Alburnam's Archive

2000-2001  Stephen A. Shepherd

Repairing Furniture Hardware

Over the years I have had to repair many pieces of antique furniture and one of the more common repairs is to the piece is where the hardware is attached and the hardware itself.  Many pieces of hardware were missing and I deal with that in Moses T's Guide to Furniture Hardware Casting, 1989.  Hardware that has been damaged can be repaired in most cases.  Bent leaves on hinges can be straightened, screw slots can be re-cut and nails straightened.  Locks can be cleaned and re-keyed, stays straightened and casters tightened and trued.  Dealing with old hardware is dealing with old metal.  The high sulfur brass is difficult to obtain today as is wrought iron and these materials will behave differently than new metals.  Wrought iron is soft and care must be taken when straightening to avoid deforming the metal.  Wrought iron also has grain similar to wood as a result of its unique manufacturing process.  The metals can be work hardened in its manufacturing or application and this can make the material brittle.  Heating can help make the metals workable but can completely remove the patina.  Gentle warming may work but if the piece needs to be annealed, it will remove any patina.  To replace the color to the metal see Coloring Metal.  Ferrous metals such as steel and iron anneal (soften) by heating to a dull cherry red and allowing to gently and slowly cool.  Heating to a dull cherry red and quenching in oil or water can harden ferrous metals.  Non-ferrous metals such as copper, silver and brass are annealed (softened) by heating to a dull cherry red and quenching in oil or water and heating and allowing to slowly cool to harden them.  Ferrous and non-ferrous metals behave opposite each other as to how they are annealed or hardened.  Straightening and hammering these metals flat will cause them to work harden, so you might need to anneal more than once in order to straighten badly bent pieces.

Bolts & Nuts - You may come across nuts and bolts that are used on furniture that may have problems.  The threads on nuts and bolts are made with metal working tap and die sets.  These are fairly inexpensive and a set of smaller sizes is handy to have.  The threads on a damaged bolt can be freshened or chased by running them through the appropriate size die to re-new the threads.  Re-tapping the threaded hole with a tap of the right size can refresh the nuts.  If the nut has been stripped and there is no metal to re-tap the hole being too large, there is a way of making repairs.  With a blunt metal punch, the metal around the hole can be forced into the hole by striking the punch around the edge of the hole.  Done on both sides of the nut, the hole is made smaller and can be tapped to the correct size.  If the bolt needs to be straightened, grip the threads with leather in the vise to protect them as you straighten the bolt.  Sometimes just the end of the bolt is damaged and the engaging threads can be re-chased with a small triangular file to allow it to thread into the nut.

Casters - There are two basic problems you encounter with casters, problems with the stem where the caster pivots and the wheel mechanism itself.   The stem needs to be straight and if it has a piece of metal mounted in the furniture, the stem bearing must also be straight and work freely.  Some casters have collars that are attached to the furniture and the pivot is a rivet between the collar and the wheel mechanism.  If the rivet is loose re-riveting the head of the rivet can tighten it.  If the rivet or pivot is bent, it must be straightened.  See Rivet.  Problems in the wheel mechanism are bent wheel shaft (usually a rivet) or a damaged wheel.  Wooden wheels can have worn bearing holes or flat wheels.  Drilling out the hole, filling with matching wood and re-drilled to the proper size in the proper location can re-sleeve worn bearing holes.  If a wooden wheel is flat on one side, new wood can be added without disassembling the mechanism.  If the wheel needs to be replaced, the rivet is removed and a new matching wheel is added.

Catches - Catches are devices that secure a door or other moving part and usually consist of a striker plate that the catch attaches to and the catch itself.  Many catches have moving bolts and springs that are moved to operate the locking unlocking mechanism.  The travel of the bolt must be free to operate properly, any obstructions should be removed, the spring cleaned and the path of the bolt should also be cleaned and a little light machine oil applied to all moving parts.  The striker plate may need to be straightened if dented or damaged and may need to be re-installed to engage the bolt properly.

