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  1. #41
    Join Date
    May 2004
    Posts
    100

    Fixing plates for the lead-screw stepper and the encoder.

    Hi,

    the next step is to be able to attach the lead-screw stepper and the encoder. I could use Al plates to do this, which would be more "sexy", but I happen to have some 8 mm plate, a little rusty on the surface, which I like to work with. I enjoy steel fabrication, I learnt a long time ago in a quarry in Wales using an oxy-acetylene cutting torch and an ark welder. One of the things that I'd like to show in this build up is that there are other alternatives, not that I have anything against machined alloy plates, just that other things can work as well. One of the things that is important to me is to keep the lathe working, to build it's self. I have taken of the lead-screw drive mechanism and replaced it with a stepped steel plate.

    Photo.1 Bare bones, where the drive gears used to be.
    Photo.2 & 3 Stepped steel plates welded together and bolted on using two existing bolts and a locating dowel, not yet visible, I also added two M10 studs, nuts and spring washer to strengthen the mounting.
    Photo. 4 Turning a shoulder on the lead-screw spacer to take the drive belt wheel. It was really nice to turn, not like the hot rolled I use a lot!
    Photo. 5 Spacer in place on the lead-screw(I haven't fixed it yet)
    Photo.6 Drilling out the toothed wheel, 30mm bit!
    Photo. 7 Boring out to 36mm, to fit the spacer on the lead-screw.
    Photo.8 The other side of the wheel, recessing to allow both nuts to resume their original position on the lead- screw.
    Photo.9 & 10 Cutting out the motor mount.
    Photo. 11 Drilling the motor mount.
    Photo. 12 Today's mistake, I had planned to mount the plate horizontally, but, as I'm improvising to a large extent, I hadn't realised that the belt would not clear the mounting posts. So, cut off two corners and drilled two new holes to make it work! This might not be very clear, but in the next episode, all will become clear.


    Matthew
    Attached Thumbnails Attached Thumbnails bareiron.jpg   mount1.jpg   mount2.jpg   turningspacer.jpg  

    spacerturned.jpg   drillingtothedwheel.jpg   boreingtoothedwheel.jpg   nutrecesse.jpg  

    cut1.jpg   cut2.jpg   motormount.1.jpg   motormount2.jpg  


  2. #42
    Join Date
    May 2004
    Posts
    100

    Blunder fix!

    Hi,

    just a word to complete yesterdays post, I had enough time to make one of the four fixing posts for the 495 oz/in stepper that I hope is going to be adequate for my lead-screw. The mounting plate is held on with a "G" clamp, it's not quite in it's place, but it shows how it works, and why I had to rotate the plate 45° so that the motor mounts posts wouldn't foul the belt!

    Regards, Matthew
    Attached Thumbnails Attached Thumbnails blunderfix.jpg  

  3. #43
    Join Date
    May 2004
    Posts
    100

    Mounting posts and fixing plate.

    Me again,

    well, I have a lot of pics today, maybe I'm going into too much basic detail? I notice that people keep reading my entries, but I'm not getting any feed-back, so I don't know where I'm going.

    Today I carried on from where I left off! First of all I made the three remaining mounting posts and then I placed the mount, drilled and tapped the support plate and bolted the whole thing together.

    1. I chucked up a piece of very ordinary hot rolled steel bar, roughly 16mm in diameter, it's oval, so I turned it down until it was round, and about 15mm diameter. It isn't critical, so I wasn't very precise!
    2. I centre drilled it to start the through hole.
    3. The next step was to drill it through, more than 36mm,deep 4,2 mm, the threading diameter for an M5 (5mm) thread.
    4. Step four was to drill out to 8,5mm, tapping size for an M10 (10mm)thread, to a depth of 25mm, long enough for the countersunk fixing bolts.
    5. The M10 tap is chucked up in the tail-stock and the thread is begun manually, turning the four jaw by hand, ensuring a straight thread.
    6. To continue tapping, I transferred the tap to a tap wrench, leaving the piece in the four jaw.
    7. I forgot to photograph the parting cut! So the photo is an "after" shot. I had measured of 36mm and cut of the post.
    8. I threaded the M5 side by hand in the vice. The tap wrench is one of the first things I made on my shaper, it's a simple design that I would recommend, the plan came from the late Art Volz on the metal shapers yahoo group.
    9. The finished object.
    10. Having made four posts, I clamped the assembly into place to mark the mounting holes. I could only access two of the four holes with the motor in place. I drilled through the plate with a 6,75mm bit, to mark it to place the first two bolts.
    11. Once the first two threads were drilled and tapped, I could bolt the plate in place to mark drill and thread the other two holes
    12. Having marked the remaining holes I preceded to drill the 6,75mm holes to 8mm to accept the bolts.
    13. In this photo, I'm using the plate as a guide to thread the backplate holes.
    14. This is a view of the part that you can't normally see! Just to show how it went together.
    The last three pictures are self explanatory!

