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Thread: ENCO RF45 Clone CNC Conversion - LinuxCNC

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    Default ENCO RF45 CNC Conversion - Z-axis build

    It might seem a little odd to start the conversion with the Z-axis, especially since I was original thinking about doing an X-Y only conversion and adding the Z later, but that is what I did.
    I actually made the Z-axis ballnut mount sometime during the end of the summer, but just started working on the rest of the Z a few days ago.

    I'll start with some picture of making the ballnut mount. As usual all the drawings and CAD models will be available in the Google drive folder linked in post #9.

    I started off with a nice piece of 2.5" x 4" aluminum and used my trusty Horror Fright band saw to cut off a 4.75" chunk. I must have just cleaned it, it does not look like that often.


    I then used the vertical bandsaw to cut the 4" dimension down to about 3.15" to leave some room for facing to the final 3.1" Who says you can't cut metal on a woodworking bandsaw.


    That left me with a just oversized blank.


    I then faced it on all sides and used an angle plate to get the ends nice and square. I used a machinists square to square the face perpendicular to the angle plate before clamping.


    That left me with an accurately sized block (within about .002") that was square so I'd have good reference faces for the following operations.


    Next I drilled the large hole for the ballnuts to fit into. I started with the largest drill I had (only .5") and worked up from there with a boring head. The hole goes all the way thru the 2.5" part so I cranked the mill head up and down instead of using the quill to improve accuracy. I ended up about .002 over the diameter of the ballnut so it was a snug but not too tight of a fit.

    I then drilled the six .25-20 tap holes on each side for mounting the ballnuts. This was a pain because I had to turn the part over and drill the holes on the opposite side. I clamped a small block to the face of the angle plate to act as a stop on the far end of the part so I could hopefully turn it over without having to re-indicate. The extra work in making the blank accurate was well worth it as when I turned it over it was symmetric enough to be positioned very accurately by the angle plate and stop and did not need to be indicated.


    Ballnut mounting holes complete, now time to machine the boss for locating in the Z-axis slide.


    Boss being machined on end of part. I also drilled three holes with a center drill in the part. The outer two will later be tap drilled for 5/16-18 SHCS. The center hole was used for locating the part on the lathe and supporting it with the center while turning the neck. See pictures below.


    View of how the part was fixtured for machining the boss.


    I then pulled out the rotab to machine the rounded ends on the boss.


    Over at the G0602 I used the 4-jaw to hold the part while machining the round neck. I ran at about 300rpm since it was an unbalanced and interrupted cut.


    Almost done at the lathe.


    The part came out better than I expected it would.


    I hope I did not overdo the pictures, let me know if I did.

    More on the Z-axis next.

    Thanks for looking!
    Kurt

    Last edited by KCJ; 01-22-2017 at 01:58 AM. Reason: Fix typos


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    Default Re: ENCO RF45 Clone CNC Conversion - LinuxCNC

    Quote Originally Posted by KCJ View Post
    Mike, I was thinking you were in south Ga!
    I just graduated a few weeks ago with a degree in Mechanical Engineering Technology form Southern Poly, which long ago started as a more practical offshoot from GT. Incidentally I was the Engineering Technology Student of the year 2016 for Ga. Right now I am working on finishing up some projects I did not have time to work on while in school, working in the schools nuclear lab, and deciding if I want to pursue a masters or not.

    I have some free time so if your in the area I'd be glad to show you around my little shop, it's not anything to write home about, though.

    Kurt
    Kurt, that is awesome man. Graduating from an engineering program is no joke and that is something I am sure you are proud of.

    Yes indeed, I will have to get up with you sooner than later.



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    Default ENCO RF45 CNC Conversion - Z-axis build

    With the Z-axis ballnut mount complete I moved on the the Z-axis motor mount / end bearing support.

    This is a CAD model of what I was shooting for. Sorry for the image being so big.


    I did not have any .75" aluminum plate laying around so I melted down an old alloy wheel I found in the neighbors trash and cast a 5.5" diameter disk to use as a blank. I then machined it on the lathe.
    I did not get any pictures of the casting process, I'll try to be more diligent next time.


