Bench grinder bearing lubrication

[Roger Owen 5Participant @rogerowen5]

I have an old 6" Pinnacle bench grinder from the early 1980's and the bearings sound a bit dry. bearings are a bit dry. Should I attempt to pack with grease, straight 30 SAE oil, heavier oil (EP90) – or does it not really matter.?? Thanks.

[Roger Owen 5Participant @rogerowen5]

Old Pinnacle bench grinder bearings a bit noisy / dry.

[not done it yetParticipant @notdoneityet]

It would not matter if you changed them for new (non-chinese) bearings. I would.

[John RuddParticipant @johnrudd16576]

More than likely, the bearings will be sealed for life types….So how do you envisage adding grease/ oil?

As ndiy suggests, replacements would be a far better option.

A new grinder from Screwfix is less than £20, as another consideration….?

[HopperParticipant @hopper]

+1 on suggestion to replace bearings. Bearings don't usually "sound dry". If they are noisy, they need replacing as suggested. Get good brand name bearings such as SKF etc. not cheapie no name far eastern items off the interweb that are of unknown quality.

You will find a lot of bench grinders use the steel shielded bearings, which are not 100 per cent sealed due to small gap around the ID of the shield. This is to reduce torque requirements on start up. But it does allow some grit to get in. Nonetheless, best on the motor to replace with same type of bearings you take out.

Edited By Hopper on 01/07/2017 02:00:14

[Swarf, Mostly!Participant @swarfmostly]

Posted by John Rudd on 30/06/2017 21:15:24:

SNIP!

A new grinder from Screwfix is less than £20, as another consideration….?

But, before you buy, make sure you're comparing like with like. Your present grinder probably has a half-horse motor (maybe continuous-rated) whereas many of the cheapies are rated at 150 Watts or thereabouts and with a 25% duty cycle. When you present the tool-bit to the wheel, you need the grinder RPM to stay high enough for the wheel to cut properly.

Best regards,

Swarf, Mostly!

[Roger Owen 5Participant @rogerowen5]

Posted by John Rudd on 30/06/2017 21:15:24:

More than likely, the bearings will be sealed for life types….So how do you envisage adding grease/ oil?

As ndiy suggests, replacements would be a far better option.

A new grinder from Screwfix is less than £20, as another consideration….?

My old grinder was bought new by me in 1983 when equipeing a Special Effects Film workshop for my engineer who specifield only the best of everything – Start-Rite band saw and pillar drill, Myford Super 7 Lathe etc., etc, so I guess the massive British made Pinnacle bench grinder was considered to be the best at the time. It's been laid up for the last 30 years. I can see the balls by looking in and I should be able to pack in some grease with the blade of a medium sized screw driver blade – got to be worth a try.

[SandgrounderParticipant @sandgrounder]

I should be able to pack in some grease with the blade of a medium sized screw driver blade – got to be worth a try.

Not too much though, the majority of bearing failures are down to having too much grease in them.

John

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