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  • A bevy of scraping question

    Quick preface to this, ive been getting a little frustrated with my surface grinder lately. Ive got to the point where my ability to competently use it is actually showing its shortcomings on the parts that i make with it, i.e it now no longer looks like i cut the parts with a chainsaw so crappy finish doesnt hide the flaws in the process. It finally pissed me off enough yesterday to flip the table and see what i was dealing with. Now, from where i tore this thing down when i got it, i knew that the ways were in poor shape, and that the turcite/rulon wear sheet was... i mean, it was present. Peeled up and beat to crap, but present. Anyways, heres what the ways look like, cleaned off and with the remnants of the wear strip removed:



    Pretty impressive amount of wear on the saddle side, and i was surprised to see the table surfaces had only been milled under the wear strip, not ground or anything. Looking at this, i can see 2 options, i can either find a tool reconditioning place local to me, pay more than i did for the machine itself and have them take care of the ways, or i can scrape it in myself. Well, 3 i suppose, i could also source some rulon, slap it on the ways and pretend i never saw anything before selling the machine... Anyways, scraping it myself seems like the most cost-effective option, so im just going to shotgun some questions about scraping in general out

    - How do prismatic ways get scraped into alignment? I can understand getting one surface flat. I can understand getting surfaces parallel. I can even understand getting dovetails parallel. But how do you make sure that the flat surfaces of a V are parallel to each other? Ive got the book on Machine Tool Reconditioning that im working my way through, but i figured id ask here just in case someone could explain it

    - Is the wear strip 100% necessary? Ive been looking into it, and ive found that the turcite/rulon/moglice/whatever is there for a few reasons. For one, it provides an easier to wear surface, so that instead of the expensive-to-recondition iron taking the damage, the somewhat cheaper plastic takes that. Ive also heard that it reduces the static friction and stick slip in a machine. For the first section i doubt the benefit would show itself in a home shop, as the amount of wear id be putting on these ways would necessitate a second rebuild sometime after 2050, but the second one is where im stuck. Should i really be caring about the stick-slip on a machine with 20+ year old spindle bearings, mounted on a lightweight steel tube stand on a wooden floor, operated by a monkey with a pipe wrench? Seems to me like tilting on windmills, but i figured id ask someone who knew better

    - References surfaces. Is there something special that gets used for V ways, or just a straight edge on the individual sides. Im assuming a straight edge will do, since the 2 pieces are scraped to match each other so the angle isnt critical

    - Straight edges are expensive. This part isnt the question, just a lead-in. From what i know, you want a straight edge thats preferably as long as the piece youre working on. In my case, thats about 2 feet. Shars sells 2 foot granite straight edges for $280 + shipping costs. Grizzly sells 18"x24" granite surface plates for $80, and i could drive to the store for one. Is there any reason i couldnt just get the surface plate, take it to a counter-top place, have them drop it on their diamond saw and cut me off a 2" wide slice? Only difference I can see is the Shars option is grade A, the surface plate is grade B, but im not exactly working to laboratory specs or on a B&S grinder

    - Should i look into just having the ways on the table ground, then using that as the master to scrape the ways on the saddle in? Im guessing probably not, as then id be working off the unknown tolerances of the grinding job instead of the know tolerances of a reference surface. Also sounds expensive to have done

    Ive got a few million other questions on the process, but like i said ive got the Machine Tool Reconditioning book that people say is the bible for this sort of work that i intend to read cover to cover before touching a tool and im hoping that answers most of them. Never know though, maybe if i ask here itll summon someone like Richard King to impart some wisdom on my clueless self 🤣

  • #2
    Originally posted by epicfail48 View Post
    ive got the Machine Tool Reconditioning book that people say is the bible for this sort of work that i intend to read cover to cover
    If you can manage that feat, you can do anything.

    Too many Q at once, but to knock off a couple, you don't need anything special for the V ways (if you needed a specific angle you'd make an angle gauge). The grades of those I think are just a stock keeping number 🙄. While they can be used, I used one once and was getting a very different pattern depending where the piece was laid for bluing. Kind of defeats the point of it. No idea what happens to granite if you saw it.

