scraping is to limit as much as possible any stick-slip (i.e. "Jo-blocks effect").

    Paolo

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    Just to play devil's advocate. One can get the desired flatness by spot grinding using a technique similar to the one you use when scraping. When I rebuilt the HLV, the bed was severely worn and hardinge don't do replacements for the 1952 model... The surface grinder used to get rid of most of the surplus material is, itself, undersized and badly worn (rebuild this year after calibrating/re-lapping/calibrating surface plate). The bed on Hardinge's is also hardened to the low 60's HRC.

    Scraping didn't work. The hand scraper wouldn't bite and I couldn't get a grind on the Biax bits that didn't either skid or nearly take my shoulder out of it's socket.

    The job was done with an electric die grinder and abrasive points for the main work, followed by Cratex points for the finish work. A lapping plate was used to increase the total amount of bearing in the same way that stoning is sometimes used for that purpose. None of this was for oil retention. That's handled by the underside of the lathe's saddle. Oil retaining grooves/flaking should never be on a visible surface for the reasons Bill put forward.

    The bed part way through. Still showing the results of grinding in two sections on the surface grinder.


    A closeup of the work in progress.

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    Quote Originally Posted by Mark Rand View Post
    Just to play devil's advocate. One can get the desired flatness by spot grinding using a technique similar to the one you use when scraping.
    ISTR Demon73 did something similar. I'd not WANT to do that. Lathe that small and light, I'd rather ship it off to a shop with a more appropriate grinder.

    Even so, if it worked, it worked.


    None of this was for oil retention. That's handled by the underside of the lathe's saddle. Oil retaining grooves/flaking should never be on a visible surface for the reasons Bill put forward.
    "Visible" is OK. Think underside of the dovetailed over-arm on many mills.

    Lower surface is not so OK. Gravity helps let fretting corrosion debris find a way out of flaked pockets, underside of a saddle, but helps trap them if on the upper side of the ways.

    I say "helps" because not even gravity totally dominates.

    The pressure of oils under even modest movement stress is far stronger a force than gravity as to pushing that sort of smut off to "somewhere else". Might not be as far as an escape point, though. Just moving back and forth and continuing to abrade and accumulate.

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    Quote Originally Posted by Mark Rand View Post
    Just to play devil's advocate. One can get the desired flatness by spot grinding using a technique similar to the one you use when scraping. When I rebuilt the HLV, the bed was severely worn and hardinge don't do replacements for the 1952 model... The surface grinder used to get rid of most of the surplus material is, itself, undersized and badly worn (rebuild this year after calibrating/re-lapping/calibrating surface plate). The bed on Hardinge's is also hardened to the low 60's HRC.

    Scraping didn't work. The hand scraper wouldn't bite and I couldn't get a grind on the Biax bits that didn't either skid or nearly take my shoulder out of it's socket.

    The job was done with an electric die grinder and abrasive points for the main work, followed by Cratex points for the finish work. A lapping plate was used to increase the total amount of bearing in the same way that stoning is sometimes used for that purpose. None of this was for oil retention. That's handled by the underside of the lathe's saddle. Oil retaining grooves/flaking should never be on a visible surface for the reasons Bill put forward.

    The bed part way through. Still showing the results of grinding in two sections on the surface grinder.


    A closeup of the work in progress.
    Thanks for the reply Mark. If you posted photos I'm not seeing them....Rick.......Never mind, now I am seeing the. Nice photos BTW.

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    Quote Originally Posted by Tyrone Shoelaces View Post
    Hydrostatic ways were another style of machine tool way design that negated the need for scraping for oil retention. A very effective system but quite expensive to equip machines with.

    Trying to reproduce scraping style effects with an angle grinder won't bring you much success, the depressions will be too deep for starters.

    Regards Tyrone.
    A pump failure is a catastrophic event on a hydrostatic way while in motion.

    dee
    ;-D

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    Quote Originally Posted by dcsipo View Post
    A pump failure is a catastrophic event on a hydrostatic way while in motion.

    dee
    ;-D
    A "show stopper", literally, but no more than that. "Catastrophic" in that case leaves a smidgen of time to shut-down and plan recovery before the damage is severe. May well be a decision taken FOR you by the machine's controls anyway.

    Driving a motorcar or flying on airplanes?

    "Catastrophic" can be considerably less.. "convenient".

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