Fellows one thing I am very familiar with is the Roundtable. Their only draw back is having a wide and long enough building or lean to off the side of a building to protect it from the weather.

For as size of table, the best over all working size is 16 feet to 24 feet across,16 feet being the minimal working size. Is best to set it low to ground around knee high to you or sitting down in a normal height chair. The dog will not feel like it is going to fall off the edge, slam on breaks and burn the pads. You will be close to the dog and it will be easy to put the dog on and off the table. With no struggle and less chance of hurting your back. Being close to the dog you can encourage it and even love on it while it works.

The over head pulling beam should be placed across the table one foot forward of the center circle of the table. You need at least three pulling adjustments on the pulling beam to adjust how the dog trots or pulls. To keep it running out front in the sweet spot of the table. To also prevent dog from falling back and running on the back side. Want the dog at center or out front.

Preparing the running surface is no different than putting down carpet padding and carpet in a house. Will help to have the proper type tools for putting down the pad and carpet. Make sure where the center hole of table is. The carpet is well secured down. Since you will be pulling the carpet tight from inside to the out side.

Best glue a good quality standard carpet pad down to the plywood and let set before putting on the carpet. To prevent any bunching up of pad and carpet.

This is very important for safety reason to you. Allow your metal frame measurement to be around 4 to 6 inches less than the total length of the wood surface. So you can completely over lap the padding and felt and take under the table and staple down. This padding and carpet will protect your legs and knees from the outer turning edge of the table. If Part of that metal frame should catch your leg or knee cap could cause serious damage to the body.

Never allow children to play on it or underneath it. When in use keep all children away. Were to get under it while moving could result in serious body and head injuries.

The best type running surface, if possible is 100% cotton felt. Most pulp paper making companies have lots of it and dump it at the dumps. It comes in long wide section pieces. This very durable cloth material was used for filtering the water etc.

Type axle or axles used can be Trailer axles or a heavy duty truck rear end axle. If you use a heavy duty truck rear end. You can leave in the gears for helping the table run and slow down at a normal rate to effort applied. Just make sure plenty of oil is in the hog head casing and all bearings tight, greased and sealed. Make sure you put the right end of the axle and turning direction of the hub correctly before you seal that end in concrete. Probably not so with a positive traction rear end.

With a larger table if using the Trailer axles, might be best to cut the shaft length down and use both axles. One for the running part and the other for running/strength support on the bottom.

This was all a mouthful. Have anymore questions just post. This is not a easy project and does take some mechanical, welding and carpenter skills etc. If you successfully build one and use it for awhile. You will be spoiled by it. When bad weather days set in on you. No biggie you just keep on keeping on.

P.S. A lot of those dog men that used a Swinging Jenny. Some where on the property was a round table and slat mill for back up. Cheers