Hi Martin wear characteristics are better with cast iron than mild steel although it is cheaper than cast iron it depends on the use that the slide is put to and the amount of use. A mild steel slide would be stronger in certain circumstances T slots less likely to break but depends on thickness and load. The graphite in cast iron gives a better slide and will not pick up and smoother slide but may wear as all slides do to some extent. Just think cost versus usability.

David

Hot rolled is one of my go to materials in the shop as it is easy to source. I like machining it (it takes a bit to get adjusted as indicated above).

Just make sure you size your material to allow for cleanup. Most hot rolled sections aren't all that square so you have to remove a fair bit of material to clean it up. Obviously cold rolled doesn't suffer from this problem but it suffers from residual stresses.

For most home shop tools hot rolled works quite well.

Just be warned if you wish to scrape the slide in for fitting purposes, scraping steel can be miserable compared to cast iron. If you are going to scrape I would spend the extra money on the cast iron.

Do you have any links to suppliers please, looking around I can see bright and black.

Hi Adrian have you tried M machine metals they gave a great selection of materials and usually quick delivery.

David

Might sound like a stupid question,but for turning jobs I assume it would be work for the four jaw chuck ?

I doubt if the three jaw chuck would like it. Would this be correct ?

Adrian,

I am not too familiar with UK terminology but I would assume that black refers to hot rolled steel and bright refers to cold finished. Some apparently bright sheet is actually hot rolled that has been pickled and oiled. In the US we are seeing supposedly cold rolled flats that are merely sheared from plate and the edges slightly rolled to remove shear marks.

That's interesting. In the UK it's common for stainless steel flats to be sheared from plate, but not seen it for low carbon steels.

Andrew

For the less pecunious of us, often using "pre-loved" metals, hot-rolled steel has the advantages of stability described above, and you are less likely to be caught out by some nice shiny stuff from the local scrap-yard being anything but free-cutting!

It is also usually readily welded, which is not recommended for leaded free-cutting steels. (EN1A will fuse, but the welds can be brittle.)

Recently I made a set of dovetail nuts to hold the magnetic read-out strip to my milling-machine table, using the slot that originally held the limit-stops. I saw this is the only practical way, on a Myford VMC mill not designed to take a DRO set. My stock was cut from old miniature-railway rail, flat-bar not profiled, scrapped as too worn and rusted for continued railway use. The worst corrosion pits were quite deep, but the nuts are sufficiently thinner than the stock to avoid them.

Years ago I worked as materials store-keeper for a manufacturer of industrial screen-printing machines, when it received a one-off order for special jigs to hold long surveying-poles for printing their rule scales (not ruler – I've read that thread!). The longest was at least 2m long, and after the miller had cut the requisite facings and channels along the BMS stock, it naturally warped. So it went off to a heat-treatment firm for normalising, but came back even more normally bent. I can't remember what they did eventually – might have used aluminium-alloy instead.

A further tip:

Those DRO nut's dovetail chamfers are at 45º. No suitable cutter, so I drilled and tapped all the holes regularly-spaced along the strip, then drilled matching holes along a piece of angle-steel, at the same settings. Screwed the nut-strip to the angle, clamped that to the mill table so it acted as an inside-out V-block; then kept the assembly together to hold in a vice for junior-hacksawing the nuts apart.

I marked the cuts first by tiny drill-spots during the drilling and tapping process: the nuts' ends do not need be more square than by eye, and a file soon tidied them.

Note: this process order will not work in all cases. What surprised me, when at the printing-machine manufacturers, was the number of times millers making extra T-nuts would drill and tap all the holes in a bar length then expect me to separate them on an auto-feed hacksawing-machine with a well-made but poorly-designed geared-roller vice. It was definitely not for such tasks and incapable of holding short bars anyway. I had to gently suggest to these apprentice-trained, skilled machinists that the repetition would be far easier and more reliable if I cut the embryo nuts from the stock bar before machining.