32 mm vs 40 mm Bore Cold Saw Blades: How They Differ
The bore must match your saw's arbor. Compare 32 mm and 40 mm bore blades, how their pin patterns differ, and when a reducing ring applies.
Your saw’s arbor sets the bore. A 32 mm bore blade fits a 32 mm arbor, and a 40 mm bore blade fits a 40 mm arbor. A blade whose center hole is smaller than the arbor cannot be mounted. The workaround suppliers list goes the other way: a reducing ring that lets a 40 mm bore blade sit on a 32 mm arbor.
Thickness, pin holes and diameter can match or differ across the two bores, so this post covers what changes and what does not.
Key takeaways
- Match the blade bore to the saw’s arbor. Measure it instead of guessing from the saw brand.
- In the published examples, 32 mm and 40 mm blades use different pin patterns, so a matching diameter does not mean matching pins.
- Bore does not fix thickness. One distributor sells the same 350 mm blade at 2.5 and 3.0 mm in both bores.
- A 40 to 32 mm reducing ring exists. Ask the saw’s maker before using one.
32 mm vs 40 mm at a glance
| 32 mm bore | 40 mm bore | |
|---|---|---|
| Diameters in the SAS M2 HSS listings | 200 to 370 mm | 250 to 400 mm |
| Pin patterns in the published examples | McMaster-Carr: 2/8.5/45 + 4/9/50 + 2/12/64. Haberle: 2/8/45 + 4/9/50 + 2/11/63 | McMaster-Carr: 2/9/55 + 4/12/64. Haberle: 2/8/55 + 4/12/64 |
| Saw brands in Scotchman’s list | Bewo, Marathon, StartRite, IBP, Kalamazoo, Amer Brown, Soco, Emerson | Bewo, Haberle, Eisele, Brobo |
Sources: Penn Tool Co., Scotchman cold saw blades, McMaster-Carr 32 mm, McMaster-Carr 40 mm, Haberle stock chart, and the SAS M2 HSS product listings in the catalog (read October 23, 2026).
The saw decides the bore
The bore centers the blade on the arbor. The arbor is part of the machine, so changing the bore means changing either the blade or adding an adapter, and the adapter is the saw maker’s call.
Do not read the bore from the machine’s name. Scotchman’s blade page lists Bewo under both the 32 mm and the 40 mm columns, so brand alone does not settle it. Measure the arbor with calipers, or measure the old blade’s center hole. For the pin side, see how to measure a cold saw blade’s bore and pin holes.
Which sizes come in which bore
The SAS M2 HSS cold saw blade listings offer these bores for each diameter, as of October 23, 2026. Examples: 250 × 2 × 32 mm, 250 × 2 × 40 mm, 300 × 2.5 × 38 mm, 450 × 3 × 50 mm.
| Diameter | Bores listed (mm) |
|---|---|
| 200 mm | 32 |
| 225 mm | 32 |
| 250 mm | 32, 40 |
| 275 mm | 32, 40 |
| 300 mm | 32, 38, 40 |
| 315 mm | 32, 40 |
| 350 mm | 32, 40, 50 |
| 370 mm | 32, 40, 50 |
| 400 mm | 40, 50 |
| 450 mm | 50 |
Both common bores are offered from 250 to 370 mm. The 38 mm bore appears only on a 300 mm blade, and 50 mm bores appear from 350 mm up. Other suppliers show a similar spread: Haberle’s chart lists a 300 × 2.5 × 38 mm blade and a 350 × 3 × 50 mm blade (Haberle).
Thickness is a separate choice from bore. Excision lists its 350 mm HSS blade in both 2.5 mm and 3.0 mm for each of the 32 mm and 40 mm bores (Excision 350 mm HSS cold saw blade). See cold saw blade thickness for more.
Pin holes differ between the two bores
In the published examples, the 32 mm bore uses circles of 45 and 50 mm plus a third near 63 to 64 mm. The 40 mm bore uses a 55 mm circle and a 64 mm circle. Hole sizes vary by maker: 8.5 mm versus 8 mm on the 32 mm bore’s 45 mm set, and 9 mm versus 8 mm on the 40 mm bore’s 55 mm set.
Because the holes must line up with fixed pins, a blade with the right bore and the wrong pin pattern may not seat on the flange. Confirm both. The numbers above are from two makers and are examples, not a standard.
When a reducing ring applies
If your saw has a 32 mm arbor and your blade has a 40 mm bore, a ring fills the gap. Hoffmann Group lists a 40 / 32 steel reducing ring: 40 mm outside diameter, 32 mm bore, 3 mm thick, with H7 fit tolerances on both diameters, for 40 mm bore circular saw blades on machines with a 32 mm arbor (Hoffmann Group, reducing ring 40/32).
Three limits:
- A ring reduces a bore. A 32 mm bore blade has a hole smaller than a 40 mm arbor, so no ring helps. You need a 40 mm bore blade.
- The listing is for Hoffmann’s own blade range. It does not cover how a ring behaves on your machine.
- Whether a ring is appropriate on a given saw is for the saw’s maker to say.
If you are unsure, buy the blade with the bore your saw’s arbor needs. Inch arbors need care too: a Dake saw lists a 1-1/4 in. arbor, which is 31.75 mm, not 32 mm. Check the saw maker’s stated arbor size and the blade’s stated bore before you order. The size chart has the conversions.
How to choose
- Measure the arbor (or the old blade’s bore).
- If it reads 32 mm, shop 32 mm bore blades. If it reads 40 mm, shop 40 mm bore blades. For 38 or 50 mm, check the catalog for your diameter.
- Match the pin pattern.
- Then choose thickness, tooth count and material.
Frequently asked questions
Can a 32 mm bore blade run on a 40 mm arbor? Not directly. The blade’s hole is smaller than the arbor, and the reducing ring in this post only works the other way.
Does a 40 mm bore blade mean a thicker blade? Not as a rule. Excision sells both bores in both 2.5 and 3.0 mm.
Next steps
Pair this with the replacement cold saw blade checklist before ordering.
To compare the two bores at one diameter and thickness, see 350 × 2.5 × 32 mm M2 HSS and 350 × 2.5 × 40 mm M2 HSS. For questions about a specific saw, use the contact page.