DIN 609 Hex Fit Bolts (Fitted Shank)

DIN 609 hex fit bolts, M8–M52 with K6 fitted shank — bolts with a ground cylindrical bearing shank for shear-loaded reamed holes, with the collected per-size tables: coarse/fine pitches, three-regime b ladder, d s K6, d 0, e, k, k 1, r and s.

Last updated: 2026-11

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DIN 609 Hex Fit Bolts (Fitted Shank) in an industrial setting — Illustrative image redrawn from real product references — not a photograph of stocked items.

Specifications

A fit bolt (Passschraube) is a bolt whose unthreaded shank is ground to a K6 tolerance so it can be dropped into a reamed hole and carry shear as a precision dowel — the bolt and the pin in one part. DIN 609 is the long-thread version: the thread starts immediately below the head and runs long (the collected b ladder runs 14.5–27.5 at the small sizes), leaving a generous fitted shank to bridge the joint. Where vibration or reversing shear loads would hammer an ordinary clearance bolt into its hole wall, the fit bolt's K6 shank bears across the full joint thickness with no slack — the standard answer for locating bolts on gear housings, press frames, crane slewing rings and dies. The collected tables run M8 to M52 in coarse plus two fine pitches, with the fitted shank d s printed as "Nominal Size (K6)" with min/max, the unthreaded portion d 0, across-corners e, head height k, bearing-check k 1, fillet r and across-flats s. Note the fit-bolt arithmetic: the nominal thread size and the shank differ (M8 bolt → 9 mm shank, M10 → 11 mm), so the reamed hole follows the shank column, not the thread. Property classes and finishes stay per RFQ.

Standard	DIN 609 — hexagon fit bolts with long thread (fitted shank for reamed holes)
Series	M8 – M52 (six source column groups; parenthesized non-preferred sizes) — coarse plus fine thread-1/2 pitch rows as printed
Tabulated geometry	Per size: pitch P (coarse/fine-1/fine-2), b ladder (L≤50 / 50<L≤150 / L>150), fitted shank d s Nominal Size (K6) with min/max (K6 tolerance), unthreaded shank d 0 (min/max), e (min), k (nominal/min/max), k 1 (min), r (min/max), s (max=nominal, min)
Shank fit	d s ground to K6 as printed — the reamed hole is sized to the shank column (M8→9 mm … M16→17 mm), not the thread designation
Property classes / finishes	Not tabulated by the collected specification — per RFQ (fit bolts for shear duty are typically 8.8 or 10.9 with reamed holes H7/K6 mating; confirm at quotation)

DIN 609 hex fit bolts - per-size dimensions (M8 - M12)All dimensions in millimeters. Attribute labels follow the source: P = thread pitch (coarse plus fine thread-1/2 rows, '-' where a fine pitch does not apply); b = thread length in three regimes (the source prints the regime boundaries with full-width characters, '50＜L≤ 150' / 'L＞150', kept verbatim); d s = fitted shank diameter with K6 tolerance as printed; d 0 = unthreaded shank diameter (min/max); e = width across corners; k = head height; k 1 = head-bearing check height; r = fillet radius (min/max); s = width across flats, max = nominal size. Parenthesized sizes are the non-preferred series as printed.
Attribute	M8	M10	M12
P — Pitch — Coarse thread	1.25	1.5	1.75
Fine thread-1	1	1.25	1.25
Fine thread-2	-	1	1.5
b — L≤50	14.5	17.5	20.5
50＜L≤ 150	16.5	19.5	22.5
L＞150	21.5	24.5	27.5
d s — Nominal Size (K6)	9	11	13
min	9.001	11.001	13.001
max	9.01	11.012	13.012
d 0 — min	7.9	9.9	11.5
max	8.2	10.2	11.8
e — min	14.38	17.77	19.85
k — Nominal Size	5.3	6.4	7.5
min	5.15	6.22	7.21
max	5.45	6.58	7.79
k 1 — min	3.61	4.35	5.05
r — min	0.4	0.4	0.6
max	0.55	0.55	0.75
s — max=nominal size	13	16	18
min	12.73	15.73	17.57

