Löwenherz Thread Size Chart
The Löwenherz fine thread series, 1.0 to 16 mm nominal diameter: metric diameter with inch equivalent, pitch in mm, and approximate threads per inch — the shallow 60° thread form behind instrument and precision work.
Last updated: 2026-11
Specifications
The Löwenherz thread is the fine-pitch instrument series most buyers meet as "that odd 9 mm x 1.3 thread on old optical and measuring equipment" — a 60° form cut deliberately shallow (crest depth 0.75 x pitch against a metric ISO 0.61 x pitch) so thin-walled parts keep their section. The collected chart runs 1.0 to 16 mm in two side-by-side column groups: 1.0 mm at 0.25 pitch (~101.6 tpi), 2.0 at 0.40 (63.5), 9.0 at 1.30 (19.5), 10.0 at 1.40 (18.1), 16.0 at 2.00 (12.7) — pitches sitting well under the ISO coarse series at every diameter (M10 coarse is 1.5; Löwenherz 10 is 1.4, and the whole ladder is finer). Inch equivalents are printed per row (10 mm = 0.3937 in) and the tpi column is marked approximate. The series survives today mostly in restoration, instrument service and fittings where the thread form itself is the legacy interface — ordering it is a drawing-controlled decision, not a catalogue substitution for M threads, because the shallower engagement changes strength and the pitches rarely interchange.
| Series / scope | Löwenherz fine thread, 60° form, nominal 1.0 to 16 mm — diameter (mm/inch), pitch (mm), approximate threads per inch, as printed side-by-side |
|---|---|
| Small end | 1.0 mm (0.0394 in): pitch 0.25, ~101.6 tpi; 1.2: 0.25, 101.6; 1.4: 0.30, 84.7; 1.7: 0.35, 72.6; 2.0: 0.40, 63.5 |
| Mid ladder | 9.0 mm (0.3543 in): pitch 1.30, 19.5 tpi; 10.0 (0.3937): 1.40, 18.1; 12.0 (0.4724): 1.60, 15.9; 14.0 (0.5512): 1.80, 14.1 |
| Large end | 16.0 mm (0.6299 in): pitch 2.00, 12.7 tpi — the ladder ends at 16 mm as printed |
| Not tabulated | Thread depth/tolerance classes, stress areas, availability by size — the series is drawing-controlled legacy stock, per RFQ |
Materials
- Löwenherz threads appear on brass, steel and aluminum instrument parts; the shallow form is why the series suits thin-wall components. Do not substitute an ISO M thread of the nearest pitch — the depth difference and the fit change the joint. Quote legacy sizes by drawing number and nominal/pitch pair per RFQ
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 (Löwenherz Thread Size Chart) 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 10,000 pieces. Stock items run 3–7 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
Is a Löwenherz thread interchangeable with a metric ISO thread of the same diameter?
No, and the chart shows why in its own columns: at 10 mm the Löwenherz pitch is 1.4 against ISO coarse 1.5 and ISO fine 1.25 — neither meshes fully, and even at a pitch that happened to match, the Löwenherz form is shallower (0.75 x pitch crest depth vs the ISO 0.61 x pitch depth with a different crest/root layout), so engagement and strength differ even where a bolt threads in part way. The series exists because thin-wall instrument parts needed more thread turns in less depth, not as a fine-pitch alternative for general engineering. Treat it as what it is on this chart — a defined legacy series — and order it by the nominal/pitch pair or the drawing; substituting "M10x1.4 fine" for a Löwenherz 10 is a scrapped part or a stripped instrument thread.
Why does the tpi column print non-integer values like 101.6 and 19.5?
Because the series is defined in millimeters and the threads-per-inch figures are conversions: pitch 0.25 mm is 25.4/0.25 = 101.6 threads per inch exactly, and pitch 1.30 gives 19.5. The source marks the column "Approximate" for that reason — the mm pitch is the definition, the tpi is arithmetic on it. The practical traps are rounding and the inch-equivalent column next to it: 0.0394 in at 1.0 mm is a conversion, not a BSW/UNF size, and no UN thread runs 101.6 tpi. Work the series in metric, use the inch column only to sanity-check what you are holding, and quote sizes as "diameter x pitch (mm)" exactly as the chart prints them.
Related knowledge
- Thread-Forming vs Thread-Cutting vs Thread-Rolling Self-Tapping Screws: What the Evidence Settles on Base Material
- Screw Family Selection by Base Material: Wood, Machine and Self-Tapping Threads, Engagement and Coating
- Hex Bolts vs Socket Head Cap Screws: What the Evidence Settles on Strength, Clearance and Cost
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