Craftsman is fond of making all sorts of unusual things from wood. You can see his products here.
In this article, he will tell us how to make a machine for making wood spirals. If we talk about the practical use of such products, then here it is rather a decorative purpose or as a toy for children. Can also be used as a password/tip for spies, especially in Australia. If the two halves of the spiral converge, then the binder is yours-)))
The general principle of the machine is as follows. The machine consists of a carriage that moves along an axis using a stepper motor and an additional assembly resembling a lathe with a tailstock and headstock. The workpiece is placed between the headstock and the machine is placed on the band saw table. Then, according to the program, the carriage moves along the axis and additionally the workpiece is rotated by a certain angle using the second stepping motor.
Tools and Materials: – CNC Linear Actuator Kit (Linear Actuator, Cables, Metric Screws and Nuts, Gaskets, Angle Connectors, V-Slot Profiles, NEMA 23 Stepper Motors; -Arduino (Arduino, CNC Shield, Stepper Motor Drivers, power supply 24 V); – Coupling; -Spiral saws for cutting wood No. 2 and No. 4;
-3D-printer; < br> -Clips;
Step two: linear actuator
Now you can start assembling the machine. The linear actuator is a fairly simple and lightweight design. Just follow the instructions in the video. Perhaps the author's drive model will be slightly different, but the principle is the same. The wizard recommends that you first assemble and test the linear actuator before installing any additional components.
Assembles the carriage and installs it into the aluminum profile. The carriage should slide freely on the drive.
Next prepares a 3 “(7.62 cm) wide and 18” (45.72 cm) long plywood strip from 1/2 “(1.27 cm) thick plywood. Do not use thicker plywood, or the attachment will not fit under the band saw. Drill holes at each end as shown in the illustrations.
The plywood strip is attached to two carriages.
A cross-section is attached to the plywood skids. On this profile, the engine will be mounted, on one side, and the quill on the other. You can call this node a headstock by analogy with a lathe.
Step Three: Mounting Plates
For the headstock and tailstock, the master cuts two mounting plates from acrylic. The templates can be downloaded below.
head stock plate.svgtail stock plate.svg
Step four: assembling the headstock
The two helical gears were 3D printed. Specifications: 20 teeth, 1.5 inch pitch, 1/2 inch thick, 1/4 inch center hole. One gear has a notch to hold a hex nut. The other gear has a bore to fit the stepper motor shaft. Files for printing gears are included.
motor drive gear.stldowel drive gear.stl
If you don't have access to a 3D printer, you can remake the headstock assembly with a belt and pulley.
Headstock is assembled at the base stepper motor NEMA. A plate is attached to the front of the engine, then the gears and a second plate are installed. A quill with a cruciform tip is installed on the pinion axle.
Step Five: Assembling the tailstock
The tailstock consists of two acrylic plates and an axle that will abut the workpiece.
Step six: installation of the headstock and tailstock and calibration
Next, the master installs headstock and tailstock assemblies for transverse profiles. Checks how easy the slide moves.
In this step, you need to calibrate the machine.
Start with a GRBL of 100 = 400 (steps/mm), then change this value based on your actual travel measurements. This machine is calibrated at 395.062 steps/mm. For reasons related to the very low feedrate in GRBL, the master uses half this speed, i.e. 100 units = 197.531 (steps/mm in the x-axis). This means that you have to enter (desired helix length in mm) multiplied by 2 into the software.
It is also necessary to mark the position x = 0 using masking tape on the C-shaped beam. This will be needed later.
For the Y-axis (dowel rotation), you need to calibrate how many mm are required per revolution. For this machine, this is 20 mm per revolution. Note this: the millimeters that need to be entered into the software are equal to (the desired number of turns of the helix) multiplied by 20. For example, 100 mm gives 5 turns.
Step seven: staples
With these brackets, the machine will be attached to the working table of the band saw. The master printed the staples on a 3D printer. It is clear that on different machines these staples will differ, but you can edit the attached files for this device.
mounting clamp plate.stlmounting hook.stl
Step Eight: Electronics and Controls
The fixture is controlled by the Arduino Uno, CNC shield, stepper motor drivers and power supply.
To get the necessary GRBL software and upload it to the Arduino, follow this link.
CNC Shield must come with instructions. Here are instructions for using Zyltech and similar devices.
To configure, you need to set jumpers for two stepper motors. The wizard is using a 1/16 microstep setting for the x and y axes.