Escutcheons - These decorative and functional plates are normally used to protect a keyhole opening in a cabinet.  They are also backing plates for knobs or handles.  Many are thin stamped brass that can be easily dented or damaged.  With the plate removed a shaped wooden stick is used to work the dented plate back to its original shape.  This work is done from the backside with the front resting on a piece of thick leather or very soft pine.  You may have to anneal the escutcheon to prevent it from breaking.  When they are stamped, the brass becomes work hardened and can be brittle.  Reshaping the metal at the hole can repair damage to areas around the pinholes.  If metal is missing and the hole is too large for an escutcheon pin, a small piece of thin brass can be glued to the inside of the plate and re-drilled to the proper size.  Plates made of other material such as mother of pearl, bone or ivory will require matching the material and replacing missing parts.  When working mother of pearl or nacre, working underwater should control the dust, you do not want to breath this dust. Keep as much of the original as possible and only replace that which is missing in order to preserve the historical integrity of the piece.

Handles - Handles and knobs are among the highest casualties of lost and damage.  Both cast and stamped yellow brass they can be bent, dented or broken.  Stamped brass knobs are usually made of several pieces and they may need to be disassembled in order to work the dented brass from the inside.  Using a shaped piece of hardwood (boxwood is excellent) is used to carefully reform the shape back to its original shape.  Use the same precautions when working work harden materials, broken pieces can be carefully silver soldered to mend.  Careful fluxing and heat sinks are used during soldering.  Pure tin solder can also be used if the repair is not too structural, if a cast brass bail handle is broken it would be better to silver solder.  Handles and knobs can have escutcheon plates, rivets, nails, screws, and nuts and bolts as part of their construction.

Hinges - Hinges are up there with knobs and handles that are either damaged or missing and the most common are the simple butt hinge.  One problem is bent and distorted hinges.  These should be carefully removed and examined for damage.  Bent leaves on the hinge will prevent it from seating properly or operating smoothly.  On a flat metal surface or anvil the leaves can be gently straightened.  Bent pivots or hinge pins can also prevent the hinge from operating properly.  The barrel that surrounds the pin needs to be straightened.  When you pound too hard on the barrel, it will pinch the pin and may not freely pivot anymore.  A metal working vise or even a parallel jaw clamp can be used to gently straighten out the barrel without crimping on the pin, use caution.  If the pin is removable it should be straightened, and polished smooth.  A little light non drying oil to lubricate the hinge after all restoration work is done and it can be reinstalled.  Mostly of wrought iron some hinges on finer pieces are of cast or even stamped brass.  The same precautions should be used; excessive hammering will leave marks, use leather pads and blocks of wood to prevent surface damage from the iron hammer.  Screws holding the hardware must be of the proper size, if it has too large a head it will not seat properly possibly preventing the hinges from closing all the way.

Inlays - Metal inlays are found in brass stringing, inlayed escutcheon plates and other surface decorations such as bole.  One problem is that the wood moves and the metal does not, and damage can occur to both the surrounding wood as well as buckling the inlay.  A unique problem with metal inlays I have found is that of the surrounding veneer will expand over the metal, so if it needs to be removed to be straightened or repaired, the metal must be out-layed, some of the wood will need to be removed to get the metal out.  Only a very small amount of the wood needs to be removed to extract the metal.  Inlays that have buckled need to be straightened and shortened to fit back into the wood or other material.  If the stringing has mitered corners, these are good places to refit the metal to fit.  When re-gluing the metal back in, use hide glue and etch the back of the metal with a clove of garlic, simply rub it on the metal, wipe off any residue and the metal is easily glued with hide glue.

