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### Question #: 862

Question: What maximum weight will my motor torque be able to lift? Effort = Sf + (Load/(2 x pi x (R/p) x Se)) In this formula, is Sf (static force) include gravity? how much usually is static force? can you please give one example to calculate max. weight Z-axis can carry?

Current Solution

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)
R = radius of the lead screw

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

Respond:

### Other Possible Solutions to this Question

• thank you for the reply. I would be really good to know the calculation. The lead screw is 1/2" diameter with 13 TPI. Please provide the calculation for determing the maximum weight motor can handle on Z-axis on book build cnc. And one more question. If I am cutting 18mm MDF with 6mm cutting bit (so 6mm pass), what can be the maximum speed rate of cutting and spindle speed of router? thank you

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)
R = radius of the lead screw

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

• hello there, i am using servo motor for my X and Y Axis but i dont know how to calculate steps/mm for that, the lead screw i am using is have pitch of .5 mm. please helpme on this i have done everything only this point is pending.

The formula for finding the steps per mm is found in the units itself. First, you mentioned that the motor is a servo. This needs to be clarified as a servo is different than a stepper motor. Some servos behave similar to a stepper motor, so I will continue with this in mind.

The formula is (steps/mm):

You need to find the steps. The stepper motor has a natural number of steps per a full revolution. This is typically 200 steps per revolution.

The driver for the stepper motor allows you to increase the number of steps per revolution by adding a specified number of steps between each step. For instance, if you set the driver to 1/4 microstepping, then instead of having 200 steps per revolution, you would have 200 x 4 = 800 steps per revolution.

So now we have the first part of the formula:

Steps / mm = (200 x 4) / mm

Lets determine the mm side of the formula:

You mention that the pitch is 0.5 mm. Check to insure that the lead is also 0.5 mm. This could be a multiple start lead screw where the pitch is different than the turns per mm. If in this case, that the 0.5 mm is the travel for one full revolution, then you can simply plug this into the formula as:

mm = .5 mm

Otherwise, determine how fat the travel is for one complete revolution.

Therefor, with what we know and the driver is set at 1/4 microstepping and the stepper motor has a natural step count per revolution at 200:

steps / mm = (200 steps x 4) / 0.5 mm = 800 steps / 0.5 mm = 1600 steps / mm

If your travel for one revolution is not 0.5 mm, then plug in your travel distance instead.

i know about steps/mm calculation for stepper motor, because i am using servo motor that why i asked about that. please tell for servo motor.

because its my first time with servo motor i have no idea about calculation of parameter with servo.

Have you attempted to contact the manufacturer or seller of the servo? We typically respond to customers of our products on this customer service area, unless we have extensive knowledge of the subject and can answer the question efficiently.

• Regarding 1/2" 5 start and 10 TPI ACME precision lead screw, what the maximum length you can ship within USA? I'm looking for something like 100" and I could use a 1" screw if available. Please include estimated price. Thanks.

The maximum length we can ship is a total of 78" inches. However we can send your required length in portions. Please refer to adding the total items you require to your cart to get a visualized amount and shipping cost.

• Hi my names is Minh Truong I would like to said thank you very much for your video I got the system mach3 working fine but one thing I can NOT set and config the digitizer on the board IN4 I am not sure how to setup because in the Mach3 pin 14 for digitizer Please shoe me hoe to set it up for the digitizer.

Can you send me a link to the digitizer you are using?

• My Z-axis seems to be reversed on a fully assembled machine... I've tried reversing it in the config settings on Mach 3, but to no avail. What do I need to do? IS this a wiring issue that was not done correctly at the factory?

If your Z axis is moving in the opposite direction, go into Mach3, click on config, ports & pins, then click on the motor outputs tab. You will see the axes labeled on the left and the parameters labeled on the top of this dialog box. Toggle the dir low active for the z-axis.

What if I'm having the same issue on a different axis?

You can follow the same procedure as with the z-axis. When you get to the motors outputs tab, toggle the dir low active checkbox for the axis that you would like to change.

If you are using another control program, let me know and I will add the recommended action here.

Girbl

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I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

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• FIRST OF ALL, THANKS FOR DESIGNING A WONDERFUL SITE. MY QUESTION IS: HOW DO YOU CALCULATE EME (ELECTROMAGNETIC EMISSIONS) AROUND THE TRANSMITTER (ANTENNA) AT ANY GIVEN POINT AND WHAT ARE MEASURES TO KEEP IT UNDER SAFETY CODE?

Conceptually it is straightforward to predict the radiofrequency (RF) exposure intensity at any point in the vicinity of a cellular radio base station antenna. Simply multiply the effective radiation power times the inverse square of the distance times the relative gain of the antenna in the direction of the interest. The relative gain in different directions is know as the antenna radiation pattern and is usually available from the antenna manufacturer in graphical or tabular form.

