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Question #: 871

Question: How do I keep the lead screw from moving back and forth?

Current Solution

The lead screw needs to be stabilized axially. The lead screw should turn, but not move any other way. The method to keep the lead screw stable is to use two bearings with ID (inside diameter) that match the diameter of the lead screw. The bearings are positioned before and after a stable structural part. A collar is positioned at one side of the bearing assembly and another collar, or end of a coupling is positioned at the other side of the bearing assembly.

How many times do you need to turn the handle to move the lead screw 1 inch?

For our 5 start 10 tpi, the lead nut will travel one inch with two turns of the lead screw.

Respond:

Other Possible Solutions to this Question

• How do I order a pacific length of lead screw?

Just specify the full length in the quantity field in the shopping cart and give us a call to inform us of the cut lengths (you can also email customer service - link in the contact us page - link at the footer). We are working on a way to do this at the product page, but won't be finished for a few more days.

20

How do I order a pacific length of lead screw?

• If I buy the 1/2" 5 start lead screw and the 3/8" 5 start lead screws will it all work together

If the turns per inch on a lead screw is different, then the nut on the lead screw will move at a different velocity.

Let me explain in more detail.

Let's say you have two lead screws:

- 1/2" 5 starts at 10 TPI = 2 turns per inch. (5 starts / 10 TPI = 1/2 inches per turn or 10 TPI / 5 Starts = 2 turns per inch.)

- 3/8" 2 starts at 10 TPI = 5 turns per inch. (2 starts / 10 TPI = 1/5 inches per turn or 10 TPI / 2 starts = 5 turns per inch.)

So, if two stepper motors (one connected to the 1/2" lead screw and the other connected to the 3/8" lead screw) turned 10 revolutions in 2 seconds, the 1/2" lead nut would travel 5 inches and the 3/8" lead nut would travel 2 inches at the 2 second mark.

If I buy the 1/2" 5 start lead screw and the 3/8" 5 start lead screws will it all work together

• HOW DO I DETERMINE THE AMOUNT OF SCREW WEIGTH THAT MY MOTOR CAN HANDLE

There are two main questions that we can answer with respect to motor torque and the mechanical advantage of lead screws, 1) What torque motor do you need to lift a particular weight, or 2) What maximum weight will my motor torque be able to lift.

This formula uses Newtons (N) as it's final unit. Use this with the included radius (R) to determine the torque. Newtons can easily be converted to lbs or ounces using online conversions.

Effort = Sf + (Load/(2 x pi x (R/p) x Se))

where:
p = pitch of the screw
Se = screw efficiency = Standard lead screw will be between 20% (.2) and 40% (.4)
Sf = static force. This is the force that is needed to start the movement. The number may be eliminated, but it is good to use a number in the 5 N to 20 N range.
Load = the expected load that the effort will need to carry (i.e., the router and the included axis assembly that the motor will need to lift)

This formula is based on the "law of the machine"

The final effort amount with its unit of newtons and R will be the torque. For example, if the effort comes to 100 N (newtons) and the R is .5 inches, then you can assume that the effort is 50 N-in since it would take twice the effort to turn form the one inch mark from the center of the shaft.

Example:

Load = 90 N (20.2 lbs)
R = 1 inch since that is the length from the center of the shaft that the motor is rated
p = 1 inch / 13 = .08 inches

Effort = 5 N + (90 N / (2 x 3.14 x (1 / .08) x .2))
Effort = 5 N + (90 N / (6.28 x 12.5 x .2))
Effort = 5 N + (90 N / (15.7))
Effort = 5 N + (5.73 N)
Effort = 10.7 N = 2.4 lbs = 38.4 oz-in

I am putting the oz-in on the end because the formula considers the distance from the center of the shaft to be one inch.

Therefore, a 425 oz-in motor would be able to lift a 20.2 lb Router with its accompanying assembly. If the assembly and router is heavier, plug in the numbers and determine the effort required.