    I drilled all the holes in the part for mounting to the top of the mill's column, securing the motor, and attaching the bearing block standoffs. I also made the standoffs from some .5" 1018 rod, making sure to make them all as close to the same length as possible. They ended up within about .0005" of each other which should be good enough to ensure that the axis of the bearing is sufficiently perpendicular to the mounting plate.


    So that is were I was on October 29th. I did not have time to work any more on the conversion until just a few days ago, and I'll pick up there.

    Thanks for looking!
    KCJ



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    Default ENCO RF45 CNC Conversion - Z-axis build

    Last summer I took the mill apart, measured it as accurately as I could and made the CAD models. I then designed and made all the parts for the Z-axis conversion based on the dimensions in these models, without being able to verify that they were even close to correct or that the parts fit like I intended then to. So I was fairly certain that I would have to do a good bit of hand fitting to get parts like the boss on the ballnut mount to fit correctly in the Z -axis slide. I guess I did a better job measuring than I had though, or just got lucky, because everything fit almost perfectly with very little fine tuning.

    Below is a picture of the ballnut mount in place on the Z-axis slide.


    The slot in the Z-axis slide had a lot of "hills" and "valleys" from the original milling which made the boss a very tight fit. A few draw strokes with a fine file leveled everything and Bob's your uncle. It ended up being almost a piston fit.


    I machined a "washer" from some 2.5" 1018 bar and drilled and C-bored two holes in it for 5/16-18 SHCS. The slide is effectively clamped between this washer and the ballnut mount on the back side.


    Unfortunately, the Chinese did not get the slot in the slide centered in the round pocket, so the clearance holes in the washer did not line up with the taped holes in the ballnut mount. The quickest solution was to cut the heads off two SHCS, turn points on the ends and harden to make some blind hole spotters. You can see them and their handy work in the fuzzy picture below.


    Here is the final result, ugly to be sure, but you and I are the only ones who will know what is back there behind the head.


    At this point all Z-axis parts were pretty much complete and so I proceeded to reassemble the mill with the new components. Here is a top view of the motor mount plate sowing how the motor fits and the jaw coupling. I ran out of 1/4-20 SHCS so while waiting on those I am using BHCS with washers to help avoid adding to the already severe case of shop rash the plate has.


    Here is a short video of some of the very first Z-axis moves under CNC control. The head is moving at 130ipm.


    Thanks for looking!
    Kurt



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    Default ENCO RF45 CNC Conversion - Z-axis build

    When I designed the Z-axis I thought that the 1600oz-in motor might have trouble moving the 200lbm head at anything like a respectable speed with out some sort of counterbalance, but it actually moved the head very reliably up to around 165ipm, which I was more than satiated with. However, when the motor faulted the head would fall, fast. I would guess it might get to about 3-400ipm, which was scary to say the least. When the power was cut it would also fall, but at a much more reasonable speed, actually more of a creep. I guess the windings are more or less shorted when the power is removed, but in a fault condition they are left open?

    Since I was happy with the rapid speed I thought about adding an electromagnetic break to the screw, but that looked like it would be more expensive and complicated than simply adding the gas struts, so I preceded with the initial design.

    I made the strut brackets that mount to the ballnut mount out of some 2.5"x3/16 angle iron. Since I had the Z-axis under CNC control I though I would break it in by using a drilling cycle to drill some of the holes, and I almost all to literally broke it in. Yes, I crashed on my very first part. I had used a center drill to spot the holes, and when I changed to the 5/16 drill I forgot to set the TLO. I had the max rapid set to 100ipm and the drill made a rapid right thru the part, more punching than drilling its was thru the 3/16 steel. Surprisingly, nothing was damaged and the drill did not look any worse for the treatment, so I got lucky, really lucky. I did have to file the biggest burr I've ever seen off the back of the part. Needles to say, I will be much more careful now when changing tools to remember to enter the TLO!

    After that I was not much in the mood for taking pictures, so this it the only one I've got that relates to installing the gas struts. Just cutting off the corners so the bracket would clear the internal bracing in the column.




