Crankshaft key (Woodruff key) 2,5X3,7X9,5 DERBI

Crankshaft key 2,5 × 3,7 × 9,5 mm, DERBI – a segment key, also called a half-moon key: a steel part with a flat top edge. It fits into the shaft's groove and holds the flywheel so it cannot turn on the shaft.

• Three numbers in the name – thickness 2,5 mm, height 3,7 mm and length 9,5 mm; that is the order they are marked in on this category's manufacturer drawing
• The bottom is curved to match the shaft groove, the top is flat – the same profile is seen in every photo in this category
• You will recognise a worn key by a rubbed-down side and rounded edges – a key like that already lets the flywheel shift on the shaft, and the ignition timing drifts along with it
• It is this product's drawing specifically that has arrows marking which number means what: 2,5 mm thickness, 3,7 mm height, 9,5 mm length
• DERBI is given in the name – that is the only reference to the machine
• The same category has a 3 × 3,7 × 9,6 mm key – the same height, but 0,5 mm thicker
• You will find crankshafts and the gudgeon-pin needle bearing in the same category
• Supplier code SS 015847215 – quote it again when ordering

We write only what we know. The supplier calls this part a cotter pin, but the photo shows not a cotter pin but a segment key; these are different parts, so we are checking the name with the manufacturer. Before ordering, measure the old key or the shaft groove – thickness, height and length – and send us a photo; we will check it before you order.

24-month warranty · tel. +370 685 777 56