NSK Bearings 100% Failure

Bearing ‘quality’ in the Portamate PM-P254 variable speed router motor is dreadful, with 100% failure rate.

I have not yet fitted a Portamate router motor into a horizontal router table; I have only ever used it in a vertical router table.

I have had four Portamate router motors, all of which were fitted with NSK bearings. As there are two bearings in each motor that is a total of eight bearings. In all four router motors every single bearing was of extremely poor quality, and failed.

The first three routers all had bearing problems within a few months of light use. They all started producing worrying noises particularly when stopping and starting. And when they started to get noisy they all caused the router lift to noticeably vibrate. In actual fact the motors never sounded particularly healthy from the outset.

In the case of the fourth router motor I decided to replace the bearings from new, before I even used the router, and I did that because of the problems I experienced with bearing failure in all the previous motors. When I stripped the new router motor down I inspected the bearings, and when I saw NSK Japan on them I thought that maybe these would be good quality.

However, they are terrible; absolute rubbish. The small 6000-2Z bearing spun freely enough and I could not detect any ‘play’ in it but when I removed the metal shield to inspect it, there was absolutely no sign of any grease or lubrication whatsoever; it was dry.

The larger 6004-2Z bearing was very tight, difficult to spin by hand and very ‘notchy’ and rough as it revolved. I suspect that both of these bearings would have failed within a short period of time. So I’m glad I decided to change them before using it.

All four Portamate PM-P254 router motors were originally fitted with NSK bearings and they had either China, Indonesia or Japan stamped on them. Because of the poor quality bearings that are fitted, you get the impression that the router motors themselves are of poor quality, but that is not the case. Because when they are fitted with good quality bearings the router motors are improved dramatically. Now the router motors are perfect, run much quieter and with no vibration whatsoever. They could now be described as good quality motors, at least that’s how they feel and operate. Certainly the armature seems to be well made and good quality.

I do not understand why a manufacturer would bother to save a few pennies by fitting poor quality bearings when they have such a dramatic impact on the performance of the motor. It really is like two different router motors after changing the bearings. What was a knackered router motor is now better than it was when brand new. Good quality bearings are not expensive anyway.

In all of the Portamate PM-P254 router motors I replaced the bearings with SKF bearings.

I’d always been under the impression that NSK bearings were good quality. The advertising for these Portamate routers says “…premium NSK bearings for extended life…”

It could well be that the bearings in these Portamate routers are copies, and not actual NSK bearings. Before writing this article I did contact NSK to seek their observations but I never got the courtesy of a reply.

In the future I would like to make a carrier for the Portamate PM-P254 router motor so it can be fitted into a horizontal router table.