Start at the door, not the anvil

A handle that looks beautiful on the bench but rattles against the architrave is a handle you will curse every morning. So before you light the forge, spend twenty minutes at the door with a tape, a pencil and a notepad. Everything you measure now saves you hammering later.

• Door thickness. Measure it in three places — old doors are rarely even. Use the thickest reading. Your spindle must span this with a good 15–20mm of engagement into each handle.
• Backset. This is the distance from the door's edge to the centre of the existing spindle hole. It is almost always 45mm or 57mm. Your new handle must repeat it exactly or the latch will not line up.
• Screw centres. Measure the distance between the fixing holes on your existing backplate or rose. If you are making a backplate, copy these so you can reuse the existing mortice holes.
• Spindle size. Most UK latches take an 8mm square spindle. Check yours with a vernier or by offering up a short offcut of 8mm square bar.
• Handing and clearance. Decide which way the lever should point. Keep the tip clear of the frame and the architrave, ideally 50mm or more, so knuckles never meet timber.

Draw the whole thing full size on a sheet of card and hold it against the door. You will spot problems — an awkward droop, a button that fouls the frame — long before they are forged in.

Choosing your stock and design

Mild steel is your friend here. It forges sweetly, welds easily and takes a wax finish beautifully. For a domestic lever, 12mm square bar gives a slim, elegant handle once drawn down; 16mm gives a chunky, farmhouse feel. Anything under 10mm will feel whippy in the hand.

For the spindle, use 8mm square mild steel — EN3B or similar. Do not be tempted by stainless or high-carbon stock. Stainless fights you at the anvil, and high-carbon can snap where a spindle needs just a little forgiveness.

Work out your proportions before you cut. A comfortable lever is roughly 100–130mm from the spindle centre to the tip, with a grip section of about 20–25mm diameter. Sketch the scroll or finial at the end, and mark your stock with a cold chisel so you know where the boss, the grip and the tip begin.

Forging the lever

Bring the steel to a bright orange, around 1,100–1,200°C. If it throws sparks and glows a pale yellow, it is too hot — pull it out and let it cool a shade.

• Form the boss first. Upset or fuller the end to build up the mass you need around the spindle. A little extra thickness here stops the handle feeling like a nail.
• Draw out the grip. Work from the boss outward, turning the bar a quarter turn between blows. Aim for a gentle taper, thicker near the boss and slimmer at the tip.
• Shape the tip. A simple scroll, a flattened leaf or a small ball all read well. Scrolls want a rounded horn or the beak of your anvil and patient, light hammer work.
• Keep it comfortable. Round off every edge the hand will touch. Run a file over the grip while it is still warm from the last heat — it cuts far easier.

Work both ends of the handle as a pair, matching weight and length by eye and by scale. Slight asymmetry is charm; a mismatched pair is a mistake.

Making the spindle and the square hole

The square hole in the boss is the job that makes or breaks the project. A sloppy hole will round off within a season.

Centre punch the boss, drill a pilot of 4mm, then open it out to 7.5mm. Now square the corners with a square file or a small broach, checking constantly against a short offcut of your spindle. You want a snug sliding fit — the spindle should need a light tap to seat, never a hammer.

If you prefer, drill slightly under size and drift the hole square while the boss is at a dull red heat. It is quicker, but it distorts the boss, so plan to true it up afterwards.

Fit a small M5 grub screw in the side of the boss to lock the spindle. Cut the spindle to door thickness plus 30mm, chamfer both ends so they enter cleanly, and dry-assemble the whole handle on the bench before you finish anything.

Finishing with wax, not lacquer

Wire-brush the steel at a dull red heat to strip scale and leave a soft, satin sheen. Then choose your finish: beeswax blended with a little linseed oil for interior doors, or a boiled linseed and turpentine mix for anything exposed. Warm the metal gently, wipe the finish on, let it soak, and buff off the excess.

Skip clear lacquer. It chips, traps moisture underneath and looks tatty within a year. A wax finish can be refreshed in five minutes with a cloth, which is exactly what you want on a handle that is touched fifty times a day.

Fitting and fine-tuning

Offer the handle up, slide the spindle through the latch, and check the action with the door open. The lever should fall under its own weight but return crisply. If it droops, the latch spring is tired — fit spring cassettes behind the roses.

Mark the screw holes through the backplate, drill pilot holes slightly smaller than your screws, and fit with slotted brass or black japanned screws, aligned horizontally. Test the door closed, listening for any scrape against the frame. A quarter turn of the grub screw, a touch of wax on the spindle, and the job is done — a handle that fits your hand, your door and nobody else's house.