Riving knife too thick for the blade on a table saw
Updated: 22 October 2026
You have fitted a new 210 mm blade, the motor starts, and the offcut pinches or the knife simply will not enter the slot. A riving knife too thick for the blade is a geometry fault, not a blunt tooth and not a reason to unbolt the knife. The knife has to be thicker than the plate and thinner than the kerf. This page uses DeWalt's DWE7485 UK manual as the worked example, plus HSE's WIS16 and the eleven amazon.co.uk listings in the [210x30 saw blade comparison](/hub/saw-accessories/210x30-saw-blade), read on 20 October 2026. It is not a lab measurement of your saw. A qualifying purchase can earn a commission at no extra cost to you.
You have fitted a new 210 mm blade, the motor starts, and the offcut pinches or the knife simply will not enter the slot.
You have fitted a new 210 mm blade, the motor starts, and the offcut pinches or the knife simply will not enter the slot. A riving knife too thick for the blade is a geometry fault, not a blunt tooth and not a reason to unbolt the knife. The knife has to be thicker than the plate and thinner than the kerf. This page uses DeWalt's DWE7485 UK manual as the worked example, plus HSE's WIS16 and the eleven amazon.co.uk listings in the 210x30 saw blade comparison, read on 20 October 2026. It is not a lab measurement of your saw. A qualifying purchase can earn a commission at no extra cost to you.
Our top picks
| Badge | Product | Kerf | Plate | Against a 2.2 mm knife | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  Saxton Blades Saxton Blades TCT21080T 80-tooth | 2.6 mm | 1.6 mm | Clears | 8.5 | about £15.99 | View offer |
| Best value |  Rennie Tool Company Rennie 80-tooth blade | 2.5 mm | 1.6 mm | Clears | 8.0 | about £12.99 | View offer |
| Alternative |  Trend Trend CSB/21060TC 60-tooth | 1.8 mm | Not stated | Binds | 7.0 | about £27.48 | View offer |
On this page
What the riving knife does
On a table saw the riving knife holds the kerf open so the timber does not close on the rising teeth. That closure is how a rip turns into kickback. HSE's WIS16 says the knife should be rigid, in line with the blade, thicker than the body, slightly thinner than the cut, and within 8 mm of the blade at table level. These files do not print BS EN 847-1:2017, so this page does not claim the mark. PUWER 1998 applies when the saw is work equipment. Do not run without the knife, including for thin strips.
Plate, kerf and knife thickness
The plate is the steel disc. The kerf is the slot the tips cut, and it is wider than the plate. The knife must be thicker than the plate and thinner than the kerf. DeWalt's DWE7485 manual states a 2.4 mm kerf, a 1.6 mm body and a 2.2 mm knife. A 1.8 mm kerf fails because 1.8 is less than 2.2. One reviewer measured a DWE7485 knife at 2.4 mm, which does not match the manual, so a 2.4 mm kerf then has no clearance. Do not grind the knife. A thickness field of 30 mm is the bore, not the plate.
Thin blades in this comparison
Trend CSB/21060TC, at £27.48, states a 1.8 mm kerf and names cordless saws such as the DCS7485 and the Milwaukee M18 FTS210. Three reviews say that kerf is too thin for a DWE7485 or DWS7485 knife. DeWalt DT99567-QZ, at £34.87, and DT99566-QZ, at £43.31, say thin kerf with no millimetre figure. Reviews say the knife was thicker than the cut. A 2019 review says the narrow kerf helps battery life on a FlexVolt saw. That is the duty a thin kerf is for.
Safer blade choices on a 2.2 mm knife
If the knife is the published 2.2 mm, look for a stated kerf of about 2.4 mm or more and a plate around 1.6 mm. That is the Saxton 80-tooth (2.6 mm and 1.6 mm), both Rennie blades (2.5 mm and 1.6 mm), the Saxton 100-tooth (2.4 mm and 1.6 mm) and the Trend 48-tooth (2.4 mm, no plate). The best 210mm saw blade page names the Saxton 80-tooth as the top pick and the Rennie 80-tooth as the best value. A 2.4 mm kerf against a knife you measured at 2.4 mm is not clearance. Evolution's R210SMS publishes a 1.7 mm kerf, so this DeWalt example does not transfer.
