80mm fan adapter for chinese milling spindles

Here we have an fan adapter for converting milling spindles of Chinese design with 80 mm size.

There are two versions available - one for the additional installation of a specific speed control and one with just the adapter.

If you want to retrofit your milling spindle with an external fan, you need an adapter to attach the fan. The 2 kw spindle shown in the pictures has an 80 mm mount on the top. If you only need an adapter, take the second variant in the print profile.

To be able to use the adapter, 4 x M4 fusion nuts are required for the top and 4 x M4 screws of the appropriate length (approx. 5 mm longer than the height of the fan). I reused the screws from the original cover cap to attach the adapter to the spindle.

Converting the spindle

To do this, the original 80 mm spindle cap must be removed (4 screws) and the original fixed fan wheel unscrewed (note: usually left-hand thread!). Then the adapter can be screwed back onto the spindle with 4 screws and finally the external fan is mounted on the adapter.

In my case, I use a very powerful external 24 volt fan (EBM Papst 8214 JH4, 80 x 80 x 38 mm, 2 pins).

This fan has an enormous air throughput and is correspondingly loud in the upper power range. That's why I also use a 6 to 35 volt voltage regulator to regulate the throughput and noise level. At around a third of the power, the air volume and noise level are suitable for me - but that is of course personal preference.

If I know that the spindle has to work at full load for longer than 30 minutes, I increase it to around 50 to 60 per cent in advance. The spindle doesn't get warmer than just under 50°C.

However, I do not recommend doing this conversion unless you really know what you are doing!

Also - if you absolutely want to convert - don't use an extra quiet fan with low airflow! The spindle needs a lot of cooling air and the most 80 x 80 x 25 mm fans can't deliver the required amount! From 120 CMPH (m³/h) you can go for it, below that I wouldn't do it!

Miscellaneous:

The version with the box for the voltage regulator has a matching cover. The side with the longer end is at the back.

And there is a slot at the top to lead the two cables from the fan to the box. I would recommend wrapping some adhesive tape around the cables at this point to make the slot airtight again.

I would also wrap the cables that are routed into the box so that vibrations from the machine do not rub through them.

Used hardware

I ordered the matching voltage regulator for 6 to 35 volts from Amazon. The adapter with controller box is suitable for these and others of the same size and design.

https://www.amazon.de/dp/B07X5JZX4M?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

And the EMB Papst 8214 JH4 (2 pin, 24v):

https://www.amazon.de/dp/B00R3E7EJ6?ref=ppx_yo2ov_dt_b_fed_asin_title

As I have no idea how long these links will be valid, you will find some views of the fan and the control system below the pictures.