Locks - Locks are complicated mechanisms that can have a variety of problems besides a missing key.  The most common lock of the historical period is the half-mortise lock.  Other type of plate locks are used for other purposes but the half mortise lock with barrel key is by for the most used lock and the problems with one type is the same for different types of locks.  All locks of the period are made of wrought iron, some examples in both cast and sheet brass are found on European Antiques and rarely on American examples.  The first thing to do is remove the lock carefully from the cabinet and it is cleaned.  Some can be done with the lock together and it does not need to be disassembled, other require more work.  Most have flat lock plates that are bent at a 90ļ angle at the top where the bolt comes through.  The mechanism is simple and can be made of few parts, which are simply riveted together with, both square and rectangular or round self-rivets.  In other words parts of the mechanism are shaped to form these rivet heads with the appropriate holes to receive and secure other parts.  The heads of the rivets on the back plate are compressed with a pair of pliers until the lock parts can be removed.  If the pin for the barrel key is loose, it can be re-riveted by carefully peening the head of the pin where it passes through the lock plate.  A missing pin, a common problem, can be fashioned from a large wire nail, the same size as the original with a shoulder to seat it properly on the lock plate and the tenon going through the plate and riveted in place.  There are usually springs that hold the bolt in both positions and these may need to be worked on to exert the proper pressure.  The plates need to be flat and square and the bolt must operate properly.  Missing keys can be replaced by fitting a blank to the lock.  The more complicated the lock such as one with wards require careful and precise fitting of the key to the lock mechanism.  Once the lock is repaired, a little non drying oil should be applied to the mechanism to help it operate better.  For further information see the Technical Leaflet Half Mortise Locks.

Nails - The most common nail of the nineteenth century are cut nails.  Prior to the nineteenth century most nails were made by a blacksmith one at a time and have a double tapered shank to a point with a rose head formed by the hand heading process.  The cut nail has a blunt tip with two parallel sides and two tapered sides with a machine formed head that is flat and square.  The most common problem is nails that are bent and need to be straightened.  Made of wrought iron these nails will rust but the nature of the wrought iron helps prevent rusting from completely consuming the nail.  When straightening a nail place it on an anvil or metal plate with the head over the edge.  With the bow in the nail up, it can be gently straightened by lightly hammering on the bent nail while avoiding hitting and distorting the head.  The iron is soft so do not hit it too hard or it will distort the nail.  When reinserted in the nail hole, the wedge sides of the cut nail needs to align with the grain of the wood.  If it is placed in with the wedge shape going cross grain there is a possibility of splitting the board.  If the nails are put back in their original hole you may need to add some wood to the original hole to hold the nail securely.  I always use a softer wood such as basswood to make these hole repairs.  A thin sliver of basswood with a little glue is placed in the hole and trimmed flush.  A bradawl can be used to enlarge the hole.  A bradawl does not remove wood like pre-drilling, it spreads the fibers of the wood and when the nail (or screw) is inserted the wood will fill back in and secure the nail.  Soaking them in warm linseed oil can stabilize heavily rusted nails.  Round wire nails were developed and in common use by the 1870's.  See Nails.

Rivets - Rivets are seldom found by themselves but are usually in conjunction with other pieces of hardware such as casters.  Rivets are pieces of metal used to secure something to something else.  They are usually made of a softer metal that can be riveted or headed.  When you have to remove a rivet for a repair or to replace it, you must make one head of the rivet small enough to pass through the rivet hole.  This can be difficult but it can be done.  Using a pair of pliers, diagonal cutters, what ever tool can access the sides of the rivet head where it is mushroomed.  A hacksaw can also be used as can a file to remove the mushrooming at the head.  If the rivet is going to be replaced, the head can be cut off.  Using these tools you can compress the mushroomed metal back to the size of the shaft of the rivet to allow it to be removed.  Sometimes you can file off the sides of the head, but if you are going to re-use the rivet you do not want to remove too much metal.  Once the head is small enough to pass through the opening it can be punched out.  Support the opposite side to prevent split out when the rivet is driven back out.  Once the rivet is removed, it is straightened and the head hammered to form a smooth shank so it can be reinserted after repairs.  One problem with rivets is that they can split the wood if they bend or kink during the heading process.  This usually happens if the rivet is too long.  The rivet head should be just above the surface with enough metal to spread out as you peen the top with a hammer.  Hammer around the edge of the end of the rivet to form the head uniformly.

