How to make a makeshift assisted pull-up machine

[Brian Li]

Hey guys, do you know how to make a platform based counterweight system that is similar to an assisted pull-up machine instead of a harness based counterweight system? Thanks in advanced guys!

[Daniel Burnham]

why can't it be harness?  You could put that below a pull-up bar.  Otherwise you need a rigid platform setup and that would make it slightly more difficult and more expensive.

[Brian Li]

I'm actually asking this for a friend so I will have to ask him why first then I will post his response.

[Brian Li]

Ok, he said he feels more comfortable standing on a platform than wearing a harness. He originally wanted to make this: DIY, but he isn't allowed to drill holes and that it takes too much space. So he said he wants to make something similar, but it has to be hung off of a pull-up bar.

[Cole Dano]

I've tried making these kinds of systems a couple of times. My final conclusion is more trouble than it's worth. So unless there is good reason I'd steer your friend away.

 

As the link you provided mentions, one issue (of many) is the pulley. Most of the less expensive climbing pulleys stick, the rescue quality ones are fairly expensive iirc $75-$100.

 

With that in mind you can make one with a couple of good pulleys and a longer length of climbing rope and a shorter length of climbing rope.

 

Fix one pulley to one side of the  pull-up bar.

Tie the long rope to the other side.

Make a short loop of rope for the platform your friend will stand on, you can put a piece of PVC pipe around it to make it more comfortable.

Tie the loop to the anchor holes on the pulley

Thread the platform pulley through the rope and the the rope through the pulley attached to the pull up bar.

You'll have a U shaped rope with one pulley and platform at the bottom and the remainder of the rope hanging off the other pulley.

Tie that end of the rope in a loop to facilitate adding weights.

 

You'll have to adjust exactly where you put that loop so all the lengths of the system are just right.

[Sam Rea]

Another idea:

For a freestanding machine, a seesaw arrangement comes to mind. So you would need some sort of lever (say a piece of 2" x 6"), a platform at one end to stand on and a platform/rack at the other end to load counterweights onto. The fulcrum could be of the same material as the lever, with a couple of large diameter bolts to pivot around. To stop the fulcrum from moving you would need to either: attach it to a very large base plate; fix it to the floor; or design a base plate which could be loaded with more weights.

 

As Cole says, it does seem like more trouble than it's worth. What's wrong with just progressing through rows, isometrics and negatives?