With a bit of algebra, the formula can be rewritten to find the load:

Load = (Effort - Sf) x (2 x pi x (R/p) x Se)

Another formula that does not consider friction at all:

Effort = (Load x p) / (2 x pi x R)

Lets see if we get similar results:

Effort = (20 lb x .08 inches) / (2 x 3.14 x 1)
Effort = 1.6 / 6.28 = .255 lbs = 4.08 oz-in

The results from both formulas appear to be very small because a 13 TPI screw will have enormous mechanical advantage.

It is evident that the first formula that does consider friction that we are loosely estimating is far more conservative than the second formula. Either way, even the most conservative formula shows that the 425 oz-in motor will handle very large weights. If you are using a lead screw with only two turns per inch, .5 inch pitch, you can determine the requirements with the first formula.

Example for a 10 TPI 5 start (2 turns per inch) lead screw:

Load = 90 N (20.2 lbs)
R = 1 inch since that is the length from the center of the shaft that the motor is rated
p = 1 inch / 2 = .5 inches

Effort = 5 N + (90 N / (2 x 3.14 x (1 / .5) x .2))
Effort = 5 N + (90 N / (6.28 x 2 x .2))
Effort = 5 N + (90 N / (2.512))
Effort = 5 N + (35.83 N)
Effort = 40.828 N = 9.18 lbs = 146.88 oz-in

Customer Response:
thank you so much

how do i calculate torque of stepper motor if lead screw coupled to motor shaft and load applied by lead screw on plate is 100 kg by vertically

Pls

1m 16mmdiameter ball screws calculations

What is the max load that 2 NEMA 17 stepper motors (spaced 2 feet apart, both will be pushing up on the same gantry) can lift while using a rod with the following specifications T8 OD 8mm Pitch 2mm Lead 4mm for each motor.

1

HOW DO I DETERMINE THE AMOUNT OF SCREW WEIGTH THAT MY MOTOR CAN HANDLE

• What is the longest 1/2" Acme lead screw that I can buy?

We can supply 1/2" lead screw with a maximum continuous length of 77 inches.

Please give me a cost on a 6'x 1/2" lead screw. Thank you

no

what is the total cost for 77 inches of 1/2 inch lead screw?

what is the cost of 6 feet lead screw.

What is the longest 1/2" Acme lead screw that I can buy?

• I couldn't find any information about how to mount the "z-axis lead screw in the book" (Build Your Own CNC)

The details will differ depending on the type of lead screw you use.

For allthread lead screws, you will need the 1/2" square nut, 1/2" allthread lead screw, two 1/4" screws and nuts to hold the square nut in place, two 1/2" ID bearings, two standard 1/2" nuts, and one coupling hub.

Attach the square nut to the nut support using the two 1/4" screw and nuts. The bearings will need to be inserted into the seats of the lower and upper part of the z-axis. Insert the lead screw through the top bearing. Use one of the standard 1/2" nuts and start threading it on the allthread screw just below the bearing. Lower the lead screw to the square nut and start to screw the lead screw into the square nut. Continue until the screw is near the lower bearing. Add another standard 1/2" nut to the screw and keep turning the screw until the screw just passes the lower bearing. Add the coupling hub to the top of the screw just above the upper bearing. Turn the lower and upper standard 1/2" nuts until they are snug against the bearing. If the standard 1/2" nuts become loosened, consider adding another nut to each end against the existing nut to keep them in place.

For 1/2" acme 5 start lead screws, you will need to use an antibacklash nut in place of the square nut. This nut attaches with a flange using two #8 screws and nuts. The standard 1/2" nuts are replaced by clamping collars.

I couldn't find any information about how to mount the "z-axis lead screw in the book" (Build Your Own CNC)

• How do I configure my control program (i.e. Mach3, EMC2, etc.) for lead screw steps per inch?

