Weight-Stack-FAQ
Selectorized Weight Stack FAQ:
If you are modifying an existing weight stack configuration, or replacing broken or missing components, it is strongly recommended that you read through this FAQ for detailed answers to questions you may have that will help insure a smooth transition. Not all weight stack systems were created equal. Our goal with this FAQ is to answer the many questions we typically receive during pre-sale tech support. If you do not find the answer to a question or concern below, please feel free to contact us and we will amend this FAQ for future reference.
We offer a variety components for 3 different weight stack systems. Components are both generic and modular - meaning they are not linked to any particular fitness machine manufacturer (or brand), and they are interchangeable within the same system type. Interchangeability allows flexible modification to an existing weight stack configuration.
Interchangeability makes it possible to:
*Add weight by swapping 5 lb plates for 10 lb plates. Or 10 lb plates for 15lb or 20 lb plates for example.
*Add weight by swapping an existing center selector shaft for a longer one, for a taller weight stack with more plates.
*Scale down an existing weight stack by swapping heavier plates for lighter ones - in any combination. (AKA "pyramiding")
*Replace components that are missing or damaged - without the need for modification.
We offer 3 types of weight stack systems:
(1) Cast Steel
*Virtually unbreakable when compared to cast iron
*Round weight stack pin holes that accept straight, round selector pins.
*Weight stack pin center line is 1/2" from top (and bottom) of weight plate.
*Available for both 3/4" and 1" diameter guide rods.
*Nylatron guide rod bushings are pressed in
*Durable black powder coated finish.
*Very accurate and consistent weight.
(2) Cast Iron (Gray)
*Breakable when abused due to the fragility of cast iron
*Rectangular weight stack pin holes that accept straight, round selector pins with welded-on locking tab.
*Weight stack pin center line is 3/4" from top (1/4" from bottom) of weight plate.
*Available for 1" diameter guide rods only.
*Nylatron guide rod bushings are the "snap in" type.
*Painted hammertone gray and baked on for more durability.
*Weight consistency varies 2-3% due to porous nature of cast iron.
(3) Cast Iron (Black)
*Breakable when abused due to the fragility of cast iron
*Rectangular weight stack pin holes that accept straight, round selector pins with welded-on locking tab.
*Weight stack pin center line is 3/4" from top (1/4" from bottom) of weight plate.
*Available for 1" diameter guide rods only.
*Nylatron guide rod bushings are pressed in
*Painted flat black but not baked on.
*Weight consistency varies 2-3% due to porous nature of cast iron.
All 3 System types have the following parameters in common:
*All weight plates are 1" in thickness ( industry standard).
*All weight plates and top plates have guide rod hole spacings of 5" on-center (industry standard)
*All center selector shafts have a 1/2-13 female coarse thread for engaging a cable terminal or pulley (industry standard).
If you plan on mixing and matching your existing components with ours, your existing components must also require 1" thick weight plates with guide rods 5" on center. This covers more than 98% of the equipment out there in use. If you are needing components that fall outside of these two parameters, then they are not available "off the shelf" and must be custom made if you can't get them from the original manufacturer. We can custom machine any weight stack components in-house - more on that later.
Nearly all interchangeability problems arise from from one or more of the following things:
(1) Attempting to mix cast iron weight plates with cast steel plates. This won't work because the selector pin hole center line in cast steel plates are on-center with respect to the 1" wide face. Whereas the cast iron selector pin hole center line is 1/4" off set from center with respect to the 1" wide face. Since all selector shafts have pin holes 1" apart along the length of the shaft, synchronicity of the pin hole alignment is lost. Generally, black and gray cast iron plates with offset pin selector holes are interchangeable with each other.
(2) Attempting to swap center pin selector shafts without checking dimensions beforehand. Selector shafts for cast iron plates and cast steel plates are not interchangeable because the selector pin center line is on-center in cast steel plates, and 1/4" off center for cast iron plates.
