DIN 609 Hexagon Fit Bolts
We supply DIN 609 hexagon fit bolts in grade 8.8, from M10 to M24. The shank is ground to a k6 tolerance and bears in an H7 reamed hole, so the bolt itself locates the joint and carries shear without movement - doing the work of a dowel and a bolt in one fastener.
Also known as: fit bolt, fitted bolt, close tolerance bolt, reamer bolt, shear bolt.
DIN 609 dimensions
| Diameter | Pitch | Thread length: L ≤ 50mm | Thread length: L > 50mm | Shank diameter (k6) | Hole tolerance | Head depth | Across flats |
|---|---|---|---|---|---|---|---|
| M10 | 1.5mm | 17.5mm | 19.5mm | 11mm | H7 | 6.4 | 16 |
| M12 | 1.75mm | 20.5mm | 22.5mm | 13mm | H7 | 7.5 | 18 |
| M16 | 2.0mm | 25.0mm | 27.0mm | 17mm | H7 | 10 | 24 |
| M20 | 2.5mm | 28.5mm | 30.5mm | 21mm | H7 | 12.5 | 30 |
| M24 | 3.0mm | - | 36.5mm | 25mm | H7 | 15 | 36 |
What is a fit bolt used for?
Fit bolts suit joints that must not shift under shear - couplings, flanges, machinery feet and repairs where elongated holes would be trouble. The ground shank in a reamed hole gives positive location that an ordinary clearance-hole bolt cannot.
What hole should I ream for a DIN 609 bolt?
The shank is ground to k6 and is designed for an H7 reamed hole of the shank's nominal diameter - the dimension table lists the shank diameter for each thread size. The controlled shank and reamed-hole tolerances provide accurate location and minimise movement compared with an ordinary clearance-hole joint.
What materials are DIN 609 fit bolts supplied in?
Grade 8.8 steel is the standard offering. Other grades and stainless versions are quoted to order - tell us size, quantity and the joint details and we'll come back within 24 hours.
Need DIN 609 in a non-standard size or material?
Send us your drawing — specials quoted within 24 hours.