Securing items to metal cabinets can be tricky. The hard surface doesn’t allow for traditional hardware meant for wood. Fortunately, with the right tools and techniques, you can securely fasten almost anything to a metal cabinet. Here is a comprehensive guide on how to screw things into metal cabinets.
Selecting the Right Fasteners
Choosing suitable fasteners is the first step for a solid hold. Consider the following options when fastening items to metal cabinets:
Self-Tapping Screws
As the name implies, these screws tap and thread their own holes as they are driven into the material. The tip is shaped like a drill bit to bore into the metal surface. The ridges on the lower portion of the screw cut corresponding threads into the cabinet wall.
Self-tapping screws are available in various head styles and finishes. They can securely fasten items like shelves, racks, and drawers into sheet metal and thin steel. Opt for self-tappers with a flat head for a lower profile.
Machine Screws
For attaching items to thicker steel, use machine screws. They have a smooth shank and machine thread for tapping into a pre-drilled hole with matching threads. Use machine screws with nuts or threaded inserts. The inserts get embedded into the cabinet metal, providing durable threaded sockets for the screws.
Sheet Metal Screws
These have sharper threads meant for piecing sheet metal. The fine threading grips better to prevent tear out. Sheet metal screws work well for mounting smaller and lighter items onto metal cabinets. Opt for a pan or oval head for a cleaner look.
Rivets
Though not screws, rivets provide another solid fastening option. Blind rivets can be inserted into a pre-drilled hole and bucked to mushroom against the inside surface. Rivets exert clamping force to hold items in place. Use them for items that will rarely or never need removing.
Drilling Holes in Metal Cabinets
With the right drill bits, properly sized pilot holes can be made in cabinet walls. Follow these tips for clean and accurate holes:
Use High-Speed Steel Bits
Standard twisted drills are prone to overheating and wearing out quickly in hard metal. Invest in high-speed steel or cobalt bits. They remain sharper for much longer under high heat and friction.
Choose the Right Bit Diameter
Consult manufacturer specs for recommended pilot hole sizes. As a general rule, clearance holes for machine screws should be around 75% of the screw diameter. Holes for self-tappers can be slightly smaller at 60-70% diameter.
Drill Slowly with High Speed
Rushing the job leads to wobbly holes. Maintain a high bit speed between 800-2000 RPM. But gently feed the drill with light pressure. Let the bit work without forcing it. Slow and steady gives the best accuracy.
Use Cutting Oil
Apply some lightweight cutting oil before drilling metal. The oil cools the bit and reduces friction. It extends the life of the bit while also giving smoother cuts. Maintain oil flow by periodically lifting the bit out of the hole.
Deburr Holes
Metal drilling leaves burrs around the edges of holes. File down any rough edges for safety. Chamfering the entrance of holes also eases screw insertion. Remove debris so cut threads engage cleanly.
Using Threaded Inserts
For frequent access or heavier items, threaded inserts provide durable screw sockets. Follow these best practices for installation:
Select Insert Material
Common options include brass, steel, and stainless steel. Match the insert metal to the cabinet material. Brass inserts are softer for sheet metal while steel is better for thicker gauges. Stainless steel gives the best corrosion resistance.
Determine Insert Length
Inserts are made in varying lengths based on material thickness. Measure the cabinet metal and get inserts that fit the depth. They should be equal or slightly shorter than the thickness. Too long and the insert can’t be fully seated.
Use the Proper Tool
A dedicated installation tool pulls the insert inward as it threads into the hole. The flanged head bears against the surface while the tool draws the threads inward. Don’t try driving inserts in with just a hex key or screwdriver.
Drill Proper Size Hole
The holes must match the insert’s minor diameter. Look up the exact drill size needed. A tight fit keeps the insert from spinning loosely. But don’t over-drill or the threads can’t grip. Use cutting oil and go slow.
Install with care
Turn the installer smoothly without forcing. Over-torquing can damage threads and distort the insert. Turn just until the flange draws down fully flush. Wipe excess oil before driving screws in to avoid fouling the threads.
Using Clip Nuts
Clip nuts offer quick mounting options, especially for lightweight items or temporary fastening. Here are some useful clip nut tips:
Choose Appropriate Clips
They come in a range of styles suited for sheet metal or thicker steel. Measure cabinet thickness and get the recommended clip type. Prongs, teeth, or tabs provide retention by biting into the surface.