Screws - There are generally two basic problems with screws that of bad threads and bad slots.  You may have a problem with removing screws but that is covered in a Technical Leaflet Take it Out!  The problem of bad threads is usually the result of rusting of the course of time.  It is possible to freshen up the threads with a process called chasing.  Done with a triangular shaped file the spiral is followed and one of the points of the file cut or chase new threads into the screw.  All screws prior to 1846 are blunt, after that date they were all manufactured with points.  Carefully re-file in new threads where needed and remove excessive rust from the screw or stabilize the oxidation by dipping the warmed screw into linseed oil.  The second basic problem is that of the slot.  Many old slots, originally cut by hand, were only cut deep enough to allow it to be installed.  With repeated removal and re-installation, the slot can be rounded enough that you can't use a straight screwdriver to remove or reinstall.  Once the screw is removed it is held in a vise, with wood or leather to protect the threads and a thin blade hacksaw is used to re-cut the slot so it can be used again.  Do not cut too deep, just enough for a thin screwdriver blade to engage the screw.

Stays - Stays are devices for stopping a hinged door or drawer front or desk front at a certain position.  They are usually arcs or quadrants that are attached to the part that moves and is secured at a predetermined position of the part that doesn't move.  They have pivots, screw holes, stops and other parts that must all work together in order to function properly.  Problems with bent quadrants can be straightened by hammering, rivets can be repaired, plates flattened, stops re-secured or replaced.  Replace missing or excessively damaged parts with the proper materials matching the original.  Lubricate working parts with light oil and make sure they move freely without binding.

Hardware is an important part of furniture and other woodwork and it must be working properly so as not to further damage either the woodwork or the hardware.  All moving hardware such as hinges, locks and casters need to be well lubricated with a non drying oil and should be kept clean with periodic maintenance.  The nuts, bolts, screws or rivets holding the hardware in the woodwork should be tight, securing the hardware properly.  Moving hardware and other hardware as well can come loose, so the maintenance will reveal any problems as they come up.

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Repairing Drawers

Drawers are one of the most common parts of antique furniture that needs repair other than chairs, which is the leader in furniture that is most commonly damaged.  Drawers are used in tables, chests and other cabinets for convenient storage and easy access.  The frequent access wears both the drawer and the carcass that holds the drawer.

Drawers in most nineteenth century furniture are self-guided drawers, in other words there is no additional drawer guide added to the drawer or carcass.  Some drawers do have guides, which are usually wooden runners in the carcass that a groove in the side of the drawer glides in and out.

While the outside of the furniture is usually of a hardwood, the carcass can be made from a secondary woods as can the drawers.  Some old pieces especially in the West were made entirely of softwoods. Most drawers are made of poplar or pine and that contributes to the problem of wear and damage.

The constant use of drawers can wear the bottoms of the drawers called the runners, the part that rubs against the carcass.  Most of the wear is on the bottom edge but some can occur on the side of the drawer as well as the top.  This is the most common damage to drawers that need to be repaired.  Also just loose joints are also a common problem with drawers.  Remember most drawer bottoms are not glued into the drawer but float freely in the groove and are usually just secured with a few nails along the back.  They are made of thin wood that is also easily damaged and any splits need to be repaired.  Because these bottoms shrink with time some come out of their grooves and no longer help hold the drawer square and the joints fail on the corners.

Not all drawers were dovetailed in the nineteenth century but it certainly is the most common method to join drawers.  Simple glued butt joints with nails, rabbet joints with dowel pegs were used but these do not last like dovetails and canít take much weight or extensive use.  Mechanical fasteners are used as clamps until the glue dries.  Do not rely on nails, screws or even pegs or dowels to hold the work together; it is the glue that does the work.  The dovetail joined drawer will even stay together, more or less, if all of the glue in the joint has failed.

