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  • #46
    Originally posted by flylo View Post
    I still wonder why all lathes didn't come with replaceable ways like the American Pacemaker & a few more as it seems like a great idea to me.
    Because it is pretty pointless as by the time the bed ways are worn, the saddle ways will be really really worn.
    Precision takes time.

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    • #47
      Here is a picture of a lathe bed being ground.

      JL...............




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      • #48
        Originally posted by .RC. View Post
        Because it is pretty pointless as by the time the bed ways are worn, the saddle ways will be really really worn.
        And. if so, so what?

        That's what Turcite is for. (and some other materials also)
        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.

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        • #49
          Originally posted by J Tiers View Post
          And. if so, so what?

          That's what Turcite is for. (and some other materials also)
          His point is that replaceable ways are not that useful because, by the time they need to be replaced, the saddle needs attention, too. It's not as easy as slapping on a new way and calling it good. For most lathes, the time and cost to refurbish a lathe is going to be the same whether or not it has replaceable ways, which is why most lathes do not have replaceable ways. Replaceable ways only become an asset on really large machines that would be difficult to transport, difficult to setup on a grinder, etc. Some of the larger Pacemakers fall into that category so they came with replaceable ways.

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          • #50
            Originally posted by Fasttrack View Post
            His point is that replaceable ways are not that useful because, by the time they need to be replaced, the saddle needs attention, too. It's not as easy as slapping on a new way and calling it good. For most lathes, the time and cost to refurbish a lathe is going to be the same whether or not it has replaceable ways, which is why most lathes do not have replaceable ways. Replaceable ways only become an asset on really large machines that would be difficult to transport, difficult to setup on a grinder, etc. Some of the larger Pacemakers fall into that category so they came with replaceable ways.
            Which would be why they are the ones that HAD such ways.

            But, don't forget, back then, just as replacement Atlas zamak was easy to get, so were parts of all sorts for those industrial machines. so it would not have been the huge expense and hassle then, that it is now.

            NOW, you could no longer get the way replacements to begin with. And if you could, they would cost more than the machine. So would a saddle. Back then, it was not like that, AND it was common to fix capital equipment, not throw them in the landfill.
            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


            • #51
              Originally posted by J Tiers View Post
              Which would be why they are the ones that HAD such ways.

              But, don't forget, back then, just as replacement Atlas zamak was easy to get, so were parts of all sorts for those industrial machines. so it would not have been the huge expense and hassle then, that it is now.

              NOW, you could no longer get the way replacements to begin with. And if you could, they would cost more than the machine. So would a saddle. Back then, it was not like that, AND it was common to fix capital equipment, not throw them in the landfill.
              RC was responding to Flylo's question asking why *all* lathes don't have replaceable ways. I was just saying that I agree with RC (and most lathe manufacturers) that replaceable ways don't make sense for smaller, less expensive machines. Even back in the day, replacing the ways was a complicated and expensive undertaking.

              At least with Pacemakers, you actually can still get a set of replaceable ways. I priced a set for my 1963 16" by 30". New ways cost just under $5000 - probably about what I would expect to pay to have the bed ground at a reputable place. Whether I replace them or grind them, I would still need to address all the other worn points (whether that be with Turcite, Moglice or etc) so just having replaceable ways isn't a perfect solution as some people might imagine. When I first started looking at Pacemakers, I was under the naive impression I could just slap a new pair on and be good to go, kind like changing tires on a car!
              Last edited by Fasttrack; 07-12-2016, 01:08 PM.

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              • #52
                The traditional material for way repair is "Moglice" which comes in different forms but is basically an epoxy type material optimized for this use. I'm not sure IDE recommend it for lathe ways though.

                Originally posted by John Buffum View Post
                Thanx for the info, esp George.

                The issue I have is that I set up to cut, and eliminate taper, etc, but when the carriage gets close to the head, I get taper. It tapers toward the head. If I adjust for that taper, I get taper toward the tail, at about 2" from the head. I haven't measured this, but there is a very visible gouge on the outboard track, away from the operator. It isn't very deep, but then, it doesn't have to be, to bollox things up.

                I just found out about a glue on Youtube, which is used to join iron and aluminum parts on aircraft. It is called PC-7®. PC-7 is supposed to be stronger and more durable than JB-Weld®. Another alternative is steel dust impregnated Bedrock®. Bedrock is a stock bedding resin. It sticks to grease coated jello, and is very tough. I have rifles I've shot for 20 years, bedded with that stuff. Anyone used a plastic or resin filler to fill in way irregularities?

