Here we go again . . . MK4

[routercnc]

There are a few jobs to do on the main spindle housing. Boring pilot holes on both sides of the block:


Then the pilot holes for the M8 taps for the spindle clamp brackets. Spindle block is so big I had to get inventive on the fixture to machine these parts:


Then onto the tapping 16 off M12 taps and 4 off M8 taps - took a while !


Quick assembly check:


Then noticed that some of the bolts were loose on the current machine. Wondered why it had been chattering more recently - was worried the small 15mm profile rails had worn, but then spotted this:


So I had to dismantle the Y axis and tighten them up. 2 bolts had come right out, and one more was loose. The rail has also lost a bolt. I guess that is what happens if you ask a machine designed for wood to plough through endless 20 mm aluminium plate for months on end. Used loctite and tightened them back up. Also doesn't help that on 15 mm rail they use M3 bolts which are very small and you can't put much torque on the heads.

Then onto making the spindle clamps:






Although I've got to bore out the spindle hole on the spindle block, I thought I'd check everything was going to fit together. Aligning first rail to master datum:

(note the rails are slightly too long - have marked them up for gentle grinding back to length)

Dialing in the second rail, ref the first:



Then checking the vertical alignment showed that the 2nd rail was ~0.05-0.1 high towards one end. The large side plates they sit on will need the M12 bolts loosening and knocking round slightly when this goes together for real.


Coming together:


Then discovered a problem! The whole assembly is ~2 mm to big! The plate at the top of the photo should be flush with the side plate but is clearly too high.


Bit of head scratching, and checking the drawings couldn't find anything I'd made which was out of spec. Then checked the profile rail and carriage and they were ~2 mm taller in total than the drawings I'd down loaded from Hiwin. I know it has been mentioned on this site many times but check the hardware before committing the drawing and making the other parts !
Luckily this is easy to resolve, just take ~2 mm off one the side pieces and everything will be back in line again. I'll leave that till later because everything has to be set up to get it all very parallel otherwise the rails will bind.

Onto making parts for the lathe to bore out the main spindle housing to final size . . . more to follow