Unfortunately, in real life the calculations involved in base station antenna evaluations are quite complex and require expert knowledge and experience to deal with the many parameters that are involved. An excellent reference summarizing this process is the Federal Communications Commission OET Bulletin No. 65 titled "Evaluating Compliance With FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic Fields," available on the Federal Communications Commission (FCC) website.

To assess the RF hazards associated with handheld cell phones it is necessary to predict the rate of absorption in the body of radiofrequency energy, a parameter called the specific absorption rate (SAR). This is a very complex calculation, and cell phone manufacturers often rely on measurements of SAR in fluid-filled cylinders or plastic containers in the shape of a head. The FCC requires cell phone manufacturers to provide this data to FCC. You can obtain the data for your model phone on the the FCC's website. Unfortunately only cell phones manufactured in the last couple years are listed here.

As to your question about keeping RF exposures within the safety code, please read the other questions posted on this website this matter. Cellular radio products that meet FCC requirements will be within the guidelines established by safety standards organizations for users' and public exposure to RF radiation fields.

Gary H. Zeman, ScD, CHP

• I am trying to purchase a kit for our school in Singapore, and your site keeps refusing our corporate AMEX card. Can you help us figure out what is up with that? Are you not ship to Singapore or something? Our AMEX rep says that the account is authorised for this purchase from our end, so the problem may be with your site? Please advise.

• My X-axis on the Blacktoe cannot run above ~40 ipm. I've checked all connections,tensions, sprocket locks, etc. All is fine. Can the 425 OZ stepping motor be replaced with a bigger motor, or could a second 425 OZ stepper be added to increase torque?

it is possible to install 2 motors on a single axis but you will require another driver and motor, but wire it directly to the same pins on your breakout board. Also the orientation of your motor since it is opposite side of the original so getting it to move accordingly to the original motor it will need to be orientated correctly. The slight shift could be the cause of the rod not being completely flat where the set screws are suppose to tighten the sprocket to the rod, so sanding it to a flatter surface might fix the shift in directions.
Currently do not have a kit or schematic available.

• Since I am using normal all-thread lead screw 13 TPI 1/2" for the book build cnc, what can be the maximum feed rate of machine and how can I change the mechanical setup in mach 3? I am using 1/4" steel carbile endmill with 2 flutes and router is 2 HP with variable speed

Book build (scratch build), feedrates and recommendation.

Using standard allthread will provide around 20-30 ipm using 36 volts. Although it allows for a working CNC machine, the RPM of the spindle/router will need to spin at the lowest setting to provide the beat efficiency and life for the end mill at 1/4" cut diameter and higher. The speeds may be fine for smaller end mills.

If you would like faster speeds, you should change the lead screws on the CNC machine to the 1/2" 5 start 10 TPI which translates to 2 turns per inch which means, the stepping motor will not need to turn as fast to produce faster motion. That is to say, the stepping motor will only need to turn two revolutions for the machine to travel one inch and with the allthread, the stepping motor will need to turn 13 times to reach one inch.

Link to the lead screw and other mechanical parts needed:
https://www.buildyourcnc.com/CNCMachineMechanicalParts.aspx

To change the lead screws you will need (for each axis):

1. The lead screw for that axis.
2. Two 1/2" collars to keep the lead screw axially stable.
3. One Antibacklash nut.

20

• Building one of your greenBull 6X Long and 2.2 kilowatt spindle does not fit. Seems lead screw you sent with kit is short 42" looks like it needs to be 5 or 6 inch longer. Is this correct? What is the needed length of lead screw for this unit?

The leadscrew length for the greenBull long Z-axis is 47 inches.

• For the XL Vertical Laser Machine I see it won't cut metal as it is only 80w. However, I noticed that you are working on 100w and 130w versions so will that be sufficient to cut through sheet metal? If so, how much longer until those are available?

Cutting metal with lasers even at 100W and 130W is difficult. The main problem is molten is a byproduct of lasing, which can severely damage the laser.

• BUILDING ONE OF YOUR GREENBULL 6X LONG AND 2.2 KILOWATT SPINDLE DOES NOT FIT. SEEMS LEAD SCREW YOU SENT WITH KIT IS SHORT 42" LOOKS LIKE IT NEEDS TO BE 5 OR 6 INCH LONGER. THIS CORRECT? WHAT THE NEEDED LENGTH FOR UNIT?

The leadscrew length for the greenBull long Z-axis is 47 inches.

• I am looking at purchasing the greenbull 5X system with the laser/spindle combination. Can the laser do both rastered engraving as well as vectored cutting with the same breakout board and software? If I have this wrong please let me know what would be needed to accompish this.