    Brackets attached to ballnut mount and struts in place. The head is perfectly balanced and can just barely be pushed up and down by hand. The nut on the top of the one strut was to keep it from shooting across the room in the event that the lower end slipped off the casting, but the precaution proved unnecessary.



    Here is a shot up the column after the ballscrew was reinstalled. It was removed in the previous picture for replacing one of the ballnuts which was rough due to incompletely ground races.


    The counterbalance did not increase the max rapid speed very much, but tuning the hybrid stepper driver did. Here is a video of the Z doing 200ipm rapids up and down.



    The Z is now complete except for limits and method of lubing the ballscrew.

    I got most of the Y done yesterday and today, I'll post on that tomorrow if I get a chance.

    Thanks for looking!
    Kurt

    Last edited by KCJ; 01-23-2017 at 10:07 AM. Reason: Fix Video Link


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    Default Re: ENCO RF45 Clone CNC Conversion - LinuxCNC

    I assume the Idea with the struts is to balance the Z axis head to where the load on the motor going up or down will be as close to the same as possible? Do struts have a progressive lift capacity or do they support the same load throughout the entire stroke? I had seen machines with cables and a heavy counterbalance weight hanging off the rear of the machine. That could even be accomplished with weight being mounted low maybe even in the mill base or cabinet. The only thing I can see which would be a huge plus would being able to load the weight to the exact weight needed to fully balance the Z axis. If course I am again a newbie and may totally be missing something. The cable system could possibility mounted in the Z axis column so as to not look all cluttered.



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    Default Re: ENCO RF45 Clone CNC Conversion - LinuxCNC

    I assume the Idea with the struts is to balance the Z axis head to where the load on the motor going up or down will be as close to the same as possible?
    Exactly, the idea of the counterbalance it to make it so all the motor has to due is overcome static and dynamic friction in the slides, and not actually have to lift the head. Of cource with the head counterbalanced the maximum downward thrust that can be developed, needed for drilling large holes, is reduced by the heads weight. But this is not a problem since when great thrust is needed the axis will be feeding at a relatively low rate and the motor speed will be in the range of greatest torque. For example, even with the counterbalance my Z should be able to produce around 500lbf of thrust (as opposed to 700lbf without), more than enough for most drilling jobs.

    Do struts have a progressive lift capacity or do they support the same load throughout the entire stroke?
    Gas struts don't produce constant force, but they do produce much more constant force than a spring would.
    It is very easy to calculate the max and min force produced by a gas spring using the basic gas laws. The ratio of the compressed force to the extended force for a gas spring is given by a value K, which is equal to the ratio of the volume of the gas in the cylinder when it is extended to the volume then it is compressed. Many suppliers don't publish the K value, (shame on them!) but you can easily estimate the volumes from the physical dimensions of the strut and then work back to K from there. Based on the drawings on their website it looks like the 100# struts I got from McMaster have a K of about 1.37. The 100# rating is at close to full extension so is the minimum force the spring will produce while not moving. The maximum force is then 100# * 1.37 = 137#. I discussed my strut selection towards the end of post #2.

    I had seen machines with cables and a heavy counterbalance weight hanging off the rear of the machine. That could even be accomplished with weight being mounted low maybe even in the mill base or cabinet. The only thing I can see which would be a huge plus would being able to load the weight to the exact weight needed to fully balance the Z axis.
    Many older machines use weights for counterbalance as you describe, and even some newer machines, Hurco comes to mind. The OKK in our school shop is a classic example. The head is counterbalanced by a weight in the column connected to the head by roller chain. Although it is very massive I can quite easily crank it up and down with one finger, literally. This seems like it would be an ideal arrangement, and so it is for a manual machine, but not so much for CNC.



    The main thing that makes a CNC machine sluggish is poor acceleration, and since F=ma the mass of the head/counterweight assy directly effects the acceleration attainable. When you use a weight to counterbalance you will reduce the work the motor has to do lifting the head, but you will also double the mass of the system that the motor has to accelerate, cutting the machine's max acceleration capacity in half. It is likely that the acceleration would still be sufficient, but it would be worth running the number first to make sure.