    I hope that this is of some use to somebody!

    Matthew
    Attached Thumbnails Attached Thumbnails 6roughingout.jpg   7centrebore.jpg   8throudrill.jpg   9-10mmtapping.jpg  

    10startthred.jpg   11handtap.jpg   12partoff.jpg   13handtap2.jpg  

    14finishedpost.jpg   1positioned.jpg   2markout.jpg   3drillout8mm.jpg  

    4guidedtap.jpg   5asembledmount.jpg   fin1.jpg   fin2.jpg  

    fin3.jpg  

  4. #44
    Join Date
    May 2004
    Posts
    100

    keying the lead-screw drive.

    Hi!

    in the original set up, the gears drove the lead-screw through the spline. The transporter that brought the lathe over the channel to me, was kind enough to bend the splined end of the lead-screw. I decided that it would be easier to use the spacer to drive the screw. I managed to straighten the lead-screw with a steel pipe and my body weight! I ended up wit 1/10mm, 0,004" of run out at the toothed wheel, which I deemed acceptable! The splined bit is about as straight as a dog back leg! The spacer had a key way in it that a grub screw keyed to the shaft. As a spacer, it didn't have much load on it, so the screw threads were adequate. I was afraid that the threads would wear, developing back lash. I had the choice between a shouldered screw and cutting a key way in the lead-screw. The shouldered screw was easiest! As I'm doing this to have threading on my lathe, I had to start with an existing thread, in the land of metric threads, whitworth is not very common! I retrieved a couple of slightly bent bolts from the gear cover that need. Too bent to chuck up, I filed the head round and sawed it to length.

    i. The first photo is of the original grub screw, which would have been threads against the key-way, with "built in" back-lash.
    ii. Photo N°2 just show the key-way in the spacer.
    iii. N°3, the two grub screws side by side, difficult to photograph, the screw on the right was the one I made, it has a thread free 2mm that is filed to fit the key-way with no play.
    iiii. The shouldered screw in place.
    v. The next to last picture shows shows the toothed wheel/spacer covering half of the key screw.
    vi. Finally, the two lock-nuts that adjust the end float on the lead screw. there are two steel spacers, one each side of the cast iron lug that carries the lead screw. The key-way allows adjustment.
    Attached Thumbnails Attached Thumbnails grubscrew.jpg   cogkey.jpg   grubs.jpg   key screw.jpg  

    keycog.jpg   loknuts.jpg  

  5. #45
    Join Date
    May 2004
    Posts
    100

    finishing the leadscrew timing belt gear.

    Hi,

    just a small post, I've been earning my living, it takes time!

    I wanted to finish off the lead-screw drive, there wasn't much to do, but, it wasn't done!

    I had managed to reduce the run out on the timing belt gear to 0,1mm, / 0,004", which I deemed acceptable. The thing that remains to be done is to bolt the gear to the spacer, completing the drive.

    1. Drill to 3,2mm, tapping size for 4mm metric thread.
    2. Tap 4mm, I don't know where I put my tap wrench, so I did it with an adjustable spanner, not something that I like! I know that the tap wrench will turn up now that I don't need it!
    3. Three 4mm blots with spring washers to keep things in place. I tapped each hole and bolted it as I went, so that everything fitted without alignment problems.
    I didn't use a clearing bit, the thread starts in the Al and ends in the Fe, no play!
    4. The last pic is of the finished drive.

    I noticed that the thread has gone over the 5200 hits mark! Wow

    Regards, Matthew
    Attached Thumbnails Attached Thumbnails drill3,2mm.jpg   tap4mm.jpg   4mmbolts.jpg   inplace.jpg  


  6. #46
    Join Date
    May 2004
    Posts
    100

    encoder mount

    Hi!