    Its a ton of work, I wouldn't head into it without a lot of confidence in the references. I'd start with a good plate and then make a reference out of a piece of durabar or one of the raw castings available...I think TomS just bought one. Way grinding the long part and scraping in its mate are always an option, but you're paying a commercial shop 70-100/h or whatever so it gets up there quickly and you don't want to just go to anybody.

    Turcite Moglice etc have the problem of swarf embedding in them. I've not used, but it seems it might be more a commercial solution, i.e. if it controls rebuild costs and gets X year of it go for it....whereas I want the machine perfect for the rest of my days. Just my view on it.
    Last edited by Mcgyver; 03-30-2020, 11:36 PM.
    in Toronto Ontario - where are you?

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    • #3
      Originally posted by Mcgyver View Post

      If you can manage that feat, you can do anything.

      Too many Q at once, but to knock off a couple, you don't need anything special for the V ways (if you needed a specific angle you'd make an angle gauge). The grades of those I think are just a stock keeping number 🙄. While they can be used, I used one once and was getting a very different pattern depending where the piece was laid for bluing. Kind of defeats the point of it. No idea what happens to granite if you saw it.

      Its a ton of work, I wouldn't head into it without a lot of confidence in the references. I'd start with a good plate and then make a reference out of a piece of durabar or one of the raw castings available...I think TomS just bought one. Way grinding the long part and scraping in its mate are always an option, but you're paying a commercial shop 70-100/h or whatever so it gets up there quickly and you don't want to just go to anybody.

      Turcite Moglice etc have the problem of swarf embedding in them. I've not used, but it seems it might be more a commercial solution, i.e. if it controls rebuild costs and gets X year of it go for it....whereas I want the machine perfect for the rest of my days. Just my view on it.
      I read through more then a few history textbooks in school cause i was bored, and i hate history. A book on machine tool recondition while im quarantined and laid off anyways? Cakewalk. Sorry about the wall of questions, seemed more economical to do them all in the one post.

      I fully expect it to be a lot of work, but i can live with that if its my work and im saving a bit of cash doing it. If i can do it all myself and only end up paying, say, $250 for tools, that beats out spending $1500 to have someone else recondition an import machine built in the mid-80's. Better things to put that money to i feel. Far as the references go, getting a bar of iron and making a straight edge was an option as well, i was thinking about getting a bar of cast iron, granite just seemed easier. From what i know its stiffer than iron for a given size. Dunno what id have to get, size wise, for a 2 foot iron straight edge to not have it warp, and camelback castings are expensive from what im finding. Plus, id need to buy a larger surface plate anyways, my current ones are large enough for my present needs but not this size of project. If i end up buying a straight edge, itll probably be the granite anyways, just wanted to find out if i could get away with something more field-expedient

      That matches with what ive heard about wear surface materials, that in dirtier environments stuff has a habit of embedding in them and wrecking the matching iron surfaces. Frankly i suspect thats what happened with my machine, the ways arent exactly shielded and the damage looks like a stone just god dragged across the surface. Part of why im leaning towards skipping out and just going iron-to-iron

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      • #4
        Originally posted by Mcgyver View Post

        Turcite Moglice etc have the problem of swarf embedding in them. I've not used, but it seems it might be more a commercial solution, i.e. if it controls rebuild costs and gets X year of it go for it....whereas I want the machine perfect for the rest of my days. Just my view on it.
        IMO, used properly, Turcite / Moglice / Rulon have their place and can actually outlast cast iron on cast iron, especially if it is being used in an environment where lubrication is - ahem - less than ideal. There were some white papers floating around out there about the longevity of plastic on cast-iron sliding surfaces that seem to suggest this is the case.

        I'm not sure about it's use on grinders. On one hand, I'm inclined to say it would be an advantage and provide superior performance because you'll get smoother motion, which is important for very fine surface finishes. On the other hand, I've not seen any data on foreign material embedment and I would think grinder swarf / dust would be an ideal candidate for making it under wipers and into the plastic material. From that perspective, iron on iron would seem a better solution.

        Epicfail48 - I've read Connelly's book cover to cover but it does take some doing. Tons of great information there but also a fair amount of language devoted to telling the reader what the reader is going to read next, if you know what I mean. It's actually kind of charming, definitely a different aesthetic from today's shop texts. That said, I am still very much a novice. What's more, I only recently bought a surface grinder so my experience with abrasive machining is practically nil.

