Alburnam's Archive

Ó 2000-2001  Stephen A. Shepherd

Cabinet Repair

Many parts of a cabinet can receive damage over the course of the history of the piece.  I will discuss repairing and restoration of common problems with cabinet and its associated hardware.  These can be a simple cabinet, blanket chest or a complex construction with legs, doors, drawers and hardware such as a desk or secretary.  You may encounter any or all of the problems talked of here, but rest assured that you will be given challenges you can’t possibly imagine.  I have been restoring and repairing furniture for nearly 30 years and I am constantly faced with new problems.  Many of the repairs are common and become second nature but be ready for something you have never had to do before, because you will run into them.

The carcass, the box or the cabinet itself usually stay together but might need repair on part of the cabinet.  At times the carcass will be loose and in need of repair.  A cabinet consists of two sides, a bottom, a top and a back.  It may or may not have doors.  A common method of construction is to dovetail the base onto the sides and a top rail at the front of the cabinet and one rail at the back.  Also sliding dovetails and mortice and tenon joints are used in the construction of cabinets.  Some simple cabinets might just be butt or rabbet joints with glue and nails.  The top rails are usually used to connect the top from underneath.  On nineteenth century furniture the backs are of a secondary wood and usually attached in a rabbet or groove around the edges of the cabinet.  Made of individual boards they are either lapped or tongue and grooved on their edge for a tight joint to keep out dust.  While it is common to mount them vertically, some are horizontal.  Backs are usually nailed onto the cabinet.  Of course pieces that have finished backs will have different construction.

One of the main problems with a square cabinet is that many times it is situated on a floor that is not level and the cabinet over time adjust to the un-square conditions.  Old pieces are glued together with hide glue and over time it is thermoplastic, it will move.  On one large armoire I was asked to repair because the doors that would no longer close was a victim of this condition.  After sitting for many years in an old house with uneven floors, the mortice and tenon joints on the cabinet and the door had sagged to compensate for the pull of gravity.  Instead of taking it apart and reassembling it square, I decided to just add an internal cable and turnbuckle to two eye screws in opposite corners of the case.  I placed wedges under the front legs to level and tightened the turnbuckle to plumb up the cabinet.  While the customer had to be inconvenienced for a couple of months with the cable, the armoire was brought back to square condition.  I had to visit occasionally and retighten the turnbuckle, but it did bring it back square.  I removed the apparatus and the cabinet was none the worse for the repair.  I have made cabinet doors line up and work perfectly merely by placing a small wedge under one of the legs.  Before attempting any major work, try this simple trick first, square up the cabinet, and make sure it is plumb, level & square.

The backs of cabinets can be loose after years of the boards shrinking.  Backs usually do not have a finish unless they are exposed in the front.  Some backs float in grooves in the back edges of the cabinet while others are nailed on in rabbets.  Seldom glued, the back does add strength and prevents racking of the cabinet.  Carefully remove the nails securing the back to the cabinet.  Then straighten the nails if necessary.  In order to strengthen the cabinet, the usually tongue and grooved backboards need to be reinstalled and secured to the cabinet.  You may need to add an additional filler backboard to compensate for the shrinkage of the collective boards.  Match the original wood and make the board wide enough to fill in the required space.  You may have to stain and age the piece to make it blend in to the rest of the cabinet.  Position the new piece on either end or behind a divider or shelf to make it as inconspicuous as possible.  The joints between boards should be snug together with a 1/16th inch between to allow for any further adjustments that might occur in the future.  Try and use the original holes in the back and pre-drill the new nail holes in the cabinet.

 Repairs to damaged cabinet dovetails (tail)   Damage and repair to cross rail dovetail (pin)

You may need to disassemble the entire cabinet in order to make some repairs.  Carefully examine the cabinet to determine how it is joined together, what types of fasteners were used and attempt to determine the order in which the cabinet was originally constructed.  Reverse the process and take the cabinet apart.  Look for fine finish nails that may have been set below the surface and filled.  The old wrought iron cut nails can be brittle, so use caution when removing moldings and other parts fixed with nails.  During the course of repair work you will encounter a lot of nails used to 'repair' the old pieces in the past.  I have a special pair of diagonal cutters that have been ground with sharp thin ends to deal with nail removal.  Tops are usually attached from the underside with screws; some pieces the tops are pegged onto the cabinet.  Remove the top and determine how the cross pieces are secured and carefully remove them.  If some pieces such as dado drawer runners are secure in place and need no repair, leave them in place.  Some of the runners will have excessive wear and may need to have patches to fill in the worn out wood, or in some cases you can reverse the original guides and use the fresh underside of the old wood. 

