In the sheet metal fabrication design phase, hardware installation can be an afterthought. It’s often one of the last steps in the design process and easy to breeze right through when engineers are ready to finish the design and begin collaborating with a sheet metal shop.
However, it’s well worth your effort to give it the attention it deserves. Hardware installation is one of the last steps in the precision sheet metal fabrication process as well, and oversights can result in scrapping nearly finished parts, leading to higher costs and longer lead times.
Don’t let hardware installation be an afterthought. Instead, follow these eight DFM tips for seamless hardware installation:
If your part has press-in hardware, make sure your non-hardware holes are a different size to ensure the hardware always goes into the correct hole. Each hole size should correspond uniquely to its function to facilitate error-free assembly.
Ensure there is enough space around the location for the machine to install the hardware. Avoid part designs that “trap” hardware holes in inaccessible locations after forming, as well as flanges and similar obstructions that can inhibit installation.
If a design can’t be adjusted to accommodate installation, choose alternate hardware our fabricators can install from the front.
Some hardware manufacturers recommend unilateral hole tolerances, like +.003”/-0.0”
Most engineers will use the nominal hole size in their design, which leads to errors following” wear and tear on the tools.
Instead, size the hole in the center of the tolerance. For example, if the nut you want to press requires a .250” hole and the tolerance is +.003”/-0.0”, you should size the hole at .252”. This way, the nut will still fit even if the hole sizes vary slightly.
Our press-in machine has a throat depth limit of 24”, so hardware can only be installed with the press-in method up to 24” from any edge. An alternate option for hardware installation in locations exceeding 24” is using a rivnut gun. Which allows us to install from the front side, but
Will leave a slight raised head on the front side.
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Rivet nuts are an excellent, all-round solution. They are installed from the front face of your part using a gun similar to a rivet gun. Installation can leave a raised edge where nuts collapse into the metal, but using washers is an easy way to improve the aesthetic appearance.
We recommend using rivet nuts for difficult access points where flanges or other components might obstruct access for our press-in machine. It’s helpful for your precision fabrication partner if you indicate whether rivet nuts are an appropriate substitution for hardware installation if access becomes an issue.
It’s important to note that the holes for rivet nuts are typically larger than those used for other hardware like PEM studs.
If parts require welding, welding in hardware while already at the welding process is an alternative to press-in installation. This is an especially good option for internal components, as welding is less aesthetically pleasing than traditional installation.
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Threaded inserts offer sturdy reinforcement for softer materials like aluminum and copper. These components are threaded to size on the inside, and oversized threads on the outside. They require a special oversized thread in the part (see hardware manufacture for oversize thread chart).
When designing parts for threaded inserts, ensure the inner threads on the threaded inserts are the final size required, not the outer threads.
Our best advice is always to engage early with your precision sheet metal fabrication partner! No one knows our shop capabilities like we do, and our expert team can advise you on the best hardware installation options depending on your part design.
Request a quote to get started with our precision sheet metal fabrication shop. For more helpful DFM tips, check out our free guide.
