So this is a little off the beaten path for me, usually I am posting about one of my plugins, but here goes anyways. Since Covid started a couple years back I’ve had to give up on going to the gym and instead have managed to cobble together a fairly decent personal gym in my garage. I’ve got a treadmill, a couple benches and some dumbells and other free weights. It actually isn’t too bad of a setup.
The only thing I have really been missing is a decent lat pulldown machine. I was about to purchase one on Amazon but after reading a lot of reviews it seems that a good quality machine will come at a not so good price. That being said I thought it might be interesting and fun to try and build one instead with my teenage boys (get them off their games for once). Here is my first crack at a design:
My biggest issue or concern is rigidity and stability. Don’t need this thing toppling over on me or one of the kids. I also haven’t shown the hardware in the model yet but it will be pretty simple, a couple of pulleys, wire rope and the 10 lbs pulldown bar.
The link to the model is below if you care to take it for a spin:
Comments?
P.S. When it comes to strength and rigidity my concern is largely due to the amount of weight I typically pull (120 - 175 lbs) on a machine like this. I will probably construct it with glue and screws, but it may need more bracing with OSB or plywood.
Are the weights going to be in the tall vertical column or off the back? They might need something to keep them from swinging sideways. Not sure if needed but you could reinforce the two forward column boards by making each a “T”, adding a 2x down the center of the length. Looking forward to seeing the model with all the hardware. Should be a fun project.
Interesting project. I’d be inclined to use half lap joinery where the verticals meet the horizontal members. Through bolts at the connections of the major load bearing parts. Also would use a good wood epoxy at the various joints. As already been mentioned figuring out the weight carrying portion is going to be the trick. Needs to be strong and stable while maintaining free running capabilities. If it was me I’d be inclined to save my $ for a well made commercial machine but that’s me…… sort of a cost of materials plus my labor $ thing….
I was thinking about having the weights drop out the back of the machine but maybe it would be better to increase the distance between the two columns and have the weight drop between the columns.
You’ve stimulated my backyard engineering brain with this…. Would the plan be to stack barbell plates on it and be relatively easy to add and remove weight ? My brain is now going into overdrive…
The knee pad (or stop) is designed to project through the seat as shown with holes drilled for a bolt through the 4x4 (not visible) so that it is vertically adjustable.
The problem I see with this design is that if you don’t pull down straight the whole thing will twist sideways, I really don’t see a good way to prevent this, at least with the current design.
The only way to minimize this torsional deflection or twist of the vertical column is to sheet all sides of the column and essentially turn it into a vertical box beam.
