[EBEACH]

Alan,

I had suggested the rod end. We went through this about 2 years ago. At that time, I picked up 16 stainless steel rod ends, had a cnc router available to me, and I needed dimensions. The rise and run dimensions are most important along with the mounting width. I’m not sure how to best mount the thing (hardware).

I believe the tie rod method is the best way to engineer the ladder with the ability to fold flat and have the hardware concealed for the most part. The rod ends I have are about 7/16” on the ball end with a hole for a 0.187 shaft. The end is female with about a 1/4x20 thread. View FK Bearings website.

My thoughts on how to make it:

Using quality Baltic birch plywood (3/8 ~ ), machine two pieces that will be glued / laminated together to form each tread. The treads would be routed out to accept the 0.187 shaft using a cove bit (half round cut out on each half). Also, each tread would need a cut out to conceal and house the ball of the rod end. Install two rod ends on the 0.187 wire/rod (on each end of the tread), place in the cove cut out on the tread, and laminate the two halves together. Each tread will have 4 rod ends (two on each end).


The risers would have through holes for the 1/4x20 screw to mount the treads to the riser. Furthermore, the riser would have a recessed hole (not all the way through) that is concentric to the 1/4x20 hole to house a portion of the rod end (give it support) on the inside of the riser. Screws with finish washers are inserted from the outside of the risers through the 1/4x20 hole and thread into the rod end that mount inside the recessed hole.

Keep in mind that the inside width of the riser (stringer) would determine the space between each tread, in order for the ladder to fold flat. I would also suggest that a more stout piece of wood be used on the risers, and maybe so on the treads. In order to reduce weight, I would also suggest removing some of the material (hollow out) on each half. Leave ribs and bosses in there to provide support where needed. Drill holes in each mirrored piece to place dowels for alignment when gluing the halves together.

Unfortunately, my project is on the back burner, and the ladder is not the first thing I need to tackle at this moment. I can help out with some CAD work if you come up with some dimensions (width of tread and riser, rise and run, and mounting options). There are plenty of shops in Long Island that can rout wood with a cnc router. Check your local sign shops or die board houses.

Jim