 Split panel - repair and leveling

Take this opportunity to make any repairs to splits in panels, loose joints and any missing or worn wood while the cabinet is apart.  Adding a piece of wood to replace that, which is missing, can repair splits that do not go completely through a board.  The edges of the split need to be squared off to give a good glue joint.  Some splits can be repaired without any squaring of the edges, some rough or angled splits will require squaring of the edges.  Test the fit repeatedly in order to insure that it is a perfect fit before gluing it in place with hide glue.  Make sure both planes of the split are even and level during gluing to insure a joint that is not visible when finished.  Loose joints should be cleaned of any dirt or other debris.  If hide glue was used, you don’t need to remove all, as it will be reconstituted when fresh hot hide glue is introduced, just remove any excess that prevents the joint from going together.  Dry fit the joints to make sure that everything fits before gluing and clamping.  Repairs at joints can be as simple as repairing splits to adding missing wood.  When repairing splits, I first clean out the split add hide glue then I clamp plastic blocks on both sides of the board then clamp the split tight.  I remove the blocks and clean off excess glue on the split and the blocks then place them back in place and clamp them and allow to dry overnight.  The blocks insure that the split will be flat back in place and both surfaces will line up.  When adding missing wood, you will need to prepare an area to accept the new wood that matches the original wood and grain orientation.  You want as flat and smooth a surface as possible to insure good surface for gluing in the new wood.  Make the new piece of wood to perfectly fit into space and is of adequate size to make the ‘new’ joint tight.  Glue and clamp overnight, then the next day the excess wood can be removed and the joint made anew.  You will find missing wood at dovetail carcass joints, along grooves at the back edge of the cabinet, at mortices or on tenons.  Make sure you match the wood; many old pieces have a secondary wood for non-visible pieces with the fancy primary wood reserved for the exposed front surfaces.  When you are replacing wood at joints make sure you leave enough wood to make a tight joint when you are finished.  Clean any glue out of the joint during the repair process and pre-fit all pieces after repairs to make sure the piece goes back together properly.

Cabinet construction and repair to drawer frame

Cabinets with drawers have internal frames that form drawer guide supports.  Some are simply two pieces nailed to the inside of the cabinet, others are mortised frames with elaborate sliding dovetail joints securing them to the insides of the carcass and may have thin dust panels just like a rail and style door with a flat panel.  Problems can be loose joints, excessive wear on the edges where the drawers run and can cross grain cracking problems with the sides of the cabinet.  Merely reversing the frame in the cabinet can expose new wood for the drawer guides.  The frame should be disassembled if possible, the joints cleaned, any repairs that need to be made should be done while the frame is in pieces.  Add new matching wood to areas of wear or missing wood.  Reassemble the piece square but allow the dust panel to float in the framework, gluing only at the joints.  The framework when installed in a solid side cabinet can create cross grain problems so it should float somewhat in the dado to prevent further problems.  See Repairing Drawers.

Cabinets with doors will invariably have damage to the hinge area where the door hinges are attached.  Stripped out screw holes are common problems and can be repaired with side grain plugs of matching wood.  I use side grain plugs to get the proper grain orientation.  Splits at screw holes are more common and while the splits can be successfully cleaned and glued, I sometimes do an additional step to provide for a better repair and new wood for the screws.  I place blocks on both sides of the hinge mortise and place a clamp to prevent spreading or further splitting.  I then make a narrow mortise into the hinge mortise and large enough to replace all of the wood where the screws are located.  I then make a loose tenon with matching wood and grain orientation and even though it is called a loose tenon, it should fit tight.  I glue in the new wood, wipe off excess glue and allow to dry overnight.  I then trim it down to match the bottom of the hinge mortise and make holes for the screws.  I make these holes usually with a bradawl.  This tool cuts the wood and pushes it out of the way.  In doing so when the screws are driven in the wood can expand back around the threads holding them even more securely.  Apply some wax to the screws before reassembly.  If there is damage to the cabinet where the hinges are located, this must be repaired as the hinge mortise takes the weight of the door, you should not allow the screws to hold the weight, they just hold the hinge to the cabinet.  For more information on hinge repair see Door Repair.

