Some months ago the handle of my acoustic guitar case broke off. The case was otherwise in great shape and a handle replacement looked like a simple fix, so I decided to fix it myself.
Naturally, in a classic twist of DIY-narrativesque dramatic irony, this ‘simple fix’ took six months of procrastination, dozens of hours of research, weeks of delays when the wrong parts were ordered initially, and a much longer afternoon of manual labour than I had anticipated.
It turns out there’s actually quite a lot to know about the modest guitar case, so I’ve compiled my hours down the rabbit hole into a handy beginner resource for fellow DIY enthusiasts.
hardcase design & construction offers an overview of the basic materials used in a guitar case
fasteners talks about screws and rivets
hardware & components is basically a list of keywords to help with your search for replacement parts
hardcase design & construction
While the shape and material of your guitar case is pretty self-evident, awareness is a crucial step towards understanding the fasteners and hardware you will need to repair or replace any failing components.
Guitar cases usually come in one of the following shapes:
- rectangular box or coffin style, with flat sides for mounting hardware
- moulded in a guitar shape, with the sides exhibiting a combination of flat surfaces and curvature of various degrees
Various case designs will typically feature the following combinations of primary structural materials:
- moulded ABS plastic, fibreglass or carbon fibre shell with aluminium edge trim. (Seen in both box and moulded case designs.)
- ~5mm plywood front, back and sides with internal timber reinforcement along joints and seams. (Seen in both box and moulded case designs.)
- Solid timber (12-19mm) sides with plywood (or MDF) front and back. (Typical in box designs only.)
It is very common in timber, plywood and MDF cases to protect the external surface with any of the following:
- paint or varnish
- high-strength textured epoxy coating
- wrap of textured vinyl, leather (synthetic or genuine), Tolex or similar.
Internal case materials typically consist of fitted high-density foam blocks (carved for a snug fit), or occasionally thin cork lining in older non-fitted cases. The internal padding is then covered in a soft, fluffy liner material such as polyester velvet to protect the instrument from scratches.
When repairing or replacing guitar case hardware, the ideal fastener always depends on the construction of your case.
For solid timber-frame cases, you should use timber screws of an appropriate length.
Mounting hardware on thin plywood may warrant some extra care depending on the hardware application (i.e. lock, hinge, handle or foot), quality of the timber used and overall design of the case. Where possible, I would suggest slightly over-length timber screws (say, 8 to 12mm shaft) with a small timber reinforcement block glued to the interior.
- When buying new screws, measure existing screws carefully and match dimensions, head shape and thread count.
- If you decide use different screws (or are building your own case from scratch), always factor in the depth of the hardware when calculating the desired shaft length, and measure the screw hole diameter on your hardware. M3 or M4 diameter screws are usually a good ballpark for timber.
- Never use rusty or stripped-out screws or damaged screw holes. Always fill, pre-drill and use fresh screws.
- Use radiused screw heads such as oval or button for a nice finish. Be sure to check whether your new hardware is designed to be used with oval heads (half countersunk) or button heads.
- Buy only quality hardware made of rust-resistant material such as stainless steel or brass.
On moulded ABS plastic or carbon fibre cases, rivets are almost always the best choice for mounting hardware.
Don’t use just any old rivets, and don’t be confused into buying the wrong type like I did. There are dozens of different types of rivets and almost all of them are wrong for this application. You need oval head semi-tubular rivets.
Your common hardware store pop rivets are NOT the right fasteners for the job. Also, your typical craft store snap rivets are NOT the right fasteners for the job. And your local shoemaker’s bifurcated split rivets are NOT the right fasteners for the job. Crucially, your airline mechanic’s solid tubular rivets are NOT the right fasteners for the job, even though they look basically the same. Once more for the people in the back:
You need oval head semi-tubular rivets.
Oh, and you also need a tubular rivet peening tool.
The peening tool is a little cylinder of hardened steel that you hold against the hollow end of the rivet and hit with a hammer. It gradually opens and flares the end of the rivet, tightly securing your hardware to your case.