As well as repairing the drawer, the carcass must be repaired of any damage.  Troughs can be worn in the drawer supports and these need to cleaned up and filled back to the original surface.  On old furniture you should only replace the minimum amount of wood and the species should match and of course you should always use hide glue.  The guides on the sides can also have enough wear to make the drawer sloppy in the opening causing it to jam up.  Some are missing and need to be replaced.  In many cases the guides can be removed and reversed presenting fresh wood to the new wood that is invariably added to the bottom of old drawers.  The kicker also needs to be in working order.  The kicker is either the carcass, a dust panel or a separate piece that keeps the drawer from tipping down when it is opened.  Some repairs can be done before the drawer is repaired; however placing the guides on the side should be done after the drawer has been repaired to insure a proper fit.  This is done so the drawer will be square in the opening and the guides are not too loose or too tight for the newly repaired drawer.

Drawer Repair, showing added runner

I have repaired hundreds of drawers and many of them were restored to working condition without taking the drawer boxes completely apart.  If the joints are still sound there is no reason to disassemble the box.  Most drawer bottoms are captured on three sides in a groove and runs past the back piece.  Most back pieces have no groove and are not as wide as the sides.  On finished drawers such as on a desk or secretary, the bottom may be captured on all four sides.  The nails holding the bottom to the back are carefully removed and saved.  The bottom, unless someone has glued it in, should easily slide out the grooves out the back of the drawer.  The grain of the drawer bottom is usually oriented from side to side and any shrinkage will be at the drawer front as the nails hold the bottom to the back.  Some bottoms will have a gap as they have shrunk enough to pull the edge from the groove.  Sometimes it is easy to deal with this problem just by re-positioning the bottom so it fits into the groove in the back of the drawer front and nailing it back on in the correct position.  If the grain is oriented from front to back, the width of the bottom will pull one or both sides out of their grooves on the side.  The bottom is carefully removed and new matching wood is attached to the edge to make up for the shrinkage that has occurred over time.

Edge gluing small pieces on the edge of the drawer bottom can be a little tricky as the pieces are usually only ľĒ thick and seldom more than an inch wide.  It is important to join the edge of the drawer bottom to make is straight to attach the new wood, which should match the original material.  I use a toothing plane to key the butt joints and improve the glues holding ability.  Again hide glue is used and the new wood is carefully clamped in place.  Excessive pressure can bend or break the delicate bottoms so use caution.  I use clamping blocks or parallel jaw clamps to keep the material flat while it is edge clamped.  You can also use wedges on the bench top between dogs to hold the piece and apply just enough pressure to squeeze the two pieces together.  Practice repairing drawer bottoms will prepare you for the next and most common damage to drawers that of worn out drawer bottom runners.

Drawers usually wear out more on the back of the drawer runners than on the front part producing the usual wedge shape damage.  Unfortunately most of the drawers have their groove placed near the bottom of the drawer box therefore some of the wear will takes away the supporting wood under the drawer bottom.  When you add new wood the most common place to locate the repair is right at the groove.  Therefore you will be gluing on new wood at the thinnest part of the drawer, at the groove.  While it would be easier to just square off the sides of the drawer and add on new wood, but on old pieces only the damage should be removed and replaced, so you will be required to fit the pieces properly.

I start by squaring off the bottom edge (following the damage) removing all of the damage and nothing else.  I use a hand plane or chisel to straighten up the bottom edge in a straight line.  If only a small area at the back is worn, small pieces can be cut in to repair just the damage.  Once I have the edge straight and square to the sides, I will determine what needs to be replaced.  I make the replacement pieces square, it is easier to work the groove into a square piece, and then cut the new piece to the corresponding angle of the damaged part.  I use a toothing or keying plane to roughen the surface to improve the glues holding ability.  Again use blocks or clamps to make sure that it is glued on square and flush to the sides.  Some damage might go into the joints requiring that the new wood also be joined to fit into the corresponding joint.  Carefully fit up all pieces prior to gluing.  On some pieces a small rabbit joint for the new wood to the old, might be appropriate to give more glue area rather than a simple butt joint.  In most cases a well fit butt joint with a toothed surface, good fresh glue and proper clamping is all that is necessary.  If you are going to repair a number of the same size drawers it might be worth making several clamping blocks and use wedges to hold the new wood until the glue dries, usually overnight.  I always make the new parts the same thickness as the thickness of the sides and match them up so I am not planing or scraping the old work, but I make the new pieces wider.  This is to insure that I have enough wood to plane down until the drawer fits into the opening properly.  Measuring the width of the drawer side for sizing the new work is possible but some old drawers are slightly tapered in original construction and your new replacement piece might not be wide enough, so I always make them slightly oversized.

