After the initial success the mill expanded it's offerings to include products to aid and support an emerging local industry - barrel manufacturing. Being located right in the center of some of the countries largest acreage of apple orchards barrels became a product made to support the growing local commercial apple industry. In addition to barrels they began to produce and sell plow beams, pitman rods, and wagon wheels to support the local farmers. The barrel factory operated until 1935 when new apple packaging appeared.

In 1950, Marshall Longenecker bought Arendtsville Planing Mill. Under Marshall's ownership the mill continued to flourish adding custom cabinetry to their services. In Marshall's words, "We have made everything from toothpicks to rolling pins, and have served everyone from paupers to presidents."

In 1963 Marshall retired, selling the family business to his son-in-law and daughter, Elson and Jane Grim, who incorporated the business under tha name that it is known by today, APM, Inc. They continued the tradition of manufacturing quality wood products as well as adding storm window installation to the mix, a brand new invention at the time and one that would prove to be quite popular.

The business was later expanded into a lumberyard and wholesale distributor for building materials. APM Inc. moved across town to a much larger location when Elson and Jane purchased a True Value Hardware franchise, the first of its kind in this small, rural community.

After graduating college in 1991 Curt Grim, Elson and Jane's only son, joined the family business. Having spent many summers throughout his teen years helping out in different aspects of the company, it was a natural fit. In 1994, Curt Grim purchased APM Inc. from his parents. His dedication to keeping up the family tradition of providing quality goods and service at a fair price continues today.

With the addition of two more enterprises Curt has expanded APM Inc. into three strong divisions, APM Building Materials (the original business that comprises the lumberyard and the True Value Hardware Store, APM Buildings (supplier of Pole Barn and Garage building materials operating within a 225 mile radius of Arendtsville, PA), and Accent Building Products (an e-commerce website serving the 48 continental United States with products used to accent your home).