Installing butt hinges on a solid door means cutting a flat-bottomed mortise in the door edge to the exact thickness of the hinge leaf, hanging the door on two screws per leaf, transferring the positions to the jamb with the door in place, and only then driving the full screw set. Mark from the hinge, cut to the leaf, and test before you commit.
In short
- Mortise depth is set by the hinge leaf, not by a number. Set a marking gauge against the closed leaf and work to that line.
- Three hinges per door is our standard count for a solid interior door, with the third centred between the top and bottom pair.
- Hang the door on two screws per leaf first. A dry hang catches every error while it is still cheap to fix.
- Pilot every screw hole. A brass screw head shears before oak gives, and a split stile cannot be undone.
- Never cut, drill or re-mortise a labelled fire door. That is a field modification governed by NFPA 80 and it voids the label.
What you are actually cutting
A butt hinge works because both leaves sit flush with the surfaces they are screwed to, so the door closes against the stop and the knuckle is the only part standing proud. That flush fit is the whole job. A mortise cut too deep pulls the door towards the hinge side, and the door binds or will not latch. Cut too shallow, the leaves bear on their own thickness, the door stands off the frame and can spring back when closed. Both failures are fractions of a sixteenth of an inch, which is why the method below never asks you to measure a depth.
This article assumes you have already chosen the hinge. If you have not, our pillar on solid brass butt hinge sizes, weights and door types does the sizing work: leaf height against door weight, open width against jamb and trim, hinge count by door height, and the selection logic drawn from ANSI/BHMA A156.1. Everything from here on is the cutting and hanging.
Three doors you must not cut
Stop before you reach for a chisel if the door is one of these. A labelled fire door carries its rating as an assembly, and cutting a new hinge mortise or drilling new holes in the field is an alteration under NFPA 80, the standard for fire doors and other opening protectives. Only preparations permitted by the standard, performed by an authorised party, keep the label valid, and the authority having jurisdiction decides. A door in an egress path in a commercial building is governed by the building code and by accessibility requirements, so hardware changes there are not a weekend project. And a hollow core door has a solid lumber block at each hinge location and paper honeycomb between them: a hinge cut outside that block has nothing to hold it, and no screw length fixes that. If your door is solid timber or engineered solid core, in a dwelling, you are in the right place.
Confirm the hinge and the door are a pair
Check four things against the door before you mark anything. Leaf height against door weight, and leaf width against door thickness and stop depth. Whether the leaf is square-cornered or radiused, because that decides how you finish the mortise. Whether the supplied screws are long enough for your stile and jamb. And how many hinges the door needs. Our six models and their real dimensions are below, read from the live catalogue today: no model offers a choice of leaf width, and only three of the six give you a 5 inch leaf height.
| Model | Leaf height x width | 5 inch option | Finishes | Price |
|---|---|---|---|---|
| Plain Brass Butt Hinge, 3.3 inch wide | 4 x 3.3 in (102 x 84 mm) | No | Satin Gold, Matte Black, Antique Brass | $39 |
| Plain Brass Butt Hinge, heavy duty | 4 or 5 x 3.5 in (101 or 126 x 88 mm) | Yes | Brushed Brass, Matte Black, Polished Gold, Antique Copper | $39 to $41 |
| Plain Brass Butt Hinge, 3.03 inch wide | 4 or 5 x 3 in (100 or 125 x 77 mm) | Yes | Coffee, Polished Gold, Matte Black, Gunmetal | $39 to $41 |
| Stepped Brass Butt Hinge | 4 or 5 x 3 in (100 or 125 x 76.5 mm) | Yes | Nine, including Matte Black and Gold and Coffee and Gold | $39 to $41 |
| Heavy-Duty Round Edge Butt Hinge | 6.22 x 4.09 in | No, larger | Brushed Brass, Matte Black, Gunmetal | $45 |
| Butterfly Brass Hinge | 4.02 x 2.52 in | No | Satin Gold, Matte Black, Antique Brass, Bright Chrome, Polished Gold, Weathered Gunmetal | $37 |
The tools, and the two that decide the result
Two tools decide whether this job looks made or looks attempted: a marking gauge, and a chisel that is genuinely sharp. The rest is convenience.
