Mortice chisel sizes: what to buy first
Updated: 23 October 2026
You have a tenon marked out, or a lock still in its packet, and amazon.co.uk puts long beech-handled chisels next to square-hole bits. Mortice chisel sizes come before the brand. This shelf sells 6 mm, 10 mm inside a set, 12 mm, 13 mm and 16 mm. Six millimetres is close to 1/4 in, and 1/4 in is 6.35 mm. Peter F. read the nine kept listings on 22 October 2026 and did not run a lab test. The [mortise chisel comparison](/hub/hand-tools/mortise-chisel) is the table. This page is the order of the decisions. A qualifying purchase can earn us a commission at no extra cost to you.
You have a tenon marked out, or a lock still in its packet, and amazon.co.uk puts long beech-handled chisels next to square-hole bits. Mortice chisel sizes come before the brand.
You have a tenon marked out, or a lock still in its packet, and amazon.co.uk puts long beech-handled chisels next to square-hole bits. Mortice chisel sizes come before the brand. This shelf sells 6 mm, 10 mm inside a set, 12 mm, 13 mm and 16 mm. Six millimetres is close to 1/4 in, and 1/4 in is 6.35 mm. Peter F. read the nine kept listings on 22 October 2026 and did not run a lab test. The mortise chisel comparison is the table. This page is the order of the decisions. A qualifying purchase can earn us a commission at no extra cost to you.
Our top picks
| Badge | Product | Width stated | Type | Side relief | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  Narex Narex Wood Line 6 mm | 6 mm | Hand mortice chisel | Taper in reviews | 6.9 | about £15.96 | View offer |
 Narex Narex set 4, 6, 10, 12 mm | 4, 6, 10, 12 mm | Hand chisel set | Tapered sides | 8.8 | about £63.00 | View offer | |
| Alternative |  Narex Narex Richter 13 mm | 13 mm (1/2 in) | Hand mortice chisel | Tapered sides | 2.6 | about £54.50 | View offer |
On this page
Start with one width
Buy the width you will actually chop. UK Workshop regulars, and a widely cited American chisel guide, tell beginners to start with one width, or two. The one-third rule is a rule of thumb, not a British Standard: on 18 mm stock, one third is 6 mm. About 10 mm, near 3/8 in, is the next width those threads name. You do not need 4, 6, 10 and 12 mm on day one unless those mortices are already drawn. A 16 mm chisel is the heavy end. The Richter pairs 1/2 in with 13 mm, and a 13 mm chisel still cuts the wrong socket if the tenon is 6 mm. Which listing fits which job is on the best mortice chisel page.
Sash, pigsticker or registered
The long Wood Line singles are the sash pattern here: beech, ferrules, and bullets of about 300 mm overall and about 145 mm of blade. A pigsticker is the short, thick English chisel with an oval bolster. None of the nine kept listings is one, and this capture has no UK price for a used pigsticker. A registered mortice chisel has square sides so the blade can register against the wall you have already cut. Henry Taylor's Hamlet registered chisel is about £31.53 on the maker's shop, and it is not in this Amazon set. Narex and Richter bullets describe a taper so the blade does not stick. That is side relief, not a register. Workshop Heaven lists 6 mm as the metric twin of 1/4 in and 13 mm as the twin of 1/2 in, close rather than identical. Whether a bevel-edge you own can do the job is on mortice chisel or bevel-edge chisel.
What this shelf sells
Hand chisels here run from about £15.96 for the Wood Line 6 mm to about £63.00 for the 4, 6, 10 and 12 mm set. The 12 mm is about £19.97, the 16 mm about £24.00, and the Richter 13 mm about £54.50. Toolnut was about £16.68 for a single and about £69.90 for four when that page was fetched. Classic Hand Tools listed Richter chisels from about £46.95, and Workshop Heaven about £49.50. Those figures are context. The prices that belong here are the amazon.co.uk rows. From the Holy Feather at about £7.99 to luolety at about £49.99, a hollow bit is a sleeve that needs a mortiser or a drill press. That clamp is on the hollow mortise chisel page. Printed steel claims, including 59 HRc and HRC 48–50, were not measured here.
