Why Buyers Should Confirm H Dimension
When a spring washer quote looks unusually low, the first question should not be cost alone. Buyers should confirm whether the formed free height and material thickness match the intended RFQ requirement.
DIN 127B spring lock washers are often purchased by standard number, nominal size, material and surface finish. In many RFQs, the H dimension is not stated clearly. This can create confusion because H is not simply the material thickness. It is better treated as the formed free height or opening height of the spring washer after forming.
For buyers comparing China suppliers, H dimension should be confirmed together with thickness, hardness target and finish. A washer can look similar in a quotation sheet, but the formed opening height may affect how the washer sits in the bolted assembly.
What H Dimension Means
For purchasing discussion, H dimension refers to the free height or opening height after the split spring washer is formed. It is the gap or spring space created by the two offset ends of the washer. It should be discussed separately from material thickness.
When an RFQ only says "DIN 127B, M size, zinc plated", the supplier may confirm the common size and finish but not the target free height. If the application is sensitive to spring effect, assembly feel or buyer inspection, the H dimension should be written into the inquiry.
Why It Is Often Missed In RFQs
Many buyers use old purchase descriptions, maintenance lists or ERP item names. These records may include only the standard and nominal size. For regular warehouse buying, that may be enough to start a quote, but it is not always enough for batch comparison.
For export RFQs, the safer approach is to send the standard, nominal size, material, thickness, free height or H requirement, finish, hardness target, quantity, packing and destination. This lets the supplier review both washer geometry and commercial loading.
Why Low-Cost Supply Chains May Need Extra Confirmation
In some low-cost supply chains, including parts of northern China such as Shandong and Hebei, suppliers may control cost by selecting thinner material or material close to the lower side of the accepted range. This does not mean every supplier in those regions is unsuitable. It means buyers should confirm the details instead of comparing quotation cost alone.
When material is thinner or forming is adjusted for cost, the opening height or free-height margin may also become smaller. The result may still be described as DIN 127B in a quotation, but the buyer should confirm the actual RFQ requirement before approving a bulk order.
Why Cost-Only Comparison Is Risky
A lower quoted cost can come from many factors: steel grade, material thickness, forming setup, finish, packing weight, carton loading or order quantity. If H dimension is not discussed, a cost comparison may hide a geometry difference that only appears during inspection or assembly.
For critical or repeat orders, buyers should ask for a sample, drawing confirmation or batch inspection note before scaling up. This is especially useful when switching suppliers or when the previous supplier's washer has already been approved by the end customer.
What Buyers Should Specify In The RFQ
- Standard: DIN 127B.
- Nominal size and required quantity.
- Material and hardness target.
- Material thickness and H dimension / free height requirement.
- Surface finish, corrosion expectation and packing method.
- Destination country or region, label requirement and pallet loading notes.
- Any approved sample photo, drawing or inspection requirement.
See the main DIN 127B spring lock washer page for size tables and RFQ context, or review the washer surface finish guide before choosing coating options.
Include standard, size, material, H/free height, finish, quantity and destination.