T Nation

Extending a hi-lo Pulley Machine?


#1


I just bought two of these type machines from a gym going out of business. My intent is to use one as a lat machine-cum-rower, by cannibalising weights from the other.

My question is: What would be the best approach? They have 40 kg each. Do I extend the stach by welding the "lifting bars" in tandem so that the stack gets taller? The movement range would seem ok. Altenatovely, I could weld tubing to hold olympic weights. That would be a narrow squeeze,though.

Help!

TQB


#2

40kg weight stack eh?

Are you sure the wire etc. would handle doubling the weight?


#3

The structure is fine, the blocks will take it and I expect to replace the wires (ropes today)


#4

I guess if you replace everything but the frame and weights then you are OK.

Seems to me the easiest would be to make a bracket to hold Olympic weights, possibly both front and back. The only ones I’ve seen have been front-side only, but they weren’t relying on the plates being the majority of the weight.


#5

[quote]Bill Roberts wrote:
I guess if you replace everything but the frame and weights then you are OK.

Seems to me the easiest would be to make a bracket to hold Olympic weights, possibly both front and back. The only ones I’ve seen have been front-side only, but they weren’t relying on the plates being the majority of the weight.[/quote]

Some good news. I had assumed the stack was 40kg composed of 2.5kg weights. I just checked and the weights are 3.4kg, i.e. 7.5lbs Murrcan measures. The makes the stack about 58 kg and I only have to add seven plates to reach my target of 80kg. This makes the project much easier and the margins far better. I think I will try to extend the plate load rod for neatness reasons.


#6

Bear in mind, you are adding nearly 50 lbs to a machine that, more than likely, has been engineered specifically for the original weight stack. Companies do not tend to “over-engineer” products. They need to keep spacial considerations in mind and keep material and freight cost to a minimum.

If this is so you will likely run into issues later on with, at the very least, the pulleys and I would image the weight stack support tube.

There were certainly safety factors included in the design of the machine, however I would not make too many assumptions if I were you. My point with all of this being, if you are successful, you will get some life out of the machine but just be careful, you could loose an eye or something.

What I mean by if you are successful…have fun drilling holes in the stack bar extension, and how you will weld an extension on to the existing stack bar and have no failure or interference issues…geez!

Be safe :slight_smile:


#7

[quote]W.H.B. wrote:
Bear in mind, you are adding nearly 50 lbs to a machine that, more than likely, has been engineered specifically for the original weight stack. Companies do not tend to “over-engineer” products. They need to keep spacial considerations in mind and keep material and freight cost to a minimum.

If this is so you will likely run into issues later on with, at the very least, the pulleys and I would image the weight stack support tube.

There were certainly safety factors included in the design of the machine, however I would not make too many assumptions if I were you. My point with all of this being, if you are successful, you will get some life out of the machine but just be careful, you could loose an eye or something.

What I mean by if you are successful…have fun drilling holes in the stack bar extension, and how you will weld an extension on to the existing stack bar and have no failure or interference issues…geez!

Be safe :)[/quote]

The engineering of the stand and pulleys is top notch. I guess bulk buying beat engineering to spec. The joint where the extension of the stack bar is, is my concern, but:

a) it only lifts 22 kg.
b) it still looks sturdier than the pin that locks all the weight in place.