Compact Rails from Automotion
The compact rail system is a unique linear rail, or linear guide system that is very easy to install and allows for some misalignment of the structure in which It is being used. With the pre-load, or stiffness of the system also being adjustable by the user during set up makes this a very user friendly linear system. Induction hardened raceways on all rails and a precision ‘master’ rail ensure this is still a high precision system but with minimal set up time, thus offer cost savings during the installation process.
As specialists in linear motion systems we offer you a choice of materials and sizes. So whether you need lightweight aluminium rails for use in aviation applications or stainless steel components for when exposure to water or corrosive chemicals is a factor, our knowledgable technical engineers are always on hand to provide assistance.
Make sure you download a free Linear Motion Handbook here and utilise our free CAD to help you save time planning your projects.
Light duty, compact rail sliders with rubber seals.
Light duty compact sliders for long linear rails.
Light duty, compact -rails with counterbored fixing holes.
Light duty, compact U-rail with counterbored fixing holes.
Light duty, compact T-rail with countersunk fixing holes.
Light duty, compact U-rail with countersunk fixing holes.
Medium duty compact rail slider. Front fixing with side seal.
Medium duty, compact rail sliders. Front fixing with no side seal.
Medium duty compact rail sliders. Top fixing with side seal.
Medium duty compact rail sliders. Top fixing, size 28. Cast body.
Medium duty, compact U-rails with counterbored holes.
Medium duty compact rails sliders. Front fixing, size 35.
Medium duty compact rail sliders. Front fixing, size 35 without side seal.
Medium duty compact rail sliders. Top fixing, size 35 with side seal.
Heavy duty compact rail sliders. Front fixing, size 43 with side seal.
Heavy duty compact rail sliders. Front fixing, size 43 with no side seal.
Heavy duty compact rail sliders. Top fixing, size 43 with side seal.
Heavy duty compact rail. Top Fixing, size 43. Cast body.
Very heavy duty rail sliders. Front fixing, size 63 with no side seal.
Very heavy duty compact slider. Top fixing, size 63. Cast body.
Very heavy duty compact T-rails with counterbored holes.
Very heavy duty compact T-rails with countersunk holes.
Very heavy duty compact U-rails with countersunk holes.
Very heavy duty compact K-rails with counterbored holes.
Very heavy duty compact K-rails with countersunk holes.
Inidivdual rollers for use with our compact rail system products.
General Guidance
Orientation of rails
The radial load that the sliders can take is significantly higher than the axial load, so where possible the rails should be set up with the sliders taking the loads in this plane.
One of the key benefits of the compact rail system is that it compensates for misalignment in the structure. This often results in a major cost saving when compared to the use of other guideways which have to be very accurately installed.
The compact rail system achieves this by using a master (T type) rail, and a slave (U type) rail. This allows the slides in the T rail to remain fixed in place but allows lateral movement of the sliders in the U rail to adapt to any misalignment and avoid any issues of stiction.
U rails have flat, parallel raceways that allow free lateral movement of the sliders. The maximum lateral movement for each size is shown in later tables.
Using flat rails
It is acceptable (but not the preferred method), to use rails as below but the alignment accuracy needed is slightly greater and in this set-up only T type rails can be used.
In this case the axial load figure C0ax should be used in any calculations (which is considerably less than the radial load figure C0rad).
Why should I consider using compact rails?
- Compact rails have a number of major advantages over the traditional use of recirculating ball linear guideways. Using a master (T) rail and slave rail (U) rail, the structure onto which the rails are installed does not have to be machined so accurately – this can result in major cost savings for many projects.
- The raceways of the compact rail system are on the inside of the rail profile, and this, highly effective side and end sealing, and the use of large diameter roller bearings (as opposed to miniature ball bearings), means that the system is highly resistant to dirt and debris.
- Unlike linear guideways, the preload of the sliders can be adjusted as required. This can result in a very smooth running system.
- Rails can be easily joined together to make unlimited rail lengths.
- The rails and sliders can be provided with alloy coating and stainless steel roller bearings for applications that may become wet.
Are there any disadvantages?
- The compact rail system’s accuracy is around 0,15mm over a 3 metre length – this is not as accurate as recirculating ball linear guideways.
- Recirculating ball linear guideways have higher load capacities for both axial and radial loads.
How do I change the smoothness of the running of the sliders in the rails?
- Each slider is supplied with a small spanner. This can be used to push the eccentric roller towards the top of the rail (making it run stiffl y), or pulled away slightly to make the sliders run very smoothly. The eccentric rollers are clearly marked and the slider should be installed the correct way up in the rail. Generally this is with the fixed rollers towards the bottom of the rail (providing the loading points). The simple instructions are shown in the catalogue.