Listing conflicts to check
Read the bullet against the attribute block. The 6 mm and 16 mm files print about 300 mm overall and also 7 cm by 1.5 cm. The 12 mm title is one chisel, and the attribute block says a set of eight. The 16 mm file says spring steel and 280 g, against alloy steel and 113 g on the narrower sisters. The Richter line says 2.29 m by 2.29 m, a listing error. The Holy Feather bullet says any standard drill, and the only UK review says the sleeve must be clamped. The Consumer Rights Act 2015, sections 9 to 11, covers goods that match their description, so measure the tool when it arrives. The 4.7 from 376 on three widths is one parent pool. The set's 4.6 from 471, with 31 UK reviews, is a separate listing. One width means one chisel and a hone. A drawing that uses 6 mm and 10 mm is the set, still with no case on the included line.
Common questions
What size mortice chisel should I buy first?
For ordinary furniture, start with about 6 mm, which is the nearest size on this shelf to the 1/4 in that UK Workshop threads name first. About 10 mm is the next width those threads mention, and it appears here inside the four-piece set rather than as its own single. Buy 12 mm, 13 mm or 16 mm when you have already measured a mortice that wide. One third of the stock thickness is a rule of thumb, useful on 18 mm stock, and it is not a requirement to own every size.
Is 6 mm the same as 1/4 in?
No. A quarter of an inch is 6.35 mm. The Wood Line single is sold as 6 mm. The Holy Feather hollow bit is sold as 6.35 mm, and that bit is a drill-press sleeve, not a mallet chisel. Workshop Heaven's size notes treat 6 mm as the metric partner of 1/4 in and 13 mm as the partner of 1/2 in. Close enough to choose a starting width, not close enough to ignore if the tenon was cut to a measured inch size.
Do I need a mortice chisel set?
You need a set when you will chop more than one of those widths. The Narex 863600 box is 4, 6, 10 and 12 mm at about £63.00. If the job is a run of 6 mm mortices, the £15.96 single does that width without the other three. UK forum advice and the American note against buying the full set agree on that point. They do not agree on a brand, and this page is not ranking brands.
What does a tapered side change?
The blade is narrower behind the edge, so it is less likely to jam on the way down. Narex and Richter both state that taper. You give up the square side of a registered chisel, which some people use to keep the wall flat as they deepen the hole. Taper is not a fault by itself. It is the wrong pattern only if you specifically wanted a register.
Is a pigsticker the same as a Narex sash chisel?
No. The sash pattern here is the long Wood Line chisel, about 300 mm overall on the bullets. A pigsticker is shorter and thicker, the old English mortice chisel people look for second-hand. This Amazon capture does not sell one, so there is no price here to quote. If a seller calls a long beech-handled Narex a pigsticker, the name is wrong even when the chisel is fine.
What if the listing says 7 cm and the bullet says 300 mm?
Treat that as a broken attribute, not as two optional lengths. The bullets on the 6 mm and 16 mm files say about 300 mm overall and about 145 mm of blade. The 7 cm line cannot describe the same chisel. Check the tool against the bullet when it arrives. Goods have to match their description under the Consumer Rights Act 2015, and a page that prints both figures has not described one length.
Related pages
Sources
Public UK sources and amazon.co.uk listing files. Checked on 22 October 2026.
- HSE: PUWER overview (retrieved 22.10.2026)
- Consumer Rights Act 2015, goods contract rights (retrieved 22.10.2026)
- HSE: using the right type of PPE (retrieved 22.10.2026)
- Eyecare Trust: eye protection for DIY (retrieved 22.10.2026)
- UK Workshop: recommendations for mortise chisels (retrieved 22.10.2026)
- UK Workshop: mortise chisels (retrieved 22.10.2026)
- Toolnut: Narex mortice chisel (retrieved 22.10.2026)
- Workshop Heaven: Narex Richter mortice chisels (retrieved 22.10.2026)