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Mll Drill Maintenance

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  • Mll Drill Maintenance

    Hello All,

    I recently picked up an Enco milling drilling machine at an estate auction....same deal as the Rong Fu/Grizzly/HF/etc machines I think. I believe its the the RF30 or 31 style.

    It appears to be in good working order and I'd like to keep it that way. Since I didn't get a chance to talk to the original owner, I pulled up the manual and read through all that. Not the most informative read

    The table is in good shape and no tool marks! It had set for a while in the PNW, so it had some light buildup on the column. Got after that with a rag and wd40 and its looking pretty nice again.

    So far I have some vactra #2 way oil and an oil injector can on the way. How much oil does one typically inject at a time?

    I also see spindle oil out there, but no mention of it at all in the manual on this thing. Is that something I need and if so which one and how/where/when is it applied?

    Should I apply some kind of lube to the outer portion of the quill? Grease for the ball screws on the table?

    I also saw a video where a guy mentions adding a needle bearing between the drawbar and the spindle...he talks about replacing a washer with it. My unit doesn't even have a washer there...drawbar tightens right down on the top of the spindle splines. Anybody have one of these that has a washer or has installed a needle bearing?



  • #2
    On the way oil, inject where? If the table or ways have ball oilers (small circular ports into which you pump oil) I'd say several pumps the first time (they may be dry) and after that one or two pumps periodically. Machine tools live in oil, and if it's dripping out, that's almost enough.

    Spindle oil is a question. Are the bearings open or sealed? I'm not familiar with your particular model, but my considerably older model has a panel on the side that you unscrew to access the spindle preload adjusters at the top of the quill. I have no manual either, but I've assumed that this is where I'm to dribble spindle oil too. As it's total loss (the top bearing drips down to the bottom bearing, and eventually drips out the spindle nose) I plan on oiling it quite frequently, like every few hours. (I'm still rebuilding it.)

    Is that correct? I don't know. I'm guessing. But too much oil is a lot better than not enough.

    Outside of the quill, yeah, I'd lightly lube that too. I can access to top of mine through that same port/panel, and several drops at the top of the quill will work their way down. Don't need a huge amount, just enough to keep it from running metal-on-metal. Just keep in mind these kinds of machines usually use simple bolts pushing on brass wear plates as a spindle lock- too much lube and the "lock" might not hold well.

    As for the ball screws, unless it's a CNC retrofit, I doubt you have ball screws. The table lead screws should be lubed, yes- oil rather than grease, again, and there should be a port or ball oiler to access them. Or you may have to find a long-neck oiler and just make a habit of having to reach up in there.

    The needle bearing is, as they say, contraindicated. That means no. The drawbar is there to hold the toolholder or collet in place, and as such needs to be cinched reasonably tight when in use. A bearing here reduces or eliminates the friction that holds the "nut" on the end of the bar in place, very possibly allowing vibration to work the drawbar loose very easily.

    My mill-drill not only didn't have a washer, but the end of the spindle splines was kind of rough. They hadn't turned it flat, somebody just ground it more or less flat with a belt sander. I turned mine square/true, and will be using a thin hardened washer when I reassemble.

    Doc's Machine. (Probably not what you expect.)


    • #3
      Thanks Doc...Impressive shop you have there! A couple of those rebuilds look better than new.

      The only panel I see would basically be the whole front face of the machine in behind the depth stop mechanism. If my oiler is long enough I could probably shoot it through the depth stop slot actually. I haven't torn the pulley off the top to see if the bearings are sealed or not. I would assume they are since they don't have any oiling protocol in the book...but we all know about assumptions and where they can lead! I've been afraid to tear into it that far...your photo documentation on the Jet makes me feel a bit better about going there.

      How thick of a washer are you thinking on the drawbar and what grade? My spindle wasn't as rough as yours...I can make out some milling marks, but it certainly wasn't precision turned either. Looks to have some fairly heavy grease remnants on there too. Would you grease or oil the splines?

      It looks to have been run pretty much exclusively at 465 RPM by the belt/pulley combo selected. The other pulleys look virgin. Looks like you have a lot of aluminum you have any speed recommendations to try out on the following? I seem to be getting decent chips, but with my limited experience I don't know for sure. It will run all the way up to 2500 rpm.

      For now I will mostly be punching 1/4" dia through holes in 6061 1/8" stock...looking to add a bit mounted countersink or deburring tool to the mix soon. Just running a regular HSS TiNi drill bit for now.

      I also mill .125 flats onto the back side of 6061 angle. I've got a wide variety of HSS end mills in 4 and 6 flutes. Seem to be doing ok with 3/4" six flute now. Most of the aluminum stuff I'm reading says to use 2 flute mills. I plan on picking up a couple of them to test as well.



      • #4
        i've got an Enco RF-30 I bought used five or 6 years ago (picture from back when I bought it in the link below). Basically way oil on the moving surfaces, a little oil on the feed screws, and the handwheels on mine have oil ports to hit too. Aside from those as regular operations, you might want to look into the quill. A couple years ago I had the motor out to have the bearings and centrifugal switch replaced, so while it was down I pulled the quill out. What I found was 20 year old dried grease, and very little lubrication on the bearings. basically I just regreased and retightened the bearings and reinstalled the quill. It wasn't too big of a deal, but it does involve pulling everything out of the head, including the fine down feed, so find a walkthrough on the internet and you'll be fine. Also, mine's an early 90's model if I remember correctly. If yours is fairly recent then you may not worry about it, but if it's older, I'd pull it apart to inspect.


        • #5
          Keep in mind I'm not a mill-drill expert in general. I've owned only the one, and even it hasn't been functional in ten years. I'm also not directly familiar with your model, which is in some cases substantially different from mine.

          The spindle lube issue I'll have to defer to the experts. I'm not even sure how mine needs to be maintained, and I'm just kind of formulating a plan as I go. I do, however, operate on the idea that lots of oil is good. Machine tools need oil, and very few manual ones recirculate it. Oil is applied, it drips off, more oil is applied to replace it. Oil is cheap- bearings aren't.

          On the drawbar washer thickness, it really doesn't matter. Too thick starts taking away thread engagement with the collet, but I doubt too thin is an issue. Most mills don't even use a washer there. As long as the top of the spindle and the underside of the drawbar nut are both reasonably smoothish, I doubt you'll ever have a problem. I was just planning to add a thin washer just to try to improve a somewhat poor design, but it's more for peace of mind than anything. I used to for years with no washer and the badly-machined ends with no real issues.

          On oiling the splines... maybe the occasional light oil. But the belt box can get dusty from the belt itself, and oils just attract and hold the gunk. Unless you're doing a lot of quill work (as in, using it as a drill press) might be better to leave it dry. Keeping in mind that's opinion, not a factory recommended maintenance technique.

          As for cutting speeds and feeds, that's an entirely different subject that can, and has, filled some very thick books. Long story short, it depends on the material (steel, aluminum, brass, iron, plastic) the cutter (two flute, four flute, drill) the size of the cutter, the depth of the cut, whether or not you're using lube or coolant, etc. etc.

          Doc's Machine. (Probably not what you expect.)