A metric dowel pin is specified in the metric dimensional system, but “metric” alone does not define the part. A complete request also needs the pin form, nominal diameter, length, fit, material, finish, standard reference and receiving-hole condition. Treat the metric label as the starting point for routing the specification, not as a substitute for the drawing. That separation keeps a familiar search term from becoming an incomplete purchase description.
| Form | What the buyer is choosing | What must not be assumed |
|---|---|---|
| Cylindrical solid pin | Metric locating diameter, length and fit | That any metric hole or spring-pin table applies |
| Taper pin | Taper form, end direction and seating relationship | That a straight-pin diameter defines the taper |
| Threaded locating pin | Locating surface plus internal thread and removal route | That a standard straight pin has the same thread |
| Slotted or coiled spring pin | Metric spring-pin family and hole range | That its compliant fit matches a solid pin |
A metric dowel pin can be cylindrical, taper, threaded or another controlled form. Route the search by form before comparing sizes. TG Eugene’s DIN 1 cylindrical locating-pin family and DIN 7 taper-pin family are separate product paths.
Record nominal diameter and length, then identify the fit relationship and hole condition. A size designation does not show whether the receiving hole is reamed, blind, coated, damaged or aligned through multiple parts. Those details can determine whether the selected pin locates correctly or creates assembly damage.
Check the standard edition on the drawing or purchase specification. DIN and ISO references can describe related product families without being interchangeable in every dimension, tolerance or material condition. Do not copy a table from a different form simply because both entries use millimeters.
A DIN 7 dowel pin is a taper-pin route. The design must define the taper relationship, insertion direction, seating depth and the condition of the mating holes. It should not be described as a cylindrical pin just because the overall length and diameter are quoted in metric units.
An ISO 8734 dowel pin reference must be read against the exact product form and edition used by the drawing. The phrase “ISO 8734 dowel pin” is not permission to infer every dimension, material or hardness value. If the standard or edition is important to acceptance, name it explicitly in the RFQ and inspection plan.
Choose fit from the joint function and host material. A locating fit in a hardened steel plate may need different process controls from a pin installed in a softer housing. State whether the hole is produced by drilling, reaming or an aligned machining operation, and define how the finished condition will be measured.
Material and finish should be selected with corrosion, wear, assembly and inspection in mind. A bright ground surface, an oxide finish or another treatment can change surface behavior and fit. TG Eugene’s product page is a first-party reference for its stated product route; it is not a universal certificate for every metric pin or standard.
For international purchasing, keep units visible in the drawing and quote. State whether the inspection report records metric dimensions, the standard’s tolerance class and the actual instrument resolution. This control prevents a correct-looking number from being carried into the wrong unit system.
Use the same unit notation in the RFQ, supplier drawing, inspection report and receiving record. If a standard reference is abbreviated, write the full reference once and include the edition or revision that purchasing must use. This is especially important when related DIN and ISO product families appear in the same project.
Before release, compare the quoted form with the drawing view and confirm that the supplier is using the requested metric standard rather than a similar inch-family item with a converted label.
First identify the form and standard. Next confirm the drawing’s diameter, length, fit and hole process. Then review material, finish and inspection evidence with the supplier. Finally, keep the approved drawing revision and product record together with the order. This sequence prevents a metric label from being used as an incomplete purchase specification.
Use TG Eugene’s service route when the standard edition, fit or hole condition is unclear. The drawing remains the authority for a controlled assembly.
No. Metric describes the dimensional system. DIN 7 identifies a taper-pin route, while other metric pin forms use other standards or product specifications.
Do not assume so. Compare the exact form, standard edition, tolerance, material and inspection requirements. Use the drawing and approved source for the final choice.