DIN 609 hex fit bolts - per-size dimensions ((M14) - (M18))All dimensions in millimeters. Attribute labels follow the source: P = thread pitch (coarse plus fine thread-1/2 rows, '-' where a fine pitch does not apply); b = thread length in three regimes (the source prints the regime boundaries with full-width characters, '50＜L≤ 150' / 'L＞150', kept verbatim); d s = fitted shank diameter with K6 tolerance as printed; d 0 = unthreaded shank diameter (min/max); e = width across corners; k = head height; k 1 = head-bearing check height; r = fillet radius (min/max); s = width across flats, max = nominal size. Parenthesized sizes are the non-preferred series as printed.
Attribute	(M14)	M16	(M18)
P — Pitch — Coarse thread	2	2	2.5
Fine thread-1	1.5	1.5	1.5
Fine thread-2	-	-	2
b — L≤50	22	25	27.5
50＜L≤ 150	24	27	29.5
L＞150	29	32	34.5
d s — Nominal Size (K6)	15	17	19
min	15.001	17.001	19.002
max	15.012	17.012	19.015
d 0 — min	13.5	15.5	17.5
max	13.8	15.8	17.8
e — min	22.78	26.17	29.56
k — Nominal Size	8.8	10	11.5
min	8.51	9.71	11.15
max	9.09	10.29	11.85
k 1 — min	5.96	6.8	7.81
r — min	0.6	0.6	0.6
max	0.75	0.75	0.75
s — max=nominal size	21	24	27
min	20.16	23.16	26.16

DIN 609 hex fit bolts - per-size dimensions (M20 - M24)All dimensions in millimeters. Attribute labels follow the source: P = thread pitch (coarse plus fine thread-1/2 rows, '-' where a fine pitch does not apply); b = thread length in three regimes (the source prints the regime boundaries with full-width characters, '50＜L≤ 150' / 'L＞150', kept verbatim); d s = fitted shank diameter with K6 tolerance as printed; d 0 = unthreaded shank diameter (min/max); e = width across corners; k = head height; k 1 = head-bearing check height; r = fillet radius (min/max); s = width across flats, max = nominal size. Parenthesized sizes are the non-preferred series as printed.
Attribute	M20	(M22)	M24
P — Pitch — Coarse thread	2.5	2.5	3
Fine thread-1	1.5	1.5	2
Fine thread-2	2	2	1.5
b — L≤50	28.5	32.5	-
50＜L≤ 150	30.5	34.5	36.5
L＞150	35.5	39.5	41.5
d s — Nominal Size (K6)	21	23	25
min	21.002	23.002	25.002
max	21.015	23.015	25.015
d 0 — min	19.1	21.1	23.1
max	19.4	21.4	23.4
e — min	32.95	37.29	39.55
k — Nominal Size	12.5	14	15
min	12.15	13.65	14.65
max	12.85	14.35	15.35
k 1 — min	8.51	9.65	10.26
r — min	0.8	0.8	0.8
max	0.95	0.95	0.95
s — max=nominal size	30	34	36
min	29.16	33	35

DIN 609 hex fit bolts - per-size dimensions ((M27) - (M33))All dimensions in millimeters. Attribute labels follow the source: P = thread pitch (coarse plus fine thread-1/2 rows, '-' where a fine pitch does not apply); b = thread length in three regimes (the source prints the regime boundaries with full-width characters, '50＜L≤ 150' / 'L＞150', kept verbatim); d s = fitted shank diameter with K6 tolerance as printed; d 0 = unthreaded shank diameter (min/max); e = width across corners; k = head height; k 1 = head-bearing check height; r = fillet radius (min/max); s = width across flats, max = nominal size. Parenthesized sizes are the non-preferred series as printed.
Attribute	(M27)	M30	(M33)
P — Pitch — Coarse thread	3	3.5	3.5
Fine thread-1	2	2	2
Fine thread-2	-	-	-
b — L≤50	-	-	-
50＜L≤ 150	39.5	43	45
L＞150	44.5	48	50
d s — Nominal Size (K6)	28	32	34
min	28.002	32.002	34.002
max	28.015	32.018	34.018
d 0 — min	25.7	29.7	31.7
max	26	30	32
e — min	45.2	50.85	55.37
k — Nominal Size	17	19	21
min	16.65	18.58	20.58
max	17.35	19.42	21.42
k 1 — min	11.66	13.01	14.41
r — min	1	1	1
max	1.15	1.15	1.15
s — max=nominal size	41	46	50
min	40	45	49

DIN 609 hex fit bolts - per-size dimensions (M36 - M42)All dimensions in millimeters. Attribute labels follow the source: P = thread pitch (coarse plus fine thread-1/2 rows, '-' where a fine pitch does not apply); b = thread length in three regimes (the source prints the regime boundaries with full-width characters, '50＜L≤ 150' / 'L＞150', kept verbatim); d s = fitted shank diameter with K6 tolerance as printed; d 0 = unthreaded shank diameter (min/max); e = width across corners; k = head height; k 1 = head-bearing check height; r = fillet radius (min/max); s = width across flats, max = nominal size. Parenthesized sizes are the non-preferred series as printed.
Attribute	M36	(M39)	M42
P — Pitch — Coarse thread	4	4	4
Fine thread-1	3	3	3
Fine thread-2	-	-	-
b — L≤50	-	-	-
50＜L≤ 150	49	51	56
L＞150	54	56	61
d s — Nominal Size (K6)	38	40	44
min	38.002	40.002	44.002
max	38.018	40.018	44.018
d 0 — min	35.7	37.7	41.7
max	36	38	42
e — min	60.79	66.44	71.3
k — Nominal Size	22	25	26
min	21.58	24.58	25.58
max	22.42	25.42	26.42
k 1 — min	15.11	17.21	17.91
r — min	1	1	1
max	1.15	1.15	1.15
s — max=nominal size	55	60	65
min	53.8	58.8	63.1

