Warding file for keys: when a small file belongs on a key
Updated: 23 October 2026
A warding file takes its name from the wards inside a lock and from the notches in a key. You may be holding a spare you are allowed to ease, and wondering whether a small Amazon set is what a locksmith would use. Sometimes the length matches. Sometimes a patent sends the copy through the lock maker. This page is that boundary. It does not explain how to cut a blank or impression a lock. Prices are on the [key file comparison](/hub/hand-tools/key-files). Peter F. did not test a lock. A qualifying purchase can earn a commission at no extra cost to you.
A warding file takes its name from the wards inside a lock and from the notches in a key. You may be holding a spare you are allowed to ease, and wondering whether a small Amazon set is what a locksmith would use.
A warding file takes its name from the wards inside a lock and from the notches in a key. You may be holding a spare you are allowed to ease, and wondering whether a small Amazon set is what a locksmith would use. Sometimes the length matches. Sometimes a patent sends the copy through the lock maker. This page is that boundary. It does not explain how to cut a blank or impression a lock. Prices are on the key file comparison. Peter F. did not test a lock. A qualifying purchase can earn a commission at no extra cost to you.
Our top picks
| Badge | Product | Length | Cut | Handle | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  Draper Draper 14185 6-piece warding file set | 100 mm | n/a | Plastic | 7.0 | about £13.23 | View offer |
 GEDORE GEDORE red 6-piece key file set | 177 mm | n/a | Wooden | 8.7 | about £7.58 | View offer | |
| Best value |  BGS BGS 50204 6-piece key file set | 100 mm | 2nd cut | Wooden | 7.2 | about £8.63 | View offer |
On this page
What the file is for
Drillfix describes warding files for narrow grooves and keyways, and says locksmiths use them on ward notches. JMA lists files for finishing keys in 4, 6, and 8 inch. Those are descriptions of a job, not a sequence for a key in your hand. The stroke itself is on the how to use a key file page.
The single profile is the slim rectangle. A boxed set adds other shapes because a notch, a groove, and a rounded edge are not the same cut. Buying the set does not give you a coded blank or the right to copy a restricted key. A German-language review of the GEDORE set mentions filing a key blank. That text is not a UK legal permission.
The set locksmith merchants sell
Trade pages start at 4 inch, which is 100 mm, and they care that a handle stays on the tang. Souber's key file set, reference KFS, is six 4 inch files. THM Key lists it at £22.81 with wooden handles. Souber's own page has described plastic handles and restricted the sale to the trade. This page does not explain impressioning.
BGS 50204 and Draper 14185 both state 100 mm, with handles fitted, wood on the BGS listing and plastic on the Draper listing. That is the length the trade pages use. It does not make either row a locksmith service. BGS is the only one of the three that prints second cut. GEDORE red states 177 mm, a longer set with a case, not the 100 mm pattern. The Amazon sets already include handles.
Keys you must not copy yourself
Possessing a key is not a right to cut another one. The Door and Hardware Federation's note on key copy protection says trademarks and design rights do not, by themselves, stop a functional copy. A patent on the key or the cylinder can. A bow stamped do not copy is a warning, not an invitation. If the key or the cylinder is patented, an unauthorised copy can infringe.
Banham says Mark III keys are patented until 2032, and that an unauthorised physical copy infringes. Copies go through Banham's registration. If the key says it is patented, restricted, or registered, use the manufacturer's route. A landlord's cylinder or a key you found is not a practice piece.
When a locksmith or the manufacturer takes over
Hand the job over when you do not have authority to open the lock, when the key has to work a cylinder you do not control, or when the blank is restricted. A snapped key left in a cylinder is a locksmith's job, not a filing project on the remaining bow. Impressioning is locksmith work. Knowing the word is not a reason to try it.
You can ease a key you are allowed to alter, with a 100 mm handled file, when you already understand the notch and the key is not restricted. Nothing in the three listings claims hardened steel. If you are guessing at depths so a key will turn a lock you should not be learning on, put the file down.
Common questions
Is a six-piece Amazon set what a locksmith buys?
Locksmith merchants sell 100 mm files with a real handle, often as a named set such as Souber's KFS at £22.81. BGS and Draper state 100 mm and include handles, so the length matches that pattern. The listing is still hardware. GEDORE at 177 mm is longer than that 4 inch pattern.
Do I need a handle?
Yes. INDG229 says a file should have a proper handle and should never be used as a lever. Some trade files are sold bare, and the handle is fitted before use. The three Amazon sets already include wooden or plastic handles. If the handle rocks or the ferrule comes off, stop. A bare tang is not a safer way to file a key.
Can I copy any key I possess?
No. A patent on the key or the cylinder can stop an unauthorised copy even when you hold an original. The Door and Hardware Federation distinguishes that from a trademark, which does not by itself protect the key's function. A do not copy stamp is a warning to read, not a prompt to file. Restricted and registered keys go through the maker.
What is a patented or registered key?
It is a key or a cylinder the maker protects with a patent, sometimes with a scheme for who may cut copies. Banham says its Mark III keys are patented until 2032 and that unauthorised copies infringe, with copies handled through Banham's registration. Mark I and Mark II are not described that way on Banham's FAQ. Check the brand's current page for the key you hold.
Will these sets cut a hardened key?
Do not plan on it. The listings do not claim hardened steel. GEDORE names steel, iron, wood, and aluminium. BGS names no workpiece. A small steel file can skate on hard metal, which one UK review described on a stainless washer, not on a key. If the key is hardened, restricted, or not yours to alter, the file set is the wrong next step.
Related pages
Sources
Sources from the research digest, last checked on 22 October 2026.
- HSE, INDG229 Using work equipment safely (retrieved 22.10.2026)
- Provision and Use of Work Equipment Regulations 1998 (retrieved 22.10.2026)
- Consumer Rights Act 2015 (retrieved 22.10.2026)
- BS 498:1990 Engineers' files (retrieved 22.10.2026)
- Wonkee Donkee, what is a warding file (retrieved 22.10.2026)
- Wonkee Donkee, needle and escapement files (retrieved 22.10.2026)
- DIY Doctor, using a hand file (retrieved 22.10.2026)
- amazon.co.uk, GEDORE red key file set B07CNV82JJ (retrieved 22.10.2026)