You’ll also need:
- a bucking bar – this is a tool that you hold firm at the rivet head and catch the hammer impact during peening. (I just use a chunk of hard steel).
- stainless steel flat washers – these protect the surface at the peened end of the rivet.
A typical riveted guitar case finished assembly is (exterior to interior): rivet head > hardware component > guitar case > washer > rivet flange. Riveted hardware is fastened very securely for normal use. However, it can also be easily removed by drilling out the flange with an oversized drill bit. (Note that this destroys the rivet.)
- Stainless steel rivets are the strongest and most commonly used in factory-built cases. However, I must recommend aluminium rivets for your first attempt at DIY riveting. Semi-tubular aluminium rivets are plenty strong too and are much easier to set by hand.
- Tubular rivet peening tools may produce one of two finishes: a smooth round flange, or a ‘star peen’. The star peen is very beginner-friendly (and star peening tools are easier to find), though it is certainly a more rough, DIY-looking finish.
- Measure your existing rivets, washers and mounting holes on the case and your new hardware, to make sure you find semi-tubular rivets in a nice snug fit. From my experience, M3 diameter seems to be a good ballpark.
- To calculate rivet length, you must sum the thickness of the case material (including trim, if relevant), the depth of the hardware, and the thickness of the washer(s). Then add approximately 2-3mm to give the total length of the rivet.
- Though preferable, it is not strictly necessary to peen the entire hollow section of a semi-tubular rivet.
- Semi-tubular rivets can be used with plywood, though they are usually not the best choice. The tendency of timber to expand and contract with humidity may lead to a loose fit and cause damage to your case and/or hardware assembly – especially so if the rivet is used with plywood in a load-bearing capacity (such as mounting the handle).
Note that the selection of rivet lengths may be limited when buying online in small quantities, so always check the component spec sheet for the depth of the hollowed end (usually 1.8mm-3mm of hollow section at the lengths we need), and consider the hardness of the rivet material when making a selection.
As an example, let’s say we’re looking to fasten 10mm worth of material (including the washer). We’re seeking a 12.5mm rivet, but only 11.5mm and 14mm lengths are available. Being a softer metal, aluminium can be slightly over-peened (beyond the hollow section) without much difficulty, so we would probably be fine using aluminium rivets of 14mm, and could manually cut down any excess length before peening. By contrast, stainless steel rivets would pose a serious challenge without pneumatic equipment, but seeing as they are considerably more robust we don’t need quite so much flange diameter – therefore 11.5mm steel rivets are a fine option in this scenario.
hardware & components
As it happens, my case is a guitar-shaped moulded fibreglass shell sporting tight L-OO shoulder curves exactly where the handle is mounted. Despite hours of searching I had no luck finding a replacement handle assembly that would fit the curvature, and ended up fabricating my own hinge straps and reusing most of the original assembly. Nonetheless, I did learn a little about components along the way:
Search terms include guitar case handle, briefcase handle, luggage handle. Usually sold as a complete assembly with simple rivet hinge and mounting hardware. Prices start at a few dollars for generic briefcase handles and shoot up to the stratosphere depending on brand, vintage & country of origin.
Guitar case hinges come in a super wide array of designs. Carefully check the style and dimensions, and make sure you know what you’re looking at: keep an eye out for jargon like offset, lift off and 90° stop.
Specifically drawbolt latches and toggle latches. Thankfully there’s only a small range of fairly standard designs of each, just check the technical drawing for exact measurements and location of the mounting holes.
countersunk finishing washers
Most cases have one or two finishing washers somewhere along the top and bottom edges. They’re used with oval head timber screws to fasten internal structural pieces to the case body (e.g. neck support blocks, accessory pockets).
feet / studs / bottom buttons
No one seems to agree on what to call these things, but I call them feet. There are many options, ranging from rubber to nickel and steel, and designs range from screw-mount to in-built bifurcated split rivets. It’s pretty simple though so you can’t really go wrong!
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