When it is time to put the cabinet back together all of the joints should be clean and you should dry fit the cabinet together to determine that everything will fit back together.  Make sure that any captured pieces such as dust frames and backs are in place when the cabinet is assembled.  Warm the pieces to prevent the hot hide glue from setting up too fast.  Cold wood will shock the glue causing it to congeal.  Apply hot hide glue to all surfaces of the joints, reassemble and clamp the pieces together making sure the cabinet is square.  Check the diagonals to determine squareness of large cabinets and use a small square to determine that face frames, door and drawer openings are square.  Do not over tighten the clamps as it can starve the joint of flue.  I let the glue set up for a few minutes then use a putty knife to remove the excess glue.  I then use a sponge to clean off any glue residue and allow the piece to set up overnight.  Some gluing of minor non-structural repairs will be dry enough after 4 to 6 hours or so depending upon temperature or humidity.  For structural work it is best to allow the hide glue to dry overnight, a minimum of 10 to 12 hours.  The longer the piece remains in the clamps the better.

Because the top of a cabinet is like a top of a table I will discuss them in much more detail in the article on Repairing Tables.

Just how much work to do to a particular cabinet is determined by several factors.  A piece should always be repaired or restored if not restoring will result in further damage to the cabinet.  The use of the cabinet by the current owner is another consideration.  We are only temporary custodians of the material culture of our historic past.  Someone owned the piece before you and someone will ‘own’ it after you. You should leave as much of the original as possible to maintain its integrity and future value.  Some things like stains from inkwells are part of the history of the piece should not be removed and can actually enhance the value.  Natural wear should be left and not restored as it adds to the look, charm and history of the cabinet.  See General Repairs.

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Repairing Tables

Pine Table

Tables have problems in two place first is the tabletop and the second is the legs or pedestal. You might encounter other parts such as drawers or table leaves but for the most part problems happen to either the top or the leg(s).  A problem can be as simple as a loose top that needs reattaching to complex problems of broken legs, warped or split tabletop.  Carrying the table by its top is a common mistake people make when handling old furniture.  Tables should be lifted by their apron rather than the top and should be lifted and not dragged across a floor.  Many of the repairs to cabinet tops are identical to repairs on tabletops.

A warped tabletop is one of the most common problems when it comes to table repair.  This can be caused by uneven exposure, improperly secured top or a poorly designed glue-up or from just shrinking with age.  A warped top can cause hinged leaves to operate improperly.  Shrinkage can cause the leaves to not hang straight down.  Warped tops usually occur across the grain but some problems such as twist can cause a rule joint to bind and even damage the top or leaf.  The top relies on being secured to a strong apron to keep it flat.  Some tabletops such as on a pedestal table have no such edge support but can have a single batten on the underside to help maintain flatness and to provide a place to attach the pedestal.  When you make the batten make a slight convex bow to the side in contact with the tabletop if the edges are cupped up.  This will counteract the pull from the warped top producing a flat end result.  Some experimentation as to how much belly to put in the batten may be necessary to get it perfectly flat.

One simple method that will straighten out a warped tabletop is to place the top cup side down on an unfinished concrete floor overnight.  This surprisingly usually works in straightening out a cupped tabletop, but you still need to deal with the fact that it will recover and it needs to be secured to the apron or base to hold it flat.  Another method that can work is to simply veneer the underside of the table and the shrinkage of the veneer as it dries will straighten some badly warped tabletops.  This is not a terribly accurate method of straightening out a top but it does work on some tops.

If the warped top can be pushed flat without splitting the wood or any joints then you might consider adding battens to the underside of the tabletop.  The batten should span the warp and by securing with screws on each end will hold the tabletop flat.  Best if used on tables with aprons to hide the battens but can be done of matching wood, shaped, stained and finished to match and can be used on tables without aprons.  The battens should be slightly convex on the surface that goes against the tabletop.  This is to compensate for the pressure that the warped top can exert.  It only takes a slight belly in the batten to counterbalance the stresses.

