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  1. #1
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,434

    Thumbs up DRO Instalation !

    Hi Guys,

    I've been getting on with installing the scales for the DRO that turned up last week. Earlier I fitted the bracket for the display support arm. I had to turn a sleeve for it because they had supplied an M8 fastening bolt and used a 10 mm hole in the display support arm and mounting bracket.

    17-02-2021-003.jpg 17-02-2021-004.JPG 17-02-2021-005.jpg
    These pictures show the sleeve and M8 bolt. I used M6 cap screws to secure the bracket to the mill column.

    Today I've made and fitted a pair of brackets to support the vertical scale on the side of the mill column.

    20-02-2021-002.jpg 20-02-2021-003.JPG 20-02-2021-007.jpg
    I used some 3 mm aluminium plate to make these two fastening plates. I used an M6 CSK screw to fasten the plate and M4 cap screws and nuts to support the back end. I threaded the holes for the screws M4 that hold the scales as well.

    You can see in the third picture just how close to the head of the CSK screw I had to get in order to clear the radiused corner on the mill column.

    The zinc plated M4 cap screws simply press against the mill column and the black long M4 cap screws hold the scales in position. I used a nut to lock the screw when I had adjusted the scale square to the milling slide.

    20-02-2021-005.JPG 20-02-2021-008.jpg 20-02-2021-009.JPG
    These three pictures show how the scale fits to the mill column and the gap between the read head and the vertical slide. Unsurprisingly the gap only needs a piece of 3 mm thick aluminium plate to secure the read head to the slide. The important part was getting the scale parallel to both the column and slide, however there is plenty of adjustment there.

    Next Job is the "Y" axis.
    Best Regards:
    Baron J.

  2. #2
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,434

    Default More DRO Instalation !

    Hi Guys,

    Today I have been making the brackets for the "Y" scales !

    21-02-2021-001.jpg 21-02-2021-004.jpg 21-02-2021-003.jpg 21-02-2021-002.JPG

    First job was to determine the slope angle of the base and then bend up some aluminium plate to suit. The angle turned out to be almost exactly 60 degrees. So after cutting a couple of pieces of 3 mm aluminium plate 40 mm wide, I clamped them in the vise and used a hammer and wood block to bend them until they fit. I also found a block of steel that just happened to be the right thickness when I sat the scale on it with a spare piece of aluminium on top.

    So after marking out and drilling two holes 6 mm in diameter 20 mm apart it was just a matter of using the steel block and sitting the bent aluminium pieces on it and positioning them against the sloping base. A 6 mm centre punch and a few hammer taps and I was ready to drill 5 mm diameter ready for holes for tapping M6. The very end pair of holes are blind, but the inner pair went all the way through.

    Drilling the holes was really easy, the casting was very soft and drilled easily, producing more dust than chips. Same with threading ! Just putting the tap into the battery drill chuck and away we go. I just let the tap run until it hit the bottom of the hole or ran right through, and the drill clutch clicked when bottomed out on the blind holes. Reversed the drill and backed the tap out. I wish all threading was that easy. Does make you wonder about the quality of the casting though. I seem to remember that drilling castings was much harder.


    21-02-2021-005.JPG 21-02-2021-006.jpg

    Next step I didn't have any short M6 Cap screws, so I had to shorten some that I had. I have loads of M6 by 40 mm, but the threads stopped 15 mm from the cap, so I ran a die down them to get the threads down nearer the cap so that I could part them off at 15 mm thread length. A washer on them and they fit perfectly, as can be seen in the pictures.


    21-02-2021-007.jpg 21-02-2021-008.jpg 21-02-2021-010.JPG

    I placed the scale on the brackets to measure how much clearance I had above the measuring head and also how big a spacer I would need to make for the head to slide distance. I measured 24 mm. The read head clears that lip by 1 mm just over the thickness of the steel rule/scale that I used to measure it. You can just see over the top in the second picture.

    The DRO scale is secured by two M4 by 12 mm cap screws right at the ends.

    I've still lots of work to do making some of the mill modifications before I can start to put the mill back together.
    Like the three bolt modification. I bought three M10 by 75 mm coach bolts for this purpose but need to file the edges off the head to create flats on them. Now to find the template !

    Thanks Guys.
    Best Regards:
    Baron J.

  3. #3
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,434

    Default Three bolt mod !

    Hi Guys,

    I got a number of things sorted today. I've made a new washer for the top of the vertical leadscrew to replace the temporary spacer that I used so that I could adjust the gear mesh at the top of the column.