You will first need to derive the number of turns per inch that your lead screw produces. If there is only a single start (typical all thread screws), then the turns per inch is the same as TPI (threads per inch). If there is multiple starts, then the number of starts is divided by the TPI to determine the turns per inch. For example, 10 TPI with 5 starts is 10 / 5 = 2 turns per inch. Now that we know this, we can get the number of steps per inch as described in the previous question: take the number of steps per revolution that the motor will output. This will be the number of full steps that you motor produces (typically 200, or 1.8 degrees per step) multiplied by the microstepping per step to which the driver is configured. Simply multiple the number of turns per inch and the number of steps per revolution and you will get the steps per inch. Ok, lets see the formula:

200 steps * 16 microsteps * 2 turns per inch = 6400 steps per inch

14798

hallo i have cnc with ball screw 2.5mm of pith..n driver stepping 1/16 how to setup step value

i have ball screw with 2.5 mm of pith n 1 start motor 200 step 1/16 driver stepping

How do I configure my control program (i.e. Mach3, EMC2, etc.) for lead screw steps per inch?

• On the book build machine I changed the Z axis from a 13 tpi lead screw to an acme 10 tpi 5 start lead screw. What numbers do I put into the motor tuneing boxes.

The settings that will have to be change will be your steps per inch in motor tuning (mach 3), or settings/axes(planetCNC). But we do not have the actual numbers/specs that will fit your 10 TPI 5 start lead screw, here is a tutorial video which explains how to get the exact numbers you need! (

)

On the book build machine I changed the Z axis from a 13 tpi lead screw to an acme 10 tpi 5 start lead screw. What numbers do I put into the motor tuneing boxes.

• HOW DO I WIRE FROM THE BREAKOUT BOARD TO DRIVER?

CP+ to COM
CP- to STEP
CP+ to CW+ (small jumper wire)
CW- to DIR

If the driver does not have CP or CW labels, the CP is Step and the CW is Direction or DIR. If you connect the 5v to CP+ (or Step+) and CW+ (or DIR+) and the pin to CP- (or Step-) and another pin to CW- (or DIR-), then in software, the configuration for the step on that axis must be active low. Otherwise, if you connect the GND to CP- (or Step-) and CW- (or DIR-) and the pin to CP+ (or Step+) and another pin to CW+ (or DIR+), then in software, the configuration for the step on that axis must be active high.

If you have a driver that is labeled pul, dir and ena: Pul+ is the Step+ and Pul- is the Step-. Pul is short for pulse. A pulse will create a step. Don't worry about the enable terminals.

On the x-axis, pin #2 can go to pul- and pin #3 can go to dir-. The 5v will go to pul+ and dir+. The configuration for each axis for step will be active low and toggle active low for the dir on each axis to make it go in the direction desired.

HOW DO I WIRE FROM THE BREAKOUT BOARD TO DRIVER?

• I want to purchase some items from your co. How do i go about it. I already have the buildyourcnc book and wand to begin.

For purchasing on our website, our account log in is a safe way to keep your personal data at hand for future orders. However we do not keep any bank information in our systems, it is a single use system.

Now dealing with the cnc book, you can view our web version of the book with a list of materials and hardware that will be needed here (https://www.buildyourcnc.com/cnckitintro.aspx).

Adding the items to your cart in the quantity's needed, now for certain items for example, or ACME screws, and aluminum angles will require a total length needed, but the specific lengths required will have to be email here (customerservice@buildyourcnc.com) or called here (281-815-7701) with the completion of your order.

I want to purchase some items from your co. How do i go about it. I already have the buildyourcnc book and wand to begin.

• Hi, I need the lead screw and bearings for x/y/z axis of the CNC. What is the length of "1/2" Lead Screw per inch (Steel)"?

Depending on the size of your CNC machine, it will vary the length required for your application.
Please verify the CNC machine, and we can go into detail on the specific lengths or methods for the linear guide mechanics.

We sell our ACME Screw (1/2" per inch), also our longest length of ACME Screw is 76-3/4".