Repairing warped top with kerfs and battens

Another method that is much more invasive is that of running saw kerfs on the underside of the table.  These shallow saw cuts go a little more than half way through the thickness of the tabletop.  The cuts should stop short of the edge, so the repairs do not show.  If the table has an attached molding around it edge, this can be removed and the kerfs run out the end and will be covered when the molding is reattached.  Some will cut thin strips of wood and glue them in to fill in the kerfs after the table is flattened.  I have examined old pieces that cut in this manner and the kerfs left unfilled.  The kerfs relieve the tension of the wood and allow it to go back to its original flat condition.  Gluing in these thin strips can actually hold the table flat.  Some additional battens may need to be added to the bottom of the tabletop to hold it flat.  Once the tension or compression in the wood has been relieved simply reattaching to the apron may be all that is necessary.  The spacing of the kerfs depends upon how much the top is warped.  If they are too far apart when the table is flattened, you will see facets in the top.  I usually space the kerfs a little farther apart than the thickness of the top.  I use an adjustable rabbet saw or stair saw.  This is a short handled saw that works well for the purpose but other short rip tooth saw can be used.  I set the depth of the saw to the proper depth between ½ to ¾ the thickness of the top.  Sometimes I use a straight edge to keep the saw kerf straight and to get the proper spacing.  I will sometimes clamp stops on both ends of the top to keep the kerfs the same length.

If the joints have failed in the warped top, there is an opportunity to make almost invisible repairs by rejoining the joint and gluing the boards back together flat.  Sometimes this will remove too much wood in order to straighten out the joints, so additional matching wood should be added to make up the difference.  The wood should be added where is will show the least, usually on the edge.  This is a common repair to tables with folding leaves.  When the boards on the top shrink the leaves don’t hang straight down but slightly ‘spread eagle’ caused by the leaf hitting the apron.  Many of these tops have rule joints along their edge and this precludes adding new wood to the edge.  In this case I will add wood to a loose joint, if there is one or make a cut next to the rule joint and add wood there to maintain the original rule joint.  When gluing in new wood I always key or tooth the edges of the joint to add extra glue surfaces.  Tops with molded edges will require new wood be added elsewhere so as not to have to remake the molding detail.

A modern non-flexible finish may also cause a top to warp.  This is caused by the wood tabletop moving, either expanding or contracting and the thick finish not moving at all.  The modern finish must be removed in order to straighten out the warped top.  Uneven finishing can also contribute to a warped tabletop.  In order to maintain a balance the underside of tables should be finished to minimize uneven exposure to the atmosphere.

When the worst case is encountered you might have to carefully saw the top apart, rejoin the edges, add new wood and glue up flat.  This is something that can be considered if the piece is going to be re-veneered.  Speaking of veneered tabletops, some ground works are constructed using breadboards to stabilize the glued up woods.  The difference in the cross grain directions can cause the surface veneer to buckle, crack, loosen or fall off.  The groundwork must be stabilized before the veneer is reattached.  If possible new wood should be added and measures taken to prevent further damage because of unanticipated movement.  Some warped veneered tabletops can be straightened by cutting kerfs in the groundwork from the underside and not disturbing the surface veneer.

Mortise RepairTenon Repair

There are two basic types of bases those with four legs and an apron and a pedestal base with a central column and three or four legs.  Of course there are other types but I will concentrate on the most common problems on the more common types.  Tops are usually attached to the base through screw holes in the apron or on the batten on a turned pedestal table.  There must be allowances in the screw holes for movement of the top from expansion and contractions.  The screw holes need to be elongated to allow for this movement.  If the holes are damaged, new wood needs to be added.  If done from the inside the repair will go unnoticed.  Joints between the apron and legs can be damaged and will need to be repaired to make the table stable.  Repairs to the mortice and tenon joints will strengthen the overall structure.  On pedestal tables a common repair is to the slip dovetails that hold the legs in place.  Because the dovetail (tail) is cut along the grain of the base it is susceptible to damage.  The grain on the ends of the legs can be short and the dovetails (pin) can also break off.  If the dovetail is too damaged to repair it can be replaced with new matching wood (with better grain orientation) which can be fixed with pegs.

Repairs to dovetail table leg joint

The feet on the bottom of table legs can be worn off from being used for years and may need to be extended back to their original height to be able to be used today.  The new parts need to be as inconspicuous as possible, leaving as much of the original as possible.  If the legs are turned make the transition to new wood at a detail on the lower end.  Turn a tenon on the end of the new work to go into a hole drilled in the table leg.  Carefully cut the damaged lower section of square at the appropriate location.  Then drill a hole to accept the tenon on the new work and glue it in place using hide glue.  Table legs with pad feet can be repaired at the pad by adding new wood.  This makes the repair invisible and gives a good visual transition to the new work.  See General Repairs.

Table Leg Repair


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