    As the title indicates, to-days offering is the encoder mount. The first picture is the mount held in position with a "G" clamps just to give the idea of where I'm going. I decided to "carve" out a curved shape on the lathe, not the quickest solution, but I liked the idea of doing it this way!

    2. Two pieces of 10mm X 100mm plate, one is the support, the other is the part it's self.

    3&4 clamping and welding the two pieces together.

    5&6 Mounted in the four-jaw, (a great investment, 250mm/10" four jaw, I use little else, face plate occasionally!) beginning the outer radius. Sorry about the focus in 6, I didn't realise it was so bad, too late to go back to it now! the inner radius, from the edge of work piece to the centre of the lathe's axis is equal to the radius of the disk plus clearance for the tallest opto/interupter on it's spacer.

    7. "Carving" the outer radius.

    8. "Carving" the inner radius.

    9. Finished profile, I made the curved part 30mm wide, the thickness was arbitrarily determined by what was left after both sides had been machined over their whole surface.

    10. The angled plate is drilled to 14mm at the point which was the axis on the lathe. I drilled my home-made 90° angle plate to 14mm and bolted the two together. (The bolt head can be seen between the two "G" clamps.)

    11&12. This is where I start making mistakes! I mis-calculated the position of the tool in relation to the work, I was working with a 2mm end mil to make 3mm slots, it would have been better to wait and but a 3mm end mill. I should write everything down when machining, maybe I'd make fewer mistakes. It didn't matter, but it was annoying!

    13. Another mistake, I used a 1/2", 12,7mm bit to drill the hole to start the slot through which the encoder wires will pass, it wasn't too wide for the centre encoder, as I slotted the holes in such a way as to be able to adjust the encoder nearer or farther from it's pair. not serious, just not enough fore-thought.

    13&14. I clamped a steel rule to allow me to tilt the piece, the 14mm bolt and the two "G" clamps are slackened, and the piece is tilted on it's axis to move into the next working position.

    15&16. The result of my mistake! In the centre holes, rather than being elongated holes, they're sort of square shaped! In 16, you can see the 0,7mm too much in the centre hole, and on the right, a mark from when I got my up/down mixed up! I nearly destroyed the piece, well, I've only had this machine three months, haven't used it much yet!

    17&18. During the winter in a period of insomnia, I made the circuit in the photos, not very pretty, but I'm a debutant!

    In the first picture, you can see the holes on the edge of the wheel and their relationship with the top two captors. Their are 100 holes, 2mm in diameter, with a 2mm space between each one. To enable EMC2 to distinguish which way the spindle is turning, these two captors have to be out of phase by a quarter of a cycle, 90°, this is why I made the centre slot to allow adjustment, when correctly adjusted, there will be a half hole difference between the two captors. I was told on the EMC forum here, that the difference could be from 90 to 120° (my apologies, I don't remember who told me!) so there's some lee-way. As you can see, it isn't quite right yet, but as this is only held on with a couple of "G" clamps, I wasn't going to spend time adjusting it for nothing!

    The third captor is for the one per revolution "tick", it is mounted on 2mm spacers to make it line up with the single slot in the wheel. Ooops the slot isn't visible! I'll correct this in the next episode!

    I hope I'm not too vague, remember, I'm not a machinist, most of my set-ups I invent as I go, learning all the time!.

    Regards, Matthew
    Attached Thumbnails Attached Thumbnails encoderstart.jpg   encodermount1.jpg   encodermount2.jpg   encodermount5.jpg  

    encodermount7.jpg   encodermount8.jpg   encodermount10.jpg   encodermount12.jpg  

    encodermount13.jpg   encodermount14.jpg   encodermount15.jpg   encodermount17.jpg  

    encodermount20.jpg   encodermount21.jpg   encodermount23.jpg   encodermount25.jpg  


  7. #47
    Join Date
    May 2004
    Posts
    100

    Encoder box and wireing.

    Hi,

    it's been a while, I've been earning my living!

    The encoder needs to go in something to make it a bit "clout-proof" and swarf free! So, here goes;

    1. Having drawn out the shape on a piece of 1,5mm plate, that was a little thicker than necessary I cut it out with a cold chisel in the vice. (three days later, somebody left me a 2 square meter piece of Al 1mm thick which would have been better, but it was already finished!)

