Has anyone got any advice on Bearings?

[symatic]

I am starting this as a new thread separate from the 14B thread as it's a specific question....

I've just cleaned the bearing from under the platter on the Presto 14B, and it looks like it's missing some parts.

it's just 11 ball bearings rolling around freely, and they've impressed a groove into the parts they contact, so I am trying to figure out what to do.

Does anyone have any knowledge about these things? I'm guessing anyone with a Presto 8DG or similar might have the same type of Bearing Assembly...

anyway, heres some pics of the setup before and after cleaning, and the shaft with it's groove worn into the underside.

[Jccc]

i dont own a Presto 14b. But from the pictures you posted the loose balls in the Bearing kinda remind me of the loose balls in threaded headsets for Bicycles.

With the threaded headsets on bikes if you over tighten them it will cause it to not move as smoothly and cause indentation in the cups causing binding and damage.
If you have it too loose it will have alot of play and could cause damage as well.

Is there a way to adjust how loose you can set the bearings on the machine?


Also if you can measure the diameter of the ball bearing you could find a replacement for them.

i wonder if you could change it out and put a sealed bearing in it similar to skate board bearings?

[symatic]

Thanks for the reply
I am thinking about replacement, could be the way to go, especially if these ball bearings are all worn...
I really wonder how it’s supposed to work with those two big screw holes in the path of the ball bearings.... but also, what WOULD those holes be for? Some sort of mounting for a smaller bearing or the bottom half of a race assembly?
This machine gets more complicated the closer you look haha

[symatic]

Oh and about the skateboard bearings and bike bearings... yes they look similar to things ive encountered trying to research this online... but those bearings take loads at 90degrees to this... i need a thrust bearing i think, designed to take weight from above.

Funny its you replying - was just listening to one of your albums on my walk home

[boryo]

Maybe it is worth to search for some mechanical school/university in your area and get in contact with some of the machinists working there.

[Soulbear]

[quoteI really wonder how it’s supposed to work with those two big screw holes in the path of the ball bearings.... but also, what WOULD those holes be for?][/quote] I hope I've viewed and interpreted the images correctly
In many pieces of industrial type equipment, and even in some other domestic items where bearings are fitted ito "Blind Housings" the "Conventional Wisdom" is that the two threaded holes are machined into the "Bearing Housing" at the time of manufacture, simply as an expedient to facilitate "Ejecting" the Bearing from its housing for maintenance/ replacement in the future.
Set screws/bolts are entered into the housing from the opposite side, utilising the threads holes, and press upon the bearing "Ball Race" to make removal of the bearing easier. The "Ball Race" being the name of the Grooved component in which the Ball Bearings carrying the load run Smoothly. This looks to be what is termed a "Thrust Type Bearing" designed to perform well with the load applied vertically, inline with the shaft, rather than at a right angle to the shaft, as would be the case in say a "Foot Mounted" electric motor. Hope this helps Soulbear

[juba bc]

I would try one of these https://en.wikipedia.org/wiki/Thrust_bearing

[symatic]

Thanks for the clues guys! a few things for me to research. Soulbear thanks for clearing up some terminology too!

[dmills]

Is there not possibly a missing ball cage?

Ordinarily I would expect the balls to sit in a metal or plastic spacer ring that keeps them from touching, but that is clearly an old bearing so this may or may not have been a feature of that design.

Regards, Dan.

[symatic]

I think there could have been a ball cage, but possibly not, it seems some bearings can work without them, BUT there's no proper race or groove for the ball bearings to move in, and the one you can see there looks like its just worn into the bottom of that housing. I think there's a whole section missing that would have held a more smooth raceway for the ball bearings.... but that's gonna be a custom part i reckon

[Soulbear]

BUT there's no proper race or groove for the ball bearings to move in, and the one you can see there looks like its just worn into the bottom of that housing. I think there's a whole section missing

Nooooooooooo!!!! Surely Not???

Bearing.jpg

This is the "Ball Race"" unless 50 years after I did my Engineering Apprenticeship I've now developed a Bad Case of Pre-Senile Dimentia?? (Lord above, I don't want That AGAIN!!! Soulbear

[symatic]

Thanks for taking a look Soulbear - I thought the same when I first looke at it, but when I cleaned the Ball Bearings and what looked like the Race, it turned out it was nothing more than a pile of old grease that had formed into the shape of a race.... underneith it was nothing but the flat base you see in the lower pictures.
The Ball Bearings were just rolling round the bottom af that well, with no bearing races, no housing, nothing but old dirty grease! as you can see they've worn a circular groove into the well they were sat in, but they were just rolling over those two screw sockets too! horrible!
So I think I need to get a bracket manufactured to hold a proper Thrust Bearing, and that will have to be press-fitted to the shaft I think. As you can see from the other picture, the Balls have worn a shoulder into the black Thrust Plate on the drive shaft.

worst case scenario I will have to replace that whole assembly urgh!