How to Measure a Cold Saw Blade's Bore and Pin Holes
Measure the bore, pin-hole size, circle and count with calipers, then write them as count/diameter/circle, the format suppliers use.
Four measurements identify how a cold saw blade mounts: the bore diameter, the pin-hole diameter, the pin-hole circle, and the number of holes. A pair of calipers is enough. Write the result as three numbers, such as 2/8/45 (two holes, 8 mm across, on a 45 mm circle), and compare it with the supplier’s listing before you order.
Diameter and thickness are easy to read off a blade. Bore and pin holes are where replacement orders go wrong, because suppliers list them in different formats and the numbers differ slightly between makers (see the table below).
Key takeaways
- Measure in millimeters. Most cold saw blade listings are metric.
- Bore and pin pattern are separate requirements. A matching bore does not guarantee matching pin holes.
- Many blades are drilled with more than one set of holes, so group the holes by size before you measure.
- Published patterns for the “same” bore differ by manufacturer. Measure your own saw or old blade instead of assuming a standard.
What you need
- Digital or dial calipers with inside and outside jaws, or a set of pin gauges
- The old blade, or access to the saw’s blade flange
- A clean rag
- Paper and a pen, or your phone
Before you touch the arbor, follow your saw manual’s procedure for isolating and locking out the machine. This guide covers measuring only, not blade installation.
Step 1: Clean the area you will measure
Wipe chips, coolant and wax off the blade’s center and, if you are measuring from the saw, off the flange and drive pins. Debris in a hole or on a bore edge gives a false reading.
Step 2: Measure the bore
The bore is the center hole that sits over the saw’s arbor. Close the calipers’ inside jaws, insert them into the hole, open them until they touch both sides, and read the value in millimeters.
Most listings use 32 mm or 40 mm. Larger and less common sizes exist too: a Haberle stock-blade chart lists a 350 × 3 mm blade with a 50 mm bore and a 300 × 2.5 mm blade with a 38 mm bore (Haberle stock blade chart). If your reading is close to, but not exactly, a standard size, re-measure before you assume the blade is nonstandard.
Do not guess the bore from the saw’s brand. Scotchman’s blade page lists Bewo under both its 32 mm bore and its 40 mm bore blades (Penn Tool Co., Scotchman cold saw blades), so the machine name alone does not settle it.
Step 3: Count the pin holes and find the sets
Pin holes are the small holes around the bore. On a pin-drive saw, drive pins on the arbor flange pass through matching holes in the blade and transmit the turning force.
Count every hole, then group them by size and position. Blades are often drilled with more than one set. On McMaster-Carr’s listing for 32 mm bore steel-cutting blades, the 9 in. blade lists three sets: 2 holes at 8.5 mm, 4 holes at 9 mm, and 2 holes at 12 mm (McMaster-Carr, 32 mm arbor cold saw blades). A 14 in. blade in the same listing has two sets.
Your saw’s pins match the set whose holes line up with them. Measure that set.
Step 4: Measure the pin-hole diameter
Use the inside jaws (or a pin gauge) to measure one hole in each set. Read to a tenth of a millimeter. Hole sizes of 8, 8.5, 9, 11, 12, 14 and 15 mm all appear in published charts, and several of them are only half a millimeter apart.
Step 5: Measure the circle the holes sit on
The pin circle is the circle that passes through the centers of the holes in a set. Its diameter equals the distance between the centers of two opposite holes.
With calipers:
- Measure from the far edge of one hole to the far edge of the opposite hole.
- Subtract one hole diameter.
The result is the circle diameter. For a two-hole set, that is simply the distance between the two centers.
McMaster-Carr labels this column “Pinhole Center-to-Center.” Its values for the 32 mm sets (45 and 50 mm) match the circle diameters in the Haberle chart, which suggests the same measurement, but McMaster does not state it for four-hole sets. If a listing’s convention is unclear, ask the supplier.
Step 6: Write it in the standard format
The common shorthand is count / hole diameter / circle diameter, so 2/8/45 means two holes of 8 mm on a 45 mm circle. The Haberle chart uses this style. A blade with several sets joins them with plus signs. Haberle lists a 32 mm bore as 2/8/45 + 4/9/50 + 2/11/63.
Step 7: Compare with the listing
Check your three numbers against the supplier’s description. They should match one of the listed sets. If the listing has no pin-hole data, ask the supplier before you buy. SAS Blades product pages state diameter, thickness and bore. For pin-hole questions, see the SAS Blades contact page for the partner support line.
What published patterns look like
The table shows pin-hole patterns for the same bore from two sources, retrieved October 23, 2026. It shows how much the numbers move. It is not a reference to order from.
| Bore | McMaster-Carr (steel-cutting blades) | Haberle stock chart |
|---|---|---|
| 32 mm | 2/8.5/45 + 4/9/50 + 2/12/64 (9 to 12 in. blades). A 14 in. blade lists 2/8.5/45 + 2/11/63. | 2/8/45 + 4/9/50 + 2/11/63 |
| 40 mm | 2/9/55 + 4/12/64 | 2/8/55 + 4/12/64 |
| 50 mm (350 × 3 mm) | not listed | 4/15/80 + 4/14/85 |
Sources: McMaster-Carr 32 mm, McMaster-Carr 40 mm, Haberle stock chart. McMaster-Carr values are copied from its “Pinhole Center-to-Center” column.
The two makers agree on the circle diameters (45 and 50 mm on the 32 mm bore, 55 and 64 mm on the 40 mm bore) but not on every hole size or on the largest circle: 12 mm on 64 mm versus 11 mm on 63 mm at 32 mm bore, and 9 mm versus 8 mm on the first 40 mm set. Hole size and circle diameter both have to line up with fixed pins, so check these against your saw.
Common mistakes
| Mistake | What goes wrong | Fix |
|---|---|---|
| Treating the outside diameter as “the size” | Diameter and bore are separate specs | Record both |
| Measuring only one hole | Blades carry several sets | Group holes by size, then measure one per group |
| Reading edge to edge | You get a number larger than the center distance | Subtract one hole diameter |
| Skipping pin holes because the bore matches | Bore and pin pattern are separate | Match both |
Frequently asked questions
What does 2/8/45 mean? Two holes, 8 mm in diameter, on a 45 mm circle. Some suppliers list count, diameter and spacing in separate table columns instead.
Can one blade have more than one pin pattern? Yes. McMaster-Carr lists three sets on its 9 in. 32 mm bore steel-cutting blade.
Next steps
Once you have your diameter, bore and pin pattern, move on to the rest of the order specs in the replacement cold saw blade checklist, or read about the difference between 32 mm and 40 mm bore blades.
For tooth pitch, speed and feed tables, Cold Saw Blade Store keeps a reference: the Cold Saw Blade Guide. To browse blades by diameter, thickness and bore, see the SAS Blades catalog.