        That said, if the surface grinder is in as rough shape as it seems, it might be a good candidate for a "learning machine". In some ways, surface grinders are easier to scrape than other machine tools, at least partially because the ways tend to be short so you don't need to invest big bucks in large straight edges / surface plates.

        Cutting a surface plate thin is an interesting idea but it's hard telling what would happen to the strip after cutting. There could be some small internal stress that results in the strip no longer being in tolerance. Or there could be other damage done to the surface during the cutting process. Personally, I agree with Mcgyver that buying a high quality plate and scraping a cast iron straightedge is probably the way to go. If nothing else, it's good practice at pin-point scraping. I'm just of the mind that every shop needs a few good masters - things you can trust absolutely. Otherwise you're always just guessing and, when it comes to reconditioning machine tools, you can run into a situation where the tolerances quickly stack outside of your favor.

        The last chapter in Connelly is all about reconditioning surface grinders, which is nice.
        Last edited by Fasttrack; 03-31-2020, 12:06 AM.

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        • #5
          The wear strip may be necessary if only because it took up space to begin with, and without it, the table may be tilted and lowered in a way that is difficult to fix with any other reasonable method. The alignment with the table drive will also be "off". There will be some added tilt etc, because the worn surface that was in contact with it will also cause some added tilt when it is worked (machined, then scraped, presumably) down to a good surface. That suggests the use of turcite etc to build up to fill the place of the missing metal, which is often done on lathe carriages after grinding the bed, to bring back the original alignment.

          The material (which I have not used) is supposed to be easy to scrape, although I expect there is a technique to scraping it. it also, since it is soft, embeds grinding dust and the like, so needs to be used in a location where it is always covered. The underside of lathe carriages, or the saddle side of a grinder or mill, would be natural locations, since they are never exposed.

          No idea how the sawed off surface plate would work. Stone presumably does not have the locked-in stresses that cast iron etc may have. But I expect that you could not guarantee that there would be no change.

          For a V-way, one would use both a straight edge, and a reference block with the V shape scraped into it. That block can be made so that it can be measured for height vs an adjacent known straight surface (plane, flat way), to show any rising or lowering tendency vs the plane .

          I do not know that you can actually call the other surface of a V"parallel". Or that it could be non-parallel. A line is defined by the intersection of two planes which are NOT parallel. That line may be parallel to a third plane, to which neither of the others is parallel...... and that is the condition which is wanted, really, with the third plane being the flat way. There are several methods to check that condition. A "King-way" tool is capable of being set up to perform most if not all of the measurements shown in Connoley's Machine Tool Reconditioning book as being done with various frames that carry indicators or levels. A level for instance, is a good way to ascertain the parallelism of the V with an adjacent flat way, or, two V ways, in the latter case using the V-block mentioned above.

          Having the ways ground is a good approach for the longer surfaces. They can then be a master for the shorter. But scraping can also be done, it's just more trouble for you.

          There are two portions to scraping. One is the mechanical action of scraping, and the ability to produce a surface conforming to the master. That is a prerequisite to the other, which is doing that while simultaneously maintaining a desired alignment to other parts of the machine.

          The simplest variety of that would be getting the flat and V of a grinder table parallel with the table surface, so that the grinder does not produce a "wedge" on the parts put on the surface (or a mag chuck). You want it very close to perfect, so that when you dust off the top surface of the chuck, you are not removing much past a slight amount.

          Or getting the path of the table at a good 90 deg to the cross-ways of the saddle etc. Getting the crosslide of a lathe to 90 deg to the ways so that facing produces a dead flat to slightly concave surface, etc, etc.

          Doing those alignments is an excercise in "shading" your scraping so as to "come in to" a flat surface at the same time that you satisfy the alignment. It can be quite tricky and painstaking to do, especially when you are not that confident of getting a good surface with proper contact to the opposing surface. There are proper points of contact per square inch (PPI) for the various uses, from static alignment of bolted parts, to basic slide ways, to reference surfaces, and ultra precision reference surfaces. For static contact, 5 or 10 PPI, for slide ways , 15 to 25, regular references, 25 or 30PPI, precision references, 40PPI.

          here is a King-Way type tool that I made, checking the parallelism of the tailstock flat way to the carriage ways of a lathe. The indicator is on the flat way of the T/S, the cylindrical 'foot" is riding the V (the cylinder has a cut-out to straddle the V), and the other "foot" is riding the carriage flat way. This setup can be found in Connoley.

