Sagging Panel Door? Pick Screw-On Hinges by Load, Metal and Hand

A panel door that drops, binds or rusts at the hinge is a nuisance on site and a hazard if it falls. The cure is usually a hinge rated for the door’s weight, made in a metal that suits the weather, and handed correctly.

PartsForMachines lists 145 Metrol screw-on hinges, mainly in zinc, stainless steel and nylon, from fixed and lift-off to friction and detent types.

Why Is My Panel Door Sagging, and Will Another Hinge Fix It?

Often the fixings have worked loose or the hinge itself has worn, so tighten everything before you add a hinge. Lift the free edge of the door gently and watch the knuckles. If a leaf rocks on its pin or the knuckle looks worn, that hinge is due for replacement.

Start with the top hinge, which Metrol says carries most of the load on a tall door. If the fixings are tight and the hinges are sound, they may simply be too light for the door: work out the load each one carries, then fit stronger hinges or add a third.

How Much Weight Should Each Hinge Carry, and How Many Do I Need?

Divide the door’s full weight by the hinge count (usually two or three), add a margin, and choose a hinge rated above that figure. Weigh the door with everything fixed to it, such as locks, gauges and seals. Metrol suggests multiplying the per-hinge figure by 1.5 to allow for vibration and shock.

Ratings are quoted per hinge, and most hinges in the range carry two: axial and radial. Check both against your figure. They vary widely: a small concealed lift-off hinge is rated at 27kg axial, for example, while the 2101-600-10 60x60mm screw-on hinge is rated at 896kg axial and 580kg radial.

Zinc, Stainless or Nylon: Which Hinge Lasts in Damp or Salty Air?

Fit zinc die-cast hinges indoors or under cover, stainless steel outdoors, and grade 316 where there is salt in the air. Metrol specifies 316 for marine and coastal sites, and 304 for general outdoor use away from salt. Salt matters: chlorides in coastal air speed up zinc corrosion, while the molybdenum in 316 resists pitting better than 304 does.

The 2101-500-316 stainless 316 hinge is a 50x50mm option rated at 828kg axial. Where rust is the main worry on a lighter door, consider a glass-filled nylon hinge such as the 2120-640-90, though its pin is zinc-plated steel.

Worn Hinge: Repair It or Fit a New Screw-On One?

Usually fit a new one: once the pin or knuckle has worn, tightening the fixings will not stop the drop for long. A screw-on hinge fitted through holes can be unbolted later, so the next swap is quick.

Match the old hinge before you order. Measure the leaf size, the hole size and centres, and note whether it has studs or plain holes. If the door lifts off its hinges, check the left- or right-hand marking in the product name against your door, or send our team a photo of the old hinge in place.

What Should I Check Before I Order a Hinge?

the door’s weight with fittings, divided by the number of hinges, against both load ratings
where the door lives: indoors or under cover, outdoors, or near the coast
fixed or lift-off and, for a lift-off hinge, left or right hand
the mounting: through holes, M5, M6 or M8 studs, or weld-on, plus the hole size and centres
the leaf size, the panel thickness and whether the door must hold itself open

Browse the screw-on hinge range, or contact the PartsForMachines team by WhatsApp, telephone or email with a photo of the old hinge and its measurements.

Product options, delivery options and returns terms are shown on each product page. A 30-day return policy applies to eligible items.

Frequently Asked Questions

Can I use stainless screws on a zinc or aluminium hinge?

Indoors and dry, usually yes. Where it stays wet, two different metals in contact can corrode, and the less noble one, such as zinc or aluminium, suffers. On damp sites, match the metals or separate them with non-conductive washers.

Why do my hinge bolts keep working loose?

Vibration and shock let bolts slip and slowly unwind, especially if they were never tightened enough. Tighten them properly, and consider locking nuts or a thread-locking compound.

Lift-off or fixed, left or right hand: which do I order?

Choose lift-off if the panel must come off for servicing without undoing any fixings. Some are handed, such as the 2106-500-L10 left-hand lift-off hinge and its partner, the 2106-500-R10, so check the hand in the product name. Most of the range is unhanded.

Studs, through holes or weld-on: which mounting suits me?

Studs are quickest, because the hinge goes straight into a prepared panel, as with the M6 studs on the 2101-501-20. Through holes let you unbolt the hinge for replacement. Weld-on hinges, such as the 2401-111-10, suit permanent fixing.

Which hinge holds a lid open without a stay?

A friction hinge, which holds the lid at any angle through controlled torque. Asymmetric versions, such as the 2118-123F-20, have different forward and reverse torque ratings, so the hinge resists more in one direction than the other.

What do 80°, 115° and 150° detent hinges do?

They click into a set hold-open position at that angle, so the door stays put. The 2105-11511-90 115° detent hinge has medium torque; the same hinge also comes with low or high torque, and free-swinging.

Is a nylon hinge strong enough for a machine panel?

For lighter panels, yes. The glass-filled 2120-640-90 is rated at 349kg axial and 535kg radial per hinge. Check its rating against your door weight as you would for any hinge, and remember that the pin is zinc-plated steel.

Does a powder-coated or chrome finish make a zinc hinge weatherproof?

No. The finish protects the surface, but underneath it is the same die-cast zinc hinge, meant for indoors or under cover. Many have a 316 stainless pin, such as the 2101-5761-20, but the body is still zinc. For wet or salty sites, choose stainless steel.

What is a quick-release hinge for?

It makes a door or cover removable, for example for service access. The range includes screw-on and weld-on versions, such as the 2129-762-304 in 304 stainless steel, rated at 266kg axial per hinge.