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Tolerances to BS EN 10061 for hot rolled hexagon stainless steel bars


Tolerances for hot rolled stainless steel bars are included with the general standards for hot rolled steel bars. The various sections are covered by:-
BS EN 10058 – Flat bars
BS EN 10059 – Square bars
BS EN 10060 – Round bars
BS EN 10061 – Hexagon bars

All of these can be used in conjunction with bars specified to BS EN 10088-3 This article covers hexagon bar tolerances to BS EN 10061, and cover cross sectional (width across flats) dimension, corner radius, length, straightness, twist, and ‘out-of-section’.

The data given is not intended to replace that shown in individual standards to which reference should always be made.

Dimensions and tolerances for stainless steel long products are covered in more detail in the BSSA special report ‘A Specifiers Guide to the New EN Standards for Stainless Steel Long Products’ available in the publications area of the web site.

Size (width across flats), corner radius, straightness, twist and ‘out-of-section’

The table below, based on tables 1 and 2 of the standard, summarises width across flats.
Corner radius and straightness tolerances are included in the table below. Tolerances on twist are not specified in EN 10061.

Width across flats (s) Nominal width across flats Limit deviation
between 13 and 15 +/- 0.4
between 16 and 23.5 +/- 0.5
between 25.5 and 33.5 +/- 0.6
between 35.5 and 47.5 +/- 0.8
between 52 and 78 +/- 1.0
between 83 and 98 +/- 1.3
103 +/- 1.5
Corner radius (r) Nominal width across flats Radius
below 20.0 up to 1.5
over 20.0 up to 28.5 up to 2.0
over 28.5 up to 48.0 up to 2.5
over 48.0 up to 83.0 up to 3.0
over 83.0 up to 103.0 up to 3.5
Straightness (q) Nominal width across flats Tolerance in the plane
below 39.5 Not fixed
between 39.5 and 83.0 q up to 0.004 x L
between 83.0 and 103.0 q up to 0.0025 x L

The tolerance on out-of-section must be within 75% of the tolerance bands given in table 1 of the standard.
All dimensions are in mm.
If agreed at the enquiry and order stage the limit deviations on width across flats can be all plus, minus zero, rather than equal plus / minus.

Length tolerances

The standard states ‘Depending on the type of length, hexagon bars shall be cut to lengths within tolerances given in Table 3’. Table 3 categorises the type of length and notes that it is the purchaser’s responsibility to indicate at enquiry and order stages the type of length required and the length range or length required. No further explanation of the terms used in the standard is given. The table below is based on Table 3 of the standard.

Type of length Range Limit deviation
Manufacturing length (M) 3000 to 13000 with a range of 2000 per order item 10% of bars may be below the minimum for the ordered range, but not less than 75% of the minimum of the range
Fixed length (F) 3000 to 13000 +/- 100
Exact length (E) below 6000 +/- 25
between 6000 and 13000 +/- 50

All dimensions are in mm.
If agreed at the enquiry and order stage, limit deviations (ranges) can be all plus, minus zero, rather than equal plus / minus.

Methods of measurement

BS EN 10061 specifies methods of measurement for the dimensional tolerances given.
These are summarised below.




The width across flats must be measured at least 100mm from the end of the bar.


The length must be measured as the longest length of the bar.

Corner radius



The radius must be measured by a radius gauge at any point, at least 100mm from the end of the bar.




Straightness is measured as the maximum distance from a flat bed on which the bar rests to the underside of the “hogs back” shape of the bar. Straightness must be measured over the total length of the bar.

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