If you need to swap the selector shaft from an existing cast steel weight stack, you can still run into issues: The selector shafts for cast steel systems are mounted to the top plate via a roll pin (AKA "spring pin") that may be either .400" (10 mm nominal) in diameter or .450" *7/16" nominal) in diameter depending on the manufacturer. We offer cast steel top plates and selector shafts which require a 10 mm roll pin only. If you are swapping the selector shaft from a cast steel system that uses a 7/16 roll pin, you will need to purchase both a matching top plate and selector shaft. The roll pin hole in our top plate is .416" in diameter and is too small for your existing 7/16" roll pin. Another option - to be performed at the customers own risk and liability - is to drill out the roll pin holes in your existing top plate and new selector shaft to accept your existing 716" roll pin.
You can easily determine if your existing top plate uses a 7/16" roll pin: If you can insert a known 7/16" diameter bolt into the roll pin hole of your existing top plate, then your top plate requires a 7/16" roll pin and therefore you must purchase a matching top plate with the selector shaft you will swap. However, if a 7/16" bolt will not fit into the roll pin hole of your existing top plate, then you have a 10mm roll pin hole which matches our selector shaft and it will not be necessary to purchase a new top plate.
(3) Upgrading a weight stack so that it is too tall for the frame or swapping for heavier weight plates that are too wide for the frame. Be sure to check if the dimensions of your newly configured weight stack will not interfere with the mechanics and/or framework infrastructure of your machine. A taller weight stack will "bottom out" against upper frame members with less range of motion. Make sure there is enough clearance to accommodate a taller weight stack. In some cases, the cable attached to the taller weight stack will need to be shortened depending on the application.
Custom Made Components:
If you have a proprietary weight stack system in need of non-industry standard components that are not available off-the-shelf, then the only choice is to have them custom made. Whether you need hard to find replacement parts or needing an entire weight stack system built to suit, we can build solid steel components from scratch using our in-house CNC machining facilities. We can finish components in paint, powder coating, or chrome plating. Contact us with your requirements.
If you are modifying an existing weight stack configuration, or replacing broken or missing components, it is strongly recommended that you read through this FAQ for detailed answers to questions you may have that will help insure a smooth transition. Not all weight stack systems were created equal. Our goal with this FAQ is to answer the many questions we typically receive during pre-sale tech support. If you do not find the answer to a question or concern below, please feel free to contact us and we will amend this FAQ for future reference.
We offer a variety components for 3 different weight stack systems. Components are both generic and modular - meaning they are not linked to any particular fitness machine manufacturer (or brand), and they are interchangeable within the same system type. Interchangeability allows flexible modification to an existing weight stack configuration.
Interchangeability makes it possible to:
*Add weight by swapping 5 lb plates for 10 lb plates. Or 10 lb plates for 15lb or 20 lb plates for example.
*Add weight by swapping an existing center selector shaft for a longer one, for a taller weight stack with more plates.
*Scale down an existing weight stack by swapping heavier plates for lighter ones - in any combination. (AKA "pyramiding")
*Replace components that are missing or damaged - without the need for modification.
We offer 3 types of weight stack systems:
(1) Cast Steel
*Virtually unbreakable when compared to cast iron
*Round weight stack pin holes that accept straight, round selector pins.
*Weight stack pin center line is 1/2" from top (and bottom) of weight plate.
*Available for both 3/4" and 1" diameter guide rods.
*Nylatron guide rod bushings are pressed in
*Durable black powder coated finish.
*Very accurate and consistent weight.
(2) Cast Iron (Gray)
*Breakable when abused due to the fragility of cast iron
*Rectangular weight stack pin holes that accept straight, round selector pins with welded-on locking tab.
*Weight stack pin center line is 3/4" from top (1/4" from bottom) of weight plate.
*Available for 1" diameter guide rods only.
*Nylatron guide rod bushings are the "snap in" type.
*Painted hammertone gray and baked on for more durability.
*Weight consistency varies 2-3% due to porous nature of cast iron.
(3) Cast Iron (Black)
*Breakable when abused due to the fragility of cast iron
*Rectangular weight stack pin holes that accept straight, round selector pins with welded-on locking tab.