The master did not install the limit switches, so you need to work carefully. Homing cannot be commanded in GRBL unless limit switches are installed.
Just in case, he installed an emergency switch in the 24V power line to the CNC nameplate.
Step nine: software a program called Universal Gcode Sender (UGS).
First you need to test the setup by running each of the two motors separately.
Here are the important GRBL settings for this machine:
$ 3 = 3 (axis directions, you need to change the setting to cut a left or right spiral)
$ 22 = 0 (home cycle disabled!) < br> $ 100 = 197,531 (steps/mm along the X axis)
$ 101 = 160 (steps/mm along the Y axis)
Step ten: preparation of dowels
First of all, only hardwood should be used for any spiral. Softwoods such as pine, fir, etc. are too soft.
Prepare a round, hexagonal, or square dowel up to 1.5 “(3.81 cm) in diameter and 14” (35.56 cm) long. You cannot use a thicker dowel, either the saw blade or the engine will break.
Workpieces made of walnut, cherry, maple are good, oak gives a coarser cut.
Mark the center at both ends of the dowel. Drill a shallow hole centered on one end of the dowel and insert a short Phillips screw. Drill a very shallow hole at the other end and put some hand soap into the hole. Install the dowel between the headstock, screw to the headstock.
Step eleven: sawing
Now you can start sawing. First, you need to set up the machine on the working table of the band saw. The position of the saw blade is about 1 cm from the beginning of the dowel near the headstock.
< img class = "aligncenter" alt = "Wooden spirals and CNC-machine for their manufacture" src = "https://usamodelkina.ru/uploads/posts/2021-03/1616249945_1-55.jpg"/> Next, you need to make a mark on the dowel where the blade will enter the workpiece. Then turn the dowel by hand and drill a hole in it at the mark. Then the blade is pulled into the hole and fixed on the band saw. Be sure to use a spiral blade.
You will need to experiment to find the best spiral saw speed with minimal vibration. On the DeWalt saw, the master uses a setting from 6 to 8.
You will also need to experiment with the “feed rate” in the program (command F GRBL) to achieve a smooth cut. Good (slow) start – F12. It can take 45 minutes or more to cut 300 mm smoothly through a thick dowel. It all depends on the type of wood, the diameter of the dowel, the cut of the spiral blade, the speed of the spiral saw, etc. and the offset from the central axis of the dowel. You need to move slowly. Due to the fact that GRBL handles very slow feed rates, the smallest settings are between F9 and F11. Any F values below this do not affect the actual feed rate.
For smaller dowels, the foreman uses a # 2 spiral blade with a cut of 0.035 “.
For larger dowels, use a # 4 spiral blade with a cut of 0.041″.
The foreman recommends replacing the blades after one or a maximum of two cuts.
To start cutting, enter the x and y parameters into the UGS software console, that is, (length in mm) * 2 and (number of turns) * 20 mm, as in this example:
G1 X620 Y140 F12
then hit return. This will cut a 310 mm long helix in just 7 turns. The illustration shows the result on a square maple plug. Cutting took 52 minutes, blade tension 3, spiral saw speed from 6.5 to 7.5.
You cannot cut to the end of the dowel, there are no limit switches and the blade will break.
After finishing work, you need to remove the workpiece and cut the ends .
Step twelve: four spirals in one piece
If you want one dowel to have more than two coils, make the first cut as above, but do not remove the dowel. Instead, remove the blade, move the jig back to the starting point (x = 0), rotate the dowel, drill a new hole 90 degrees from the first, insert the blade, and start a new cut. Be sure to use the same x and y settings as in the first cut. The result is four intertwined – nested – spirals.
Step Thirteen: Offset Cut
Another option is to offset the cut from the centerline of the dowel. You will get two intertwined spirals of different “widths.” You need to glue the rods to the ends of the dowels. Then we make one incision with an offset from the center, remove the dowel, remove the first spiral.
Place the part again and make a new cut at an angle of 90, 120 or 180 degrees. We repeat the process and in the end we get several outer spirals and an interesting central element.
By tilting the band saw table we get another interesting variation. You can use different types of wood and cut them with the same settings. Then connect them. You will get a beautiful drawing.
You can grind any part on a lathe, with grooves, bumpers, teeth, grooves, and then cut out on this machine.
These are the products obtained by the master.
The foreman plans to further expand the functionality of the machine:
Making spirals from acrylic rods
Tapping on dowels
Adapting the machine for cutting foam products with nichrome wire
Laser engraving with diode laser