    2. Here I'm in the process of cutting the plate. The piece is held in the vice along the line to be cut, the chisel is flat on the plate. Don't try to cut in one go, first of all, mark with the chisel, over all the lines, go back to where you started and hit again, repeat this until the piece it cut. obviously you have to move the part in the vice to make all of the cuts!

    3. The cut out part. Note the 3mm holes in tne inside corners, this makes it easier to cut out and to fold.

    4. If you have one of these folding machines, a pan break, it makes it very easy to fold the box. You can do the same thing in a vice.

    5. The first fold is straight forward.

    6. As my brakes doesn't have "fingers" I use an off-cut of I beam to allow the second and third fold. this technique is exactly the same as using a vice and a hammer to fold the box. The brake is actually a very long vice with a hinged beam to fold the piece.

    7. The folded box next to the encoder.

    8. The encoder, wired and nearly ready to be installed. I need to make a heat sink and drill the end plate to take the grommets for the power supply the Index and the quadrature outputs.

    I drilled the box and tapped four threads into the mounting plate. The advantage of the heavy mounting plate is that you can tap and thread all the fixing bolts. The disadvantage is that if you break a tap on the last thread, you can be in real trouble. I've been tapping threads since I was a kid in school, I don't very often break taps, but I broke this one! It was broken bellow the surface! I ended up cranking up my arc-welder, 100 amps with a 2,5mm rod building up weld onto the tap, nice and red, when it was cool, I was able to re-drill through the softened piece of tap, fortunately it wasn't too long! Ouf! As you can imagine, I was a long way from thinking about taking photos!

    All the steel bits have been brush painted black with some eggshell enamel that I happened to have. I'm not too worried about the finish, if it's not oil resistant, at least it won't rust! Things don't rust too much in my work-shop, since I've nearly finished my roof, only one flood zone left, a long way from the lathe! I hope to re-assemble all this soon and move on to the limit switches E-stop and the supply to the cross slide stepper!

    Regards, Matthew
    Attached Thumbnails Attached Thumbnails cutout.jpg   cutout2.jpg   cutout3.jpg   folding1.jpg  

    folding2.jpg   folding3.jpg   folding4.jpg   opto-interupteurs1.jpg  


  8. #48
    Join Date
    May 2004
    Posts
    100

    Halfnut surprise

    Hi!

    this morning, I'm grinning from ear to ear! I had a really nice surprise when I took the half-nut out of it's hiding place in the carriage. I'd been mulling over for some time how I would go about replacing the half-nut. When I tested the drag on my carriage, my my results went from more than reasonable with a small amount of backlash to nearly locking up when I pushed that last little bit that took out the backlash. Well, I should have taken it apart sooner, the first photo shows the swarf stuck in the threads (fourth from the right!) and the second the piece of swarf I removed!! The locking up has gone and it's practically backlash free!

    A great start to the w/end!

    Regards, Matthew
    Attached Thumbnails Attached Thumbnails halfnutswarf1.jpg   halfutswarf2.jpg  

  9. #49
    Join Date
    May 2004
    Posts
    100

    Encoder circuits, ELS etc

    Hi

    I'm back from a ten day spell in hospital, nothing serious, I'm now minus my appendix, I had peritonitis to go with it, but all seems well now!

    Here are a few links that apply to the ELS. Although I'm making my lathe CNCable, the principal source of control will be the ELS
    John Dammeyer has designed the Electronic Lead-Screw
    Autoartisans ELS

    John has also started a Forum here on the zone:

    CNCZone ELS Forum

    This is the original ELS forum
    Yahoo ELS group

    The .pdf below is the circuit that I used for my encoder circuits. It's from John's site, I suspect that if it doesn't work it's my fault! The ELS doesn't need the quadrature encoder, just one pulse per revolution.

    I've started work on the cross slide limit switche, but I haven't done enough to start writing it up yet. I hope to be a bit more active in a couple of days! I'm itching to get back to it.

    Regards, Matthew
    Attached Files Attached Files

  10. #50
    Join Date
    May 2004
    Posts
    100

    Stepper Power supply

    Hi,

    as I'm convalescent, I have changed my plans a little, I've decided that I can put together the stepper power supply as it doesn't require much workshop work.

