Hi there, all,
I started this post (quite a long time ago!!) because I had bought a Beeston Myford Dickson-Pattern rear tool-post, part number 30/149. That version is for the Myford 254 lathe which is considerably larger than my ML7.
As bought, the tool-post looked like this:

Obviously, to use this tool-post on the ML7, its height would have to be reduced. Thanks to Stuart, I knew that the lower block for the corresponding ML7 item, part number 30/145, is 1.688 inches or 42.88 mm.
I didn't want to modify the lower block from the 30/149 so I cast about (pun intended) for a suitable piece of cast iron from which to machine a 30/145 lower block clone.
With this intention, I purchased a length of cast iron bar from College Engineering. They advise, quite reasonably, to allow for the material being as much as 5 mm under nominal size.
The finished size of my block would be that 42.88 mm high, plus a bit for the locating tongues that fit in the cross-slide Tee-slots, by 78 mm long and 48 mm wide. So, having allowed what seemed enough machining allowance, I placed my order. What arrived looked like this:

It transpired that my piece of material was actually a bit OVER nominal size, it measures 61 mm by 61 mm by 90 mm (I did up the length ordered by 10 mm).
That was going to need a lot of cast iron converting to swarf, taking a lot of time and making a lot of mess!
So I thought long and hard, trying to think of a good approach. I could have fitted the block into the four-jaw chuck and machined it to size - NO, too much swarf and too much time!
I could hack-saw off most of the excess material, just leaving a mm or so to machine off - NO, too much physical exertion for an 'oldie' like me and I couldn't guarantee the required accuracy of cut!
I enquired of the makers whether the Rage Evolution saw would cut cast iron and was told that it would not!
I wondered whether anyone I knew had a metal cutting band-saw or a donkey saw and might make it available to me - I didn't know anyone!
So, I got on with other jobs and this one receded even further back than the back burner!!

And there it stayed until ten days ago!