    The gas spring counterbalance has the advantage of not adding appreciably to the mass of the system, while still reducing the work the motor has do to lifting the head. So you can get high acceleration with a relatively small motor.

    Hope that makes some sense. Most of you know more about this than me, so feel free to set me right if I am thinking about something wrong.

    Kurt

    Last edited by KCJ; 01-23-2017 at 01:58 PM. Reason: Spelling, or lack thereof


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    Default Re: ENCO RF45 Clone CNC Conversion - LinuxCNC

    Perfect post for explaining this in a way that I totally understand why struts are more ideal for a CNC conversion. I am not included in that "most of you" hahaha I am a total newbie in the realm of machining and CNC conversions.



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    Default Re: ENCO RF45 Clone CNC Conversion - LinuxCNC

    I am a total newbie too, but have some more of that book learnin'!
    Kurt



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    Default ENCO RF45 CNC Conversion - Y-axis build

    Next up, the Y-axis.

    Here is a CAD screenshot of the final assy for reference. Again, sorry for it being so big, I don't know how to make images the size I want on here.


    I made the Y-axis ballnut mount in much the same way as the Z-axis mount, so I won't bore you with too many extraneous pictures. But I have to include a picture of my "Kurt" vise. It is no Kurt, just a 90s ENCO knockoff I found in a dumpster and cleaned up. It had been in a biomedical lab and was disgusting to say the least, I think that's the only reason they thew it out as it works OK.


    Another boring picture. Again I used the head and cranked it up and down instead of using the quill.


    As before I used the 4-jaw to machine the little boss that fit into the bottom of the saddle to locate the ballnut mount.


    If you compare what I made to the CAD model above you will notice that I was too lazy to set up the rotab and cut the curved relief so the table would have full travel. Also I dimensioned my initial drawing poorly so read it wrong and made the step were the rear ballnut flange mounts to tall by exactly .5". Other than that came out fairly well I think. I will probably make a replacement once I get the mill under full CNC.


    Anyway, it fits nice and snugly, and that's all that matters for now.


    Next on the order of operations was the Y-axis motor mount plate. Like with the Z-axis motor mount I cast a blank and then machined it. I know I promised casting pictures, but I was having too much fun. I will get some of the X-axis motor plate casting for sure. You can see my little home built crucible furnace in the background just to the left of the spindle nose.


    I cut a relief so the mount would clear the little step on the front of the base casting. I am already spoiled by having the Z-axis CNCed. It made cutting the notch and C-bores to accurate depth so easy!


    Finished motor mount. I spun it on the lathe to cut the motor recess and a belt sander made quick work of rounding the corners.

    Next is modifying the base casting and installing the Y-axis parts. We'll have 2-axis CNC soon if all goes as planned!

    Thanks for looking!
    Kurt



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    Default ENCO RF45 CNC Conversion - Y-axis build

    Since the NEMA34 motor is fairly large I had to move the Y-axis screw down so that the motor would end up below the top of the ways. This meant that I could not reuse the hole in the base casting that the old screw had passed though, but would have to drill another a little lower down large enough for the motor shaft and coupling.

    Here is a section view of the Y-axis drive assembly showing how everything fits together.


    The modifications to the the base consisted of drilling a 1.5" hole centered .9" below the ways for the motor shaft and coupling, and the drilling and tapping the holes for mounting the bearing block and motor mount. I also extended the slot in the top of the base to allow full travel as suggested by ninefinger in post #7.

    I highlighted the necessary modifications in red. They are by no means significant and do not prevent the machine from being reassembled with the original components if I want to for some reason in the future.


    I don't like to butcher things, though sometimes it is the best approach, so I was a little concerned about how I was going to neatly drill the large hole in the front of the casting, especial since it intercepts the existing hole. I had a 1.5" holesaw which I though was my best bet, and a while back I had made a heavy duty arbor for tube notching, with turned out to be just the ticket. Here is a picture of the arbor.


    I added a 5/8" shaft and turned the end down to 1/2" so it would fit in a hand drill.


    I then took a chunk of yellow pine and, following standard practice, used a peck drilling cycle to bore some holes in it.


    I was foolish enough to take a video of the drilling operation, so I guess I should post it as it is somewhat amusing.