    The first image is the piece of Al that is going to be the mounting plate for the power supply components. I've cut it out roughly with tin snips, that's why the edges are a bit raged, as it's Al that won't take much to clean up with a special Al file, really worth having, it has large teeth that don't clog easily.

    In the second photo, I've cut strips down the long edges which are going to be the fixings for the condensers. I realise that I've forgotten to photograph the plate once folded!

    The third photo shows the components in place but un-fixed. The edges have been folded up which makes the base more rigid, less likely to vibrate, this also means that the strips that are going to hold the condensers are now in the right position to encircle them.

    The fourth image shows everything in place and wired up. The transformer is a 26volt 150 va it also has an 8,5 volt winding that I won't be using. I chose a 26 volt transformer as when rectified with a diode bridge, it will give a theoretical 36,4 volts which is just below the 40 volt maximum of my stepper drivers. I doubled up on the diode bridge (I picked up a bag of 25 very cheaply) they are rated at 6 amps, which is close to the maximum output of my transformer. I used two condensers in parallel as I couldn't find one that was off the right specifications. I discovered that these condensers are to be connected with specific polarity. I noticed that there was a positive symbol on the diagram. A web search revealed that the negative connection is marked. Strange! The arrow and minus symbol are visible in the photo, the black wire is soldered to the negative terminal. I found the information necessary to make the component calculations and the wiring diagram on the "Gecko" website.

    The final photo is the power supply working, 37,5 volts on the volt meter, this will drop under load, but should be OK.

    Regards, Matthew
    Attached Thumbnails Attached Thumbnails powersupply1.jpg   powersupply2.jpg   powersupply3.jpg   powersupply5.jpg  

    powersupply4.jpg  

  11. #51
    Join Date
    May 2004
    Posts
    100

    Cross slide limit switch.

    Hi,

    well, I'm getting a bit more active now, so it's time to start the
    cross slide limit switch write up.

    I was going to write this as one piece, but it seems like a lot of photos so it'll be in two halves. Another episode tomorrow!

    As an electrician, I am in favour of single limit switches where feasible as, the fewer the breaks in the line the better. Limit switches are wired normally closed, any break in the circuit makes the "Emergency" stop work. A nice little advantage is that one switch costs less!

    My Colchester had a chip guard on the back of the cross slide (photo 1) all that remains is a rather solitary fixing screw. It's an absolute chip trap that is a real pain to clean. So to "kill" two birds with one stone, I'm making a chip guard that will as will have the adjustable stops for the limit switch.

    Photo2, this is the end result without paint.

    Pic. 3 is the plate that I used to make the box for the limit switch. It's 1,5mm thick which makes it more than strong enough to mount the switch. As usual, I drilled holes where the corners will be to make it easier to bend.

    In the fourth photo you can see the fixing bolts that I welded to the box.

    The fifth photo shows the mounting bolts with their spacers. The switch is fixed in upside-down, which is why I need the spacers this means that the lever is at the top, it would have worked the other way up, but the mechanism would have been more vulnerable.

    In the sixth picture I am tapping one of the two fixing threads for the switch box. I really enjoy tapping cast iron like that, it cuts well and you "feel" easily when you've come to the bottom of the hole.

    7 & 8 are of the box bolted to the carriage. The head of the trip post bolt was cot off at a height that will clear the inside of the cross feed screw cover.
    Attached Thumbnails Attached Thumbnails unprotected lead:s.jpg   finalook1.jpg   limitboxplate.jpg   limitbox2.jpg  

    limitbox5.jpg   tap1.jpg   limitbox6.jpg   limitbox7.jpg  


  12. #52
    Join Date
    May 2004
    Posts
    100

    cross slide limit switch second part

    Hi,

    here is the second part of the cross slide limit switch. It's fairly difficult to describe as it's well covered by the cross slide screw cover which carries the adjustable fingers that operate the limit switch.

    The first image is the 1,5mm plate cut out ready to be folded, as usual, I've drilled holes in the corners to make it easier to fold.

    Number two is the cover folded.

    Photo three, I welded the corners as I did on the switch box, again to keep out suds and chips.

    Image number four, tapping the end of the cross slide, I used the existing tapped holes, as I didn't have the appropriate Whitworth screws, I drilled them out to 5mm and tapped to 6mm.

