Home Built Hot Wire CNC Foam cutter
Day 1 - Vertical Y Axis
Day 2 - Horizontal X Axis
Day 3 - Lead Screw
Day 4 - Electronics
Day 5 - Finalizing the machine
Other CNC foam cutters
A New Design - Hot wire CNC Foam cutter
Foam Sample Cuts
Foam Cutting Videos
Links - RC stuff, Stepper Motors, Lead Screws
More information - about stepper motors

DIY Mach3 with Joystick and gamepad
FoamLinx Site - Foam Cutting CNC Machines
CNCLinx Site - CNC Router Tables
Foam Cutting Services - EPP, EPS, XPS
All About Foam Forum - Beta
Composites Prototyping and Design
Large and Configurable CNC Machines *
Low cost Hot Wire Foam Cutters
Online Store

How to coat EPS foam (Crown Moldings)
How to build an EPS Foam Recycler
How to build an EPS base and Cap cutter
How is EPS manufactured - molded
How to make RC foam planes
How to cut EPS, XPS, EPP foam
How to cut Polyurethane foam ( PU )
How to cut Acrylics - Laser cutting
DIY CNC Foam Cutter Blog - New

What is - more info about foam
What is EPS foam
What is XPS foam
What is EPP foam - Expanded Polypropylene
What is PE foam - Polyethylene foam
What is Polyurethane foam
What is Memory Foam




                Lead Screw and the Lead nut

Using parts from Home Depot, I could only find threaded rods, I later found
online, stainless steel threaded rods.
For this section, I used a lathe and a set of tap and die.
There may be ways around, but I chose to go the safe route.
We later had ACME nuts made just for us - if you are interested in purchasing
ACME nuts Please visit our online store
There are a few differences between threaded rods and ACMEs. Usually ACME
have a lower inch per turn.

If you use a 1/2-10 ACME screw and ACME Nut that means that the ACME screw
will turn 10 times and during this time it will advance 1 inch. If you use 3/4-6 ACME
rods and ACME nut - this means the ACME screw
will turn 6 times and during this time it will advance 1 inch.
When calculating the steps-per inch on a machine you need to know the ACME
value and the stepper motor steps.
For example: using 1/2-10 ACME with a stepper motor driver at 1/2 step - to
calculate the steps per inch follow these steps 10 turns per inch times 200
(which is the usually stepper motor steps per turn) times 2 (this is the half step
of the stepper motor driver) the total comes to 4000. This means that the
resolution of your machine will be 4000 steps per inch

The above is a picture of an ACME nut made of brass - we also use ACME nuts made of ACETAL

With ACETAL ACME nuts we get less noise and vibration.
Since ACETAL is also non conductive its a good method of insulating the
hot wire power from the machine

Going back to the ACME screws and nuts - and where to get them:
Due to the huge demand we now offer 36" ACME screws - 3/8-12
The screws are machined on one side down to 1/4" to fit the common couplers.

They can be cut down to size to any length. 
Since the packing and shipping of the screws is complicated (need to make sure they arrive in perfect condition)
we offer a 3 screw and a 4 screw package - Price is for the ACME screws only - nuts are not included
The 3 screw package is $100 which includes the shipping in the continental US

The 4 screw package is $120 which includes the shipping in the continental US

Search for 1/2"-10 ACME screws or search Google for ACME screws

The above picture shows the threaded nut (not ACME). I will machine its outer side and then thread it.

Threading the outer side of the threaded nut will enable me to mount this threaded nut onto the X axis carriage
As well as the Y axis carriage - make 4 of these


Lead Screw : Stainless Steel preferred

Threaded rod  USS/Course Stainless steel 1/4" x 20 x 36" 
Home Depot catalog number : 0 30699 48000 5

Lead nut:
1/4" x 7/8"   Home Depot Catalog number:  0 30699 19116 1


Here is what I used for a motor mount:


Made out of plastic - easy to saw, drill and strong enough for any NEMA 23 motor

Why use plastic ? Plastic is forgiving, if for any reason the motor shaft and the lead screw are
not perfectly aligned, the plastic mount will bend a bit and the wobble will not be
noticeable on the cut


A simple way to connect between the motor shaft and the threaded rod.
A better way is to make this "Coupler" out of rubber - this will help in case the motor shaft and the threaded
rod are not aligned.
We later moved to ACME screws that can be found on www.use-enco.com. These ACME screws come is
3' and 6' lengths. Since their diameter is 1/2" and the motor shaft is 1/4" you will have to machine these

ACME rods to 1/4" diameter. Use your lathe of stop by at a machine shop and they can do it for you.

Another look

And another one

Use rivets to hold the lead nut in place

Top end

The top end

So this is how it should look !!!!
Now, make another one just like it, but mirrored.
The last picture on this page shows that the two "T" brackets are facing each other,
This is where the hot wire will connect. For those who wish to mass produce wings,
simply add one or even two more "T" brackets and you can cut 3 cores at a time.
Thanks for the correction Steve :)

Now lets put it all together