What not to do
Do not remove the knife to finish a rip, including a thin strip. Do not grind it down to 1.8 mm. Grinding can take it out of line. A 30 mm thickness field is not a kerf. If the guard or the knife is missing or bent, stop through-cuts. BAUBECK's mild-steel bullets are not a tested limit, and the DWE7485 manual says not to fit abrasive wheels. Confirm the new kerf still clears the knife, then put the guard back, which is the last step on the how to change page.
Common questions
Can I use a 1.8 mm kerf blade on a DWE7485?
Not with the knife the UK manual specifies. That knife is 2.2 mm, and the manual's own blade is a 2.4 mm kerf with a 1.6 mm body. A 1.8 mm kerf is narrower than 2.2 mm, so the knife cannot pass. Trend's cordless 60-tooth title states 1.8 mm and the reviews describe exactly this bind on a DWE7485 or DWS7485. Use that blade on a saw specified for it.
Should I grind the riving knife thinner?
No. Grinding changes a safety part and can take it out of line with the blade. If you need a thinner knife, use the one the saw manufacturer supplies for a thin-kerf blade, if that saw has one. Otherwise change the blade to a stated kerf wider than the knife you have. The manual's combination is 2.2 mm knife and 2.4 mm kerf.
How do I measure kerf versus plate?
Kerf is the width across the carbide tips. Plate is the steel disc inside that width. The knife must be thicker than the plate and thinner than the kerf. On the DWE7485 manual those figures are 1.6 mm, 2.2 mm and 2.4 mm. A caliper is the practical tool. An Amazon thickness field of 30 mm is the bore, not a measurement of either the plate or the knife.
Will the Trend CSB/21060TC work on a corded DeWalt table saw?
The listing aims it at cordless saws, including the DCS7485, and states a 1.8 mm kerf. Three reviews say that is too thin for the riving knife on a DWE7485 or DWS7485. Owners of a 54 V DeWalt table saw in the file praise the finish. Use it where the saw was built for that kerf. Leave it off a corded DWE7485 that still has the 2.2 mm knife.
What kerf do the Saxton and Rennie blades quote?
Saxton's 80-tooth bullets quote 2.6 mm kerf and 1.6 mm plate. Saxton's 100-tooth bullets quote 2.4 mm and 1.6 mm. Saxton's 60-tooth bullets quote 2.6 mm and no plate. Both Rennie blades quote 2.5 mm kerf and 1.6 mm body. Those figures sit above a 2.2 mm knife. The Saxton 80-tooth thickness field still says 30 mm, which you ignore in favour of the bullets.
Is it safe to remove the knife for thin strips?
No. Thin strips are when the offcut closes easily, which is the kickback WIS16 is written to reduce. Reviews that say removing the knife was the only way to run a thin DeWalt blade are describing a workaround this page rejects. Fit a blade whose kerf is wider than the knife, or fit the knife meant for that kerf, and keep the guard on.
Related pages
Sources
Public UK sources and maker pages from the research digest, last checked on 20 October 2026.
- HSE Woodworking Information Sheet WIS16 (retrieved 20 October 2026)
- HSE: Woodworking machinery standards (retrieved 20 October 2026)
- BSI BS EN 847-1:2017 (retrieved 20 October 2026)
- DeWalt DWE7485 UK instruction manual (retrieved 20 October 2026)
- Evolution R210SMS 210 mm sliding mitre saw (retrieved 20 October 2026)
- Screwfix Erbauer wood TCT saw blade 210 mm x 30 mm 40T (retrieved 20 October 2026)
- Bosch Professional UK PRO Wood circular saw blade (retrieved 20 October 2026)