| Tool or consumable | What it does | Why it matters |
|---|---|---|
| Marking gauge or combination square | Scribes the mortise depth from the leaf | Removes the need to measure a thickness you cannot read accurately |
| Marking knife | Severs the fibres on the outline | A knifed line stops a chisel from running; a pencil line does not |
| Bench chisel, 1 inch, honed | Pares the mortise floor flat | A dull chisel crushes end grain and leaves a hollow floor |
| Router with a straight bit and a bearing guide, optional | Removes the waste fast | Faster than chopping, still needs chisel work at the corners |
| Vix bit or self-centring bit | Centres the pilot in the screw hole | An off-centre pilot drags the leaf sideways as the screw seats |
| Twist bits for pilot holes | Pilots to the screw root diameter | Prevents split stiles and sheared brass heads |
| Hand screwdriver | Drives the last turn | A driver clutch cannot feel a brass head about to shear |
| Brass Screws 1.5 inch | Replaces short or mismatched screws | Stocked in Brass, Black, Stainless Steel, Neutral and White |
Step 1. Set the door on edge and secure it
Stand the door on its hinge edge and clamp it in a door stand or between two offcuts screwed to the floor. It must not move while you cut, because every reference line comes from the edge it is standing on. Replacing hinges on a door already hung, leave the others in place and work one at a time: the door holds its own position and you keep the existing geometry. Check the edge is square to the face before you mark. An edge planed out of square throws every mortise, and it is better to know now than after three cuts.
Step 2. Mark the hinge positions
Our standard count for a solid interior door is three hinges, the third centred between the top and bottom pair. The conventional American layout places the top hinge about 5 inches down from the top of the door and the bottom hinge about 10 inches up from the bottom, measured to the near end of the leaf. On a door you are rehanging in an existing frame, ignore that and copy the jamb mortises: the frame is fixed and the door is what you can adjust.
Square a line across the door edge at each end of each leaf, and mark the waste side with a pencil cross. On a three-hinge door that is six lines, and cutting on the wrong side of one of them costs you a filled and re-cut mortise.
Step 3. Scribe the leaf outline from the hinge itself
Hold the leaf against the door edge, knuckle hanging over the face, line its ends up with the squared lines, and knife around its free edge. That knifed line is the width of the mortise, taken from the part rather than from a catalogue dimension, so a leaf of 84, 88 or 76.5 mm needs no arithmetic from you.
Then scribe the depth. Close the hinge, set a marking gauge so the pin just touches the back of the closed leaf, and run it along the door edge inside the outline. You now have a three-sided box with a scribed floor depth, and you have not read a number off a rule.
Step 4. Relieve the waste and pare the floor flat
Chop shallow cross-grain cuts inside the knifed outline, chisel vertical, a quarter of an inch apart, stopping short of the scribed depth line. These relieve the fibres so the waste lifts in flakes instead of tearing towards the door face. With a router, set the bit depth to the scribed line, keep the base on the door edge, and leave a sixteenth of an inch inside the knifed line to pare by hand. Never work towards the visible face: chisel and router passes both run out at the exposed edge, and a blown-out corner on a door face is a repair you will see for the life of the house.
Then lay the chisel flat, bevel up, and pare from the middle towards each end, down to the scribed line in thin passes. Check with the leaf rather than a gauge: drop the hinge in and lay a straight edge across the door edge over it. A leaf standing proud means the floor is high. A straight edge rocking on the leaf means you are deep in the middle, which is the commonest fault and the one that makes a door bind once all three hinges are tightened. Flat beats shallow, and shallow beats deep.
Finish the corners to match the leaf. A square-cornered leaf wants square corners, pared with the chisel vertical into the knifed line. A radiused leaf wants a matching radius: pare the corner in two or three small facets, then roll the edge with the chisel on its side until the leaf drops in without forcing. Our round edge hinge is where this matters most, because its radius is generous and a square-cut corner leaves a visible gap at each end. Never widen the mortise to make a radiused leaf fit a square corner: the leaf sits loose, the screws carry the load in shear instead of the mortise carrying it in bearing, and the door drops within a season.
