This is one of those things that grew out of a need to straighten really long (10-12’) boards for a house we were doing back in the early 90’s. The plans called for all the interior doors to be 8’ high and the entry doors were both 10’. It was a big undertaking and we didn’t have the money in the budget to buy a long bed jointer. There were 28 doors in all. The other reason the jointer wasn’t practical is that in those days we did not have a permanent shop. The first structure on a house would be the garage which became the shop. That meant that when the project was over all the machinery had to be moved to storage until the next project. 
  It is made primarily from one 4X8 sheet of melamine, a 2hp router and a few nuts and bolts and works extremely well. The maximum length is 8’ but you can make it any length you want short of that. We have always attached it to the side of an 8’ work bench. Starting with the 4X8 sheet slice off both 8’ factory edges at 5” wide and screw them together using lots of 1 1/4” screws. Align the two factory edges very carefully to give you a very straight 1 1/2” top edge. Next slice off two 3” pieces and cut them in half to give you four pieces 3” by 4’ long. They will become the jointer bed. Screw two of them together to make the infeed table. The other two will become the outfeed table. The outfeed needs to have spacers inserted between them to determine the fixed depth of cut. We have used just about everything for the spacers. Strips of wood but the best was some pieces on Formica we had. The bottom line is it needs to be about 1/16” thicker than the infeed table and very consistent thickness. Screw them together with the spacers in between. Now take the table support( the two 5” wide pieces) and cut a half circle at the midway point about 1 1/2” in diameter on the top edge. Time for pictures. 

Edited August 21, 20232 yr by Masonsailor

More pics

Now for the “body” which is a 16” wide by 8’ piece of the melamine. The router will need to be mounted at the center point of that piece. We have made this thing probably 4 times and we have mounted the router in several ways. The simplest way was just drilling holes in the base of the router and bolting it to the melamine. In the pictures my son did he made a router plate out of a piece of aluminum plate. Another time we bought a commercially made router table plate. They all worked. 

Now you mount the bed assembly to the body. One end becomes the pivot point. We used a 1/4” bolt. The other end is used to adjust the level of the bed to the router bit. My son actually made an adjustment device for his. We usually would use a clamp, make a few test cuts and then just screw the be assembly to the body. You will need to make an occasional adjustment when you change router bits but as long as you use the same exact router bit each time adjustment won’t be necessary. My son took the time to make a very nice version which took him several days. You can make the simple version in a couple of hours. The router bit can be just about anything that has a cutting length of 2”. We used 1/2” straight bits on the early versions and later changed to a 1/2” pattern bit with a bearing and supported the bearing to add a little rigidity. My son found a large flush cutting bit that he really likes. 
Paul

Thanks, Paul!

Great write up. Where did you find that bit? It looks like a doozy .

My son found that. Probably Amazon. 
Paul

Thanks for taking the time to do this Paul, great write-up

Back in the day we used that machine everyday. We would replace the top bed pieces about once a year. It also had the advantage back then of being a carbide bladed jointer that took about 2 minutes to change blades. At that point helical heads didn’t exist and changing blades on our 6” jointer was a pain. We didn’t use a giant bit like my son does. We were using a 1/2” straight carbide bits which were cheap at the time. 
Paul

Edited August 22, 20232 yr by Masonsailor