          The tool can have precision levels attached in place of the indicator, clamped on the cross-bar, to check for any "wind" in the relation of the carriage V and flat, which would tend to tilt the cross-arm, and show up on the level.


          Last edited by J Tiers; 03-31-2020, 12:29 AM.
          CNC machines only go through the motions.

          Ideas expressed may be mine, or from anyone else in the universe.
          Not responsible for clerical errors. Or those made by lay people either.
          Number formats and units may be chosen at random depending on what day it is.
          I reserve the right to use a number system with any integer base without prior notice.
          Generalizations are understood to be "often" true, but not true in every case.

          Comment


          • #6
            Fasttrack - you and i have the same train of though about this being a learning machine. Looking at it, theres nothing horribly complex about scraping it, and its not exactly a valuable vintage. Being somewhat compact is nice as well. I appreciate the insight into the idea of cutting down a surface plate. When i first thought of the idea, i figured that the odds of the surface moving out of flat since, to my knowledge, stone is about as dead as a material can be. I also figured that since drilling into granite plates to install threaded inserts was fairly common practice, cutting them would be to horrible, though admittedly i dunno about cutting them in half. Checking prices for everything, im thinking that at this size buying a granite straight edge will be more cost-effective, as if i was making my own id be out the $80 for the B grade plate, more for better, plus $150+ for the cast iron bar in a somewhat appropriate size, plus the amount of labor itd take. At that point the $280 to Shars becomes worth it just for the certification papers, doubly so given that for this particular project i dont believe id need the surface plate for anything other than making the straight edge. I wholeheartedly agree that good reference surfaces are a must for good work though

            J Tiers - I had actually considered the thickness of the existing turcite would be a problem, but it was applied and taken off of all the ways, and the only thing that would be affected by the change in height that i can see would be the meshing of the rack and pinion. I figured that would be an easier problem to correct by modifying the pinion, unless theres something im missing?

            Measuring off a block in the V way was about what i was picturing, good to know i wasnt going completely insane there. Im guessing that a V block would be used for the 'male' portion of a V way, for the 'female' portion would you need something with a matching angle, or could you use a precision pin as the reference and measure off the high point for alignment? Again, assuming ill find the answers to all these questions in the book but it cant hurt to ask. Also, thanks for calling out that Kin-way tool, first ive heard it named, looking into it its a pretty awesome tool

            My apologies for the incorrect use of parallel, i couldnt think of a better phrasing. Maybe keeping the axis of movement along the flat plane parallel in the X direction?

            General question on that King-way tool, it cant be that simple, can it? Just 3 shafts in a U shape, a hardened ball at the end of one of the vertical shafts, a hardened bar at the other end, and a precision level mounted in the center? Seriously, there has to be some black magic im missing there, no way should I be able to make a tool that gets used to rebuild top of the line gear... Tangentially related, why are machinist levels so bloody expensive if i can buy the vials themselves for ~$25, from the normal questionable sources of course

            Comment


            • #7
              The King way IS simple, the hardest part is getting the clamps done where they work well. If you do levels (I did not, and may yet), then you have to get them set up to adjust-in OK.

              Most all of it is non-critical. The ball on the other side you use with a little circular "foot", so it bridges over the scrape marks and you avoid the couple tenths variations

              The round part is a tube with a cut-out in it, so it fits over the male V, or can ride in a female version. A few mount holes (you can see two in the pic) at different angles and you are good to go.
              CNC machines only go through the motions.

              Ideas expressed may be mine, or from anyone else in the universe.
              Not responsible for clerical errors. Or those made by lay people either.
              Number formats and units may be chosen at random depending on what day it is.
              I reserve the right to use a number system with any integer base without prior notice.
              Generalizations are understood to be "often" true, but not true in every case.