Step 5. Drill pilots and hang on two screws per leaf
Pilot every hole. The Wood Handbook published by the USDA Forest Service sets out why screw withdrawal strength depends on an intact thread path in sound wood, and a brass screw driven dry into oak or ash shears its head off or strips its slot before the wood yields. Centre each pilot with a self-centring bit, drill to the screw root diameter and to full screw depth, and drive by hand for the last turn.
Then hang the door on two screws per leaf and stop. A dry hang with half the screws in is where you find out whether the door swings freely, closes onto the stop, holds its reveal top and bottom, and latches. Every one of those faults is adjustable at this stage with a shim of card behind a leaf or another thin pass on a mortise floor. With twelve screws driven, none of them is.
Step 6. Transfer the positions to the jamb with the door in place
With the door hung on the door-side leaves only, swing it into the frame, wedge it up to your intended bottom reveal, hold the loose jamb leaves against the hinge jamb and knife around them there. This is the step that separates a door that fits from a door that nearly fits: positions come from the door as it actually hangs, so cumulative error has nowhere to go.
Cut the jamb mortises the same way: knife the outline, scribe the depth from the closed leaf, relieve, pare flat, match the corners. The jamb is usually softer and usually painted, so knife firmly and work from the middle out so the paint film does not lift at the edges.
Step 7. Drive the full screw set and set the swing
Work from the centre hinge outwards, alternate between leaves rather than finishing one hinge at a time, and leave every screw a quarter turn shy until all are in. Then go round once and seat them. On the jamb side, one screw per hinge should reach the framing behind the jamb rather than stopping in the jamb board, because that is the screw carrying the door when someone leans on it. Then test the full range of travel: the door should swing clear of the jamb, close onto the stop along its whole height, and stay where you leave it at any angle. A door that drifts shut is telling you the frame is out of plumb, not that the hinges are wrong.
When the door binds, springs back or drops
Four faults cover almost everything that goes wrong, and all four are diagnosable from the symptom.
| Symptom | Cause | Fix |
|---|---|---|
| Door binds on the hinge jamb, will not latch | One or more mortises cut too deep | Shim behind the leaf with card or a thin veneer |
| Door stands off the frame, springs back on closing | Mortise too shallow, leaf bearing on itself | Pare the floor to the scribed line |
| Door rubs the latch jamb at the top | Top hinge deeper than the bottom, or screws not seated | Shim the top leaf, or deepen the bottom mortise a shaving |
| Hinge pulls out of the jamb over months | Short screws stopping in the jamb board | Replace one screw per hinge with a longer one reaching the framing |
| Screw turns without tightening | Stripped thread path | Plug the hole with a glued hardwood dowel, re-drill, re-pilot |
| Brass screw head sheared | No pilot, or driven with a power driver | Pilot to root diameter, final turn by hand |
Stepped, round edge and butterfly profiles
Three of our six models change the cut, not just the size. The stepped hinge has leaves offset on different planes, so the door-side and jamb-side mortises are not the same depth: scribe each from its own leaf rather than reusing one gauge setting. The round edge heavy-duty hinge is the largest leaf we make at 6.22 by 4.09 inches, so more material comes out of the stile and there is more reason to pilot deep and drive by hand. The butterfly hinge needs no mortise at all in its usual application: its shaped leaves are meant to be seen, surface mounted on a cabinet or a light door, and cutting it in defeats the point of buying it.
The finish question nobody asks until the hinges arrive
Our door hinges and our electrical hardware do not share a finish vocabulary, and on a whole-house job this surprises people. Across the six hinge models there are thirteen distinct finish names: Satin Gold, Matte Black, Antique Brass, Brushed Brass, Polished Gold, Antique Copper, Coffee, Gunmetal, Bright Chrome, Satin Stainless, Weathered Gunmetal, and the two-tone Matte Black and Gold and Coffee and Gold. Our electrical range carries eight: Aged Bronze, Antique Brass, Unlacquered Antique Brass, Satin Brass, Stainless Steel, Matte Black, White and Hammered Brass.
Only one name crosses the two lists: Matte Black. No brass name is common to both, so a hinge and a switch plate specified by name alone will not necessarily match in the same doorway. Judge them in the hand rather than by label, which is what the Finish Sample Set at $50 is for. Our rule, set out in the whole-house specification list, is to match within a single line of sight and allow variation from room to room.