    21-02-2021-001.jpg 21-02-2021-002.jpg 21-02-2021-003.jpg

    I've also made a pin wrench so that I could tighten the top nut that locks together with the one below and sets the clearance on the thrust race. You can see the wrench laid below the support block in the first picture and sat on top in the second. The third picture shows the sleeve and brass washer under the support block.

    21-02-2021-004.JPG

    This picture shows the three modified coach bolts placed into the groove in the vertical slide.

    The next job is to find the template for drilling the milling head unit so these bolts fit through and support the head. I also need to mark out the position of the holes for the vertical scale read head. It will be a lot easier to drill and thread them with it off the machine.

    Thanks Guys.
    Best Regards:
    Baron J.

  4. #4
    Join Date
    Mar 2011
    Location
    Southern Flinders Ranges
    Posts
    1,536

    Default

    Nice work so far.

    I put my slides the other way around so the cables were fixed, and the swarf didn’t get into the scale. A picture of my Y axis attached for funsies..
    Attached Images Attached Images

  5. #5
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,434

    Thumbs up Head setting blocks !

    Hi Guys,

    I've done some more on the mill !

    Thre Bolt Hole Template.png

    But first a drawing for the three bolt hole modification. This is the template that I am using to set and drill the bolt hole positions in the back of the milling head.

    23-02-2021-005.jpg 23-02-2021-006.JPG

    I've also made the spacer that fits between the vertical slide and the scale read head. Ignore the extra hole, this item was cut from a piece of scrap 3 mm aluminium plate. The second picture shows the read head and the gear head, now that I've got it properly set up. The gears are very slightly rough but I think that it will bed in with use.

    A point worthy of note is that the vertical slide has a couple of grub screws that are used to set the amount of play in the nut that is used to raise and lower the head. Without the handle and winding gear the leadscrew can be rotated with your fingers and the play in the nut felt. Its a bit iterative between the grub screws and securing bolts but you can easily feel the difference when adjusting them.

    23-02-2021-001.JPG 23-02-2021-002.jpg 23-02-2021-003.jpg

    I have also made two blocks that are fastened to either side of the vertical slide and are used to assist in setting the tram of the mill head. If the head needs to be set at an angle either block can simply be moved out of the way. The other block being used to set the tram when resetting the mill head.

    The blocks are made from 10 mm thick bits of steel plate 30 X 20 mm in size and held with M6 cap screws.

    I've completely stripped the mill head down to sort one or two other minor problems, not least is the spindle bearings feel a little rough when rotating them by hand. I can't measure any play in the spindle, but since they are tapered bearings there shouldn't be any problem checking and cleaning them. Again the whole spindle is slathered in that thick brown stuff that they call grease. It is so thick that I had to press the spindle out by standing on the end. No wonder that the fine down feed gear teeth were suffering and wearing the shaft collar.

    More about those problems later.

    Thanks Guys.
    Best Regards:
    Baron J.

  6. #6
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,434

    Thumbs up Mill Head Refitted !

    Hi Guys,

    Well I've finally managed to complete the three hole modification and got it all refitted to the vertical slide.

    24-02-2021-001.JPG

    I marked out and spotted the hole positions on the back of the mill head. The round piece that you can see in the centre is just a piece of scrap bar that I used to create a centre point for a compass. It has dropped down when I laid the head on its bottom to take its picture. I turned a small boss on one side to fit into the hole at the back and put a dimple in the other side. Putting the compass point in that dimple enabled me to draw a circle, you can just make it out in the picture. Then using a protractor I centre punched the centres for the two additional holes.


    24-02-2021-002.JPG

    Drilling 12 mm holes by hand is not exactly an easy task. I drilled 4 mm diameter pilot holes right through first followed by 8 mm and then 12 mm diameter. The casting is 25 mm thick here. I used a piece of 25 mm thick scrap steel bar to make a drill guide in order to get the hole as square to the face as I could.

    Whilst I could get the head under the chuck of the drill press, there was no way to get a drill in the chuck, so it had to be by hand. But there is plenty of room to pass an M10 bolt through a 12 mm diameter hole.

    24-02-2021-003.JPG 24-02-2021-004.jpg

    The next issue was that the bolts were far too long, as it happened I could only get coach bolts 75 mm in length, 50 mm would have been ideal. So I put a nut and washer on one of the bolts and marked it so I could cut it to length.