    In number five, the cover is clamped in position and a strip of 1,5mm plate is bolted to the cross slide. The the two are tack welded together.

    The sixth image is of the cover, welded together, I was too lazy to get out the MIG, it's only 1,5mm. OK MIG would have been prettier!

    With the cover "G" clamped in place, I drilled and tapped two more 5mm fixing holes.

    Image number eight is the end of one of the two adjustable fingers that will trip the limit switch. Two six centimetre lengths of 10mm X 15 mm CRS (it could have been anything, hot rolled mild steel, brass, Al! I just happened to have that)are drilled 8mm through the 15mm side, the other way is drilled 5mm to be threaded M6, I milled a 3mm step in the end as the bolts that I had have only 10mm of thread. The stepped side is drilled out to 6mm. Finally I cut a slot using two blades side by side in my hacksaw to give a 2mm slot.

    Photo number nine is of the two fingers on their 8mm rail prior to welding the rail in place.

    In number ten, I've welded the rail in place. I was pleased that I didn't do any more than tack it and try it as I had to reposition it.

    The last three photos are X+ limit, X in between an X-limit.

    All this will be painted.

    I will cover wiring later.

    Regards, Matthew
    Attached Thumbnails Attached Thumbnails limitcross.jpg   screwcovr.jpg   srewcovr2.jpg   tapslide2.jpg  

    coverfixing2.jpg   covweld.jpg   tappingcover1.jpg   limitfinger3.jpg  

    fingerail.jpg   fingerail2.jpg   limitwork1.jpg   limitwork2.jpg  

    limitwork3.jpg  

  13. #53
    Join Date
    Nov 2005
    Posts
    440
    Matt,keep up the good work, you will enjoy your CNC lathe more that you could imagine...Just asking, you mention the "Y" axis, ..actually a lathe has an X axis (cross) and a Z axis (long)..the easy way to remeber is picture a lathe turned up so that the chuck end is up top, as the X axis moves up and down in relation to the chuck you have "-Z" towards the chuck ,"+ Z" is towards the tail stock. "- X" brings the cutting tool away from center ( towards the operator,conventional lathe ) and "+X towards the material being cut( away from the operator, conventional lathe), I'm sure that some turning centers (cutter is behind the materal, rotation of chuck (c axis) is clockwise ) have a Y axis, which moves the tool up (towards the sky) or down. Some examples of a lathe that have multiable axis is a swiss lathe..

    All of the above is only importat if your using a cad/cam program, then you may have tooling going places you did not want .

    Again keep the pictures comming, we all enjoy !

    Adobe (older than dirt)

  14. #54
    Join Date
    May 2004
    Posts
    100

    Thanks Adobe!

    Adobe,

    thanks for your reply, I've corrected my mistake. I have a very good memory for a lot of things, maybe this time it will stick. I'm just begining to get it right on my milling machine, thanks to the DRO. I have a note to myself on my desk with the axes written on it, it say also "except lathe where Z is horizontal" Z I've got because it's driven. I'll make myself another note!

    Thanks for the encouragement, coming from you, I'm touched!

    Thanks, Matthew

  15. #55
    Join Date
    May 2004
    Posts
    100

    Cross slide stepper

    Hi,

    if there are too many photos, it's Adobe's fault, he said to

    "keep the pictures coming!"

    So here we go! I had already bought the 24 and 48 toothed pulleys and belt some time ago on a that should do it basis.

    Photo 1, the pulleys and belt, screwed to a piece of ply with a sheet of paper under it to allow me to get the dimensions un-mathematically!

    The second photo is the drawing that resulted from the information gained. The stepper motor emplacement is turned so that the belt clears (nearly! more of that later) the mounting posts, experience gained from the lead-screw stepper mount.

    The third image shows the paper cut around the line I drew 15mm outside the the final form of the mounting plate, this is the "cutter radius" of the plasma cutter. I transferred the shape to a piece of scrap ply.

    Number four shows the plywood cut out with the paper inside, not very orthodox, but I used the paper to to mark the hole centres with a centre punch. I checked it over afterwards, it was much more accurate than I thought it would be.

    Photo number five is the plate cut out with the plasma cutter, 10mm hot rolled scrap.

