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I am building a French-cleat mounted grinding system (see video below) from a motor for the purpose of sharpening and honing woodworking chisels and what seems to be a couple of "pillow blocks" with a shaft going through both. I'm not certain these so called "pillow blocks", because of this: The inner "thing" (maybe it is called a "bearing", which seems might be made of brass) does not actually move which is surprising to me, because at the top of the "pillow block" are oilers, which I've filled with motor oil, but that had no effect on the moving of that inner "thing".

Looking into the shaft of that inner "thing", I do not see any spiral flutes or holes that would dispense any oil. Had there been such a spot for delivery of oil, then I could understand why those inner "things" would not, or should not, rotate, because the inner shaft would rotate and then the oil be dispensed around the outer surface of the shaft through those holes.

So, are these pillow blocks, or some other type of thing I've not seen before? And is that inner "thing" actually supposed to move, or not?

enter image description here

enter image description here


French-cleat mounted grinding system

It has recycled hinges underneath the bottom plywood that the old motor is bolted to, from the underside:

Video of French-cleat mounted grinding system

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  • If someone can point me to a stack exchange site whereby this question is more appropriate, or if someone can simply move this question there, that would be fine. I thought of woodworking stack exchange, as this is intended to be used for woodworking (i.e., sharpening and honing chisels mostly), but I suspected it would be flagged as off-topic given its "machining" bent.
    – bgoodr
    Apr 9, 2023 at 0:31
  • It's more on topic in woodworking than here in home improvement ...
    – keshlam
    Apr 9, 2023 at 0:51
  • What you've pointed to may be the outer ring, which does not move. The inner ring, which may be hidden, rotates with the shaft (as I think you know).
    – SteveSh
    Apr 9, 2023 at 0:55
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    That looks more like a bushing, not a bearing. The copper colored part is not supposed to spin.
    – RMDman
    Apr 9, 2023 at 0:56
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    Also, is that a grease fitting (zirc?) on top, or just an opening for oil? If the assembly is just a bushing then maybe oil as a lubricant makes sense. If it's for grease, that's usually used to lube ball or roller bearings.
    – SteveSh
    Apr 9, 2023 at 1:00

1 Answer 1

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What you have there is a sintered bronze bearing pillow block. What you probably need is a ball bearing pillow block.

Sintered bronze is made by filling a mold with bronze powder, then subjecting it to pressure and sometimes heat to form the desired article. Sintered bronze is porous. It will absorb a lot of oil and release it slowly over time. Light machine oil is the usual lubricant.

The shaft that you installed will quickly destroy the bearing because of its rough finish. Sintered bronze bearings work best with hardened steel shafts that have been ground and polished to a mirror finish.

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  • Thank you. I have observed that the shaft surface has developed what seems to be to be a black surface. Maybe that is the effect of that shaft being worn away by that bearing. Now, since I acquired these bearings for free, and they seem to be fairly cheaply made, I may just let it wear out on its own and see how long it takes to get worn.
    – bgoodr
    Apr 9, 2023 at 2:11
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    You want to top the oilers up before starting to use the tool each day - something like 20W to 30W oil is typical. An oil can is pretty much part of the tool (or part of the shop if you have more than one such set of bearings in the shop.)
    – Ecnerwal
    Apr 9, 2023 at 14:38
  • Yep, and that will be either (a) something I know that I'll forget to do each time, and/or (b) be a chore that will become an annoyance. Either way, now I'm starting to "see the light" in MTA's answer here whereby he stated "What you probably need is a ball bearing pillow block". But for right now, I'm having fun being a royal cheapskate to see if I can build something for free (sans the cost of the 1/4-20 nuts and bolts) as all of the other stuff in the whole thing was from a free pile (see video link I appended to the original question).
    – bgoodr
    Apr 9, 2023 at 15:25
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    @bgoodr Not to pile-on, but just another factoid for you: these bearings also work real well for sliding shafts in addition to rotating shafts. If you don't install some kind of retainer to prevent the shaft from moving horizontally, then the only thing preventing left-right movement of your wheels in use is belt tension. So no cup wheels and probably no buffing wheels. Ball bearing pillow blocks can be had with a cam-lock that bites into the shaft or with setscrews.
    – MTA
    Apr 9, 2023 at 15:53
  • @MTA True. I have retainers that attach to the shaft with setscrews, but I would not rely upon them for much other than for orthogonal forcing, not axial.
    – bgoodr
    Apr 10, 2023 at 20:41

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