Lead Screw and the Lead
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
Please visit our online store
There are a few differences between threaded rods and ACMEs. Usually ACME
lower inch per turn.
If you use a 1/2-10 ACME screw and ACME Nut that means that the ACME screw
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
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
stepper motor driver) the total comes to 4000. This means that the
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
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
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
1/4" x 7/8" Home Depot Catalog number: 0 30699
Here is what I used for a motor
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
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
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.
And another one
Use rivets to hold the lead nut in place
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
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