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### Question #: 991

Question: I just made the book build Cnc machine with the feed rate of 11.19 inch/min as suggested in book. Can I increase it to 20 inch/min? I have 2hp of router attached

Current Solution

The book (scratch build) will be able to cut at very high rates of speed, but the speed is partly determined by the mechanical setup. Cutting wood is generally recommended between 60-200 ipm depending on the end mill and spindle being used. The larger the end mill (with increased chip load capacity) the faster the feedrate.

The stepping motors need to turn 13 times to travel one inch using standard allthread (1/2-13 TPI - threads per inch). The higher lead leadscrews shown in the link provided will move one inch with only two turns allowing the machine to move many times faster.

These speeds are especially important if you are cutting materials that have low melting points like aluminum and thermoplastics like acrylic, Plexiglas, etc. These materials require high feedrates and smaller depth per passes.

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### Other Possible Solutions to this Question

• I received the electronics for book build cnc machine. I need to know how much weight the z-axis motor can hold since my (craftsman) router seems to be heavy. It is 2HP with variable speed

The motor is helped by the mechanical leverage of the screw. The 425 oz-in motors that are included in the standard electronics combo has very high torque for that type of machine. You will have no problem using that motor for the book machine.

We use that motor for very heavy spindles on the blackToe and blackFoot CNC Machine kits.

You will need to do the mechanical leverage calculation along with the torque of the motor to determine the actual weight it will lift. The calculation will need to consider the type and pitch of the screw and it would also consider the gravity constant of 9.8 m/s/s.

If you need me to determine this formula and work out the calculation based on the screw you are using, please let me know.

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. 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

I received the electronics for book build cnc machine. I need to know how much weight the z-axis motor can hold since my (craftsman) router seems to be heavy. It is 2HP with variable speed

• 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.

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.

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• Just bought Build Your own CNC Machine book. It is missing the chapter on lead screws that is described on page 181 at the end of Chaprer 16. Where can I get this info?

It sounds like you got a misprinted book. If you purchased it from us, please contact us directly for a replacement. If you bought it from Amazon or a third party, you'll need to contact them. General information about lead screws is available on this website and at buildyourtools.com.

Just bought Build Your own CNC Machine book. It is missing the chapter on lead screws that is described on page 181 at the end of Chaprer 16. Where can I get this info?

• How do I get started I would like to build a cnc router. Making the machine I can do, but I am weak on cad,cam and mach3. I am thinking about a 4’x4’. Do you have plans I can buy?

We are developing plans for our machine, but they are not completed yet. Please let me know if you would like to be added to our list of customers wanting plans. Thanks,

If you have specific questions regarding CAD, CAM and Control, please add another question to the customer service and I will answer them in detail.

How do I get started I would like to build a cnc router. Making the machine I can do, but I am weak on cad,cam and mach3. I am thinking about a 4’x4’. Do you have plans I can buy?

• I am building the CNC in your book - Build you own CNC Machine. One of the bearing thicknesses is 1/4" I can't find that bearing online. I can find 9/32, will that be a problem. Do you have a source? Thx

As long as the bearing has a minimum thickness of 1/4" and 9/32" is a bit thicker, there will be no problem with the book build using the bearing that is 1/32" thicker. There is actually more surface area which is better.

I am building the CNC in your book - Build you own CNC Machine. One of the bearing thicknesses is 1/4" I can't find that bearing online. I can find 9/32, will that be a problem. Do you have a source? Thx

• The table top pictured with the blackFoot 4'x8' v4.3 CNC Machine Kit looks nice. I'd like to build one just like it. How thick is it? If it was made from multiple sheets, how did you make the butt joints?

The pictures of the table on the blackFoot v4.3 CNC machine page uses 2/4 studs, a torsion box, and a final top 3/4" layer.