I want to use the rail outside or in a slightly wet environment?
- A nickel or alloy plating can be applied to the compact rail, this is our preferred anti-corrosion solution. Please see our anti-corrosion section for details.
- The sliders can also be nickel plated and provided with stainless 440C roller bearings with 2RS (splash-proof) seals.
What about if I want to motorise my application?
- We have a full range of motorised linear stages based on the compact rail systems – these are our uniline stages.
- Maximum stroke for these (in a single piece) is around 6 metres.
Do you hold these parts in stock?
- In general we hold all the rail in stock as well as most the most popular C series sliders.
Can I get CAD files of these parts?
Most of the 3D models (in many formats) are available for download directly from our website www.automotioncomponents.co.uk
I am not sure which is the best rail/slider combination for my application?
Please send us a sketch listing the main points of the application and our Technical Department will deal with this promptly. If required we can also arrange a visit to discuss the application and to show you the different systems available.
Anti-corrosion treatments
The compact rail systems have the following protective coatings as standard:
- Rails: zinc plated (with the exception of the area of the raceways themselves), these are ground after the plating process.
- Sliders have a zinc plated solid steel body.
We can upgrade the anti-corrosion protection of the system by off ering the following:
- Nickel plating the rails. In this case the nickel plating is applied after the grinding of the raceways. In this way the whole of the rail is anti-corrosion protected.
- Sliders can also be fully nickel plated. Stainless steel (440C) rollers can be used with 2RS (splash proof) seals and stainless steel screws for the sliders.
- The special low head Torx screws can be supplied nickel plated.
Anti-corrosion protection option
CS type sliders type NI
Rail and screws
1 Consider the size and overall weight of the load
- There are four diff erent rail sizes (18, 28, 35 and 43).
- A large percentage of applications use size 28 or size 43 rails and sliders. Whilst rails can be used singly, for the majority of applications they are used in pairs (typically a T and a U rail).
- Normally at least two sliders are used per rail. So as a starting point, divide the total load (in Kg.) by the number of sliders and multiply by 10 to give the expected load per slider in Newtons. Compare this to the dynamic load C0rad load ratings in the load capacity summary tables. More sliders can be added to increase the system load capacity, or select a slider with more roller bearings (the standard sliders have three roller bearings), up to six roller bearings per sliders are available.
- Where possible the rails should be installed on their side as this gives the maximum load rating per slider. Typically the radial load of a slider is twice its axial load rating.
2 Type of slider
- Our standard sliders are solid body, front mount with side seal type CL. These have a wide body and are available front mount and side mount.
- Some customers however prefer to use narrow solid steel body sliders type CS. These types do not have side seals.
3 System travel
- Thinking about the physical dimension of the load will give an indication of how far apart the sliders should be positioned in the rails. This, and the distance apart that the rails and the sliders are positioned, aff ect the moment loads that the sliders experience.
- The above factors will give a good indication of the rail size to be used. In many cases the rails size that could be used might be smaller than would be expected (due to the impressive load ratings of the sliders). In many cases customers quite often “up-size” the rail so that it “looks” more appropriate to the size of the load being carried.
- Considering the distance apart of the sliders and the movement (stroke) required in the system will determine the overall rail length required.
- Rails can be joined together to make unlimited rail lengths. For this we have to select suitable rails, machine the ends and add an extra fixing hole. The rails can then be aligned with a simple tool.
4 Rail types
- Typically a T rail is used on one side and a U rail on the other. The U rail allows for lateral movement of the U slider in the U rail - this reduces the need for accuracy in the structure that the rails are used on, as the T rail becomes a master rail and the U rail a slave rail (unlike linear guideways where to prevent irregular movement the rails have to be aligned highly accurately).
- In some instances there can also be significant height inaccuracies and in this case the T rail can be replaced by a K rail (K rails cannot be used in vertical applications).
- There are two versions of each rails type. These end in either a C or a V and indicate the type of fixing screw required to fix the rail to the structure. The C (counterbored) type is most widely used compared to the V (countersunk) type. The counterbored fixing in the rails allows for more flexibility in the fixing hole position of the structure. Special low profi le counterbore screws are provided with the type C rails.
5 Environment
- In normal, dry applications, the zinc plated fi nish of the rails combined with the standard 2Z (dust proof) seals of the roller bearings in the sliders is sufficient.
- In some cases the rails may become wet. In this case we have the option to apply a special coating to the rails, please discuss with our Technical Department. This has good corrosion resistance (see notes on Salt Spray tests), and should be combined with either nickel or alloy plated sliders with stainless steel rollers (440C), and 2RS roller bearing seals (splash proof) these are generally of the CL or CS type and are shown in the catalogue. The 2RS seals are “splash proof” - they cannot operate fully immersed.