    The sixth image is of my 50mm bit (won on eBay), the first time that I've used it. I set the down feed at it's lowest, and the cutting speed at it's lowest, I didn't really think about it, off it went happily drilling a 50mm hole, well hidden by suds oil. I didn't realise that it wasn't cutting fast enough for the down feed, despite the well tightened bolts, the universal head, started turning, making my hole slightly at an angle. Lesson well learnt, check cutting speeds and feeds! The plate was not ruined, it just had a slightly eccentric hole!

    Seven shows the plate, cut off roughly horizontally held in place with a cramp to see how it looks. You can't see it from the photo, but there are a few obstacles that stop it sitting flat. I'm going to have to "pocket" the back of the plate.

    In eight, the plate is drilled and countersunk (from behind). These take the four 10mm countersunk head Allen screws that hold the posts in place.

    Nine, ten and eleven show how I milled pockets in the back of the plate so that the fixing bolts would hold at right angles to the cross slide screw.

    Photo number twelve is just before I break the 9mm mill that I had happily slotted the plate, proud of myself for having set the limit switches so that all I had to do was X left, X right, down-feed over and over until my slot was finished. I then screwed up and did a rapid on the Y feed instead of the Z and snapped the mill!

    The thirteenth image shows the damage to the slot, not enough to stop me using it, but what a dumb thing to do on the last operation!

    Fourteen, I drilled and tapped two holes in the carriage to bolt the plate to. My mistakes don't even show!

    Photo numbers fifteen, sixteen and seventeen are of me milling the tops of the stepper mounting posts to level them. I made them the same way as the ones I made for the lead-screw so I didn't document it.

    In the second photo title, I talked about placing the posts in such a way as to clear the belt. Well, I nearly got it right! In the eighteenth photo, I'm milling a flat in one of the posts, so that it will clear the belt!

    The last three pictures are of the finished thing, apart from paint!


    Regards, Matthew
    Attached Thumbnails Attached Thumbnails crossdrive1.jpg   crossdrive2.jpg   plyguide1.jpg   plyguide2.jpg  

    plyplasma.jpg   50mmbit.jpg   plate2.jpg   plate3.jpg  

    plate4.jpg   plate6.jpg   plate8.jpg   plate9.jpg  

    plate10.jpg   plate11.jpg   post1.jpg   post2.jpg  

    post3.jpg   post4.jpg   mount1.jpg   mount2.jpg  

    mount3.jpg  

  16. #56
    Join Date
    May 2004
    Posts
    100

    Z limit switch.

    Hi all,

    I wish I could just title the photos, it would be so much easier to both read and write! Lots of pics this time, maybe I should have done it in two posts.

    The limit switch it's self came from a my stock of accumulated bits and pieces. It's a good quality "Legrand" switch. OK, here goes:-

    1 The finished limit switch with adjustable stops, not very clear, I should have put a sheet up behind!

    2 &3 I blued up the 1,5mm plate marked out, cut out and drilled.

    4,5 & 6 The "Z" bend in the plat gives rigidity and makes a protective box at the same time.

    7 & 8 "G" clamped in position, I marked the first fixing hole with a 6mm bit, drilled 5mm tapping size for 6mm and bolted in place.

    9 shows how the mounting bracket also protects the switch from swarf.

    10 & 11 2°45' is the angle of the casting draught used on the bed of my lathe. The spacers are being milled to compensate. It wouldn't really matter if the rail wasn't square, but as I was going to mill the four spacers to the same length, I compensated. (more later)

    12 & 13, After drilling and counter sinking, I clamped the hot rolled 30mm X 5mm flat to the bed. I used two spacers so that the rail was parallel with the bed. The bed was marked with an 8mm bit through the holes and then drilled and tapped to take 8mm X 35mm countersunk head set screws.

    14, 15 & 16 With the rail in place, the is an approximately 2mm space under the roller.

    17 An end view of the rail, not very clear, I was trying to show the compensation for the draught angle. I'm not sure how useful this picture is!

    18 Is the rough drawing that I made the "stop wedges" from.

    19 & 20 Two pieces of slightly rusted cold rolled steel, I welded them together to make sure they didn't move. The side is blued and the incline drawn on.

    21 I swung the head to 15° to cut the "stop wedges" slope.

    22, 23 & 24 Three photos of milling the wedges, I could have cut these out with a cut off wheel, would probably have been quicker! I learn something each time I use my mill, so it was a good exercise.

