The problem of traditional dumbbells is the need to have multiple pairs if you want to minimize time when changing weight, which takes up space. Adjustable dumbbells solve this problem somewhat but then they introduce the issue of wasted time brought about when one changes resistance. However, I recently became introduced to a dumbbell system that solves the space issue and minimizes the problem of wasted time. This system is called the IRONMASTER Quick-Lock Dumbbell System.
Background
The system was developed by a IRONMASTER, a Seattle based company that was originally founded in 1978. They primarily sell their original designs and hold many patents on their unique equipment. Over 30% of their customers come from referrals and repeat customers due to the outstanding quality of the products and excellent customer service.The first time I visited the website http://www.ironmaster.com, I wondered how the system worked since on the outside it just looked like your typical traditional dumbbells. The lifetime warranty advertised on the website caught my eye as well, so I also started wondering how sturdy and secure it was in comparison to other adjustable systems. Finally, what caught my eye the most was the advertised price: $429 for a pair that went up from 5-75lbs and that included the dumbbell rack for free! After seeing all of these things I knew that I needed to know more about this system; especially since so many of my book customers were beginning to inquire on it.
Component Descriptions

Ironmaster Dumbbell Handles
The way the weights are secured is through a most ingenious locking screw mechanism. The 2-1/2 lb screws, also made of solid steel, consist of a 4-inch diameter disc with a knurled grip, and a 1-inch diameter partially threaded shaft. The disc has engravings with an OPEN arrow label and LOCK arrow indicating the direction in which it needs to be twisted in order to secure the weights.
Weight Plates
After I thoroughly examined the handles and screws, I started taking out the weight plates. The weight plates are made out of rugged precision-machined iron, capable of withstanding some abuse such as the throwing of weights on the floor. They are designed so that they can be stacked and interlocked into each other and into the handle backing plate; sort of like a LEGO piece. The plates have tapered edges that allow them to tilt in toward the handle automatically and stay in position during the weight change when the locking screws are out. The set brings twenty-four 5-lb plates (12 for each dumbbell) and four 2.5-lb plates (2 for each dumbbell) in order to facilitate 2.5-lb increments. Since we have a dumbbell handle that weighs 5lbs, two screws that weigh 2.5-lbs each, and twelve 5-lb plates with two more 2.5-lb plates, the system can provide up to 75lbs of resistance per hand.Weight Change Operation

Ironmaster Screws
To change the dumbbells, one has to set the dumbbell handles on the rack (or floor is you want to) with the notch on the side of the squares facing up. To open the locking screws you just turn the disc until the OPEN arrow points up toward the notch indicator of the handles and pull the screw out. Because the shaft of the screw is partially threaded, when the OPEN arrow is aligned with the notch, the screw easily comes out not requiring any further twisting. Then all you have to do is stack the weights that you want to add (or take out the ones that you want to remove) and re-insert the screw by again aligning the OPEN arrow with the notch. To secure the weights, just push the screw all the way in until the weight plates stack tightly and then twist them clockwise in order to engage the threads until they are hand tight.