    24-02-2021-005.jpg

    I parted the bolts off to length on the lathe. The picture shows how I used a piece of bar in the tailstock chuck to set the length. This way all three bolts are of Identical length. Also a lot less stress than hacksawing and filing to clean up the end.

    24-02-2021-006.jpg

    The end result ! Three perfect length bolts.

    24-02-2021-007.JPG 24-02-2021-008.JPG

    I put the tramming stops on the vertical slide to help support the mill head whilst I refitted it to the column.

    24-02-2021-010.jpg 24-02-2021-009.JPG

    The head now moves up and down the column smoothly and easily, which it didn't do before ! I also found that I could now adjust the tapered gib strip so that the head didn't move slightly when locking it. Before this exercise tightening the head locking clamps would move the head about 20 or 25 thou, completely ruining the tram. Now the clamps lock the head in a quarter of a turn and with less than 2 or 3 thou of movement.

    I also made new brass pins to go under the locking clamp screws. The amount of difference that all this work has made so far is surprising ! Everything feels better, more positive, makes me wonder why I didn’t do this earlier.

    Now to sort out the spindle bearings

    Thanks Guys.
    Best Regards:
    Baron J.

  7. #7
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,434

    Thumbs up "Y" Scale fitted !

    Hi Guys,

    I have now finished fitting the "Y" DRO scale to the base of my mill. I have just the splash shield to fit and the table to refit.

    01-03-2021-002.jpg 01-03-2021-001.jpg 01-03-2021-003.JPG

    Whilst I was sorting things, I've flattened the gib strip and refitted it ! I had to take a bit of a twist out of it as well. So getting it flat took quite some time. Afterwards I gave it a good fettling. No more burrs or sharp edges on it now. It also goes a fair bit further into the gap than it did and the difference in smoothness is marked.

    I've also replaced the two M4 cap screws that were in the leadscrew nut ! They were in the cavity under the mill, obviously vibrated out of the nut, they cannot have been very tight in the first place. They are used to adjust the backlash on the leadscrew nut. Once the nut is in place they are very difficult to get at to adjust them, being underneath the slide and at least 2 inches in from the rear of the slide.

    Anyway I have set the backlash to about 0.4 mm (nearer 0.6 mm according to the DRO readout.) Though remarkably the dial calibration is virtually dead nuts. Each turn being 2 mm, calibrated in half mm and 0.02 mm steps. I could have tightened the nut even more but I didn't want to cause the hand wheel to become hard to turn.

    I've just spotted that I've missed putting in a screw ! I'll sort that tomorrow.

    Thanks Guys.
    Best Regards:
    Baron J.

  8. #8
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,434

    Thumbs up Cutting a glass scale !

    Hi Guys,

    I don't remember if I mentioned that the long scale for the front of the table was about 5 inches too long and needed shortening. I vaguely recall someone say that there were videos on Utube showing how to cut one down. I did look and found several, all using different techniques. But the one that caught my eye was the one where the guy just stuck it in his bandsaw and chopped off to the length he wanted.

    Well I thought if it works for him...

    02-03-2021-001.jpg 02-03-2021-004.JPG

    After carefully marking the length I wanted, then stripping the ends off the aluminium frame and then very gingerly removing the read head, which is spring loaded against the glass scale, also removing the protective wipers. There were four of them, I stuffed a number of those blown wheat packing pellets down each side of the glass scale protecting it so it couldn't move or vibrate when being cut.

    I placed it in the bandsaw and proceeded to cut all the way through as can be seen in the second picture.

    02-03-2021-005.JPG

    This is what it looked like after cutting ! You can see the bits of shattered glass embedded in the stuffing.

    02-03-2021-007.jpg 02-03-2021-006.jpg

    I then cleaned up the end of the glass strip with a grinding stone in the Dremal. I expected this part to be much harder but it cleaned up nicely. Note: You have to set the glass back about a 1/4" inch so that it clears the moulding on the end cap.


    02-03-2021-003.JPG

    This is what it looked like after grinding the glass and drilling and threading four holes for M2 screws. To be absolutely honest, drilling and threading these four holes was the most nerve wreaking and difficult part of the job ! Even with lube the aluminium is a real pig to drill. Even with a new 1.6 mm drill, the aluminium got hot and snapped the drill. I used six drills to get those four holes. At my age holding a Dremal steady whilst drilling is not an easy task. On the other hand tapping using a tapping guide was quite straight forward.