You can do raster and vector engraving on the greenBull laser/spindle combination. The methods of this process is not accomplished in the same way as the typical laser machines where CorelDRAW is used. The Mach3 laser plug-in can be used for the raster engraving and standard CNC g-code can be used for vector cutting and engraving.

The raster method will not be fast on the greenBull since the z-axis is heavy and there are inertial limitation on doing fast raster back and forth movement. Vector is the best use of this machine.

• I have one of your smaller stepper motors running my X AXIS bridge crane and if it is moved to fast the stepper motor sounds like it is skipping steps will the 651oz stepper motor require a different power supply and controler?

Yes, the 651 oz/in motor requires a driver that is compatible to the motors (the motor will draw 6 amps max and the driver paired with this motor will be able to allow for a 6 amp draw). I would also recommend a 36 volt power supply for better high velocity performance.

• Hi I built a 2x4 cnc machine in 2013 using you Hardware kit and plans. I want to speed up my cnc machine by purchasing your acme leadscrew 1/2"-10 5 starts. I have an X axis at 52", a Y axis at 32" and a Z axis at 14". How do I order all 3 length pre cut to size on your website? Also can you give me a rough estimate on the shipping to Ottawa, Ontario Canada please.

You can purchase the entire length and select local pickup. Then you can email us the cut lengths for the order and let us know that you need to be invoiced for shipping. We will provide shipping estimates according to the real lengths and dimensions of the package. You can select the estimate that meets your shipping budget and we will invoice you the shipping amount and send the order.

• LIMIT SWITCHES FOR AXIS. THE PRINT SHOWS THAT YOU CAN WIRE LIMITS EITHER N.O. OR N.C. SO IF THIS IS CORRECT I WOULD NEED TO TELL BOARD IN SOFTWARE HOW LOOK AT THESE LIMITS, I'M GOING GET AN INPUT LOOSE DEPEND ON IT.

BYCNC Response:
This is correct. You will need to use a method appropriate for the software you are using. Also remember that NC switches are typically wired in series, while NO switches are normally wired in parallel.

User Response:
I am using the cnc planet software for your USB board. Are the limit configurations in this software?

BYCNC Response:
Yes, Planet CNC software is compatible with the use of limit switches. Configuration information will depend on your specific application. You can view Planet CNC's information here: http://www.planet-cnc.com/files/CNCUSBController.pdf

• How do I order 3 specific lengths of lead screws in one order? I could only order a single total amount via the shopping process. I require 36", 60" and 14". If I order 110", I will get 79" + 31". Do I have to order 115" and pay for an extra 5" to get around this?

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

• You built the first 36 inch Blue Chick for me. One of the V-Groove bearings on the X-axis froze. Is there a method of repairing this? Or do I order another and a spare. If so, what is the procedure to repair or order?

If your bearing does not turn anymore, it is possible to repair the frozen bearing.

You can carefully remove the shield on one side of the bearing. Use a very thin blade to remove the shield.

Once the shield is removed, use WD-40 or kerosene to wash out and clean any debris that exists within the bearing. WD-40 is a cleaner, not a lubrication agent.

You will then need to re-lubricate the bearing. Packing grease into the bearing will provide good protection not allowing too much metal on metal friction. There will be a layer of grease separating the ball bearings from the inner and outer races.

If you have a production environment, you may want to purchase extra bearings so that you will not have any down time.

If you have a rubber shield, just pry it out using any sharp object, like a utility knife. If your bearing has a metal shield, there may be a retaining ring along the outer race keeping the shield in place. Simply remove the retaining ring and the metal shield will fall out easily. If the metal shield does not have a retaining ring, that shield will not be able to be removed and a new bearing will need to be purchased to replace the frozen bearing.

• [422] I have a probotix cnc router purchased in 2014, used to run on linyx, now Mach3, WindowsXP, printer port, i would like to be able to use a modern computer usb, do you have something like a plug & play or control box i can wire this into, 2 Y axis, i lost my auto tool length when i switched to XP also, any help appreciated

You have motors and drivers that already work with your machine (unless the drivers are an all-in-one setup and not modular. I would advise you to keep your current electronics and replace the parallel port breakout board with a controller that uses the USB to operate.

Here are two controllers that work under Mach3, or Mach3 or Mach4:
Mach3 USB controller (works under Mach3 only)
https://buildyourcnc.com/item/electronicsAndMotors-electronic-component-breakout-Mach3-USB-Board
Pokeys57CNC full-featured controller works under Mach3 or Mach4:
https://buildyourcnc.com/item/electronicsAndMotors-electronic-component-breakout-Mach4-mach3-USB-ethernet-Board

Alternatively, you can purchase a complete plug-and-play system or have your control system sent over to Buildyourcnc to modify the control system to use one of the above controllers.

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