Is RSJ Steel machinable?

Our conservatory is being replaced - it has 3 large RSJ's that came out of the old one that are now surplus to requirements.

It seems a shame to scrap them. I don't have an immediate "construction" use for them, but was considering hacking them up with an angle grinder and storing the steel for use with general machining.

I don't know if they are in the category of things like Rebar which I beleive as being well documented as terrible/horrible to machine.

So basic question is does RSJ Steel machine/weld well?

Thanks, Ace

Welds well and is reasonable to machine if a littly gummy.

This part was cut from the other corner that made up a steel channel

Never had any real problems machining RSJ material. If you have the space, keep it, you will find a use for it.

Andrew.

It cuts, drills and files well.

Cutting up RSJs just to keep the steel is daft. It's much more likely to be of use in long lengths.

Certainly will not be free cutting as it's weldable.

regards Martin

Cut it up only as you need it ! Much better left in lengths.

The RSJ are worth money as is chopped up they are not, a 5 x 3 rsj is £25 per M

When we refurbished our bathroom there was an RSJ spanning the bathroom under the floorboards and we needed to route some pipes through it so used a standard hole saw in an electric drill, with a bit of oil to aid cutting, and it was no problem it cut easily. I wouldn’t hesitate to use it for projects. Dave W

It machines ok, I used an offcut for a vise modification.

Some people would love some to mount their lathe on to increase the mass.

Edited By old mart on 24/03/2021 15:00:13

Should be machinable but it does depend rather on what steel a particular RSJ is made of. They're not all the same.

Usually RSJs are made of a mild-steel plus a dollop of Manganese for extra strength. EN3 is similar but weaker and an older RSJ may have been made from it. Modern RSJs are tougher, but still machinable, OK rather than good.

High-specification RSJs are sometimes made of exotic steels which might not machine well, but the chances of anything special coming out of a demolished conservatory is low!

Try it and see. I think it'll be fine.

Dave

My Warco lathe & M16 Mill both sit on standard Warco cabinets. 3 short lengths under the lathe cabinet & 2 under the mill cabinet raising them both 9 inches makes a h..ll of a difference to one's back after a couple of hours playing at either ( i am 6 ft 6ins tall) . Easy to bolt to the floor & to the cabinets & no flexing.

RSJs are worth good money and there is a ready market for them. A 6 or 8' length will make a mighty fine wood splitter. Cutting it up would be tiresome. Noel.

RSJs are made from BS EN 10025 S275. The 275 refers to it's yield stress which is 275 N/mm^2. It welds well and machines reasonably, although it wouldn't be my 'go to' choice.

Put it on Ebay, someone might be building an extension near you

Could you give an example please of a 'high specification RSJ' and while you are at it, please give an example of a low or normal specification one just so we understand the distinction you are trying to make.

Structural steel will be either S275 or S355, properties for which, including machinability, will be easily found with the aid of a nearby Google.

I had a hell of a job drilling holes in an RSJ for my house. 275 is proper strong stuff and the cheap drills didn't like it.

Sell for its proper use and buy something useful I say.

I had a beam outside for a decade. A good coat of red oxide and bitumastic paint kept it in good condition.

Drilling holes in RSJ is what mag drills and rotabroaches are for ! A joy to use for almost any size. Noel.

They'd make the basis for a useful hydraulic press if you add a cheap bottle-jack and a couple of bits of angle..

Certainly!

As RSJs were being rolled long before S275 existed, a joist recovered from an old building might not be made of it. Not unlikely to be something similar but it could a plain carbon mild-steel. Bessemer didn't know about Manganese, and as adding it puts the price up, ordinary mild has been rolled as a structural steel. Pre-war British structural steel wasn't made to a standard at all - it varied by maker. Counterfeiting is another possibility.

At the 'better' end, I first heard of Nickel-steel RSJs being used in shipbuilding to save weight. Strong alloys are used in super-towers for the same reason. Like railway lines, they are made to order but stainless steel RSJs can be had for more ordinary purposes.

The comment came from my bad early experience with scrap, explained when I twigged there are thousands of different alloys out there, and many don't machine well. Unknown metals should be tested because it's unwise to assume anything. Great if scrap works, just be aware should trouble occur that not all metals machine well. The answer to 'Is RSJ steel machinable' is probably yes, but it has to be tried to prove it.

Dave

The beans you have would probably machine satisfactorily, and weld easily, but it is a gamble.

I have used off-cuts and scrap-yard pieces of hot-rolled sections and plate for various things without too much trouble - the worst I recall was that used years back for bed-frames. (Our club went through a phase of using those for all sorts of projects, and some of the frames were scavenged from fly-tips in local quarries!)

Really, for the amount of metal you are likely to use from your RSJs, and the number of cutting discs expended cutting them into bits, it would be better to sell them as serviceable building components, and keep the cash for buying known steel to appropriate sizes as and when you need it.

Drill a hole in it and see for yourself how it machines. If good, keep it. If bad, flog it off.