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                • #53
                  Follow manufactures recommendations!!!! This should be obvious but you can get a lot of advice that is let's say counter productive.

                  Originally posted by John Buffum View Post
                  I'll try the PC-7 or the Moglice first. Cheepa. Less time.

                  Any advice on prepping? I plan to wipe first with mineral spirits, then two or three times with Dawn, then, finally, with acetone. Just before application, use a NEW piece of 220 wet or dry to rub briefly.
                  The problem with cast iron here is that it is porus and it takes a bit of effort to get all of the oils out of the work area.
                  While the Moglice sets, make a straight edge out of mild steel scrap. Carefully ensure it is FLAT. Glue 220 wet or dry to it, and tape the rest with blue painters tape, to ensure the 220 is not a high spot. Sand about 5-10 strokes. Dust with a toothbrush. Repeat.

                  Sound like a plan?
                  Nope. Often with Moglice we used it to fill in gross gouging in the ways and then machined or ground the area. You can do something like hand scrapping the material in. In any event I'm not getting warm fuzzy feelings about sandpaper near the ways.
                  $700-$1200 is a bit more than I planned to spend. There was a service advertised in HSM that wanted $100/ft. Been searching, but cannot find.
                  You need to get a quote for your specific machine. The type of ways are a big factor in what it will cost you to get a bed ground.

                  Do realize, as others have already pointed out, that grinding the bed is only a small part of the job. Once the bed is ground the saddle must be properly married to the new ways through hand scraping. Gibs will have to be made or acraped in. Just getting that saddle married to the ways is a lot of work and might not be all the work that needs to be done.

                  As for tools you need real straight edges that have been scraped in and are known to be accurate. Generally you need multiple straight edges deepening upon what part of the machine you are working on. Some of These can be made in shop from cast iron but a humpback straight edge that can span the length of the ways will be hard to find and probably expensive.

                  In a nut there are lots of expense when setting ones self up to rebuild a machine. If you don't set yourself up properly you can easily end up making the machine worst.

                  I'm a bit late to,this thread so maybe the comments won't help but for small machines the economics of a rebuild are very hard to justify if you can't DIY most of the way. You can't really DIY unless you invest in time and tooling which in many cases explodes the cost of the rebuild. You will need the mentioned straight edges but also scrapers, large micrometers, a hoist if the parts are heavy.

                  Look at it this way there are a lot of machine tool rebuild shops around the country, few of them will even bother with the smaller lathes. It generally isn't cost competitive when you figure in what a brand new Chinese machine costs.

                  Comment


                  • #54
                    Originally posted by John Buffum View Post
                    OK. Maybe you're right. I ran some numbers on my machinist's calculator, and a .005 drop in one side of the carriage does not produce a measurable difference in the cut, if one looks at three decimal places.
                    that entirely depends on the diameter. However think about how and when you need accuracy. as far as diameters are concerned, for very accurate work like interference fits for roller element bearings, it is usually over short distances....so the drop over say several feet does not matter. Whats the drop over 1/2"? For medium distances such as a large model engine cylinders, there is enough clearance so that it probably doesn't matter, but I always lap for a perfect finish and cylindrical shape anyway. For long distances, say making a feedscrew, diameters aren't that critical (a couple of thou is the tolerance of even the higher grade acme thread fits) you'll need the traveling steady any which can used to control diameter.

                    A freshly reconditioned machine, or one built and fit properly in the first place is a joy to use and makes life easier and shop time more pleasant......it doesn't, in the great majority of situations mean, if you know the what and why, that you can't still make parts to the required tolerances with a worn one
                    in Toronto Ontario - where are you?

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                    • #55
                      On the contrary side, while straight-down wear on both ways can be minimal as far as net effect, wear primarily on ONE way is not the same.

                      Wear on one side vs the other will cause that side to fall relative to the other. Eqivalent to twisting. And it will then move the tooltip toward or away from the work by an amount depending on the relation between the center height and the distance between ways.

                      The OP described wear on one side, so ....... If that is accurate, it can be much more of a nuisance than it seems.
                      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


                      • #56
                        Originally posted by Fasttrack View Post
                        by the time they need to be replaced, the saddle needs attention, too. It's not as easy as slapping on a new way and calling it good.
                        well that's for sure...and the replacement ways themselves are going need some real care - you're not going get 6, 10 whatever number feet of hardened steel ground to a great finish and dimensioned to say .0002" on your harbour freight grinder. otoh that $5000 sounds like everyone along the way marking it up 100%....I bet if you did a drawing and got quotes it be less (guessing I don't really know what the part looks like)

                        I suppose the market spoke, no else seemed to do it and other buyers at the top of the price range didn't insist so a less than great idea. Still when you're looking at a reconditioning job, it seems like it would have been brilliant! yeah you still have to do the rest, so what? My snowblower does the driveway but I still have to shovel the steps. Its still a huge amount of work after the bed, but each is a smaller, easier job than the bed
                        Last edited by Mcgyver; 08-06-2016, 11:35 AM.
                        in Toronto Ontario - where are you?

