Click to move up one level  
manual products motor driven stages downloads in stock itmes FAQs site map about velmex
  HOME > MANUAL PRODUCTS HOME > LEAD SCREWS 1 (800) 642-6446 or 1 (585) 657-6151 (in NYS)
  enter search word
 
  RELATED
  What do you make?
  Show me more examples
  Request Assistance
 
  Lead Screw Sizes
  I need motorized
 
  Drive Nut
  End Bearing Details

Velmex makes high quality lead screws by rolling through precision dies.

They are used in our positioning equipment.
You can also buy the lead screws alone. Sizes

And we can combine left and right hand threads on a single shaft for together + apart motion.

Photo 1

Material
Our lead screws are either 303 stainless steel or electroless nickel plated, cold rolled steel. See chart below for details.
Lead Screw Accuracy
The linear accuracy of Standard lead screws is 0.007”/10" or less.
The linear accuracy of Graduated Knob Model is more accurate. Called Precision Grade it is 0.0015”/10” or 0.033 mm/20 cm of length. See Velmex
screw letter codes.
Thrust Bearing Design
A15 and A25 lead screws are constrained and supported with pre-loaded DelrinŽ thrust bearings (except A25 W1, and P10, which have pre-loaded ball bearings). A40, A60 and B90 lead screws have pre-loaded ball bearings. Details
Back driving
Because of their steep helix angle, 5 and 2.5 pitch screws (W2, W4, P5 and P2.5), may back drive (coast back down) when supporting a vertical load or, if horizontal, a linear thrust load is applied. If you want the slide to stay where you put it, be aware of this characteristic and use a finer pitch screw and/or lock.

Photo 2
More examples of Manual and Motorized UniSlide Assemblies.

 

Available lead screw diameters and pitches.

Pitch
Diameter
Turns per inch
English Thread Lead Screws
0.25"
0.375"
0.50"
2.5 *
no
yes
yes
5 *
no
yes
yes
10
no
yes
yes
20
yes
yes
yes
40
yes
yes
yes
Maximum length available
3 ft.
8 ft.
8 ft.
Turns per centimeter
Metric Thread Lead Screws
7 mm
10 mm
14 mm
5
yes
yes
yes
10
yes
yes
yes
Maximum length available
3 ft.
8 ft.
8 ft.

*Not recommended for vertical units because it will back drive.

Lead Screw Letter Codes
In Velmex model numbers, lead screws are specified by a letter/number after the base length.
This table defines the letter. Accuracy

Pitch
UniSlide Letter Code
XSlide
Code
BiSlide® Code
Turns
per inch
Advance per revolution
Screw
Drive
Model
Graduated Knob Model    
Standard*
Standard
2.5
0.400"
W4
P2.5
E04
E04
5
0.200"
W2
P5
E02
--
10
0.100"
W1
P10
E01
E01
20
0.050"
B
P20
E50
--
40
0.025"
C
P40
E25
--
Turns per cm
Advance per revolution
Screw
Drive
Model
Graduated Knob Model    
Standard*
Standard
5
2 mm
K2
Q2
M02
M02
10
1 mm
K1
Q1
M01
M01

* More accurate screws are optional. Call Velmex.

Lead Screw Materials
SS = 303 Stainless Steel
CRS = Cold rolled steel with electroless nickel plating

  Lead Screw Letter Code

Lead Screw
Diameter

UniSlide: B, C, K1, K2, P20, P40, Q1, Q2 UniSlide: W1, W2, W4, P5, P10
BiSlide: E25, E50, M01 BiSlide: E01, E02, M02, E04
XSlide: E25, E50, M01, M02 XSlide: E01, E02, E04
1/4 in SS  
7 mm SS  
3/8 in SS CRS
10 mm SS  
1/2 in SS CRS
14 mm SS CRS

Drive Nuts
BiSlide drive nut

Photo 3a Tension adjustable UniSlide drive nut made of Delrin AF®. XSlide also uses Delrin AF. Photo 3b Tension adjustable BiSlide drive nut made from low friction polymer
Photo 3c Tension adjustable XSlide drive nut made of Delrin AF®. >>> xslide drive nut

End Bearing Block and Thrust bearings

The End Bearing Block supports and constrains the lead screw

end bearng components

Photo 4: This design is for small diameter (1/4" or 7 mm) lead screws.
It uses Delrin bearings and threaded retainer nut.


Photos 5 and 6: Threaded retainer nut and wrench P-N A15-A25W


lead screw and bushings
Photo 7: Split Delrin thrust bearings


end bearing block
Photo 8: All other lead screws use
steel bearings and snap ring retainer.
Used with 3/8", 1/2", 10 and 14 mm diameter lead screws

radial thrust bearing details
Photo 9: Lead screw with two R4 Bearing separated by 2 E clips. In the photo below the regular end bearing block has been replaced by translucent pink plastic.