Hi, I need the lead screw and bearings for x/y/z axis of the CNC. What is the length of "1/2" Lead Screw per inch (Steel)"?

You can see the component list on the hardware and plans machine (scratch build machine) since it is the same machine in the book:

https://www.buildyourcnc.com/Item/cnc-machine-scratchbuild

• I just changed my X and Y to the ACME 1/2" 5 start lead screw. What are the motor tuning numbers. I have the book built machine.

The settings that will have to be change will be your steps per inch in motor tuning (mach 3), or settings/axes(planetCNC). But we do not have the actual numbers/specs that will fit your 10 TPI 5 start lead screw, here is a tutorial video which explains how to get the exact numbers you need! (

)

I just changed my X and Y to the ACME 1/2" 5 start lead screw. What are the motor tuning numbers. I have the book built machine.

• 3d printer motors not moving fast enough. How should I configure the motor drivers?

This will depend on the 3D printer that you are using and the mechanics involved. Specifically regarding the motor drivers, software is really what determines the speed of the motor. If the computer is not able to product the high number of pulses that is required for faster motion, then you can reduce the microstepping and configure the software appropriately for the new microstepping so the resolution is corrected (steps/inch or steps/mm).

3d printer motors not moving fast enough. How should I configure the motor drivers?

• THE LEAD SCREW IS VERY HARD TO TURN. BACKLASH BUSHING SEEMS BE TOO TIGHT AND BINDING ON SCREW. DO IT NEED LUBRICATION OR DID DAMAGE NUT WHEN INSERTING SCREW?

Yes, you can use lubrication, like 3-in-1 oil to make it a bit easier. You will need to run it up and down to break it in.

THE LEAD SCREW IS VERY HARD TO TURN. BACKLASH BUSHING SEEMS BE TOO TIGHT AND BINDING ON SCREW. DO IT NEED LUBRICATION OR DID DAMAGE NUT WHEN INSERTING SCREW?

• I HAVE THE REDFLY SYSTEM AND A 2.2KW SPINDLE - 110V HOW DO CONNECT SPINDAL?

It is not necessary to connect the spindle VFD (Variable Frequency Drive also called an Inverter) to the computer or CNC motion electronics. The VFD can be controlled independently using the control panel on the VFD. The control panel has the ability to control all aspects of the spindle including Speed, Torque, limits, etc. However, you can connect the VFD to the computer so the CNC control program can control the spindle during the CNC Machine operation. You will need to connect the VFD to the computer via a serial conection (in this case, it is the RS-485 protocol).

The following are instructions on how to connect the VFD to Mach3 via this RS-485 serial connection.

The first thing you will need is the dynamic link library to pair with mach3 called the Huanyang VFD Mach3 PlugIn. You can find this file at the mach3 support forum here: http://www.machsupport.com/forum/index.php/topic,14182.0.html

Follow the pdf that comes with the library file, but here is a synopsis of what you need to do (I also added a lot more information that may be useful during this process as the manual does not cover the main connections that need to be done):

You will need to program your VFD so that it knows how to communicate with mach3 and the computer (go into the programming mode of the VFD and change these parameters):
- PD001 - value 2 - Enables with communication aspect of the VFD
- PD002 - value 2 - Enables frequency control from the communcations port
- PD163 - value 1 - VFD address
- PD164 - value 1 - Baud rate of 9600 (speed of the communication)
- PD165 - value 3 - 8N1 RTU - 8 bits (that's the size of the word that gets communicated), N (No parity or no error checking) and 1 (1 stop bit)

Copy the dll file to the PlugIns folder of mach3.

Connect the RX and TX lines to your computer. There are a couple ways you can do this, but the recommended way would be to use an FTDI USB device which converts a USB to a serial com port. The device will have Rx and Tx connectors to connect to the VFD terminals with the same labels. This method is recommended since serial ports are not as common in computers these days.

Next, you will need to configure mach3 to use the plugin library. Start mach3 and click on Menu -> config ->Config Plugins. Enable the new plugin by clicking on the red cross on the left column next to the plug in. Restart mach3 after doing this.

