North American material handling professionals like you and I have pretty much always accepted that welded pallet rack uprights are superior to bolted while our European colleagues have been building their frames with nuts and bolts for decades. Which is best? Let’s find out.
Bolted structures are everywhere in both our personal and professional lives. From the buildings we live or work in to the bridges we drive over and the mezzanines and cantilever systems we install. So why are welded frames preferred?
One of the big reasons is that almost every rack manufacturer in the U.S. produces only welded rack, so it’s easier to get than bolted and the manufacturers have a vested interest in maintaining the status quo.
With that said, bolted uprights do have several advantages over welded:
- Less Expensive: While the manufacture of the major components is pretty much the same between welded and bolted uprights, welding adds more labor and thus more cost.
- Easier to Repair: With bolted frames, you can replace just the damaged column or strut but welded frames require custom repairs or replacement. Additionally, a bolted connection is easy to see, test and replace where a weld covered by paint may or may not be structurally sound after an impact to the upright.
- Cheaper to Ship: Welded frames take up as much room as needed on the truck while bolted can be shipped knocked-down and assembled at the destination. This can make the difference between one truck or two (or more).
- More Flexible: If you need a custom height for a customer, welded rack can be cut down, but this involves cutting out a horizontal and possibly a diagonal brace, cutting down the columns and then re-welding the bracing. There are also limitations on what’s possible. Customizing bolted uprights involves cutting down the columns and adjusting the bracing as the frame is assembled, which is a lot easier and as a result, cheaper too.
- Better for Seismic Applications: Like the buildings and bridges I mentioned above, bolted frames can flex and give when the earth moves, while welded structures are rigid and can break.
Many people who aren’t familiar with bolted uprights think that the bolts loosen over time and need to be tightened back down occasionally. As you can see to the right, our K3 Werks frames are assembled with a serrated lock nut and once tightened down prior to shipment or by your installer if you ship knocked-down, they are locked in place.
As I mentioned in an earlier blog post, DAK Equipment only stocks equipment from RMI certified manufacturers so you can be confident that you and your customers are getting racking that’s been tested and meets all the current standards, whether the uprights are bolted or welded.
So which is best, bolted or welded? Well, that depends on your customers’ preferences but as I think you’ll agree, a lot of the misconceptions about bolted rack just aren’t true.