    02-03-2021-008.jpg

    This picture shows the offcut off the scale after I had re-assembled it.

    Whoever said that cutting glass scales was easy, wasn't telling the whole truth !
    The manufacturers add the length of the read head to what ever length that you tell them ! So you end up with over long scales. Otherwise I am quite happy with what I've got.

    The other two scales even though they were over length fitted in place quite nicely. I'll take some more pictures as work progresses.

    Thanks Guys.
    Best Regards:
    Baron J.

  9. #9
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,434

    Thumbs up Refiting Mill Table !

    Hi Guys,

    After the tribulations of yesterday cutting the glass scale down to size, I started re-assembling the mill table and setting up the leadscrew.

    03-03-2021-004.jpg 03-03-2021-005.jpg

    But first a couple of pictures of the guts of the piece of glass scale that I cut off. In the first picture you are looking down into the scale onto the glass strip. The yellow pieces are the cut off ends of the four wipers that protect the scale from swarf and other debris. The second picture has turned out to become one of those optical illusions !

    The glass strip is laid down flat with the micro etched divisions in the middle and a metallized strip above and below it running from end to end. The scale reader runs on those metallized strips using tiny 2.25 mm diameter ball races, four of them. Two at the top and two at the bottom, being firmly pressed in place by a quite strong spring. This arrangement supports the optical readers. I'm not sure if there are just two or four infra red devices on a pair of tiny circuit boards.

    03-03-2021-001.jpg 03-03-2021-002.jpg 03-03-2021-003.jpg

    These are the pictures of the re-assembled table. You can see the finished "Y" scale in the first two pictures. The third picture is of the front of the "X" slide showing the two table lock screw holes and the scale fastened along the front of the table. Immediately below that is a wedge shaped groove that would normally carry the two table stops. It is this groove that I am going to use to carry the "X" scale, with the reader mounted and secured by the two M6 threaded holes directly above the hand wheel bracket.

    03-03-2021-006.jpg 03-03-2021-008.jpg
    03-03-2021-007.jpg 03-03-2021-009.jpg

    These last four pictures show the filed to shape 5 mm thick aluminium fastenings that locate in the slot under the numbered scale. The holes are tapped and threaded M6 and M4.

    I didn't have any short M6 grub screws so I made some using some off cuts from some M6 screws that I had previously shortened. I just put a hacksaw slot across the end for a flat bladed screwdriver. The M6 grub screws are used to secure the brackets supporting the glass scale. The glass scale is secured and mounted by a pair of M4 screws one at each end.

    I've still got various bits to make before I can call the scale fitted and finished.

    Thanks Guys.
    Best Regards:
    Baron J.

  10. #10
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,434

    Thumbs up "X" Scale fitted !

    Hi Guys,

    I've now got all the rest of the bits done and fitted the scale to the front of the mill bed.

    04-03-2021-001.JPG 04-03-2021-002.jpg 04-03-2021-003.JPG

    This first picture is the plate that is screwed onto the front of the "Y" slide and secures the read head to it. The two small holes in that plate are threaded M4 for the read head fastening screws as seen in the middle picture. The last picture shows the mounted display. The supplied protective cover for the display is a nice touch. Keeps greasy mitts off the buttons. Now to learn how to use it and find out what all those buttons do.

    Thanks Guys.
    Best Regards:
    Baron J.

  11. #11
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,434

    Thumbs up "Y" slide protector !

    Hi Guys,

    I've been doing a bit of playing about today ! I've made a sheet aluminium protector for the ways on the column and have yet to finish that, you can see it in the pictures. I've also made a new flexible cover to protect the "Y" leadscrew and extend over the "Y" glass scale, even though I have put the splash guard in place over it.

    IMG_0541.jpg IMG_0542.JPG

    I have used a piece of treadmill running belt for this cover. It is stiff and very robust. It is just bolted in place using the existing clamp plates and screws. You can also see the aluminium plate currently bolted to the bottom of the head slide. I'm going to put another piece of aluminium behind it so that it forms a full length guide protector. It has got to be better than the corrugated one originally fitted.

    I've also come across another issue ! One of the thrust races was missing on the inside of one of the table leadscrew guides. I didn't realise it until I came to replace my table traverse drive assembly. Anyway I have got a replacement on its way, I should have it on Monday.

    I also got the electric control box refitted and everything rewired, problem is the motor no longer runs...