DIN 609 hex fit bolts - per-size dimensions ((M45) - (M52))All dimensions in millimeters. Attribute labels follow the source: P = thread pitch (coarse plus fine thread-1/2 rows, '-' where a fine pitch does not apply); b = thread length in three regimes (the source prints the regime boundaries with full-width characters, '50＜L≤ 150' / 'L＞150', kept verbatim); d s = fitted shank diameter with K6 tolerance as printed; d 0 = unthreaded shank diameter (min/max); e = width across corners; k = head height; k 1 = head-bearing check height; r = fillet radius (min/max); s = width across flats, max = nominal size. Parenthesized sizes are the non-preferred series as printed.
Attribute	(M45)	M48	(M52)
P — Pitch — Coarse thread	4	4	4
Fine thread-1	3	3	3
Fine thread-2	-	-	-
b — L≤50	-	-	-
50＜L≤ 150	59	63	65
L＞150	64	68	70
d s — Nominal Size (K6)	46	50	55
min	46.002	50.002	55.002
max	46.018	50.018	55.021
d 0 — min	43.7	47.7	52.7
max	44	48	53
e — min	76.95	82.6	88.25
k — Nominal Size	28	30	33
min	27.58	29.58	32.5
max	28.42	30.42	33.5
k 1 — min	19.31	20.71	22.75
r — min	1	1	1
max	1.15	1.15	1.15
s — max=nominal size	70	75	80
min	68.1	73.1	78.1

Materials

Material and property class specified per RFQ — state hole diameter and ream tolerance with the order: the K6 shank only fits what the mating parts were reamed to

Ordering & documentation

Documents

Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.

Quotation

The fastener family (DIN 609 Hex Fit Bolts (Fitted Shank)) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
Quantity per size and your target delivery date.
Destination country, and any required documents (for example a mill test certificate) so the quote includes them.

Sample & supply

Minimum order quantity is 1,000–10,000 pieces depending on size. Stock items run 3–7 days. High-strength and custom parts run 15–25 days. Quantities or variants outside the standard range are confirmed at quotation.

Storage & shipping

Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.

Frequently asked questions

DIN 609 (long thread) or DIN 610 (short thread) fit bolts — which one?

By the joint's grip versus the shear length you need. Both carry the same K6 fitted shank and the same head; the collected tables show the difference in the thread-length ladders — DIN 609's b runs 14.5–27.5 at M8–M12 (long thread, more clamping adjustment), DIN 610's runs 11.5–15.5 (short thread, the shank-dominated version). The short-thread DIN 610 puts more of its length into reamed bearing, which is the pick where the joint is a pure shear/dowel connection and the two plates are fixed in position; the long-thread DIN 609 buys nut engagement for joints with a stack-up or where a locking nut runs a long way. One trap worth naming: the shank is one size up from the thread (M10 bolt, 11 mm shank), so a "DIN 609 M10" never fits a 10 mm hole — order by shank diameter for the hole and thread size for the nut. And because the fit is the whole point, state the reamed hole tolerance and any running-fit requirement (H7 is typical) at RFQ; the property class rides along with that confirmation.

What is the MOQ and lead time for this bolt type?

The minimum order quantity is 1,000–10,000 pieces depending on size. Stock items ship in 3–7 days; high-strength and custom parts in 15–25 days. Common sizes in this bolt type are widely stocked; confirm the exact schedule against quantity and size mix at quotation.

Related knowledge

Request a Quote

Get factory-direct pricing from the manufacturer.

What to include in your inquiry

✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
✓ Sizes, lengths and thread type (metric or inch).
✓ Quantity per size and your target delivery date.
✓ Destination country, plus any coating or finish requirement.
✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.

✓ Factory-direct pricing
✓ Standard and custom specifications
✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
✓ Full fastener family support

DIN 609 Hex Fit Bolts (Fitted Shank)

Specifications

Materials

Ordering & documentation

Documents

Quotation

Sample & supply

Storage & shipping

Frequently asked questions

DIN 609 (long thread) or DIN 610 (short thread) fit bolts — which one?

What is the MOQ and lead time for this bolt type?

Related grades & products

Related knowledge

Request a Quote

What to include in your inquiry