    I pressed in a old used bearing and I had a nice horizontal boring device.


    Here she is in operation. Whatever you may think about the setup it was very ridged and made cutting a clean hole in the right location a piece of cake. It was well worth the few minutes it took to make the jig. The bearing certainly helped reduce friction, but was more for fun than anything else.


    It is hard to get a good picture, but the hole came out very well and I don't feel like I butchered anything.


    Next I drilled the holes for mounting the bearing block. I was starting to get a little impatient to get the Y together, so I used the bearing as a guide to drill the holes. Since the tap drill was a loose fit in the clearance holes in the block I made a little bushing to keep it centered. The free end bearing it there only to support the piece of wood I'm using as a strap clamp.


    I tapped the holes and called it a day.


    That holesaw jig comes back for another round, stay tuned.

    Thanks for looking!
    Kurt



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    Default Re: ENCO RF45 Clone CNC Conversion - LinuxCNC

    Looks fantastic.

    You're doing a great job.



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    Default Re: ENCO RF45 Clone CNC Conversion - LinuxCNC

    Quote Originally Posted by embraced View Post
    Looks fantastic.

    You're doing a great job.
    Thanks! It's been a lot of fun.
    I have not been able to work on the conversion in the past day or so due to pressing projects in the nuclear lab. Hopefully tomarrow I'll get some time.
    Kurt

    Sent from the depths of the shop using a very tiny keyboard.



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    Default Re: ENCO RF45 Clone CNC Conversion - LinuxCNC

    Looks like a great conversion
    Getting up the nerve to start mine
    Cheers
    Tim



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    Default Re: ENCO RF45 Clone CNC Conversion - LinuxCNC

    Quote Originally Posted by timbo43 View Post
    Looks like a great conversion
    Getting up the nerve to start mine
    Thanks, Tim!
    I know how you feel. It took me a long time to finally get up enough nerves to take the mill apart and start the conversion.

    Kurt



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    Default Re: ENCO RF45 Clone CNC Conversion - LinuxCNC

    I got my Enco mill home this week. I was kind of surprised at the size of this mill when I arrived to pick it up. I stopped at Harbor freight and picked myself up a nice new 2 ton engine lift just to be able to move this thing around once home. So far I have played with it only a little with the supplied worn out end mills they gave me. I did check to see if there was any run-out on the spindle and I was surprised to find that there is literately no run-out. The vice I got with the mill is HUGE, Its 6" across and I have not been able to find any markings on it anywhere to know what brand it is. I do not think this was a vise they used on this machine as it was absolutely nasty with sticky caked on gunk with aluminum chips all in it. I think the PO said he has the machine shop (part of his company) get together the vice and various other things to get me started. Anyhow I have made some chips and did some playing with the DRO. I am going to add a Z DRO while learning some basic manual milling and hopefully i will become fluent enough to make all the parts for the CNC conversion in short time. I still need to order some basic Milling tooling and have been working on making a list of what all to order first.

    Here is a short clip of the Indicator on the spindle. That little ticking sound is the indicator hitting what seems to be a deep scratch inside the spindle, I honestly do not know what it is other than you can feel it with your figure. Whatever the case it seems that this spindle is running nice and true.


    Kurt, Im looking forward to more updates. You could say its motivating to see your mill coming together.

    Attached Thumbnails Attached Thumbnails ENCO RF45 Clone CNC Conversion - LinuxCNC-20170128_174504-jpg   ENCO RF45 Clone CNC Conversion - LinuxCNC-20170128_175414-jpg   ENCO RF45 Clone CNC Conversion - LinuxCNC-20170128_175424-jpg  


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    Default Re: ENCO RF45 Clone CNC Conversion - LinuxCNC

    OK, I have not had much time to work on the conversion since the last update, but I did get the Y-axis functional.

    I also added a bunch of drawings, some parts list, and most of the CAD models to the Google Drive folder found here:
    https://drive.google.com/drive/folde...1k?usp=sharing

    I guess I left off at drilling the holes for the Y-axis bearing.