    25, 26,27 & 28 Clamping together the "bits" that go together to make the "stop wedges". Welded together and then ground flat to make them presentable!

    29 Tapping the m6 thread for the locking screw.

    30 I used two blades in the hacksaw to cut a groove in the end of some 6mm threaded bar to turn it into a "wing" bolt.

    31 A piece of plate in place, the wing of the wing bolt.

    32 A spot of weld each side, not very pretty, nothing that a lick of paint won't hide!

    33 & 34 The "stop wedges" on their rail. I had thought that I could use the normally open side of the limit switch to make a setting light, but it won't be necessary as the "click" is quite audible. There is a 2mm gap between the roller and the rail, the switch is actuated when the roller is lifted 2,5mm by the wedge. The maximum stroke of the limit switch is 15mm so it can't lock if it goes over the limit for any reason. As this is a wedge set up, the structure does not need precision construction to have very acurate results in use.

    Regards, Matthew
    Attached Thumbnails Attached Thumbnails zfin.jpg   layout.jpg   layoutcutanddrill.jpg   Zswitch2.jpg  

    Zswitch1.jpg   Zswitch3.jpg   zmount1.jpg   Zmount2.jpg  

    Zmount3.jpg   spacer.jpg   Zrail1.jpg   Zrail2.jpg  

    Zrail3.jpg   Zrail5.jpg   Zrail7.jpg   Zrail6.jpg  

    drawn.jpg   CRSweld.1jpg.jpg   bleuewedge1.jpg   cuttingzedge1.jpg  

    cuttingwedge2.jpg   cuttingwedge3.jpg   weld1.jpg   weld2.jpg  

    weld3.jpg   ground.1jpg.jpg   tap1.jpg   doubleblade.jpg  

    wing.jpg   wingweld.jpg   1stop.jpg   2stops.jpg  

    Attached Files Attached Files
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    • File Type: tilt15 (86.6 KB, 80 views)

  17. #57
    Join Date
    Jan 2006
    Posts
    481
    mattinker some very nice work you are have done and well detailed log

    keep up the great work


    cheers

  18. #58
    Join Date
    May 2004
    Posts
    100

    Thanks!

    FPV_GTp

    Thanks for the encouragement! I realised that when I read other peoples logs, I rarely responded! Now I realise to what an extent response is positive!!

    It's hard to tell if one is comprehensible, whether there are too many or not enough pics etc. Some 500 people looked at my log in two weeks, makes me think that it's worth while.

    Regards, Matthew

  19. #59
    Join Date
    Jul 2008
    Posts
    411
    Matt, I am impressed with what you are doing...

    Well I plan to CNC (eventually) my 1924 Relmac lathe for which I have a full set of change wheels etc, and a remotely controlled VFD drive. The juxtaposition of new and old is something special I think.

    I've been reading the ELS stuff and that all looks pretty straightforward, indeed I'd worked most of it out already myself (my background is software/electronics)

    Now, I read earlier that you sorted the chuck out by grinding it from the toolholder with a small grinding tool. I'd love to get more info on how you did that, and how you lined up the grinder with the chuck etc. The jaws on the chuck on my lathe are in a sorry state, to the point that it cant hold a piece of round stock cleanly. While replacing the chuck is an option the backplate is non-standard and I would need to be able to make another with the unusual spindle thread (1.25 x 12tpi) which I have no way to do at the moment. So regrinding the jaws in situ is an interesting option....

    edit: found this article, is this how you did it?

  20. #60
    Join Date
    May 2004
    Posts
    100

    Trueing chuck jaws

    Irving,

    whilst you were editing your post, I was taking a couple of picks of my chuck and the "shims" that I'd used for my chuck! The first one is with the shims in machining position, and the second is with the shims moved out to enable the grind stone to "clear". I haven't read the article you found, it's not the same as the one I followed. I was not very pleased with the results, it was better, but as the scroll wear was uneven, it was only good in some places! It's worth trying! I bought a 10" four jaw not long afterwards, I use it for most things.

    Let me know how you got on.

    Regards, Matthew

    PS. I just read the article, it's all there!
    Attached Thumbnails Attached Thumbnails chuck1.jpg   chuck2.jpg  

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