Position Properly
Clips must seat flush for a solid grip. Drill holes centered where items will mount. Test-fit clips first before installation. If prongs don’t align flat, re-drill the hole as needed for a flush fit.
Double Check Holding Power
After installing clips, check the retention strength before relying solely on them. Try firmly tugging items already mounted to verify sufficient holding power. Reinforce with secondary fasteners if any loosening occurs over time.
Remove and Replace as Needed
Clip nuts are meant for repeated assembly and disassembly. Remove them when necessary by rotating 90-degrees to release the prongs from the surface. Replace used or damaged clips for optimum strength. Keep extras on hand for such instances.
Securing Items to Metal Cabinets
With suitable fasteners and holes prepared, mounting items securely is a simple process:
Allow Proper Clearance
Leave a slight gap between cabinet walls and items being mounted. Avoid tight fits. Direct metal-to-metal contact amplifies noise and vibration. Rubber or felt washers can cushion contact points.
Tighten Screws Properly
Over-tightening distorts thinner steel and strips threads. Tighten machine screws and self-tappers just until the head or washer draws flush. Then turn an additional quarter to half-turn for optimal tension without stripping.
Use Thread Locking Compound
For critical items subjected to vibration, apply a small drop of thread locker gel to screw threads. The adhesive prevents loosening while still allowing removal and disassembly when needed.
Check Fasteners Periodically
Test screw tightness by trying to turn them by hand after installation. Recheck tension again after a few days once items have settled under vibration. Snug loose fasteners to prevent loosening over time.
Allow for Thermal Expansion
Metal cabinets and attached items expand and contract with temperature swings. Avoid tight fits and over-tightening. Allow a slight gap around drill holes. Use nylon washers to reduce friction from thermal cycling movements.
By following these guidelines, you can securely mount shelves, racks, bins, drawers, and anything else you need onto your metal cabinets. With the right methods, almost any workshop item can be fitted to cabinets for optimal organization and access. Proper installation also reduces noise and potential for loose parts or damage over time. Let this comprehensive guide help you keep things firmly secured exactly where you need them.
Frequently Asked Questions About Screwing Things Into Metal Cabinets
Securing items with screws often raises questions for those new to working with metal cabinets. Here are answers to some of the most common queries:
Can I use wood screws in metal cabinets?
No, wood screws lack the proper design for penetrating and gripping metal. Use self-tapping metal screws or machine screws with threaded inserts. The right screw thread, tip shape, and material are critical.
My cabinets are too thin for inserts. What alternatives work?
For thin sheet metal, self-tapping screws or rivets provide good alternatives to inserts. Use rubber washers to prevent pull-through. Hollow wall anchors also work, but have less holding power.
How do I keep drilled holes from becoming wallowed out or enlarged over time?
Proper pilot hole sizing and using the recommended fasteners prevents enlargement. Avoid undersized holes or overly large screws. Also be careful not to over-tighten. Snug screws up without excessive torque.
Can I just drill and tap threads into the cabinet metal itself?
You technically can tap threads by drilling and using a tap tool. But this weakens the surrounding metal over time. Thread inserts localize the threading for strength and durability.
What size self-tapping screws should I use to mount shelves?
For medium duty shelving, #10 or 1/4″ size self-tapping screws work well. Use at least 4 per shelf. For heavy duty shelves, step up to #14 or 5/16″ size screws. Apply 6-8 per shelf for ample support.
How can I reduce vibration and noise from mounted equipment?
Use rubber isolation bushings or vibration damping mounts between items and the cabinet walls. Keep mounted objects from pressing tight against bare metal. Allow slight gaps for friction-free movement.
What’s the easiest way to remove rivets if I need to?
Use a drill bit slightly larger than the rivet shaft to grind away the head down to the body. Then punch out the remaining body with a pin punch and hammer. Grind or sand away any remnants flush with the surface. New rivets can then be installed.
Can I use an impact driver for self-tapping screws?
Exercise caution with impact drivers. The torque and speed can easily shear off screw heads or strip out threads. Impacts work, but adjust force settings low and go slow. Stop when screws become snug.
Conclusion
Installing fasteners in metal cabinets calls for the right hardware and careful techniques. But with this guide’s tips, your mounted items can remain firmly planted for the long haul. Take the time to prep holes properly. Use quality screws and inserts suited for the application. And consistently check installed hardware to prevent vibrational loosening over time. Follow these best practices for a cabinet full of securely mounted workshop essentials that stay planted exactly where you need them.