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Sliding bevel for stairs

Updated: 22 October 2026

A sliding bevel copies the pitch of a string that is already fixed, then lets you mark one spindle or a handrail end. It does not, by itself, make the stair meet UK guidance on height or openings. Take the angle, cut one test piece, then see what Approved Document K still asks for. Peter F. used that document and the UK reviews in the [sliding bevel comparison](/hub/measuring-and-marking-tools/sliding-bevel), on 22 October 2026. A qualifying purchase can earn a commission at no extra cost to you. The copy-and-lock sequence is on [how to use a sliding bevel](/hub/measuring-and-marking-tools/sliding-bevel/sub/sliding-bevel-how-to-use). Other jobs are on the [best sliding bevel](/hub/measuring-and-marking-tools/sliding-bevel/sub/sliding-bevel-best) page.

A sliding bevel copies the pitch of a string that is already fixed, then lets you mark one spindle or a handrail end. It does not, by itself, make the stair meet UK guidance on height or openings.

Our top picks

Bahco Bahco 9574-300, 300 mm

Best overall

Bahco Bahco 9574-300, 300 mm
8.7/10about £35.94
View offer
PRESCH PRESCH sliding bevel, 19/27 cm

Rank 2

PRESCH PRESCH sliding bevel, 19/27 cm
9.1/10about £22.99
View offer
Hilka Hilka 9 inch adjustable bevel

Preis-Tipp

Hilka Hilka 9 inch adjustable bevel
8.4/10about £7.49
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On this page
  1. 1.Take the pitch
  2. 2.Handrail height the bevel never sees
  3. 3.The 100 mm sphere
  4. 4.The lock on a stair

Take the pitch

Set the stock against the newel and lay the blade along the string. Blueprint Joinery describes that seating, then the lock. Push the tip with a finger before you lift the tool. If the blade moves, the first spindle is already a different angle from the flight. Cut one spindle and test it on the flight before you repeat the shoulder. Handrail ends use the same copy: one end before the long rail. A 200 mm blade can take a spindle end.

Handrail height the bevel never sees

A matched pitch can still leave the handrail at the wrong height. Approved Document K, paragraph 1.34, places the top of the handrail 900–1,000 mm from the pitch line. Measure that with a tape after the rail is offered up. A new stair or new guarding is when you speak to building control.
Bahco Bahco 9574-300, 300 mm

Testsieger

Bahco Bahco 9574-300, 300 mm
8.7/10about £35.94
View offer

The 100 mm sphere

Paragraph 1.39 covers guarding where children under five may use the building: it must stop a 100 mm sphere. Paragraph 1.9 uses the same test for open risers in a dwelling. UK Stairparts speak of gaps no more than 99 mm, a fitter’s margin, not a second clause. Offer a 100 mm sphere, or measure the opening.

The lock on a stair

A centre knob can stop the stock sitting in a tight corner. Bahco 9574-300, at £35.94, puts the wing screw at the end of a 300 mm stock. UK reviews praise that for internal skirt mitres. A stripped thread goes back to the retailer. OX Trade OX-T507420, at £7.50, is titled 200 mm. UK reviews include spindle work and a horizontal bubble several degrees out, so the string is the pitch reference. If the bevel fails the finger test on the string, stop the set. The sliding bevel buying guide is for choosing a replacement.

Common questions

How do I take the stair pitch onto a spindle?
Seat the stock against the newel and the blade along the string, then lock the bevel. Push the blade with a finger. If it stays, mark that angle on one spindle, cut it, and slide it into place to see whether the rails would be parallel. Blueprint Joinery and Sandwich Handyman both stop at that first piece before the rest of the set. If the blade moved, take the pitch again. The saw should receive the string’s angle, not the angle the nut settled into on the landing.
Do I cut every spindle to one length?
Cut one, test it on the flight, and only then repeat. A single locked bevel can mark the same shoulder on each spindle if the pitch is constant and the bevel has not slipped between cuts. Check the lock before the second spindle, not after the tenth. A wedge-shaped gap on the test piece means the shoulder is wrong. Recut that piece before you commit the bundle you bought as a set.
How high should the handrail be?
Approved Document K, paragraph 1.34, puts the top of the handrail 900–1,000 mm from the pitch line. Measure that with a tape once the rail is offered up. The bevel sets the angle of the cut. It does not set this height. A rail can leave the saw at the right pitch and still sit outside that band. Older flights may have been built to an earlier rule. A new balustrade is measured against the current paragraph, and building control is the check when the guarding is new.
What is the 100 mm sphere, and does the bevel check it?
Where children under five may use the building, Approved Document K says the guarding must prevent a 100 mm sphere passing through. The same sphere test applies to open risers in a dwelling. UK Stairparts talk about gaps no more than 99 mm, which is their margin, tighter than the document’s wording. You check the opening with the sphere or a measurement. The bevel only copied the pitch onto the spindle. Correct angles with wide gaps still fail the sphere test.
Which lock helps when my hand is in a corner?
A wing screw at the end of the stock stays out of an internal corner. Bahco 9574-300 is that layout in this folder, at £35.94 and 300 mm, and UK reviews use it for skirt mitres. A centre knob is more likely to meet the wall or your fingers before the stock sits flat. The end screw still has to hold. Two UK reviews say the Bahco thread failed on first tightening, so a stripped nut goes back to the retailer rather than onto the string.
Can I use the spirit vials in a bevel handle to set the pitch?
Use the string. The OX listing includes two vials, and one UK review says the horizontal bubble is out by several degrees. Reviews that mention spindles are about the blade, not proof of the vial. Set the bevel on the newel and the string, lock it, and prove it with your finger. A spirit level can check a rail that should be level. The pitch still comes off the flight.
When does this need building control rather than a bevel?
When you are building a new stair or new guarding, not when you are marking one spindle to a pitch that is already there. The bevel can still transfer that pitch for the joiner. Height at 900–1,000 mm and the 100 mm sphere are separate checks, and Approved Document K has more in it than those two paragraphs. If the structure of the flight is changing, stop treating the job as a marking exercise and ask building control what they need to see.

Related pages

Angle finder

Sliding bevel

Best sliding bevel: top pick, Bahco end, Hilka value

Sliding bevel buying guide: lock, length and stock

How to use a sliding bevel: copy, lock, then scrap

Sliding bevel vs combination square: odd or square

Sources

Public sources named in the research digest, plus the amazon.co.uk listings compared on this page. Retrieved October 2026.

  1. DIY Doctor, Sliding bevel (retrieved October 2026)
  2. Find My Tool, What is a sliding bevel? (retrieved October 2026)
  3. Common Woodworking, Buying a sliding bevel (retrieved October 2026)
  4. MyToolShed, Sliding bevels (retrieved October 2026)
  5. ITS, OX squares and bevels (retrieved October 2026)
  6. Approved Document K (retrieved October 2026)
  7. legislation.gov.uk, Consumer Rights Act 2015, section 9 (retrieved October 2026)
  8. Which?, What to do with a faulty product (retrieved October 2026)