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diff --git a/handbook.tex b/handbook.tex
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--- a/handbook.tex
+++ b/handbook.tex
@@ -6,10 +6,11 @@
 \usepackage[svgnames]{xcolor}
 \usepackage{siunitx}
 \usepackage[french]{babel}
-
+\usepackage{graphicx}
 \newenvironment{fulltab}[1]{\begin{center}\begin{tabular*}{\linewidth}{@{\extracolsep{\fill}} #1}}
 {\end{tabular*}\end{center}}
 
+\def\N{\mathrm N}
 \def\Vt{V_{\mathrm T}}
 \def\kbT{k_BT}
 \setlength\tabcolsep{0pt}
@@ -27,7 +28,7 @@
 \chapter{Mechanics}
 \section{Metric machine bolts}
 
-\paragraph{Threads}
+%\paragraph{Threads}
 \begin{fulltab}{lccccc}
 \toprule
 Thread & Pitch & Tapping dia. & \multicolumn{3}{c}{Clearance dia.}\\
@@ -46,7 +47,34 @@ M10 & 1.5 & 8.5 & 10.5 & 11.0 & 12.0\\
 \bottomrule
 \end{fulltab}
 
-\paragraph{Hex heads, nuts}
+\begin{minipage}[c]{\linewidth}
+\paragraph{Socket head cap screws (ISO 4762)}
+\begin{center}
+\includegraphics[width=\linewidth]{sockhead.jpg}
+\end{center}
+\begin{fulltab}{lccc}
+\toprule
+Thread & s (nom.) & dk (max) & k (max)\\
+\midrule
+M1.6 & 1.5 & 3.14 & 1.6\\
+M2   & 1.5 & 3.98 & 2\\
+M2.5 & 2 & 4.68 & 2.5\\
+M3 & 2.5 & 5.68 & 3\\
+M4 & 3 & 7.22 & 4\\
+M5 & 4 & 8.72 & 5\\
+M6 & 5 & 10.22 & 6\\
+M8 & 6 & 13.27 & 8\\
+M10 & 8 & 16.27 & 10\\
+\bottomrule
+\end{fulltab}
+\end{minipage}
+
+\begin{minipage}[c]{\linewidth}
+\paragraph{Hex heads, nuts (ISO 4014, 4032)}
+
+\begin{center}
+\includegraphics[width=\linewidth]{hexcap.png}
+\end{center}
 \begin{fulltab}{lccccc}
 \toprule
 	Thread & s   & e (min.)   & k (nom.) & m (max.) & m'\\
@@ -62,7 +90,8 @@ M8     & 13  & 14.20      & 5.3 & 6.5 & 3.70\\
 M10    & 16  & 17.59      & 6.4 & 8 & 4.70\\
 \bottomrule
 \end{fulltab}
-
+m and m' are analogous to k for nuts (resp. jam nuts).
+\end{minipage}
 \chapter{Electronics}
 \section{Labelling}
 \paragraph{Color code}
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