I just took an angle grinder and ground through the angle to the bed side. It popped right off. It was easy and you could control the depth. I then drilled holes through the bed side and plug welded the new angles to the bed side. I clamped an aluminum strip on inside bed part of the angle this helps prevent burn through. I also painted the back of the angle and the bed where the angle is on the side. I used some dime store self-sticky dots to keep the paint off the angle at the weld points. You have to be very careful about the front to back position as this will affect the position of the bed on the frame. The height from the bottom edge is important to give you the right space between the front and rear supports. 3/4 inch for wood. Mar-K has most if not all the spacing requirements and how to attach the angle on their web site.