Here we go again . . . MK4

[njhussey]

It's all interesting!!!....good to see the good as well as the bad...if you want to see ugly ill show some of my stuff 😁

Sent from my HUAWEI VNS-L31 using Tapatalk

[AndyGuid]

It's all interesting!!!....good to see the good as well as the bad...

Ditto!
And this novice (little old me) finds your posts very easy and a real pleasure to follow.
Many Thanks, routercnc!

[routercnc]

Brief update. Next up were the plates which hold those bearing holders . . .

Setting it out, drilling out some of the holes and pockets:


Then bolting down through the holes so I can machine around the outside:


Quick trial fit to make sure all is well:


Went OK but broke a bit when I called for an 11 mm DOC instead of 1 mm in the CAM and didn't stop the machine in time.

I couldn't fit the standard ballscrew blocks in under the end of the gantry so am making my own. There will be 4 in total, 2 each side to allow me to pre-load one ballnut against the other to remove the 50 microns or so of ballscrew backlash. Here are 2 of the blocks, with 2 more on order:



I need to machine 45 degree chamfers on the top of the block but don't have an Engineer's vee block


So I machined up a jig with a 45 degree notch:


Here it is in position to show the idea (tabs yet to be filed off):


Then the blocks had to be squared up. There are lots of videos and info on how to do this on the internet so I won't repeat in detail. Great example here:
https://www.youtube.com/watch?v=tW8HNAlUXxU

In the photo below you can see a raw block (right) and the squared up block in the jaws (left). The brass rod is used whenever an un-machined face is against the clamping jaw otherwise it won't sit flat against the fixed jaw. The deadblow hammer is to make sure the part is seated in the vice.


Once squared up I set it up against a backstop (actually a parallel doubling up as a stop - must make something better !). It is now ready to have the details machined into the end such as the ballnut mounting holes. I can't machine the large clearance hole right through the centre because the part is 50 mm long. Even machining both sides its a bit too deep. So my plan is to bore a precise 20 diameter pocket in the end (say 10mm deep), then set it up on the 4-jaw, indicate on that bore to centre it, then bore it out.