              Comment


              • #8
                Probably end up making one of those before embarking on this particular journey, seems like just the ticket to do the saddle side of the ways. Thanks for bringing that to my attention! Any chance you wouldnt mind sharing dimensions of your example?

                Comment


                • #9
                  Originally posted by epicfail48 View Post

                  I read through more then a few history textbooks in school cause i was bored, and i hate history. A book on machine tool recondition while im quarantined and laid off anyways? Cakewalk. Sorry about the wall of questions, seemed more economical to do them all in the one post.ays arent exactly shielded and the damage looks like a stone
                  no apologies needed, just saying I didn't have the energy to hit every one. Maybe the hidden point is its a lot to take in all once, especially if you haven't scraped before. I'd first set about to make a reference flat, you'll need it and it'll get you collecting the things you need to scrape.

                  Its not the subject that makes the book a challenge. I suppose we owe Connolly a great debt for bothering at all, but man is it ever horrendous prose.
                  in Toronto Ontario - where are you?

                  Comment


                  • #10
                    The rods I used are 0.375, the cylinder was made of a piece of pipe about 1" x 4", the part cut out of the cylinder is maybe 3/8 to 7/16" wide, I can measure it. You make it so it rides on a shorter part at each end, relieve the middle part in the cutout and on the OD. I did not make drawings, I often don't do that for simple stuff.

                    The clamps I milled and filed out of steel blocks, filing them back until the clamps worked well, You have to cut away a lot more than you might think. The whole thing was copied from photos of the original, I made it the size of the model "100" King-Way, there was at least one larger size as well. The ball is a tooling ball I had, and I made the "washer" it rides on.

                    Dimensions are non-critical, you make it to fit the machines you have to work on. It's all adjustable, and being a "triangle" as it sits on the ways, with the ball, and then each end of the cylindrical part, it finds its own stable position automatically, it does not depend on precision.

                    I found that the clamps want rod that is within a thou or two of the right size, I had some 5 thou under, and they would not clamp down on it decently. Another design of clamp might.

                    If you want more pics or dims, I can do that. McGyver (M. Ward) had a series a while back on making one in the magazine, but his is quite elaborate by comparison. Mine is bare bones and no frills.

                    Originally posted by epicfail48 View Post
                    .............

                    J Tiers - I had actually considered the thickness of the existing turcite would be a problem, but it was applied and taken off of all the ways, and the only thing that would be affected by the change in height that i can see would be the meshing of the rack and pinion. I figured that would be an easier problem to correct by modifying the pinion, unless theres something im missing?
                    .........
                    Maybe.... the whole thing may "sit down" enough to drag on other parts, and the drive may not be that easy to change for a good fit. You have to look and figure that out unless someone here has done the job on that make/model machine before.

                    I figure you are talking a total of maybe 2 to 2.5mm of space to fill or compensate, between the turcite and the amount that will end up being taken off to get a good surface. The turcite wants to be ay least maybe 1.5mm thick when applied, as I understand it.

                    Which reminds me..... how you going to rough down the messed up surfaces? You will work pretty hard to take off even a couple or three thou on a long way surface, you don't want to even get into taking off 10 thou hand scraping if you have ANY other way to handle it. Normally you slap it on a bigger mill and rough it down
                    CNC machines only go through the motions.

                    Ideas expressed may be mine, or from anyone else in the universe.
                    Not responsible for clerical errors. Or those made by lay people either.
                    Number formats and units may be chosen at random depending on what day it is.
                    I reserve the right to use a number system with any integer base without prior notice.
                    Generalizations are understood to be "often" true, but not true in every case.

                    Comment


                    • #11
                      The secret to making the clamps grip is that they are not made constant bore all the way through. The middle of the bore should be relieved so they only grip at the ends.
                      Peter - novice home machinist, modern motorcycle enthusiast.

                      Denford Viceroy 280 Synchro (11 x 24)
                      Herbert 0V adapted to R8 by 'Sir John'.
                      Monarch 10EE 1942

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                      • #12
                        Originally posted by J Tiers View Post
                        The rods I used are 0.375, the cylinder was made of a piece of pipe about 1" x 4", the part cut out of the cylinder is maybe 3/8 to 7/16" wide, I can measure it. You make it so it rides on a shorter part at each end, relieve the middle part in the cutout and on the OD. I did not make drawings, I often don't do that for simple stuff.
                        ...

