Turbo Knitting Machine 5 Minute...ish Beanie

I have recently been given an Addi Express King Knitting Machine, the machine was not in fully working order, initial thoughts were that the cranking handle spigot had snapped as the handle would just spin and not rotate the drum, with nothing to lose I decided that I would try and repair the Machine.

It was at this point that I thought to myself instead of modifying the machine to as was, why not turn it into a turbo knitting machine, who wants to crank a handle hundreds of times when a motor can do the work, fair enough you still have to watch for any dropped stitches etc, but at least your hands are free to do other things.

The way these knitting machines work is you manually cast on one row, then the machine takes over whilst you crank the turning handle for however many rows you need, this could be 400+ if you are knitting something like a scarf, a double thickness beanie hat would be say 120 rows.

So with this plan in mind I started thinking on how I could automate this machine.

Addi Express Knitting Machine or Similar.

12v 400 RPM High Torque Geared Motor.

Motor driver with forward/Reverse Switch and Speed Control

Arduino Nano With Servo Shield.

TM1367 7 Segment LED Display

Momentary Switch

A1344 Hall Sensor

5mm x 2mm Neodymium Magnet

Small screws 2mm x 8mm

Hand Drill with a 1mm drill

Screwdriver

CA Glue

Hot Glue

Resin Glue

DuPont cables or similar.

After giving this project some thought I decided that the easiest but probably the best solution was to use a dc motor with a motor driver with a speed control and forward/Reverse Switch, these are inexpensive and could be used with a high torque geared 12v DC Motor, which should give enough torque to spin the drum.

There are no bearings within these knitting machines it's just a plastic ring running on a plastic base, there is a certain point where the drum meets resistance and this is the manual row counter, this needs to be replaced for a smoother operation but we still need a means of counting rows.

The solution I came up with is Arduino Nano based its a Hall Sensor and Magnet arrangement, this will be used in conjunction with a TM1637 Seven Segment Display and a Momentary Button to reset, the counter.

For the first row the drum can be turned manually, ensuring all the cast on stitches are correct then its just a matter of energizing the drum and then produce a beanie hat in Rapid time.(In theory of course)

The first motor I tried was only 200 rpm and far too slow for this project, I tried disassembling it to try and alter the gearing but that failed miserably so in the end I opted for one of the N20 500 rpm geared motors(See Image) which after putting it through a trial with some wool was clearly not up to the job, I had designed and 3D Printed a housing for that motor as well.

I sourced a 12v 400rpm high torque motor, again this was not expensive, this should be adequate, slightly larger at 25mm diameter I would need to cut away some of the plastic motor housing, hey what's to lose, the machine was a freebie!

I managed to salvage the original gear which turned the cylinder via the crank handle, this was cut-off with a Dremel cutting blade, I had to design an adapter for this, which meant drilling the center out to fit the adapter so it could be fitted to the shaft of the DC Motor, this could be glued in using CA Glue once everything is aligned correctly, Unfortunately this failed, the shaft has a flat spot on the motor and I couldn't replicate this, so I decided to design a new gear, with the correct hole including the flat spot, I also designed in a 3mm threaded hole between the gearing where I could insert a 3mm grub screw to tighten against the flat spot.

As the geared cylinder sits directly on the base of the drum its important that the gear on the motor is aligned correctly for a smooth operation.

I ended up using 5 minute resin to secure the motor, this was the best solution, it took a few attempts to get this aligned correctly, but once in place it worked well, 12v was ample to spin this motor and rotate the plastic ring, I had completely removed the row counter prior to carrying out the initial motor test as this was a major sticking point.

The next part of this project is installing the motor driver, this ideally needs to be adjacent to the motor, there was space to the right of the motor on the body for this and the easiest way to secure would be to use the mounting holes on the driver PCB, I used a manual hand drill and secured with 2mm x 8mm screws, not applying to much pressure as the body is curved, the driver has a potentiometer for speed control along with a switch for forward & reverse, I secured the switch adjacent to the motor with Hot Glue.

The top part of the knitting machine body is where all the electronics wiring will be installed as there is a usable void which is perfect, if the machine needs to be taken apart for cleaning then its just a matter of disconnecting the 2 Motor cables.

The next part of this build is the row counter assembly.

Prior to this part of the project, I had installed all the components on a bread board and compiled a custom Arduino Sketch, the install includes a hall sensor, Magnet, TM1637 7 segment LED Display and a momentary button to reset.

The way this will work is that the magnet will be placed on number one hook identifier on the red ring, this revolves when the motor is powered up and is what creates the stitching, the ring is numbered 1 to 46 and one full rotation will show up on the display, the hall sensor will be secured as close to the magnet as possible on the main body where the wiring is installed, this meant cutting a section out of the top retaining ring, which is fine as its secured with screws in 5 places, but I secured further with CA Glue just to be sure.

I wanted the display to retain the number of rows should there be a loss of power or a coffee break needed etc so the Arduino eeprom Library was used to fulfill this, the display can then be reset with a momentary switch.

For the install I secured the TM1637 display in the same place as where the original row counter was housed, securing with 4 x 2mm x 8mm screws, I applied some double sided adhesive tape underneath one end to compensate for the LED display microprocessor which was to one side underneath the PCB.

The momentary switch was installed below this, the correct size hole was drilled and the switch pre-wired prior to the install, secured with the nut that came with the switch, a blob of glue was also applied to the soldered terminals on the switch.

I used an Arduino Nano with Servo shield to control the row counter set up, this was installed on the main body on the opposite side to the motor driver using the same 4 screw method, a slot was cut out with a dremel bit adjacent to the shield for the wiring.

I used 2 dc power connectors, I male for the shield and and a female for DC power input which will be a 12v 3amp power supply.

As mentioned earlier all cables will be secured within the void of the body using hot glue and small cable ties.

I had to watch a couple of how to Youtube video's to learn how to cast on and cast off, casting on correctly is Paramount as a dropped stitch is a pain to rectify.

This machine has been modified as such that it's only possible to knit Beanie's or scarfs, this Instructable is more about adapting the machine to motor driven but my aim was to produce a 5 minute Beanie, as you can see in the video it knitted 120 rows in 5 Mins.22 Seconds which is pretty good, casting off takes a minute or so, and gathering the ends and tying off the same, so all in all a pretty rapid Beanie hat.

This broken knitting machine has been given new life and was very satisfying to watch as the drum wizzed around producing flawless knitting, I've never touched a knitting needle or anything like that before and now I can turn out a Beanie hat in minutes, Ok my wife played her part gathering the end's, but I am sure I could have done it Ahem!

To say I was impressed is an understatement, I has some initial set backs adapting the machine but got there in the end and it does exactly what it was meant to do as a project idea, what could be better!

Thanks for Looking!.