T8 CNC from GearBest

If you are looking to get a cheap CNC or engraving or milling machine, GearBest has a range of self-assembly/ DIY machines. After browsing GearBest for hours, we took the plunge and ordered a T8 CNC. It had fairly good reviews on the comments and a quick google suggested that it is a good piece of hardware.

Few days later, the T8 CNC was here by DHL Express. We had to pay an import duty and handling fee of £34.
T8 CNC box

Opening the box revealed 100’s of parts, all neatly pack in smaller boxes, bags and bubble-wrap.
T8 CNC Box contents

Assembly of the T8 CNC

This T8 CNC kit is no way targeted at everyone. You will require some level of technical ability to put this together. To start with, there was no instructions!!

A quick google gave rise to a few videos on YouTube on how to put it together. The best concise steps were from https://www.homofaciens.de/technics-machines-cnc-T8_en.htm

By following the steps on the above website and using some common sense, the T8 CNC slowly came together.

The last mechanical to go in was the DC motor and it did not fit!

Assembly of T8 CNC DC motor

The DC motor did not quite fit in the space for it.
T8 CNC DC Motor fit

After some head-scratching, it was evident that the motor was too big and not a mistake in our assembly. So we proceeded to remove the outer collar of the DC motor.
T8 CNC Motor collar

Assembly of the T8 CNC electronics

The electronics is basically an Arduino-clone with a stepper motor shield. The kit come with a piece of white perspex on which all the control PCB fits on. There is also a relay board for the DC motor control.

T8 CNC electronics

If you have a basic understanding of electronics, the connections of the stepper motor and relay to the controller board should be straightforward. You will need to solder the stepper motors to the Dupont cables.
T8_Electronics

The whole assembly took a good part of half of day but finally, we had a finished CNC.
Finished T8 CNC

Testing of the T8 CNC

We loaded up the GBRL control that was available to download from the Gearbest product page and powered everything on.

The stepper motors were responsive to the button pressed in the GBRL control software. However, the DC motor did not come on with the “Spindle on” option.

So we went back to the controller board to make sure that the relay was connected properly and it was! The DC motor just would not come on. So we probed the “SpnEn” pin, shown below, with a multimeter and turn the spindle on and off in the GBRL control software. However there was no change in the signal.
T8 CNC spindle enable

So we ended up probing all the pins on the controller board while enabling and disabling the spindle in the software and at last, we identified the pin.
T8 CNC spindle control

And pin was somehow connected to the Endstop Z- connector pin. So we wired the relay control to that.
T8 CNC relay connection

Testing of the T8 CNC

So straightaway, when we started to test it, it broke. This was our fault by failing to put movement limits on the stepper motors. One issue with this CNC is that there are no limit switches that prevent the axes from moving further when you can to the end of the moving path. In our case, we broke the coupling:
T8 CNC broken coupling

We first testing engraving plywood and the results looked OK. We would not recommend using plywood as the end results are not impressive.
T8 CNC wood

We then tried perspex but ended breaking 2 of the milling bits. The brittleness of the perspex also means that the bits slipped on the surface and the results did not look good.

T8 CNC Perspex

Conclusion

If you want an out of the box CNC machine, this is not for you. Even if you have the patience of putting it all together, do not expect amazing results. The machine does require a lot of fiddling.

On the other hand, if you want to understand how CNC machines generally works and want to spend some time improving this T8 CNC, then absolutely, get one. It is relatively cheap. You can buy one from Gearbest here. If you use our link, we do get a very teeny tiny commission!

If you have some experience with this T8 CNC, or have any general comments, please feel free to get in touch 🙂

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