Game on!

[Voicecoil]

I've been cracking on with stuff the last few days, here's a pic of some of the parts:

From LHS clockwise we have Z axis slide with clamp sitting on top of the bed cross beams, front bed end plates, Z axis top plate, gantry end plates and the Z axis back plate. Just hit a bit of a snag though - the big bit of plate for the top of the bed has been cut well off square by the folk at Smiths - thus even with the 2mm tolerance oversize by the time it's trued up it will be 2mm short causing a few major headaches - I will be bending their ears on Tuesday

[Voicecoil]

Marking out the bed plate:



I need a bigger surface plate!!!

[AndyGuid]

Marking out the bed plate:



I need a bigger surface plate!!!

As a pen-pusher, I'm guessing that your method is a very accurate way of manually Marking Out Using a Surface Plate and Height Gauge ?

[Voicecoil]

Yes, I bought the height gauge and optical centre punch for this project and I've been suprised at how accurately you can do things - I reckon on smaller pieces the max error isn't much more than +/- 0.1mm and maybe twice that on longer bits: quite a novelty not to have to file out holes to get things to line up! Mind you, when you think about it people were making accurate stuff 60 to 70 years ago before CNC was even thought of, so it had to be possible.

[Voicecoil]

Yesterday and today I've been assembling the various parts of the bed/Y-axis to check fit before doing a bit of anodising.




All went reasonably well apart from a couple of screw heads (that need to be moved) fouling stepper motor bodies and a small CAD error on the carriage side plates that I'd transferred really precisely into metal - time to get the file out!

[mekanik]

Looking Good

[Voicecoil]

Having found it very difficult (or very expensive) to get anything done on a reasonable timescale by the local anodisers, in desperation I thought I'd have a go myself. £50 worth of chems and some plant troughs later I managed to get the gantry box done this evening, took a bit of fiddling with the process but not too shabby in the end.

[Gav74]

looking good

[Voicecoil]

With all the beams now anodised I thought it was time to indulge in a bit of damping, as handling the box sections in particular showed that they were ringing a lot at mid-audio frequencies (which match up nicely with the stimulation given by typical spindle speed/cutter flutes). I thought I'd try my old fave Tecsound, but wasn't overly confident of it working as I've never used it on anything thicker than 2mm thick metal sheet before, and the box sections I've used for the side beams and gantry are 7 & 10mm thick wall. However in reality it seems to work pretty well, hanging an untreated section up on a piece of wire and giving a gentle tap with a hammer gives something not unlike a tubular bell, whereas a damped section is just a bit of a thunk. Here's some sound files from the tapping to illustrate the difference
Side beam undamped.mp3
Side beam damped.mp3
Looking at the decay time in an audio editor, the damping has been increased by something like 6X - a useful improvement I think - now to do some of the other parts!