Saddle up - we're heading in

Get ready:

Cleaned up the table of The Shiz to make way for the saddle body. One almost full Sainsburys carrier bag later, the table is clear and ready to receive.

Although the table is big enough to lay somebody out on, the actual machining area is somewhat less, not surprisingly, and requires me to move the vise from its usual position. The electronic tool setter (ETS) is at the back right of the envelope, so no need / not much point relocating it. 

The saddle base itself is machined and clean, so I can mount it on a pair of parallels. I can't sensibly avoid the clamps from rising above the top of the saddle, so will have to be careful not to pull any fancy moves when the tool is mounted and the machine is running. I will need to do some probing and tool measurement, so navigating around the saddle and its clamps will require some care.

First, roughly line it up with a pointy stick in the spindle (my old reference tool, T1):

Then use a DTI on a known good (ground) surface to get the ways lined up with the X axis of the machine:

Checking it's also flat, otherwise the dovetail surface may not actually be parallel:

All in order, although it doesn't need to be deadly accurate for the purposes of these machining operations. Nicely tightened up, ready for some machining action.....

Get set:

Tricky to set up an accurate workpiece origin, so I set it at the middle of the dovetails (Y), the top surface (Z) and the end face (X - hidden here). My trusty, broken 10mm end mills came in handy here - I have got some use out of them.

Here we are - ready for action?

Let's go - cavity first

The first couple of stepdowns didn't actually make contact but the tool was menacing the sides...

Finally it had a decent bite at the back of the slot.

Cut deeper as the tool stepped down

Finally, a clean floor and some cleaned up side walls. There's still some material left (0.5mm axial and radial stock to leave, IIRC) that I may remove later with a normal end mill using a finishing toolpath.

Encoder head:

Now create the cavity for the encoder head. This is a travesty for many owners of old iron.

But it came out OK. 

Now to perpetrate similar damage on the other side of the cavity for the home and limit switches.

Limit switch:

I've got my head up now. No holding back, full perpetration mode. Let's start with the nearest one.

Well that worked. 

Home switch:

Don't stop 'til you drop. This one is right at the heart of the saddle. Fucking up here could require new underwear. 

Bollocks - let's do it. You can see the limit switch cavity already roughed out in the foreground. 

Switch bracket shelves and cable slot:

Now I need to machine the shallow pockets for the switch brackets. And the channel for the home switch wiring:

I'll continue this tomorrow, along with some finishing passes - currently I have 0.5mm stock to leave on most surfaces. Not sure that was necessary really....