AndyUK's Build - 1.2x1.0m Gantry

[Kitwn]

If my first effort (on the ToDo list behind a few more urgent tasks) looks that good I shall be happy. What's next?

Kit

[AndyUK]

What's next?

Well... I once said this about my wooden control box:

First thing was to make a quick and temporary control box...

Turned out temporary is over a year! I've also got a much better idea about the buttons I wanted, so popped a few more on there.



Also coming up with a few ideas for design modifications. I'm considering adopting the two plates idea on the X axis to make the gantry adjustment more independent from the ballscrew and linear rails. It will also add a little height to the gantry; I'm finding that although the bed height is adjustable in theory, the work involved is quite prohibitive (its bloody heavy, you need to re-level everything, and then you're working at a non-optimal height). I've found that with tool length, my current setup can only manage a depth of about 50mm or so. With a small bed height adjustment and a few tweeks I should be able to get a bit more room. Then theres the lack of a tramming plate on the Z axis, and it would be nice to have my Z probe plate wired so that it travels around with the spindle and is always close to hand....

[Kitwn]

Also coming up with a few ideas for design modifications. I'm considering adopting the two plates idea on the X axis to make the gantry adjustment more independent from the ballscrew and linear rails. It will also add a little height to the gantry; I'm finding that although the bed height is adjustable in theory, the work involved is quite prohibitive (its bloody heavy, you need to re-level everything, and then you're working at a non-optimal height). I've found that with tool length, my current setup can only manage a depth of about 50mm or so. With a small bed height adjustment and a few tweeks I should be able to get a bit more room. Then theres the lack of a tramming plate on the Z axis, and it would be nice to have my Z probe plate wired so that it travels around with the spindle and is always close to hand....

Very interesting. Your wooden control box is much neater than my re-purposed PC case will ever be!

I used two back plates for the gantry-mounted axis (Y on my machine) mainly out of practicality. It means that I can have the fixing screws for the linear bearings for the Y and Z axis overlapping, gave greater rigidity as I could only get 12mm plate and meant that I had some wiggle room to get the two axes exactly perpendicular after marking out bearing and rail mounting holes by hand and drilling them with an ordinary drill press. It also allows the whole Z axis assembly to be removed as a unit if required.

The real trick is working out an accurate way to measure whether the two axes ( ie the rails) are really perpendicular or not that is separate from measurements of where the axis of the spindle is pointing. I haven't quite cracked that one yet. I know the axis of the spindle is accurately perpendicular to the Y axis but I have no way of knowing if the spindle itself and the Z axis movement are precisely parallel.

Kit

[MikeyC38]

Hi Kit
On my build I wish I had given more thought to tramming adjustment as I now have to use metal shims to get everything right. Some sort of screw adjustment with a wedge may work. For tramming I could'nt get on with a single dial meter so bought this and I found it to be money well spent

Kind Regards
Michael

[Kitwn]

Hi Kit
On my build I wish I had given more thought to tramming adjustment as I now have to use metal shims to get everything right. Some sort of screw adjustment with a wedge may work. For tramming I could'nt get on with a single dial meter so bought this and I found it to be money well spent

Kind Regards
Michael

My machine is covered in shims! At least I built it in a way that makes it possible to access the places I need them easily enough.

I've seen the tool you linked to before but used a different method myself which was much less costly and used the Z axis DRO as a micrometer. This uses taught wires stretched between the long axis rails (X on my machine) to create the reference plane for aligning the gantry. This seems the best way to do it if your machine design allows it since these rails (once proven parallel) ARE the plane to which the other axes have to be parallel or perpendicular. Once that's all aligned then skimming the bed brings it into same plane and is the final job to be done. I wrote a thread about it last year and there's some updated stuff on my build log after I moved house and did it all again.

http://www.mycncuk.com/threads/13627...ith-Taut-Wires

Kit