No you need to configure mach3 to use the HuanyangVFD plugin. Go to the ports & pins configuration and select the spindle setup tab. Make sure that the Disable Spindle Relays checkbox is unchecked. We don't want mach3 to output a signal for a relay since the spindle will start up and turn off within the VFD and not from an external relay.

Next, go to the HuanyangVFD settings by clicking on Menu -> plugin control -> HuanyangVFD. Set the parameters to the same settings you put into the VFD programming. The com port will be shown as new hardward when you plug in the USB FTDI device. A little bubble will be displayed at the bottom right where it will notify you that a new device is being installed (be patient while windows assigns a com port). Alternatively, you can use the windows device manager to see which port was set for the new USB FTDI device). You may need to restart mach3 several times until you get the correct information displayed in the PD001 and PD002 fields. When the com port is correct and the other parameters, like baud and VFD address is the same as you entered in the programming, then the PD001 and PD002 will show the number 2, otherwise, a 99 will appear which means that communication was not successful.

You can now control the on/off and RPM of the spindle using the RS485 communication between mach3 and the VFD.

The question was how to connect the spindle to the redfy. I did not receive a VFD.
I have the redFly system and a 2.2kW Spindle - 110V how do i connect the spindle?

Hi, how is this setup in mach4?

I HAVE THE REDFLY SYSTEM AND A 2.2KW SPINDLE - 110V HOW DO CONNECT SPINDAL?

• I want to increase my travel speeds. Can I change the lead screw to make my machine quicker?

Changing your lead screws from a tight to a lose lead will definitely make your machine move faster as long as your stepper motors can handle the new torque that the lead screws will impose.

Here is an example of a speed change from one lead screw to another:
- Existing constants in the example: Stepper Motor steps 200, microstepping 1/8 making the total steps 200 * 8 = 1600.
- New Lead Screw: 1/2" 5 starts, 10 TPI = 10 / 5 = 2 turns per inch

Old lead screw would achieve a steps per inch of:
1600 / (1 inch / 13 turns) = 20,800 steps per inch (You can also express the calculation as 1600 * 13 = 20,800 steps/inch)

New lead screw would achieve a steps per inch of:
1600 / (1 inch / 2 turns) = 3200 steps per inch

You can see that the new lead screw requires far fewer steps to get to the same length of travel. If you maintained the same velocity for both examples, the new lead screw would travel the same distance 13/2 = 6.5 times faster. So, if your velocity was say 10 ipm, your new velocity would be 65 ipm. That would translate to far fewer burned edges and longer end mill life!

Just remember, confirm that your motors will be able to handle the new lead screw. You will need to reduce the steps/inch causing the motor torque to increase quite a bit, so you should be fine.

I want to increase my travel speeds. Can I change the lead screw to make my machine quicker?

• I have motors and drivers, how can I control them from my pc?

All you need is a CNC controller like the following options:

https://www.buildyourcnc.com/item/electronicsAndMotors-electronic-component-breakout-Mach3-USB-Board

This controller is easy to connect using standard wire screw terminals and works with the mach3 control software.

https://www.buildyourcnc.com/item/electronicsAndMotors-electronic-component-breakout-Mach4-mach3-USB-ethernet-Board

This controller is a little bit more difficult to connect, but is a more feature-rich controller and will work with both mach3 and mach4 CNC control software titles.

Specifically, a CNC controller connects to the computer via a USB cable and connects to the motor drivers. These controllers also connect to the limit switches, spindle/router control, air/fluid/mist control, etc.

I have motors and drivers, how can I control them from my pc?

• How can I control my motors and drivers from my pc?

