Toothmaster solution (Introduction)

Dear visitor,

In this post we will look into the Toothmaster solution to create tight fit wood joints. The Toothmaster solution is shown in the picture above.

The following components are necessary for the Toothmaster solution:

  • Toothmaster Program: The Toothmaster program is a Android  program that runs on any mobile phone. Toothmaster is the brain behind the complete solution. Toothmaster APK can be downloaded at google play for free. Toothmaster is open source. The .APK source code can be found here. The STM32F407 discovery source code can be found here.
  • Jointmaster PCB: All movement is generated via the Jointmaster PRO PCB. You can adress up to 4 stepper motors once you have this pcb. The Toothmaster software communicates via bluetooth to the Jointmaster PRO PCB offering homing (return to start position) and automatic stop in case of stopswitch encounter. Toothmaster can adress 1 stepmotor with stopswitches whereas Jointmaster PRO can interface four stepper motors  (Jointmaster PRO can also be used for more advanced 2D/ 3D operations), 8 stopswitches and 4 encoders. Which step motor is actually used can easily be set in the Toothmaster settings menu. The Jointmaster PCB is controlled by a STM32F407 discovery board that fits on top of the board.
  • Power supply: The step motor power supply supplies 36 Volts power to the step motor driver. Note, for single axis application for the Jointmaster box joint jig, we sell this 36 Volts, 3 Amp power supply.
  • Step motor driver: The step motor driver controls the step motor.  This is a standard component that can be bought all over the world and also on this site here
  • Step motor: The step motor + trapezium spindle converts the electrical signals into very precise movement (one step motor step results in 1/ 50000 mm movement). This is also a standard component that can be bought all over the world. For the Jointmaster box joint jig you need this one.
  • Stopswitches: Stopswitches are used for homing (return to start position) and protect the Jointmaster box joint jig from jamming into the wall.
  • Jointmaster box joint jig. You need the jig to clamp and move your workpiece.


Watch the video below to see what you can do using Toothmaster:


We offer 2 options in the Jointmaster shop to get the Jointmaster PCB (and then you also get 2 Jointmaster PRO licenses for free !).

  • PRO Almost ready to go kit including: Wooden frame, step motor, step motor driver, UL listed power supply 36 Volts, soldered line Jointmaster PRO PCB in casing, Shielded cables, Jointmaster software two licenses, power supply switch + protective casing for earth connection. This package weighs around 10 kg. Thus shipment cost can be considerable.
  • PRO Low budget kit A: You will have to integrate all components yourself according to the kit directions/ your own application. This kit offers the following optional service: We ask the step motor manufacturer for an offer that is sent to you. You pay directly to the step motor manufacturer using pay-pall. Thus you will have a working set-up but you are not our customer for step motor, power supply and step motor driver.
    Thus the step motor, step motor driver and (non UL listed) 36 Volts power supply will be sent directly from China (Low budget kit A saves around 100 euro due to shipment, UL listing and customs cost). Soldered + tested line level amplifier (no casing to keep shipment cost down) is sent to you from Europe. Jointmaster software + two licenses for free. Shipment cost will be much lower because fits inside a small package. Note that you can also use low budget kit A if you already have a step motor + step motor driver + power supply.

Now what is the most important difference between Jointmaster audio, Toothmaster and Jointmaster PRO ?

  • Jointmaster PRO can only be run from Windows while Jointmaster audio can also be run from Android. Toothmaster can only be run from Android.
  • Jointmaster audio contains far less functionality/ components. For this reason it is less expensive.
  • Jointmaster PRO communicates via USB to a STM32F407 discovery board. The USB protocol should not fail because then the machine stops in the middle of a milling sequence. In order for the communication to be reliable, one has to be more strict in EMI/ EMC shielding. Lets assume a milling machine runs for a couple of days on a difficult workpiece. Next we assume that we have a Gcode file containing 1.000.000 commands. Now lets assume that only 1 in every 1000 workpieces is allowed to be ruined because of communication problems. Then this means that only 1 in every commands may fail. This is a huge reliability number.  For this reason Jointmaster PRO is the most reliable solution for fingerjointing. Jointmaster audio will be close behind Jointmaster PRO regarding reliability because the mobile phone audio signal is only amplified.
  • Toothmaster bluetooth reliability depends upon the amount of EMI (Electro Magnetic Interference) in the work area. Read the post on EMI and Reliability that shows how Jointmaster reliability can be ruined by insufficient shielding and filtering. Note that the difference between Jointmaster PRO and Toothmaster is very small regarding the grounding concept. Toothmaster is a bit more complicated because you will need a seperate power supply for the STM32 board.
  • Both Toothmaster and Jointmaster PRO have a 16 bit CRC code on every command send to the Jointmaster PRO PCB. So even if there is a lot of noise, this will not lead to erratic behaviour. A corrupted command is automatically send again.
  • Jointmaster audio (and Toothmaster) are single axis applications. Only for fingerjointing. With Jointmaster PRO and GCode you can do anything.

There are two important reasons why you might consider Jointmaster audio:
– Creating the bluetooth hardware is a bit more difficult compared to Jointmaster audio.
– In case the box joint jig does not move (for instance at first time installation or during maintenance) then it is more difficult to find the culprit using Toothmaster. It could be your phone, it could be bluetooth sender, it could be bluetooth receiver, it could be STM32, it could be bad soldering etc. Using Jointmaster you can simply listen with earplugs if the interface is functioning.

WARNING, Jointmaster PRO contain GCode processing functionality as a bonus. Jointmaster PRO GCode processing is reliable but slow.  If the GCode contains a lot of small line segments, the machine movement is too slow. Jointmaster PRO moves very reliable when you only need to cover large distances (above 5 mm per Gcode command).