Rishton CNC Mill rebuild and Auto Lube install

  1. northwest Member

    Messages:
    714
    Location:
    Manchester UK
    I need to install a Way Lube system to my recently acquired small CNC Mill. This machine has had quite a colourful and chequered history and I have known the machine for a good few years before it came into my possession.
    I have started to learn my way around it and I built an enclosure so that I could use flood coolant. That was the catalyst to cause the machine to display it's final flaw,no waylube system. My efforts of squirting a bit of hydraulic oil onto the surfaces just weren't cutting it and the ways were starting to bind.
    I looked at it and considered the options, reality was, take it apart, completely. I know, we look for the easier, softer options but it wasn't going to work; it needed to be dismantled completely. I needed the base on the big Mill so I could machine oil channels into it and drill some holes for the fittings.
    As they say, a picture paints a thousand word, this is what it looked like when I had removed the covers:

    mill-01.jpg

    I discovered the ballscrews were not zero backlash and they were tiny, 8mm! So I immediately decided to upgrade them to the biggest I could realistically fit and it was determined that a step up to 10mm diameter ball screw. I also decided that twin angular contact bearings were needed if I was to make a job of it:

    mill-02.jpg

    As it is the holidays my usual method of paint removal wasn't available to me so I knocked up a makeshift box lined with poly bags and some dichloromethane, 24 hours later, I had this and it was ready to go:

    mill-03.jpg

    Using a 4mm carbide ball end mill I started the oilways. I drilled and tapped 8x1mm for the oil fittings and decided to use the biggest I had because once this is all together it will be a nightmare to swap them;

    mill-04.jpg

    I flipped it over and machined the spot where the fittings are going to go, if it looks right it probably is:

    mill-05.jpg

    This clearly shows the difference in size of the new bearings. I decided to go with a twin angular contact bearings and just suffer the need to make new bearing carriers, I will do those once the new ball nuts arrive and I have installed them and I am sure about the centres staying the same. I might need to move the centre line of the ball screws so best wait, I hate "trial runs".

    mill-06.jpg

    I drilled into the side of the X axis on both sides and joined those canals from the top to lead the oil straight into the way channels. I must have used the same piece of string to measure with as they broke through perfectly on bothsides:

    mill-07.jpg

    Coat of primer and the first coat of Tractol before tea:

    mill-08.jpg
     
    gaz1, RichardM, galooph and 5 others like this.
  2. ukracer Forum Supporter

    Where do you get dichloromethane from.
     
  3. northwest Member

    Messages:
    714
    Location:
    Manchester UK
    I decant it from one of the 55 gallon drums. Friend of mine has LOTS. He has a tank about eight foot by four and ten foot deep. At the bottom there is a perforated grill and he has a layer about ten inches deep of dichloromethane. Under this tank is a burner so he heats it. Above is a gantry crane and he lowers whatever down into it, the results are amazing, paint just shrivels and blisters, oil and grease fall away. It is very handy.
     
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  4. Parm

    Parm I have fun doing stuff

    Messages:
    9,970
    Location:
    Towcester
    Never give out his name or address
     
  5. northwest Member

    Messages:
    714
    Location:
    Manchester UK
    I know, everybody will want to use it! :whistle:
     
    Pete., gaz1, RichardM and 2 others like this.
  6. northwest Member

    Messages:
    714
    Location:
    Manchester UK
    Bit more progress, I ordered a six way manifold from ebay and that has arrived and a passing friend was press ganged into giving me a lift back up with it. I am still waiting for the ball nuts so I thought I would press on and prepare the ball screws and see how they would fit in to the old retaining blocks.

    mill2020-01.jpg

    The ballscrews needed machining and time to press the CBN tooling into service:

    mill2020-02.jpg

    I made a short video and just for info, you should not use coolant with these tips:

     
    Hood and galooph like this.
  7. northwest Member

    Messages:
    714
    Location:
    Manchester UK
    So, when will I learn? Make a couple of nuts, not a problem right? Oh, I know, let's use stainless, drill a deep hole and run a tap down:

    Ballscr-01.jpg

    Yes, that's the remnants stuck in the end. Now, why would I want to make nuts anyway? Loads on the shelf, right? Not in 7x1mm though. I had to machine the ballscrews down (okay, i didn't have to, but these half right/half wrong affairs of clamping fittings to the ballscrews I see on these "maker" videos are just such a lash up) to accommodate the bushes that the bearings would sit right and so, I made them 7mm. Only the French use 7mm hardware, well they would wouldn't they, so make a couple of nuts.
    Then on the subject of bushes, I decided they would best be made from Manganese Bronze. Yes, I was having a real downer on myself yesterday and decided to punish myself. Manganese Bronze? I need my bumps felt. Anyway, that turned out okay in the end too:

    Ballscr-02.jpg

    The chips were coming off the stainless hot n fast, really bonny colours:

    Ballscr-03.jpg

    Wonder what I can torture myself with today? Retaining washers in Titanium maybe......
     
    slim_boy_fat and Hood like this.
  8. northwest Member

    Messages:
    714
    Location:
    Manchester UK
    So, bit of a really bad day with this. I don't buy poor toolinG so I bought from a UK seller an 18x1mm tap for the ballnuts. It is rubbish. Instead of tapping a thread, it just reamed a hole out to 18mm. It will be going back. I am not happy. I will just cut thye thread on the lathe. I wanted a tap with this thread size and pitch for other reasons. One of the brackets is finished (I machined the thread).

    MillBracket02.jpg

    In place and lined up:

    MillBracket01.jpg

    Machining a new bracket now the original has been destroyed by the spurious tap:

    MillBracket03.jpg

    This is what I am making and the finished article will have to wait until tomorrow:

    MillBracket04.jpg

    It at least has allowed me to add a little more meat to the bracket as it is getting a little thin at the bottom there.
     
    Hood likes this.
  9. Hood

    Hood Forum Supporter

    Messages:
    9,603
    Location:
    Carnoustie, Scotland
    I have done many a ballscrew and just always used normal carbide.

    For taps I get YG Prime from Cutwel and find them excellent, they are machine taps but that is all I buy nowadays even when tapping by hand, spiral point for through holes and spiral flute for blind.
    Fine pitch ones may be more expensive though as I normally buy when they are on special and I don't think I have ever seen the fine on special.
     
  10. Hood

    Hood Forum Supporter

    Messages:
    9,603
    Location:
    Carnoustie, Scotland
    Aye, just looked, £64 plus VAT :D
     
  11. northwest Member

    Messages:
    714
    Location:
    Manchester UK
    I often buy taps and dies from Tracy Tooling but on this occasion I bought from ebay. I sincerely believed it was a HSS tap of good quality. It was not :-(
    Not to worry, I will find one at the right price, it's a patience game. I have bought tooling from Cutwel, always good gear, but sometimes like now, a bit out of my price range.
    Meanwhile I will cut the thread on the lathe.

    The issue with the ballscrew is simple, because it is 10mm it is through hardened unlike say a 20mm ballscrew where the surface is glass hard, soft in the middle, well "soft" being a relative term. Was not being co-operative but it has all turned out well in the end. I am going seat of the pants make it up as you go along fabrication of the bracketry and spacers to hold the stepper motors in place. Should be interesting.
     
    Pete., galooph and Hood like this.
  12. northwest Member

    Messages:
    714
    Location:
    Manchester UK
    So, started off today by machining down a bit of 7075 to make the two pieces I need for the stepper motor mounts. Sort of "start with a big bit and end up with little bits":



    The mounts have turned out well, took a bit longer than I would have liked but they are right. Original bracket on the right, new improved model on the left being trial fitted to the Mill base:

    MillBracket202.jpg

    Front and rear views, the new 30mm twin angular bearings are a massive upgrade over the original single ball race and thrust bearing. They are actually quite a complex part with a number of setups on both Mill and Lathe:

    MillBracket203.jpg

    The other side to the bearing is bored out to 40mm as I also upgraded the Oldham couplings while I was at it, much bigger, bigger contact area and bigger ball screws, all positive:

    MillBracket204.jpg

    Hopefully back together tomorrow afternoon.
     
    galooph, Hood and slim_boy_fat like this.
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