All you need is a CNC controller like the following options:

https://www.buildyourcnc.com/item/electronicsAndMotors-electronic-component-breakout-Mach3-USB-Board

This controller is easy to connect using standard wire screw terminals and works with the mach3 control software.

https://www.buildyourcnc.com/item/electronicsAndMotors-electronic-component-breakout-Mach4-mach3-USB-ethernet-Board

This controller is a little bit more difficult to connect, but is a more feature-rich controller and will work with both mach3 and mach4 CNC control software titles.

Specifically, a CNC controller connects to the computer via a USB cable and connects to the motor drivers. These controllers also connect to the limit switches, spindle/router control, air/fluid/mist control, etc.

How can I control my motors and drivers from my pc?

• I have the redFly system and a 2.2kW Spindle - 110V how do i connect the spindal?

It is not necessary to connect the spindle VFD (Variable Frequency Drive also called an Inverter) to the computer or CNC motion electronics. The VFD can be controlled independently using the control panel on the VFD. The control panel has the ability to control all aspects of the spindle including Speed, Torque, limits, etc. However, you can connect the VFD to the computer so the CNC control program can control the spindle during the CNC Machine operation. You will need to connect the VFD to the computer via a serial conection (in this case, it is the RS-485 protocol).

The following are instructions on how to connect the VFD to Mach3 via this RS-485 serial connection.

The first thing you will need is the dynamic link library to pair with mach3 called the Huanyang VFD Mach3 PlugIn. You can find this file at the mach3 support forum here: http://www.machsupport.com/forum/index.php/topic,14182.0.html

Follow the pdf that comes with the library file, but here is a synopsis of what you need to do (I also added a lot more information that may be useful during this process as the manual does not cover the main connections that need to be done):

You will need to program your VFD so that it knows how to communicate with mach3 and the computer (go into the programming mode of the VFD and change these parameters):
- PD001 - value 2 - Enables with communication aspect of the VFD
- PD002 - value 2 - Enables frequency control from the communcations port
- PD163 - value 1 - VFD address
- PD164 - value 1 - Baud rate of 9600 (speed of the communication)
- PD165 - value 3 - 8N1 RTU - 8 bits (that's the size of the word that gets communicated), N (No parity or no error checking) and 1 (1 stop bit)

Copy the dll file to the PlugIns folder of mach3.

Connect the RX and TX lines to your computer. There are a couple ways you can do this, but the recommended way would be to use an FTDI USB device which converts a USB to a serial com port. The device will have Rx and Tx connectors to connect to the VFD terminals with the same labels. This method is recommended since serial ports are not as common in computers these days.

Next, you will need to configure mach3 to use the plugin library. Start mach3 and click on Menu -> config ->Config Plugins. Enable the new plugin by clicking on the red cross on the left column next to the plug in. Restart mach3 after doing this.

No you need to configure mach3 to use the HuanyangVFD plugin. Go to the ports & pins configuration and select the spindle setup tab. Make sure that the Disable Spindle Relays checkbox is unchecked. We don't want mach3 to output a signal for a relay since the spindle will start up and turn off within the VFD and not from an external relay.

Next, go to the HuanyangVFD settings by clicking on Menu -> plugin control -> HuanyangVFD. Set the parameters to the same settings you put into the VFD programming. The com port will be shown as new hardward when you plug in the USB FTDI device. A little bubble will be displayed at the bottom right where it will notify you that a new device is being installed (be patient while windows assigns a com port). Alternatively, you can use the windows device manager to see which port was set for the new USB FTDI device). You may need to restart mach3 several times until you get the correct information displayed in the PD001 and PD002 fields. When the com port is correct and the other parameters, like baud and VFD address is the same as you entered in the programming, then the PD001 and PD002 will show the number 2, otherwise, a 99 will appear which means that communication was not successful.

You can now control the on/off and RPM of the spindle using the RS485 communication between mach3 and the VFD.

The question was how to connect the spindle to the redfy. I did not receive a VFD.
I have the redFly system and a 2.2kW Spindle - 110V how do i connect the spindle?

Hi, how is this setup in mach4?

I have the redFly system and a 2.2kW Spindle - 110V how do i connect the spindal?

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