The torsion box and the top bed layer lays on a frame constructed by 2x4 framing studs angled to resist twisting and for greater rigidity. the joints are simply connected with long screws and you can also use framing plates/ties. The torsion box is constructed of 3/4" MOD stock and has a ribbing pattern spaced around 8 inches apart. The design is similar to this: https://www.buildyourcnc.com/ModularTorsionBoxTable.aspx

The top later is simply multiple sheets of MOD 3/4" thick to conform to the required final measurement.

The table top pictured with the blackFoot 4'x8' v4.3 CNC Machine Kit looks nice. I'd like to build one just like it. How thick is it? If it was made from multiple sheets, how did you make the butt joints?

• I have the build your own CNC kit 3 Axis CNC Machine 2008, were can I get the Gcode or vector files for it ? I wanted to have it laser cut

Gcode or digital files are not available for our machines.

I have the build your own CNC kit 3 Axis CNC Machine 2008, were can I get the Gcode or vector files for it ? I wanted to have it laser cut

• Has anyone built the machine from the book plans and made changes to the Gantry to allow an increase in the Z-axis travel. If so, what dimensional changes need to be made besides increasing the height of the Z-axis pieces? I would imagine the gantry rail and sides have to be altered as well. Am i missing anything?

If the gantry height is changed by, say 3 inches, then the z-axis front, rails and back (where the nut is mounted) needs to increase by 3 inches.

• How do I secure the non-motor end of the lead screw for my 'Book' machine build? Does it just sit inside the bearing or do i use a nut to lock it in place? I did not see any instructions for this in the book.

Use a clamping collar (if you are using an ACME lead screw) or a couple of 1/2 nuts (if using an allthread) against the bearing to keep the bearing in place and make sure there is no axial play.

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

• Can you install a more powerful laser/tube for us if we pick the \$2100 option to have you build it? It would be assumed that there would be a new price for the machine which would reflect the cost increase for the new laser. Please say yes, I know you can physically do it. I have faith in you

The space allotted for the laser tube on the blackTooth would not allow for a higher power laser tube. As the wattage of the laser tube increased, so does the length of the tube.

We do have a larger and more powerful laser in design and should be available in the second quarter of 2015.

• I just wanted to know what I can expect to pay to build the blackFoot 4'x8' CNC machine, excluding computer, software and router? Is the kit complete or do I have to purchase additional items to finish?

You will need to build the table unit for your machine. There are instructions on how to do this at the bottom of the product page here, https://www.buildyourcnc.com/Item/cnc-machine-blackFoot-v4
There is no estimate on how much this will cost though, since there are too many variables involved to do this.

- PC with parallel port and USB port
- 20awg stranded wires for the motors - http://www.buildyourcnc.com/electronicscombo.aspx
- 18awg stranded wires for power supply to drivers
- 24awg stranded wires for breakout board to drivers
(location and spacing of components varies from one person to another, so we do not provide cables/wires)
- General purpose extension cord (cut the female end off) to provide power to power supply
- USB cable to power breakout board
- Parallel cable to communicate to breakout board
- Router
- (optional - instead of router) Spindle with power inverter http://www.buildyourcnc.com/SpindlesAndAccessories.aspx
- (if purchasing spindle with inverter) General purpose extension cord (240v) (cut the female end off) to provide power to power inverter
- End Mill(s) http://www.buildyourcnc.com/ProductsEndMills.aspx
- CAD, and/or CAD-CAM software (to produce geometry, machine operations, and g-code) http://www.buildyourcnc.com/CNCsoftware.aspx
- CNC control software (to read g-code and control machine) http://www.buildyourcnc.com/CNCsoftware.aspx

This answer is applicable to most of our machines with the exception of the greenLean and the blueChick since those machines are equipped with a table structure.

I just wanted to know what I can expect to pay to build the blackFoot 4'x8' CNC machine, excluding computer, software and router? Is the kit complete or do I have to purchase additional items to finish?

