Why Locating Holes Matter On Large HSS Saw Blades

Small HSS circular saw blades are often ordered only by outside diameter, thickness, bore and tooth count. For larger HSS blades, especially 250mm and above, many machines use locating pins or driving pins on the flange. If the locating hole pattern is wrong, the blade may not sit correctly on the machine.

In daily quotation work, however, locating holes should not be treated too mechanically. Many customers do not use every locating hole on the blade. On some large HSS blades, the machine may only use two locating pins for positioning and drive. A blade may have several hole groups, but the customer may use only one group, or only two holes from the pattern.

How To Read The Notation: Hole Quantity / Hole Diameter / PCD

Chinese factories often write locating holes in a compact format:

2 / 8.5 / 45

This normally means 2 locating holes, 8.5mm hole diameter and 45mm pitch circle diameter. PCD means the circle diameter on which the locating holes are positioned.

A combined pattern such as 2/8.5/45 + 4/12/64 means the blade has two different locating hole groups. The customer may not use all of them; the extra group may be made to fit another machine or to match a factory’s standard material stock.

Close Patterns Are Not Always Different Machine Standards

Patterns such as 2/12/63 and 2/13/64 can look different on paper, but in many real installation cases the practical difference is small. The customer can often insert the locating pins without difficulty, especially when the machine only uses two pins and the flange has normal clearance.

These small differences are often used by different HSS material factories, internal material codes or factory stock standards. They do not always mean the saw blade is for a completely different machine structure.

Practical note: Locating holes still need confirmation, but not every small difference should be understood as a completely different machine standard. Be more careful with slotted holes, angled holes, special flange structures, multi-pattern blades and orders where the buyer asks to copy the old blade exactly.

Common HSS Locating Hole References

Reference Type Common Pattern How To Understand It
Export 6-hole pattern, 32mm bore 2/8.5/45 + 4/12/64 Two hole groups on one blade. Confirm which group the customer actually uses.
Export 6-hole pattern, 40mm bore 2/8.5/55 + 4/12/64 Similar logic, but the smaller two-hole group uses a different PCD.
W5 style reference 2/8.5/45, 2/10/50, 2/12/64 Common two-hole locating patterns seen in HSS large saw blade material references.
W6 style reference 2/12/63, 2/13/64 Close patterns that are often used as material-factory or internal stock distinctions.
M42 style reference 4/12.5/64 A four-hole pattern. Confirm whether the buyer’s machine flange uses all four holes.
Multiple pattern blade 2/8.5/45 + 2/9.5/50 + 2/12.5/64 Often made to cover several machine or customer requirements. Ask for the old blade photo.
Special hole style Slotted hole or angled hole Do not guess. A clear drawing, old blade photo or flange photo is needed.

What Buyers Should Send For Confirmation

The safest inquiry is not only a written hole code. Ask for a full blade photo, a close-up of the center bore and locating holes, the machine model if available, and a simple drawing if the hole shape is not round.

A clear English quotation format can be:

HSS circular saw blade 300 x 2.0 x 32 x 200T, locating holes: 2/8.5/45 + 4/12/64

Conclusion

For HSS circular saw blades, locating holes are part of machine fit, but they should be interpreted with production experience. In many cases, only two pins are actually used, and close patterns such as 2/12/63 and 2/13/64 may not create a real installation problem. The key is to confirm the hole group that the buyer’s machine actually uses, especially when the blade has slotted holes, angled holes or a special flange requirement.