Here we go again . . . MK4

[routercnc]

Update time. It soaked up many hours to get back on track. After a lot of prodding with any pointy shaped tool I could find, plus a soak in WD40, I manage to lever the broken spot drill out of the hole. The edge of the hole was a bit damaged where I'd levered against it but at least the hole was clear.

After checking the main part of the hole was still in alignment I bored it out from the 6mm spot size to the 6.8mm pilot, then ran the M8 tap into it. I had to give it a generous countersink to tidy up the damaged surface then all was well again.


I also managed to drill and tap out all the holes in the bottom of the outer edge from dia8 (should have been 6.8 for an M8!) to pilot 8.5 and then used my new M10 spiral flute tap. As per my recent M8 tap this is also a RotoGrip tap and is very sharp and cuts really well. This one was £11.03, which sounds a lot vs the cheap ones but I think it is worth it having used both.

Here is the ebay link:
http://www.ebay.co.uk/itm/2917546426...%3AMEBIDX%3AIT
In case the link expires in the future here is the description:
HSS Ground Machine Tap Spiral Flute M10 x 1.5 Quality Made by Volkel. Germany


The button head M10 cap heads had also arrived so I was able to trial fit those. All looking good:


Next job was to cut the RHS steel beams to size. I was going to mark it out and use the thin grinding wheel on the grinder to cut it but after lots of deliberation decided it was time for a new tool. In the end I went for this one which is the 355mm rage2 saw. This is because it can cut up to 120mm x 120mm which should cover all needs. It has a nice soft start and just drops through the steel with ease. It is also pretty square out of the box - helped by just having a pivot and no slides etc.


The first beam was cut out and offered up. Looks OK. It is about 0.5mm short of the 730mm length as drawn to make sure I could set the end pieces the exact distance apart.



Next I need to cut the 2nd beam to length then I'm thinking about the best way to set the ends the correct distance apart. Current thoughts are to maybe use the CNC machine to drill out the holes at each end in the side of the RHS beam, including a special hole for a hardened dowel locator pin at the far end. There would be a matching locator hole in the triangular brace side plate at the far end to push the dowel through. This should set the far end housing a set distance from the near end housing.

Another option, is to CNC machine 2 shallow pockets into a large sheet of plywood to take the 'footprint' of each end housing and set them the correct distance apart plus have them squared relative to each other. I could just use a tape measure and square but feel like an assembly jig / guide would be nice. Any other thoughts?