Accessibility, code and when to call a professional
Hinges decide how a door behaves, and where accessibility requirements apply that behaviour is regulated. The ADA Standards for entrances, doors and gates set a maximum of 5 pounds of force to open an interior hinged door under 404.2.9, a minimum clear width of 32 inches to the face of a door open 90 degrees under 404.2.3, and, for spring hinges, a minimum of 1.5 seconds from 70 degrees to closed under 404.2.8. A binding door fails the first of those long before anyone measures it.
Call a professional, and check whether a permit is required, when the door is labelled for fire or sits in a rated wall, when it is in a means of egress in a commercial or multifamily building, when the frame is out of plumb or racked and the opening needs reworking rather than the door, or when the door is an exterior unit whose weatherseal and threshold are part of the assembly. Your local code and your authority having jurisdiction have the final word and outrank this article. Send questions about a specific hinge and a specific door through our installation and compatibility page. We publish no BHMA grade for our hinges and make no fire resistance claim for them, because we have not had them tested to those standards.
Frequently asked questions
How deep should a hinge mortise be?
Exactly the thickness of the closed hinge leaf, so the leaf sits flush with the door edge. Scribe it with a marking gauge set against the leaf rather than reading a number: a sixteenth of an inch of error makes a door bind.
How many hinges does a door need?
Three for a standard solid interior door, with the third centred between the top and bottom pair. Taller and heavier doors take four. The sizing table in our butt hinge guide gives the count by door height and weight.
Where exactly do the top and bottom hinges go?
Conventionally the top hinge sits about 5 inches down from the top of the door and the bottom hinge about 10 inches up from the bottom, measured to the near end of the leaf. On an existing frame, copy the jamb mortises instead.
Should I cut the door first or the jamb first?
The door first. Cut the door mortises, hang it on two screws per leaf, then transfer the leaf positions to the jamb with the door wedged to its final reveal. That removes cumulative error.
Do I need a router to cut hinge mortises?
No. A sharp 1 inch bench chisel and a marking gauge cut a better mortise than a carelessly used router. A router removes waste faster, but the corners and the final paring are chisel work either way.
Why did my brass screw head shear off?
It was driven without a pilot hole, or with a power driver. Brass is softer than the steel of the driver and softer than seasoned hardwood. Pilot to the screw root diameter, to full depth, and drive the last turn by hand.
My new door binds and will not latch. What did I do wrong?
One or more mortises are cut too deep, which pulls the door towards the hinge jamb. Shim behind the offending leaf with card or thin veneer until the reveal is even. Do not plane the latch edge first: that is treating the symptom.
Can I install butt hinges on a hollow core door?
Only at the factory lumber blocks in the stile, which you cannot locate without probing. A hinge cut between them has honeycomb behind it and pulls out. Reuse the existing mortises if they are sound.
Can I replace the hinges on a fire rated door?
Not in the field. Cutting or drilling a labelled door is an alteration under NFPA 80, and only preparations permitted by the standard and performed by an authorised party keep the label valid.
How long should hinge screws be?
Long enough to hold in sound material, and on the jamb side at least one per hinge should reach the framing behind the jamb board. Our 1.5 inch brass screws cover the common cases in five finishes.
Do stepped hinges need a different mortise?
Yes. The two leaves of a stepped hinge sit on different planes, so each mortise is scribed from its own leaf rather than from one gauge setting used for both.
Will your brass hinges match your brass switch plates?
Not by name. The hinge range carries thirteen finish names and the electrical range carries eight, and Matte Black is the only name common to both. Judge the two in the hand, which is what the Finish Sample Set is for.
Cut to the leaf, hang dry, then commit
Every error in this job comes from measuring a number instead of marking from the part, or from driving twelve screws before testing the swing. Scribe from the hinge, pare the floor flat, hang on two screws per leaf, transfer to the jamb with the door in place, and the door closes the way it should for as long as the house stands. A newly hung door is also the cheapest moment to fit a door stopper, with five models from $29.90 to $40.90 and the heavy-duty model the only one we give for outdoor use, and to apply the same template-and-pilot discipline to cabinet knobs and pulls. The range is in Brass Door Hinges, Door Stoppers and Hardware, and the sizing decisions are in our butt hinge sizing guide.
Last updated: October 4, 2026
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