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How square should square barstock be?

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Ian P06/12/2013 22:25:09
2304 forum posts
93 photos


The picture shows the end view of some 10x40 stainless steel rectangular bar that I received today.

I bought a few metres of it, but I had it supplied cut to short lengths. As supplied its not usable, the faces are not flat, they are not at 90 degrees and the corners all have different radii! Its slightly thicker than its nominal 10mm but I doubt whether the overall size would clean up to be 10x40.

I have no idea what the steel manufacturers spec is but I bought this from a materials supplier anyway and their catalogue just lists is as 10x40mm however since its in short pieces I can hardly return it.

In theory could mill all the faces as the finished dimensions are not critical but with only a small mill it would take me a long time with a 10mm endmill.

Is there such a thing as a planer/thicknesser that works with non magnetic steel rather than wood?

Ian P

blowlamp06/12/2013 22:30:10
1230 forum posts
82 photos

I'd send it back.


jason udall06/12/2013 23:07:22
2018 forum posts
41 photos
There are standards ( of course )
But unless you bought it as rectangular section to xyz you have little recourse .

Robbo06/12/2013 23:07:46
1504 forum posts
142 photos

Depending on the length of the lengths could be a job for a Shaper. There are planing machines, but not so many about these days.

But first ask the supplier what they can do about it.

John McNamara07/12/2013 00:14:13
1311 forum posts
113 photos

Hi Ian

Will it fit in the 4 jaw on your lathe or are the pieces too long; or maybe a mate with a bigger lathe?

If so I would group the pieces and face the narrow sides and ends first, then do the faces one at a time. With a sharp tool you should get a good finish,


JasonB07/12/2013 07:29:54
17066 forum posts
1839 photos
1 articles

I think its a bit like hot and cold rolled steel, you have the equivalent to hot rolled and you really want cold rolled. I know round and square stainless can be bought in "bright" finish rather than the dull milled finish which has the rounded edges, not sure if flat comes bright. Its OK for a welded staircase or railings but not precision work.

Nicholas Farr07/12/2013 07:41:05
2067 forum posts
995 photos

Hi, it looks to me as if it has been sheared from flat plate, which is commond for fabrication purposes.

Regards Nick.

John Shepherd07/12/2013 07:48:58
216 forum posts
7 photos

I thought it looked more like the profile of hot rolled iron bar at first but I see what you mean about it being sheared from sheet material.

I would at least talk to the suppliers and determine what they have supplied, their response may help us all from making the same mistake one way or another.


Edited By John Shepherd on 07/12/2013 07:55:52

JasonB07/12/2013 07:58:26
17066 forum posts
1839 photos
1 articles

Plenty of info here on size and shape tolerance as well as surface finish. The rolled bar can be quite out of shape!! so really depends on whether you specified a type or asked for a particular type of bar.

old Al07/12/2013 09:17:11
152 forum posts

yes, the section is wrong and we have for some time had to grin and bear the rubbish that is imported into this country, because we have no other choice.

But the question I have I. What job have you got lined up for the stainless that needs all 4 square edges.

I have some stuff like yours and had it for years, but I have not been caught out so far

Ian P07/12/2013 09:43:10
2304 forum posts
93 photos

Thanks to all that replied.

I will speak to the supplier on Monday but I'm not sure what they could do. Before I ordered it I enquired about the profile and they did tell me that faces are sometimes rounded on rolled material, in fact they sent me a photo (blurred) of the actual metal before it was cut but as far as I could see I thought it looked OK.

The pieces fit nicely into the four jaw and I don't know why I didn't think of that sooner!

As to how this bar is actually produced, I'm not sure. The general shape certainly has the look of being sheared from plate but if so it must have been through some second process. The central area of the narrow edges does have a slightly crossways 'torn' surface.

Jason, your link looks a really good reference. I would not have thought of Aalco in terms of anything other than aluminium.

Ian P

Springbok07/12/2013 11:40:54
879 forum posts
34 photos

A heck of a lot squarer than that send the lot back

Stub Mandrel07/12/2013 11:43:36
4307 forum posts
291 photos
1 articles

I have some rolled steel bar and the profile is oval (e.g. a rectangle with semicircular ends)

Cold drawn steel bar should be much more accurate, being drawn through dies, but has teh disadvantage that locked up stress can cause distortion during machining.


Clive Hartland07/12/2013 11:51:11
2501 forum posts
40 photos

A lot of this stuff is imported and is of dubious quality, Certificates of Origin seem not to have any relation to the quality. A recent happening on a ship that my Son was on shows this. An elbow on a high pressure air system blew up and showered the engine room in shrapnel, he had just stepped past it through the bulkhead door and escaped injury. They followed up the origin and it all ended at a Norwegian supplier who obtained it from Korea.

I also have a photo of a S/steel shackle that snapped in half and shows crystalline fracture and it was rated at 7 tonne. This one they could not trace the origin. I have over the years found that some round s/steel bar has rings of hardness as you turn it. Very 'Iffy' I would think.


old Al07/12/2013 12:01:14
152 forum posts

you don't get much choice in this modern high tec world. Its not an English company that rolled it, so you have little chance to complain. Your local supplier is unlikely to be very helpful either. his margins are small.

NJH07/12/2013 12:16:52
2314 forum posts
139 photos


I would be on the phone to that supplier, PDQ, bending his ear and telling him,strongly, the problem and that it is not suitable for your purposes. If you ordered 10 x 40 rectangular bar and you can't even get 10 x 40 out of it  it is not fit for purpose.


Edited By NJH on 07/12/2013 12:17:42

JasonB07/12/2013 13:16:42
17066 forum posts
1839 photos
1 articles

No point in complaining or sending it back, looks like its perfectly within spec for rolled SS bar.

on 10x40 thickness can be +/- 0.5mm, width +/-1.0mm and +/- 0.5mm out of section

Just look at google images for "stainless steel flat bar" all rounded corners

If the OP did not specify a perpose or spec there is not much chance of sending it back as not fit!!

Flat rolled bar specs

Ian, you don't say what grade of stainless it is but I suspect its 304 which is often used for forming and welding and general fabrication work, you probably would have been better geting 303 which is more suitable for machining and a bit of Google searching shows it is available fit for your purpose, from one suppliers site:

"303 stainless is used for applications that require lots of machining. All of our stainless 303 flats we stock are cold finished so the edges are square with a true flatness across the flats"


Edited By JasonB on 07/12/2013 13:27:28

KWIL07/12/2013 19:16:25
3145 forum posts
57 photos

The only trouble I have had with Aalco is the minimum order that has to be placed.

Trevor Wright09/12/2013 18:04:00
139 forum posts
36 photos


That section looks exactly like the stainless plate I have always been presented with at work.

The sizes are usually plus to allow for machining so you can hit the size ordered.

Looking at your section view the long sides look parallel but the ends are skew (probably been cropped when hot). Would recommend squaring the sides to the flattest section and facing off in a 4-jaw as suggested earlier. Skim the minimum to produce a flat face as the radius where cropped will take some cleaning up.


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