*Weight stack pin center line is 3/4" from top (1/4" from bottom) of weight plate.
*Available for 1" diameter guide rods only.
*Nylatron guide rod bushings are pressed in
*Painted flat black but not baked on.
*Weight consistency varies 2-3% due to porous nature of cast iron.
All 3 System types have the following parameters in common:
*All weight plates are 1" in thickness ( industry standard).
*All weight plates and top plates have guide rod hole spacings of 5" on-center (industry standard)
*All center selector shafts have a 1/2-13 female coarse thread for engaging a cable terminal or pulley (industry standard).
If you plan on mixing and matching your existing components with ours, your existing components must also require 1" thick weight plates with guide rods 5" on center. This covers more than 98% of the equipment out there in use. If you are needing components that fall outside of these two parameters, then they are not available "off the shelf" and must be custom made if you can't get them from the original manufacturer. We can custom machine any weight stack components in-house - more on that later.
Nearly all interchangeability problems arise from from one or more of the following things:
(1) Attempting to mix cast iron weight plates with cast steel plates. This won't work because the selector pin hole center line in cast steel plates are on-center with respect to the 1" wide face. Whereas the cast iron selector pin hole center line is 1/4" off set from center with respect to the 1" wide face. Since all selector shafts have pin holes 1" apart along the length of the shaft, synchronicity of the pin hole alignment is lost. Generally, black and gray cast iron plates with offset pin selector holes are interchangeable with each other.
(2) Attempting to swap center pin selector shafts without checking dimensions beforehand. Selector shafts for cast iron plates and cast steel plates are not interchangeable because the selector pin center line is on-center in cast steel plates, and 1/4" off center for cast iron plates.
If you need to swap the selector shaft from an existing cast steel weight stack, you can still run into issues: The selector shafts for cast steel systems are mounted to the top plate via a roll pin (AKA "spring pin") that may be either .400" (10 mm nominal) in diameter or .450" *7/16" nominal) in diameter depending on the manufacturer. We offer cast steel top plates and selector shafts which require a 10 mm roll pin only. If you are swapping the selector shaft from a cast steel system that uses a 7/16 roll pin, you will need to purchase both a matching top plate and selector shaft. The roll pin hole in our top plate is .416" in diameter and is too small for your existing 7/16" roll pin. Another option - to be performed at the customers own risk and liability - is to drill out the roll pin holes in your existing top plate and new selector shaft to accept your existing 716" roll pin.
You can easily determine if your existing top plate uses a 7/16" roll pin: If you can insert a known 7/16" diameter bolt into the roll pin hole of your existing top plate, then your top plate requires a 7/16" roll pin and therefore you must purchase a matching top plate with the selector shaft you will swap. However, if a 7/16" bolt will not fit into the roll pin hole of your existing top plate, then you have a 10mm roll pin hole which matches our selector shaft and it will not be necessary to purchase a new top plate.
(3) Upgrading a weight stack so that it is too tall for the frame or swapping for heavier weight plates that are too wide for the frame. Be sure to check if the dimensions of your newly configured weight stack will not interfere with the mechanics and/or framework infrastructure of your machine. A taller weight stack will "bottom out" against upper frame members with less range of motion. Make sure there is enough clearance to accommodate a taller weight stack. In some cases, the cable attached to the taller weight stack will need to be shortened depending on the application.
Custom Made Components:
If you have a proprietary weight stack system in need of non-industry standard components that are not available off-the-shelf, then the only choice is to have them custom made. Whether you need hard to find replacement parts or needing an entire weight stack system built to suit, we can build solid steel components from scratch using our in-house CNC machining facilities. We can finish components in paint, powder coating, or chrome plating. Contact us with your requirements.
- Weight Stacks & Parts
- Weight Stack Pins
- Cable & Hardware
- Pulleys
- Foam Rollers
- Handle Grips
- Knobs
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- Shaft Collars
- End Caps & Plugs
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- Order Steel Online
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