Lead Screw Supports
By Zoe Moser (Edited by Kevin Wright and Shizu Yamaguchi)
Our lead screw support blocks are available in thread sizes of 6-24 mm with options for trapezoidal, dryspin high helix and metric threads (Acme on demand); choice of mounting: plain bearings or, for higher dynamic loads and speeds, ball bearings (BB). All lead screw support blocks, like the matching lead screw clamp rings, are supplied in hard anodized aluminium.
FL: Fixed bearings with anodized clamping ring with right-hand threads and self-lubricating iglide® plain bearings
LL: Floating bearings with self-lubricating iglide® plain bearings
LH: Optional: left-hand threads, only TR10x2, TR10x3, TR18x4, and TR24x5
Advantages:
► Self-lubricating and maintenance-free
► Practical housing for lead screw support
► Mounting holes for your design
► Prepared for connection of accessories such as position indicators and manual clamps
► Available for lead screws with diameters 6-24 mm
► Trapezoidal thread and high helix thread versions
Why are there different versions of lead screw support?
Using the right lead screw support is based on the defined parameters and demands of a given application. With high axial loads and speeds, a ball bearing in the end support is required to ensure the system operates efficiently. For positioning systems or systems with high vibration, using a plain iglide bushing offers superior performance at a lower cost. Lead screw support types need to correspond appropriately with its lead screw application requirements.
Definition of lead screw support configurations
Fixed floating bearing:
The fixed bearing clearly positions the shaft in an axial direction. The fixed bearing must therefore absorb both radial and axial forces and guide them into the surrounding structure. This absorption and guiding can basically be done by a single bearing. The floating bearing corrects parallelism errors minimally and offers thermal expansion capability, which means that the cable is not stressed.
Advantages of the fixed floating bearing
► No axial clearance
► Non-critical shaft expansion (due to such factors as temperature)
► Suitable for changing axial loads
► Clarity of forces applied
Double-sided floating bearing:
In a double-sided floating bearing, the lead screw is not clearly fixed in the axial direction. This means that without stressing the bearing, mechanical or thermal differences in length can be absorbed, but the lead screw is not protected against drifting. This is especially important to consider for positioning applications!
Advantages of double-sided floating bearings:
► Cost-effective
► Low design cost
► Non-critical shaft expansion (due to such factors as temperature) in the area of clearance
Disadvantages:
► Not clearly fixed in the axial direction
► Not suited to changing axial loads
► Only if axial clearance does not impair function
Lead screw support versions
Fixed-bearing (FL) version
Depending on thread dimensions, this version has the clamping ring clamped into the lead screw itself or to the lead screw’s outer diameter. For high helix lead screws, it is always the outer diameter that it is clamped to. To the online shop
► Note: for your application, you can also choose a lead screw support block that uses the d1 measurement for clamping onto the turned machined end.
Floating bearing (FL):
Depending on the lead screw’s dimensions, a machined end must be turned to the value d1. You can see the dimensions this applies to below. The floating bearing block merely supports the lead screw. This type does not prevent the lead screw from drifting! To the online shop
Ball bearing type (BB):
This type of bearing block should always be used in highly dynamic applications such as those in which a motor is used. To the online shop
Design tips for lead screw end machining
| Part number | d1 mm |
| SLS-16×2-LL | 12 |
| SLS-16-LL | 12 |
| SLS-18-LL | 12 |
| SLS-18x8P4-LL | 12 |
| SLS-18-LL | 12 |
| SLS-18-LL | 12 |
| SLS-20-LL | 12 |
| SLS-24-LL | 14 |
| SLS-S16-LL | 12 |
| SLS-S18-LL | 12 |
| SLS-S20-LL | 12 |
Note that the maximum load capacity can exceed the lead screw nut’s maximum load.
The dryspin® configurator enables you to quickly find the right lead screw and with end-machining configurations, including the option to define machining individually for both sides. The application generates a dimensioned drawing of the configuration for you. You can then order the lead screw or request further information.
