Here we go again . . . MK4

[routercnc]

The part was too long for the machine so only one thing for it - cut a hole in the table:


The profile pieces which make up the bed are not accurate enough to be used as a support. The sides are not flat and are not perfectly square to the bed (since that was skimmed by the machine). So I made up a 'tramming' plate:


I bolted it at the bottom, then used a screw at the top to dial it in. Here you can see that before the screw starts to be tightened there is an uneven gap to the part I am machining (which is held at 90 degrees to the bed via the precision vice:


Screw tightened until it made contact:


I made up a strap clamp to hold the part and bolted it to the tram plate. Then it was ready to dial in by running the indicator up the side and adjusting until it was vertical:


Then the features were machined:


Took the part off and put it on the lathe, then used a centre drill (as a scribe) to mark along the edge (part not shown in photo):


Then removed it and used the height gauge at 15mm (part is 30mm thick) to scribe a line. I was relieved to see it was exactly the same height as when on the lathe which meant they were both at the same point.


Basically this meant I had got the lathe platform at exactly the right height, with the centre of the chuck in line with the centre of the part. The next op on the lathe is to drill an 18 mm clearance hole (for the ballscrew) about 190 mm deep into the part.

But that is on hold until I machine the end of the second part. Before I took the first part out I had added a backstop to pickup the edge. This meant it was in the right position. Here is the second part set up for the same end machining:


Getting closer now but this bit is taking ages . . .!