                        If you want more pics or dims, I can do that. McGyver (M. Ward) had a series a while back on making one in the magazine, but his is quite elaborate by comparison. Mine is bare bones and no frills.
                        ...
                        Which reminds me..... how you going to rough down the messed up surfaces? You will work pretty hard to take off even a couple or three thou on a long way surface, you don't want to even get into taking off 10 thou hand scraping if you have ANY other way to handle it. Normally you slap it on a bigger mill and rough it down
                        Thanks for the dimensions! I appreciate the offer for more, but that information should do me, with sizes to relate to i can ballpark the rest without much issue. My mental plans were a bit on the large size, i was anticipating 1/2" or larther for the rods. Cuts down on cost, its a bit in the future still but it never hurts to put together a mental shopping list. With the dimensions you provided i think the only other unknown is the level, though i think ive seen several of your posts saying you dont use one? Dunno how necessary itd be for my application, but never hurts to price things out.

                        Far as how im going to rough down the surfaces, carefully, very carefully... Unfortunately i dont have any ready access to larger tools that could hold the saddle. Before i start anything im going to try to get in touch with some local machine shops to see what the price would be to have in all likelihood the saddle ground, but if that proves to be too expensive, well, looks like im scraping it out. Need to measure how deep that wear line is still, just not something im looking forward to finding out.

                        Okay, i actually got curious and went to check in the middle of typing this. Using all the measuring skills of a drunk monkey with a socket wrench, and a dial indicator, i was able to find that at the worst parts of those wear spots, the wear lines are only about 2-3 thou deeper than the surrounding metal. Cant exactly measure straightness with what i have on hand, but the wear on the ways seems somewhat consistent, looking at the factory flaking. More on the ends then the center, but not much by eye. Still a lot to scrape out, but im hoping its within the realm of possibility

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                        • #13
                          Keith Rucker is documenting the restoration of a big planer, on youtube.
                          He has v-ways and has them scraped in. the v-way scraping shown.
                          it is a long series of videos for the machine from initial teardown up to present
                          https://www.youtube.com/watch?v=Qn4qWildaJU

                          Comment


                          • #14
                            Originally posted by J Tiers View Post
                            . McGyver (M. Ward) had a series a while back on making one in the magazine, but his is quite elaborate by comparison.
                            I'll take that as a complement

                            A few things I tried to do with mine: 1) it uses a Starrett 199 master precision level and 2) it uses split cotters for the clamps 3) really versatile, with the adjustable feet (with brass pads - that avoids scoring your freshly scrape ways) its one size fits all; it works with any size or pretty much any geometry of way (the orginal kingway came in different sizes). A bit more work to make the split cotters, but its like riding in a Rolls, very luxurious . All the torque goes into clamping not bending the clamp material. Sturdiness is important, the clamps help with that as does using 5/8" bar. As for the 199, my logic was I had one and that one would find its way into most serious proponents bit of kit, saving the expense of precision vials. Without one, you could easily use precision vials instead....but the 199 is maybe the most accurate. That view comes from both the graduations (.0005/12") but also the distance in between graduations - easier sub graduation interpolation. The level rests in an adjustable 3 point arrangement. I've used it quite a bit and can highly recommend it (hows that for bias? )

                            Here's a few shots. It mostly gives the function of the Kingway tool with a few improvements like the split cotters, but the last photo is of my own innovation, a sweep tool. Basically a angular contact bearing spindle for sweeping with an indicator - useful for scraping in a tailstock or headstock.













                            Last edited by Mcgyver; 03-31-2020, 03:13 PM.
                            in Toronto Ontario - where are you?

                            Comment


                            • #15
                              Originally posted by Mcgyver View Post

                              I'll take that as a complement
                              That would be accurate.....

                              The sweep tool is an interesting and useful addition
                              CNC machines only go through the motions.

                              Ideas expressed may be mine, or from anyone else in the universe.
                              Not responsible for clerical errors. Or those made by lay people either.
                              Number formats and units may be chosen at random depending on what day it is.
                              I reserve the right to use a number system with any integer base without prior notice.
                              Generalizations are understood to be "often" true, but not true in every case.

                              Comment

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