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  1. #371
    Cheers Lee, I'll have a look at that!
    Neil...

    Build log...here

  2. #372
    Finished off the last of the cleaning up of the epoxy this afternoon.

    Worked out how I'm going to get the rails square. We have a 24" Mitoyo caliper which just happens to be the correct length for the spacing of the rails. I've drilled and tapped one hole (after shortening one rail to the correct length) on one rail as the base reference and ill clamp down the other ends using the caliper as a measuring stick. I'm then going to use the milling machine to mill a piece of 10mm Ali plate down one long edge and both ends, then ill drill mounting holes for the carriages and using squares off the reference face of the carriages make sure all is square before tightening down the plate. I can then use this to slide up and down to get the rails parallel and then mark and drill the holes.

    Anyone see any issues with this method?





    Last edited by njhussey; 06-01-2015 at 11:15 PM.
    Neil...

    Build log...here

  3. #373
    Neale's Avatar
    Lives in Plymouth, United Kingdom. Last Activity: 2 Hours Ago Has been a member for 3-4 years. Has a total post count of 685. Received thanks 97 times, giving thanks to others 5 times.
    Depends on whether you have a gantry to use as a gauge? I had built the structure of my gantry in advance for this purpose, so I bolted down one rail along the box section centre line, placed the second rail on its box section, and attached the carriages to use to align the rails. I think, in essence, you are doing the same thing but you will then pick off the rail spacing dimension to finalise the gantry. Hiwin recommend aligning the rail against a machined step but where this is not possible you align the second rail from the first. My only reservation is how you guarantee the straightness of the first rail but I think you can finally adjust this by test cutting. I hope so, anyway!

  4. #374
    Looks a nice epoxy job.
    To fit the first rail I clamped a good wide straight edge on top of the beam then butted the Hiwin rail up to it, like Neale said about the machined step. Then I mounted the gantry and used the bearings themselves to line the second rail, just nipping the bolts up slightly. Before fully tightening the second rail down I put the straight edge up to it to make sure there were no kinks. After that I also checked the distrance between them at points along the length just too make sure they were parallel.
    Spelling mistakes are not intentional, I only seem to see them some time after I've posted

  5. #375
    Quote Originally Posted by Neale View Post
    Depends on whether you have a gantry to use as a gauge? I had built the structure of my gantry in advance for this purpose, so I bolted down one rail along the box section centre line, placed the second rail on its box section, and attached the carriages to use to align the rails. I think, in essence, you are doing the same thing but you will then pick off the rail spacing dimension to finalise the gantry. Hiwin recommend aligning the rail against a machined step but where this is not possible you align the second rail from the first. My only reservation is how you guarantee the straightness of the first rail but I think you can finally adjust this by test cutting. I hope so, anyway!
    Quote Originally Posted by EddyCurrent View Post
    Looks a nice epoxy job.
    To fit the first rail I clamped a good wide straight edge on top of the beam then butted the Hiwin rail up to it, like Neale said about the machined step. Then I mounted the gantry and used the bearings themselves to line the second rail, just nipping the bolts up slightly. Before fully tightening the second rail down I put the straight edge up to it to make sure there were no kinks. After that I also checked the distrance between them at points along the length just too make sure they were parallel.
    Thanks guys.....

    I'm going to do a similar thing to both of you. I don't have a good straight edge that I can butt the rail up to so I'm going to use the first rail as a reference and use the dummy gantry to get the second rail square to the first. Regarding striaghtness of the rails I might look at using a small laser pointer that I have to shine along the length to check for any bend in the rail, not sure if this will work but don't see why not in principle?

    Got some more cutting discs (and G clamps to clamp the rails) on the way in to work this morning so I can cut the second rail to length. Looks like it's going to be lots of drilling and tapping today, hope there's not too much proper work to get in the way of doing this...!
    Last edited by njhussey; 07-01-2015 at 10:49 AM.
    Neil...

    Build log...here

  6. #376
    But how do you know the first rail is striaght.???

    I wouldn't waste any time setting the second rail without the gantry on the machine. Set the master rail straight and parallel to frame then run set slave rail using gantry running up n down feeling your way along as you tighten up the rail. . . Feel for binding is a very good guide in setting up.!

  7. #377
    Quote Originally Posted by njhussey View Post
    Got some more cutting discs (and G clamps to clamp the rails) on the way in to work this morning so I can cut the second rail to length.
    I rarely use metal cutting discs so I bought these after reading the description, I was amazed how good they are; quick, little mess, cuts rails like butter. !00 times better than the thicker type.

    http://www.toolstation.com/shop/p39737
    Spelling mistakes are not intentional, I only seem to see them some time after I've posted

  8. #378
    Quote Originally Posted by EddyCurrent View Post
    I rarely use metal cutting discs so I bought these after reading the description, I was amazed how good they are; quick, little mess, cuts rails like butter. !00 times better than the thicker type.

    http://www.toolstation.com/shop/p39737
    I've got some 1mm thick ones, as you say they cut through the rails like a hot knife through butter. I've got the Y & Z axis rails to seperate (curently two rails 1100mm long with 4 blocks on each soon to be split.....) but now thinking of making the Y axis rails longer to get the carriage spacing wider. Just re-drawing it to see if I can get away with slightly less Z axis travel.
    Neil...

    Build log...here

  9. #379
    Quote Originally Posted by JAZZCNC View Post
    But how do you know the first rail is striaght.???

    I wouldn't waste any time setting the second rail without the gantry on the machine. Set the master rail straight and parallel to frame then run set slave rail using gantry running up n down feeling your way along as you tighten up the rail. . . Feel for binding is a very good guide in setting up.!

    Dean, how do I make sure one rail is straight without buying a proper striaght edge? My frame is not straight enough to align the first rail, or at least I don't think so as it's just plain 100 x 50 x 4mm steel, with any sort of accuracy?

    I was thinking of getting some of my 10mm thick Ali and using the milling machine machine as much as I can down one edge and then turn it round and then using my edge finder set it parallel again and machine the rest to give a straight edge. Would this do?
    Neil...

    Build log...here

  10. #380
    Quote Originally Posted by njhussey View Post
    Dean, how do I make sure one rail is straight without buying a proper striaght edge? My frame is not straight enough to align the first rail, or at least I don't think so as it's just plain 100 x 50 x 4mm steel, with any sort of accuracy?

    I was thinking of getting some of my 10mm thick Ali and using the milling machine machine as much as I can down one edge and then turn it round and then using my edge finder set it parallel again and machine the rest to give a straight edge. Would this do?
    How about using some fishing line stretched very taut along the length. ..Clive

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