    Quote Originally Posted by ninefinger View Post
    For the Y axis - check that the ballnut isn't going to restrict the movement of the saddle away from the column. I recall having to open up that little bit at the front of the base to get even front / rear travel with the ballscrew in place. The ballnut is larger than the original bit from there.



    Mike
    My next order of operations was to heed Mike's advice and extend the slot in the base so the saddle would have full travel. I was going to just hack out the excess iron with a jig saw, but the success of the holesaw contraption was still fresh in my mind so I decided to use it to remove the bulk of the material. It also would create nice rounded corners on the extended slot.

    Here is the base with the proposed slot extension marked out. I ended up cutting to the line closest to the front which is located 4" from the front of the casting. Sorry for the cellphony picture. I just got a smartphone, and boy is it convenient, but it takes bad pictures if the light is not great.



    I clamped the holesaw jig in place and used the mill's quill to apply pressure since the saw had been declared hopelessly dull before the last 15 uses.



    I repeated on the other side and was left with three little cusps to clean up to finish the slot.



    I then used my least favorite tool to remove the bulk of the remaining material.



    It was such a pain sawing off those little chunks of iron with the jig saw I had to take a Tiramisu break. I would strongly recommend this to others in a similar situation. It really did help.



    During the break I came up with the brilliant idea of using a router to remove the last bit of material and leave a smooth square surface. I started off using a .25" carbide burr as the cutter, but wishing to avoid damaging it switched to a chinesium "end mill". Although the cutting geometry was unlike any I had seen before it worked surprisingly well at 12000rpm.



    Here is the final result. It is by no means perfect, but plenty good enough given it won't be seen.



    Next up was drilling and tapping the holes the Y-axis motor mount. Unfortunately one of the taper pin holes from the original Y-axis mounting was located such that it would interfere with the new holes. I went back and forth as to whither I should modify the mount or plug the hole. Plugging the hole won as the quicker and neater solution. I made the mistake of making the tapered plug out of whatever was in the lathe at the moment, which was drill rod. Since this was much harder than the iron it made drilling the tap hole accurately a pain, but it worked out in OK in the end.

    Here is a picture of the successfully plugged and tapped mounting hole. The two holes lower down are for the motor and encoder wires to pass thru into the base. The buggered hole to the right is courtesy of the factory.



    Finally, motor mount in place.



    To get full travel in the Y and still mount the motor up close to the casting I had to remove about .25" from the motor shaft. I simply clamped the body of the motor in the bandsaw and took it slow so the shaft would not spin on me. The shaft is quite hard but it cut fine.



    I was too impatient to get the Y running, so did not get any more pictures. But everything aligned nicely and there was no binding in the ballscrew so I tested her out. I was hoping for 100ipm on Y, but it can do 300IPM with no problem and I think could go higher, so I am really happy!

    Here is a sort video of the the mill as it is so far cutting air at 300ipm. Sorry in advance for the very poor camera handling...



    Thanks for looking!
    Kurt

    Last edited by KCJ; 01-29-2017 at 02:29 PM.


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    Default Re: ENCO RF45 Clone CNC Conversion - LinuxCNC

    Quote Originally Posted by Mike Hall View Post
    I got my Enco mill home this week. I was kind of surprised at the size of this mill when I arrived to pick it up. I stopped at Harbor freight and picked myself up a nice new 2 ton engine lift just to be able to move this thing around once home. So far I have played with it only a little with the supplied worn out end mills they gave me. I did check to see if there was any run-out on the spindle and I was surprised to find that there is literately no run-out. The vice I got with the mill is HUGE, Its 6" across and I have not been able to find any markings on it anywhere to know what brand it is. I do not think this was a vise they used on this machine as it was absolutely nasty with sticky caked on gunk with aluminum chips all in it. I think the PO said he has the machine shop (part of his company) get together the vice and various other things to get me started. Anyhow I have made some chips and did some playing with the DRO. I am going to add a Z DRO while learning some basic manual milling and hopefully i will become fluent enough to make all the parts for the CNC conversion in short time. I still need to order some basic Milling tooling and have been working on making a list of what all to order first.