    Turns out that the brushes on one side no longer make contact with the commutator ! So I am going to have to make some more new carbon brushes for it. The problem is that not only do the brushes wear fairly quickly because of the high spring pressure, but because the springs also have to carry the motor current, which causes them to get hot and collapse. This means that I have to replace the springs as well as the brushes this time around.

    The carbons in this motor are 3.6 mm thick, 10 mm wide and 15 mm long. The originals had copper pigtails. It seems that they are unobtainable. Certainly the dealers all want to sell you a new motor for an arm and both legs, no wonder that there are so many induction motor and drive belt project conversions around. The motors are still very expensive even from China.

    More to come !

    Thanks Guys.
    Best Regards:
    Baron J.

  12. #12
    Join Date
    Oct 2011
    Location
    Norwood-ish, Adelaide
    Age
    59
    Posts
    6,540

    Default

    Quote Originally Posted by BaronJ View Post
    The carbons in this motor are 3.6 mm thick, 10 mm wide and 15 mm long. The originals had copper pigtails. It seems that they are unobtainable.
    Is it worth visiting a power tool repair place and seeing if they have a similar brush? if it gets you a more secure supply of brushes, it might be worth making mods to fit them (or grinding the brushes down)

    Michael

  13. #13
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,434

    Thumbs up Carbon Brushes !

    Hi Michael G, Guys,

    Actually it was a motor re-winders that gave me some old carbon brushes that I'm currently making the replacements from. Not difficult, but very very messy ! Everything you touch gets black carbon all over it. It gets into your skin and is very difficult to wash off. I use a hand barrier cream before I start which helps.

    I'll take some pictures later !
    Best Regards:
    Baron J.

  14. #14
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,434

    Default

    Quote Originally Posted by BaronJ View Post
    Hi Michael G, Guys,

    Actually it was a motor re-winders that gave me some old carbon brushes that I'm currently making the replacements from. Not difficult, but very very messy ! Everything you touch gets black carbon all over it. It gets into your skin and is very difficult to wash off. I use a hand barrier cream before I start which helps.

    I'll take some pictures later !
    As Promised pictures:

    06-03-2021-001.jpg 06-03-2021-002.JPG
    These are pictures of the carbon brushes that I was given to make some new ones for my mill motor. I've placed a scale under them so you can get an idea of the size. The carbon brush on the right is the new one that I made and then cut in half to make a pair of new ones. You can see that I had to sand away just about half of the material thickness. That big brush is 32 mm wide.

    06-03-2021-007.JPG 06-03-2021-003.JPG
    This is all that was left of the old ones and the old springs. They are about 5 or 6 mm shorter than they should be.

    06-03-2021-006.JPG
    I have a brush carrier from another motor where the phenolic support had disintegrated from the heat. I've slid my new brush into it so you can see how it fits. The spade tag was bent over at 90 degrees, I've simply flattened it out.

    06-03-2021-005.JPG 06-03-2021-004.JPG
    Two more pictures of the brush carrier.

    If I can get hold of some suitable phenolic material, I'll make some new insulators and repair the old motor.

    This by the way illustrates the major failure of these mill motors ! The push on fix tag becomes loose for various reasons. Getting hot is the main one. The motor current then causing heating and destroying the insulation of the brush carrier support, as happened with the original motor. The vendor replaced the motor but didn't want the old one back.
    Best Regards:
    Baron J.

  15. #15
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,434

    Thumbs up DRO Instalation finished,

    Hi Guys,

    Just to wrap this thread up, I've now finished the DRO installation and got the mill back up and running. The last job was to tram the mill head and re-check everything.

    14-03-2021-001.jpg

    Here is a picture of the final tram adjustment ! It stays within half a thou now when moving the head up and down also the quill. The head moves 2 thou when you tighten the head locks, much much better than the 20 plus thou that it moved before. You can also see the splash plates that I used to replace the bellows that were there originally, and the new protector over the "Y" slide.

    I have only one issue that I cannot do anything about, and that is the mill vise. Its back on the table and clamped down, but I've discovered that whilst the top and the ways are dead square to the table, the rear jaw is 5 thou smaller at the bottom on one side and 11 thou smaller at the other side. The back of the rear jaw is a mirror of the front. The top edge is within a thou of being parallel with the table.

    It is supposed to be a precision vise, being fully ground and hardened all over. Apart from buying a new vise I'm not sure what I can do with this.

    Anyway thanks Guys.
    Best Regards:
    Baron J.

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