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  1. #49
    Join Date
    May 2004

    Encoder circuits, ELS etc


    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

  2. #50
    Join Date
    May 2004

    Stepper Power supply


    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  

  3. #51
    Join Date
    May 2004

    Cross slide limit switch.


    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  

  4. #52
    Join Date
    May 2004

    cross slide limit switch second part


    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  

  5. #53
    Gold Member
    Join Date
    Nov 2005
    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)

  6. #54
    Join Date
    May 2004

    Thanks 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

  7. #55
    Join Date
    May 2004

    Cross slide stepper


    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  


  8. #56
    Join Date
    May 2004

    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
    • File Type: 2 (97.2 KB, 89 views)
    • File Type: tilt15 (86.6 KB, 80 views)

  9. #57
    Join Date
    Jan 2006
    mattinker some very nice work you are have done and well detailed log

    keep up the great work


  10. #58
    Join Date
    May 2004



    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

  11. #59
    Join Date
    Jul 2008
    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?

  12. #60
    Join Date
    May 2004

    Trueing chuck jaws


    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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