Standard/Stock Acme Threaded Rod and Nuts -  Made in USA            

Other sizes may be available from time to time and by special order.  All sizes listed below are stocked in low carbon steel.
Pre-heatreated alloy and stainless steel can be special ordered for certain applications.

3/8 and 1/2 in diameters for desktop CNC mills, Routers, Lathes and  3D printers
(All Right Hand unless otherwise indicated)

Photo

Thread
Size

Part Number

Pitch/Lead

Lengths (Feet)

Stock Nuts

3/8-12 acme threaded rod

3/8-12 Single Start

304008

.0833Pitch
.0833Lead

 1,1.5,2,3,6 

Delrin Anti-Backlash, Cylinder, Nutblock, Threaded shaft clamp

Steel Hex

Brass Hex

3/8-8, 4 start acme threaded rod

3/8-8 Four Start

304007

.125 pitch
.500 lead

1,2,3,5

Delrin Anti-Backlash, Cylinder, Nutblock, Threaded shaft clamp

Right Hand

1/2-10 acme threaded rod

Left Hand

1/2-10 acme threaded rod Left Hand

1/2-10 Single Start

304014

.100 Pitch
.100 Lead

2,3,4,6

3 LH

Delrin Anti-Backlash, Cylinder, Nutblock, Threaded shaft clamp

Steel Hex RH & LH
Steel Coupling Nut

Brass Nut Block

1/2-10, 2 start acme threaded rod

1/2-10 Two Start

304033

.100 Pitch
.200 Lead

2,3,4,6

Delrin Anti-Backlash, Cylinder, Nutblock, Threaded shaft clamp

1/2-10 5 start acme threaded rod

1/2-10 Five Start

304035

.100 Pitch
.500 Lead

2,3,4,6

Delrin Anti-Backlash, Cylinder, Nutblock, Threaded shaft clamp



5/8 - 1 1/2 ( 1.25) diameter for larger machines
(All Right Hand unless otherwise indicated)


PhotoThread
Size
Part
Number
Pitch/LeadLengths (Feet)Stock Nuts
5/8-8 acme threaded rod
5/8-8 Single Start304050.125 Pitch3,6Steel Hex Nut RH & LH
Steel Coupling Nut
3/4-6 acme threaded rod3/4-6 Single Start304060.167 Pitch3,6Steel Hex Nut RH & LH
Steel Coupling Nut
7/8-6304066.167 PitchnoneSteel Hex Nut RH
Steel Coupling Nut
1"-5 acme threaded rod1"-5 Single Start304070.200 Pitch2,3,4,6Steel Hex Nut RH & LH
Steel Coupling Nut
Bronze Precision w/steel Flange
1"-4 acme threaded rod1"-4 Single Start304072.250 Pitch6Steel Hex Nut RH
1 1/8-5304076.200 PitchnoneSteel Hex Nut RH & LH
Steel Coupling Nut
1 1/4 acme threaded rod1 1/4-5304080.200 Pitch3,6
2 LH
Steel Hex Nut RH & LH
Steel Coupling Nut
Bronze Precision w/steel Flange
1 1/2-4304090.250 PitchnoneSteel Hex Nut RH


Acme Thread FAQ:

The Acme thread form was developed in the 1800's to supply accurate linear motion conversion from a rotary power supply or manual handle rotation.  Acme threads are commonly found on manual and CNC lathes, Mills and Routers, on devices like Cider Mills and Printing presses, and Bench and Machine vises and C-clamps.  The ACME thread is a trapezoidal form and does NOT have any metric sizes.  The metric trapezoidal threads have a different geometry and are similar to, but not compatible with acme threads.
  • 1) What does the designation like 1/2-10 mean?  1/2 is the nominal rod diameter and will generally not exceed .500 inch, unless there is a slight burr thrown up by the thread rolling process.  The 10 means 10 threads per inch.  With a one start thread, this is also the pitch. 10 threads per inch = .100 linear travel per revolution of the rod.
  • 2) What is pitch?  Pitch is the distance between two adjacent crests of  a thread.
  • 3) What is a Fast Lead screw?  Fast is usually used to refer to multiple start lead screws.  For the same motor revolution, a multiple start leadscrew will travel faster ( linearly) than a single start. In addition for the same linear travel in inch per minute, the fast leadscrew will turn at a slower rpm.
  • 4) What does one start, 2 start, 5 start, etc mean?  A one start thread has a single helical groove on the rod. A two start has 2 grooves and a 5 start has 5 grooves.   Multiple start threads have the same pitch as single start threads.  Lead is used to define the distance travelled per revolution, and pitch is used to define the threads per inch ie .1 pitch = 10 threads per inch.  Our tables above use Lead to define linear motion per revolution.
  • 5) What is the efficiency of Acme threads? Acme threads deliver 30%-85% efficiency.  Single start are less efficient than multiple start, and brass, bronze, and Delrin nuts have lower frictional losses, hence more efficient than steel nuts. All thread or standard V-threads like unc/unf are typically much less efficient than acme threads as they are designed for clamping in a fixed position, rather than to convert rotary motion into linear drive.
  • 6) What is the difference between Right Hand and Left Hand?   Facing the nut, a right hand thread will turn clockwise to thread into the nut.  With the same orientation, a lefthand rod will turn counter clockwise into the nut.
  • 7) How can I be sure that my nuts will match my threaded rod?  Make sure that the size and tpi match, ie 1/2-10, and that the number of starts and Hand also match.  a 1/2-10 single start right hand threaded rod, REQUIRES a 1/2-10, single start, right hand nut.  No other combination of specification will mate properly.
  • 8) What is backlash?Iin order for the nut and rod to turn freely, there must be some slight clearance between the two.  This clearance is called backlash.  If a rod is rotated clockwise and counterclockwise, there will be a slight rotational distance during the change in direction, where the nut does not move.  this is the backlash.  Backlash can cause flats, misshaped arcs, and inaccurate straight geometry on a CNC machine.  There are a number of mechanical techniques to reduce or eliminate this free travel distance.  Our delrin antibacklash nuts use a spring clamping mechanism to eliminate the free travel on direction change.  They are technically a zero backlash nut with automatic wear adjustment.
  • 9) What is endplay?  In addition to backlash, another source of error in mechanical CNC systemsis Endplay.  Endplay is the uncontrolled distance the leadscrew travels when the rotation direction is reversed.  This is in addition to any backlash from the clearance between thh rod and nut.  End play is usually eliminated by a preload applied to the threaded rod end support bearings.  Our threaded shaft clamps are an economical solution that permit a fine adjustment of the preload, thus eliminating any rod motion when the direction of rotation is reversed.



Deburring threaded rod.

-The factory rolled threaded rods have a conical taper on each end.  This permits a gradual increase in the rolling tool and leaves an tapered first thread with no sharp or burred edges.  The first thing most customers will do is to cut the rod to the needed length, usually not the same as the standard stock lengths.  The low carbon steel is similar to C-1018 cold rolled steel.  It can be easily cut with a steel cutting band saw or Hacksaw blade.  Cutting a threaded rod with a saw will leave a sharp burr on the first thread.  For small sizes up to 5/8 inch diameter, we use a a pedestal grinder to grind a small angle or chamfer around the end of the rod.  For larger sizes, a lathe may be used to turn a 45 degree angle.  Either deburring method may leave a sharp burred edge on the back side of the first revolution of the thread.  A triangle file can be used to remove any burr left by either lathe turning or ground chamfer machining.  Steel hex nuts will generally easily re-machine the thread start to accomodate starting of the nut.  With delrin nuts, the burr may cause damage to the threads.  Be sure to file any cut rod threads when using delrin nuts to avoid damage.


Straightening threaded rod.


-the thread rolling process can release internal stresses in steel rod stocks.  This can show up as a gradual bow from one end to another of threaded rod.  Sometimes the rod can be bent by accident and end up not as straight as desired.  For benchtop CNC machines, a bent leadscrew can cause excessive vibration and undesirable toolmarks on the machined workpiece.  We recommend that customers check and straighten if necessary within .001-.002 inch eccentricity.  This is the same as .002-.003 inch TIR - Total Indicated Runout on a contact test indicator.  We use a 1/2 inch or a 3/8 inch bearing to support each end of the rod and a 3rd bearing placed near the center of the rod to measure the runout.  For longer lengths ( 3-6 feet ) with gradual bowed bend, it may be possible to manually bend the rod straight by pressing in the opposite direction from the bend.  Support the end bearings on raised v-blocks to allow enough distance that you can bend past the flexible point to permanantly bend the rod in the opposite direction.  For shorter and larger diameter rods, we use an arbor press to exert a more precise and forceful re-bend.