    Here is a short clip of the Indicator on the spindle. That little ticking sound is the indicator hitting what seems to be a deep scratch inside the spindle, I honestly do not know what it is other than you can feel it with your figure. Whatever the case it seems that this spindle is running nice and true.


    Kurt, Im looking forward to more updates. You could say its motivating to see your mill coming together.
    Mike, I was fixing to write and see whether you had picked the mill up yet. Those pictures bring back memories of the days when my mill was blue!
    Looks like it is in good shape. Having a DRO will really help out when making the conversion components.

    If the vice is really in bad shape I have an older one I just finished fixing up that you could use until you get something better.

    Kurt

    EDIT: A 6" vice does look huge at first, but it is about the right size for this mill and you will need all 6" more often than you might think!



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    Default Re: ENCO RF45 Clone CNC Conversion - LinuxCNC

    Kurt, i do recall using a router on cast iron before and your post brought that back to memory. Cast iron does route very well and I will be doing that for possibly all the clearancing needed for my conversion. I am torn on possibly doing a belt drive system just to be able to tuck the motors in closer to the machine as my shop is even smaller than a 1.5 car garage. haha I have not researched it other than reading up on other conversion threads but it seems that most are getting almost zero backlash with belt drives which seems odd as I would figure there would be a little slop introduced with such designs. My idea would be to tuck the Y axis motor low right up against the base of the machine and the X axis just below table height and right up against the table. The only issue i may have with this idea is belt length and introducing some play in the system but, that may be a non issue with correct belts. I am still considering direct mount as an option, still in research/read phase.

    I spent a few hours halfway cleaning up the vice. It is for sure one that has been worked a lot but i think after taking it apart and giving it a good cleaning it will be fine for now. Thank you very much for the offer on using your vice.

    I may have missed it but do you plan to do a belt drive conversion someday? I was reading where Arizonavideo99 installed a 4hp 3600rpm motor on his gearbox and was getting double the RPM out of his mill. I just wonder if those gears will hold up in the Enco. I believe he was working on a PM45 or maybe it was the Industrial hobbies RF45 clone which had hardened gears. Anyhow, i have yet to find any 2-4hp motor which has the correct mounting flange as well as a 19mm shaft. It looks like the only option would be getting larger framed motor with correct flange and having the shaft turned down and re-keyed. I may just wait and do a belt conversion which I understand is one of the best mods for this machine if milling much aluminum.



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    Default Re: ENCO RF45 Clone CNC Conversion - LinuxCNC

    Mike, my original design was belt drive, but it ended up being less compact and a lot more complicated and expensive. With direct drive, both X and Y motors stick out less than the original handwheels by about an 1.25". On Y the vice extends farther than the motor so that is the limiting factor on compactness. On X the total table assembly width is about 8.25" narrower than the original set up. If you turn the X motor around and place it along the front of the table (as I did in my first design) then you still need to have the bearings, pulleys and some sort of enclosure at the end of the table which would end up taking up about 3" so you've only saved about 3.5" in total width at the expense of a dirt simple direct drive setup. Just my $.06 (have to account for inflation!).

    If designed correctly belt drive systems can have very low backlash, possibly less than a direct drive setup since most shaft couplings have some play. The best couplings for stiffness are the disk type, but they are bulky and expensive.

    I did a lot of research on belt drives for the first design. I think I decided that the GT2 type belts were best for this application since they are quiet and have very low backlash. I can't find my cad for the belt drive design, must have thrown it out. Attached are my original belt and pulley selections. Can't remember it those were for stepper or servos.

    I think I will to a belt drive conversion at some point, but I don't have time at the moment. I would like to copy Arizonavideo99 internal belt drive design as it is in keeping with my overall KISS approach.

    My ENCO has a very nice hardened steel gear train, so yours should too. I think it would have no problem handling a 3600rpm motor. I think my mill is just a little bit newer than yours, though, since it uses a standard 145TC motor and has a 7/8" input to the gearbox.

    Kurt

    EDIT: Are .docx attachments not supported? I had to save as PDF to get attachment to upload.

    Attached Thumbnails Attached Thumbnails ENCO RF45 Clone CNC Conversion - LinuxCNC-rf45-timing-pulleys-pdf  


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