• Where can I get the spec for the Cnc machine for the machine in the book build your own Cnc machine I tried the web page but no mesurments that I found
• I have a MK1 board that I just got running and I am having issues. Do you have an MK1 board at your shop that I can send you my G-Code to run? The freexing/zeroing in the middle of the program issue happens even with no step drives attached to the board.

My apologies for not getting back to you. We always answer the phones during business hours, so I would try that first. Our emails on Monday generally is stacked up as we are closed during the weekend. We can try your g-code here. Please send the g-code to the techsupport@buildyourcnc.com email address and we will test the code to see if it works.

By the way, do you get movement on the planet-cnc UI screen?

The program starts and runs normal. I have all the correct movement on the mill and the UI screen. Then one of two things happens. It either stops and resets all axis to zero in the middle of the part or it freezes in the middle of the part. When it freezes, it is not moving on the cnc or the UI screen. Sometimes after a freeze it will come up with an 'IO timeout error', but the only way to clear is to unplug USB and start over.
I will send my settings and g-code files over tonight. Please be sure to load my settings when running the g-code. No movement of the cnc is necessary as the controller will do these issues without power to any drives and just the USB board connected, on my board at least.

• Do you have any videos or plans for how to make a strong table for a large CNC router? I saw the torsion box videos but would like some more guidance on how to build just a good table.
• I've read your book and I'm looking to purchase the hardware kit with DVD as well as an electronics kit. I would like my machine to have a working area of at least 24" wide by 48" long. Can I just make the bed (and gantry) wider to accommodate larger priceslike 30"x60"? If so what electronics kit would you recommend?

Considering enlarging the machine, might have its down sides do to the structural integrity of the scratch build machine. Primarily by making the width longer it will start to sag in the center, which will lead to having to redesign the gantry to be more structurally rigid to support the added length. Which then will increase the weight and height of your gantry to support the add size, which will always end up to creating a larger CNC.

We usually do not recommend modifying the scratch build CNC, due to the very limited capabilities, and the structural design of the scratch build. We also do not recommend using longer than 48" ACME screw/leadscrew due to the increasing chance of warping and bending in the ACME screws/leadscrew in the given length.
We do recommend modifying the CNC machines we sell to accommodate the added requests that some of our customers desire, but you will be limited to the width of the gantry with our machines.

• I am having trouble connecting the cambam program with my Mach3 to my 4X8 Blackfoot CNC machine. Where can I get help on this issue. Have had my machine since 2015 and have not been able to use it. Thank you

CamBam specifically creates the g-code (machining operations) instructions to be loaded into Mach3. Make sure in your CamBam g-code file parameters, you are using the Mach3 post processor. If you have already done this, let me know. If you are not sure how to do this, let me know.

• THE CNC MACHINE IS UNSAFE WITH EXPOSED SPROCKETS THAT CAN DAMAGE FINGERS AND HAVE CLOTHING CAUGHT IN IT.

These machines are inherently dangerous. Before the machine moves, the machine should be clear of any person by a dimension of at the distance of a persons reach plus a few more feet. This is the policies we institute in our shop and what is recommend to all of our customers. Treat these machines as you would treat any major power tool in the shop.

With that said, you can certainly add some protective parts, but still keep folks away even with those installed. I would use the gantry side to do all of the mounting of the protective parts. Consider using sheet metal that you can bend and make a simple installation right on the gantry side.

THE CNC MACHINE IS UNSAFE WITH EXPOSED SPROCKETS THAT CAN DAMAGE FINGERS AND HAVE CLOTHING CAUGHT IN IT.

• I am looking to build a cnc router that will cut 4x8 i wanted to get a cnc kit with some mods i was wondering if there was someone in sales that can help me

Yes, if you give us a call, we can definitely help you. If you are looking to mod one of our 4'x8' machines, we can provide those changes for you. We have experience with meeting customers' needs where their application requires a machine with small or even large changes.

I am looking to build a cnc router that will cut 4x8 i wanted to get a cnc kit with some mods i was wondering if there was someone in sales that can help me

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