This page covers M20 Fitted (Reamer) Bolts, DIN 609 to DIN 609: the full dimensional row, hole and tool sizes, proof-load data and typical applications. All values are taken from the governing standards (DIN 609 together with ISO 273, ISO 724 and ISO 898-1 where applicable).
M20 Dimensional Row (DIN 609)
| Thread size | Shank diameter ds k6 (mm) | Reamed hole H7 (mm) | Width across flats s (mm) | Head height k (mm) | Common length range (mm) | Property class | Reference standard |
|---|---|---|---|---|---|---|---|
| M20 | 21 | 21 | 30 | 12.5 | 60~180 | 8.8 | DIN 609 |
Spanner & Drive for M20 Fitted (Reamer) Bolts, DIN 609
Drive geometry for M20 Fitted (Reamer) Bolts, DIN 609 is given by the row above; match the tool to the listed values.
Hole Sizes for M20
| Coarse-thread pitch (ISO 724) | 2.5 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 22 mm |
| Tapping drill, coarse thread | 17.5 mm |
Tightening Torque for M20
| Class 8.8 (dry, ~µ 0.125) | ≈ 420 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 598 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 700 Nm |
Indicative dry-joint values. Lubrication can lower the required torque by 15–25%. Always confirm against the joint design, especially when going up a strength class.
Proof Load & Strength for M20
| Tensile stress area As (ISO 724) | 245 mm² |
|---|---|
| Proof load, class 8.8 | 147 kN |
| Proof load, class 10.9 | 203 kN |
| Proof load, class 12.9 | 237 kN |
| Min. ultimate tensile load, class 8.8 | 203 kN |
Proof load = tensile stress area × the proof stress Sp of the class, per ISO 898-1 — Sp is a lower figure than the yield stress Rp0.2 and the two are not interchangeable. The stress area is computed from this size's own diameter and pitch, so a fine-pitch designation gives the fine-pitch figure. Design the joint so the working preload stays below the proof load of the class selected.
M20 Fitted (Reamer) Bolts, DIN 609 Weight
A steel M20 fitted (reamer) bolts, din 609 at the listed 60,180 mm length weighs approximately 163,702 g each — about 163,702 kg per 1,000 pieces. Stainless A2/A4 weighs roughly the same (density 7.9–8.0 g/cm³).
Actual weight varies slightly with head form, thread and finish; use this figure for freight estimation only.
Installation Tips for M20 Fitted (Reamer) Bolts, DIN 609
- At M20 the stretch in the bolt becomes the controlling factor — for critical joints, use angle-controlled or stretch-controlled tightening instead of pure torque.
Mating Parts for M20
For M20, pair with a M20 hex nut (ISO 4032 / DIN 934) and, where used, a M20 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.
Custom manufacturing · Made to drawing
Need fitted (reamer) bolts, DIN 609 in a size this table does not list?
This page covers M20 fitted (reamer) bolts, DIN 609. Material and finish are usually what drives a special — a grade the standard part is not stocked in, or a coating chosen against a salt-spray figure instead of a default. Made by cold heading or hot forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
