Turning a round knob takes a grip that many people lose first after a stroke or during a long illness. A lever handle lets the hand push down with the heel of the palm or the forearm. On most interior doors it is a swap of the handle set, not a rebuild of the door. The work goes wrong in the same few places each time, so the checks below come before you buy, during the install, and after the first real use.

Local option: New Plan Care gives families in the St. Louis area in-home help so a parent can stay home: companionship, help with bathing and dressing, meals, and overnight care. Call (314) 405-0887.

Measure before you buy

Measure three numbers on the door you plan to change. First, the backset, which is the distance from the edge of the door to the center of the knob hole. Most interior doors use one of two common backsets, but older doors and some replacement doors do not, so measure yours instead of assuming. Second, the bore, the large round hole through the face of the door, which on interior doors is usually around two inches across. Third, the door thickness, since the latch and the mounting plate have to fit it.

Then check the handing. Look at which way the door swings and which side the hinges sit on, and match the handing the package names for that side. If the old latch is still in the door, compare it with the package diagram before you order. Write the handing on a slip of paper and keep it with the receipt.

Choose the set and count the keys

Ask what the room needs. A passage lever has no lock and suits hall and closet doors. A privacy lever locks from inside and usually has a small hole or slot for opening it from outside in an emergency. Bathroom and bedroom doors are the usual places to look for that outside release, so check that the set you pick has one. If the old set takes a key, count the keys now and write down who holds each one, so the new set does not leave anyone locked out or locked in.

Do the install in order

Remove the old knobs and the latch, and keep the old screws and parts in a bag labeled with the door name in case the new set has to go back. Check that the latch bolt slides cleanly into its pocket. If the old hole is oversized or the wood around it is split, stop and fix that first, because a loose plate is the first thing to fail.

Set the latch first, then the strike plate in the frame, then the two lever assemblies through the bore. Tighten the screws snug, not forced. Check that the latch plate sits flush with the edge of the door so it does not drag on the frame as it swings.

Decide who does the work

Settle this before you start. A handy helper can usually do a straight swap on a sound door. A locksmith is the better call if the set is keyed, if the bore needs enlarging, or if the door binds after the first try. Either way, ask the installer to leave you the old set, the new keys, and a short note of what was changed.

Test with the hand that will use it

Test from both sides with light pressure. Push the lever down with the heel of the hand or the forearm, not the fingertips. The latch should retract fully and the door should open without a second push. Let go and the latch should spring back into the strike. Close the door and check that it latches without a slam. Then test the lock from inside and the outside release if the set has one. If the lever catches on a sleeve, a walker, or a wheelchair footrest when the door swings, change the lever angle or the swing before you call the job done.

Log the swap and the keys

Write down the door, the set model, the handing, the number of keys, and who holds each key. Put that page where the next person looking for a key will find it. If you still need a place to start for installers or help with the work, the Local Help for Husband Caregivers page is a reasonable first stop.

The Knob Turns Only With a Fist: Swap the Door to Levers From Measure to Test