I’ve been using my Warco WM240B lathe for a number of years and although I’m not a great admirer or saddle stops I thought it was about time I made one.
The starting point is a piece of square cast iron.
I marked a line with a square and a pencil, as you can see I then made a cut on one side to a depth of a few mm before rotating the peice 90° in the vice.
This first cut aligns the hacksaw blade and it’s much easier to get a square cut with a hacksaw.
The next step was to square off each end. For this I use a four-jaw chuck in the said Warco WM240B lathe.
The rough edges of cast iron can be rather hard on tungsten tools and they do tend to chip quite easily. My way around this to use a much more chunky tungsten tool for these rough cuts. Here you can see I have a fixed bit TCT tipped 12mm square tool.
The dust from machining cast iron is not so nice and so worth using the dust extractor in the workshop and even wearing a mask if it gets too much for you.
I needed a line at 45° that would allow me to align the part with the vice on the milling machine. This line would then allow me to machine the “V” section for the top of the slide.
As this is a square block the easy solution was to drop the workpiece into a V-block and use a surface table and height gauge to mark a line. My surface table is the thick granite block type, not the highest grade, but much better than a workbench and it is more than accurate enough for all of the machining work that I do as a hobby.
A permanent marker is brilliant for this type of work and I find it far less messy than engineers blue.
A first trial of the block hanging over the lathe bed.
The lack of material on the overhang worries me a bit, but the clamping forces are going to be low.
The next task is to drill and tap the corner for the stop to thread into.
I’ve threaded it 7x1mm – the 1mm pitch makes sense as 1 turn moves it 1mm longitudinally.
When tapping cast iron I tend to use HSS taps where possible and tap dry. Just take your time and wind back regularly to release the cast iron waste material.
This slot I’m machining is 4mm wide and is for a knurled nut to operate and allow me to lock-off the rotation of the stop.
I’m using a Rennie Tools solid carbide slot drill @1000rpm with no cutting fluid. This is happily taking 0.5mm cuts.
The slot is 15mm long and 13mm deep as cut in this direction, I then rotated the workpiece 90° and created the rounded end on the bottom of the slot by machining down with the slot drill.
The part hanging back over the lathe bed again does look rather good.
With the stop now made up and a threaded stud in the bottom.
The stud is also 7x1mm and designed to accept a washer and a large knurled wheel to operate by hand and lock the saddle stop to the bed.