Some damage can occur where the wear and inherent weakness of the thin piece below the bottom groove causes that piece to break off.  This leaves only the very thin edges of the sides and the bottom exposed to rub against the carcass.  Another problem can be caused by drawer stops placed below the drawer on the framework of the carcass.  These stops are used to position the drawer in the proper place when the drawer is closed.  Wear on the side rails can cause these stops to start rubbing the bottom taking the weight of the drawer.  This will cause wear on the stop and scoring of the shape of the stop into the drawer bottom, I have seen some that actually wore through the drawer bottom.  Repeated wear will also expose the nail used to secure some drawer stops and the head can deeply score and damage the drawer bottom.  If the integrity of the bottom is in tact, the repairs to the side runners should raise the bottom up enough to clear the drawer stops.

Note repair to bottom and side at runner

If you must disassemble the door to do the repairs, the dovetail joints must be loose.  To loosen the glue simply inject alcohol into the joint which will crystallize the glue allowing the joint to be disassembled.  This is assuming that it is hide glue that was used on the drawer.  If modern glues were used (and shame on whoever used it on old furniture) then you might have to get the joint wet in order for the glue to be softened.  This is a rather drastic step that should only be used as a last resort.  You might want to score around the joints with a sharp knife to prevent any split out.  Also check for any nails or other fasteners that might have been used in subsequent repairs.  If the drawer was glued with hide glue, the old glue does not necessarily need to be completely removed, it should be cleaned of any dirt or debris but introducing new hot hide glue will soften the existing glue. Make any repairs at this point it is much easier to repair each of the parts if the drawer is in pieces.  When you are ready to glue it together check the squareness of the carcass and you may want to use the framework of the piece to check the drawer for squareness.  I sometimes glue the drawer together, insert the bottom but I donít nail it in place until the drawer has dried.  I then place the drawer in the opening and make sure it is oriented properly and all surfaces are in the right location.  I then gently open the drawer and measure the diagonals to determine if the drawer is square.  If the side drawer guides are not in place, then the drawer can be glued together square.  Just in case the framework of the carcass is not square I do a trial fit just to make sure.  I have had to glue a few drawers together out of square to fit the cabinet, but most are square.  The drawer should be glued, clamped and allowed to dry overnight.  Any excess should be cleaned off before it dries.  After it is dry the bottom is inserted and nailed into position.  The bottom can sometimes be used to square up drawers.  Some drawerís sides are so thin and flexible that the bottom is required to keep it square.  See Using Hide Glue.

Repair to drawer bottom, note grain direction    Repair to feather edge of drawer bottom

Next place the drawer in the opening and plane or scrape the bottom until it runs smooth and the drawer is fit in its proper position.  If the side guides were missing or reversed they need to be either manufactured using the same materials and positioned to guide the drawers in and out.  They should be snug but not tight and should move freely.  If they are too loose, the drawer can twist and jam in the carcass.  If it is too tight you can damage the joints or handles when trying to open a tight drawer.  It is a good idea to coat the runners with beeswax to provide lubrication to make them work easier.  I keep a cake of pure beeswax that I use just for this purpose.  Soap should not be used as it may contain oils and grease that can stain the drawer sides and carcass.

Donít be tempted to add a harder wood as a drawer bottom repair, you must match the original materials and the harder wood can actually cause more damage especially to the carcass.  Use original materials; copy old techniques and your repairs should look like they were done in the early history of the piece.  Properly repaired these pieces can last for future generations to appreciate.

 

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