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                        • #57
                          Originally posted by Fasttrack View Post
                          His point is that replaceable ways are not that useful because, by the time they need to be replaced, the saddle needs attention, too. It's not as easy as slapping on a new way and calling it good....
                          Everyone is focusing on the fact of carriage wear, and suggesting that it will FORCE action on the carriage. Let's take a closer LOOK at that idea, because it likely is rather different from what might be thought.

                          Don't just easily toss off the statement "it won't do any good, the carriage is still worn.".

                          It is worth pointing out that the saddle may NOT need much attention for a number of reasons. (obviously it would not HURT to fix it also, but we are talking about "must do" stuff here)

                          1) As half the system, it may well have only half the wear, even if it were the same hardness.

                          2) It is probably softer, and so rather than being worn down, it may embed the grit, and wear down the harder piece like a lap, since the grit will not embed in the harder material (the ways in this case)

                          3) If the wipers were in good shape, the ways will have MORE wear, from chips etc, being "bulldozed" back and forth by the carriage and wipers. Less will be underneath the carriage.

                          4) the new ways are made to close limits, and will not move the carriage particularly except up due to not having the wear.

                          5) If the lathe was usable as-is, except for being in need of new ways, the carriage will be, if anything, LIFTED UP, back toward its previous position. So that will DECREASE the need for drastic action concerning the carriage.

                          6) The MAIN problem caused by worn ways will be cured by replacing them, as the machine will now move the carriage along straight ways, and this reduce the taper issues.


                          Remember, when the machine is re-ground, the grinder hand will make sure the cut taken by the grinding wheel will go down BELOW the lowest part of the wear. The net effect will be to LOWER THE WAYS. This ADDS TO THE PROBLEM, and is one reason for having to add turcite, etc.

                          Replacing the ways is DIRECTLY OPPOSITE.... By replacing the ways you RAISE them. Raising REDUCES the problem, so your need to do anything to the carriage is LESS.

                          It is entirely possible that NO action at all is really required to have an improved machine. Touch-up scraping to remove any "rocking horse" wear may be all that is needed to bring back good alignment with the ways. The wear plus scraping may easily not be enough to require any action vs the leadscrew, feedscrew, and control rod.
                          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


                          • #58
                            Ok, here's another one to ponder. I had an Atlas with wear about .005 deep on the front way at the headstock and tapering down to no wear about half way down the bed. The problem it was causing for me was not an issue of turning taper, although that was certainly an issue, but most important to me was that when working close to the headstock the vertical slop in the lightweight Atlas carriage was causing serious finish issues when turning some types of materials close to the headstock. The forces at the tool could lift the front of the carriage and let the cut deepen, then come out of the cut...lots of roughness/chatter.
                            I wasn't going to spend a lot of money on that old machine, it just wasn't a machine that was worth it. Instead, I made a fixture to hold alignment of a router with a speed control, and used mounted stones to allow me to work the wear down the full length of the front way. (Anybody trying this needs to be very mindful of end play in the router shaft when setting depth of cut.) Then with hand scrapers, I scraped the fresh surface as flat as I could the whole bed length and assure myself that any small bits of grit were gone.
                            Now with the wear being uniform, I was able to take .005" worth of shims out of the stack at the front of the carriage and the machine was tight again. Because of the risk involved to a machine, I am not advocating such treatment be used indiscriminately, but it worked well. I used that machine a whole lot for maybe 20 years before I found a better one at the right price and it worked swell.

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                            • #59
                              I think it is an excellent solution, and evidently solved the problem. I assume you had a flatness reference for scraping.
                              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


                              • #60
                                Originally posted by J Tiers View Post
                                I think it is an excellent solution, and evidently solved the problem. I assume you had a flatness reference for scraping.
                                Yes, but it was not as long as I would have liked. Still, micrometer measurements of the thickness as I went along assured me I wasn't going astray. Having only to work down only a 1/2 inch wide section of the flat way is easy peesy compared to what would be involved with v ways.

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