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[320i S]

premise: I am evolving a prototype stage project in series production; in this project, I have a lever whose core is a 40mm 36crnimo4 round very long (900mm+) that I had to support at the ends with 2 ucfl 208 flange bearings.
the round is exposed to the weather and I have to protect it with nickel from 25micron.
the problem is that the bearings are in interference at the time of assembly, for the whole length of the round, then bring the processing of the round to the correct size considering the nickeling, turns out to be expensive.
the solution at the most thrown moment, is to work the bearings internally, "picking" those 5, 6 cents.

my question is (not finding info on the site skf and similar): exist ucfl 208 bearings whose inner tolerance is in positive at least 50micron to allow for assembly without having to work?
Thank you.

 

[MassiVonWeizen]

I know that you can take more or less precise bearings, but I don't think they can be taken with positive bin tolerance
and if I put a bigger support by interposing a ring between this is the tree? the ring would do it with the hole with interference so that it does not move while the outer diameter would be as from project

 

[MassiVonWeizen]

but it is not clear if the round is 40 from trade.
Can't you take it bigger and work it to the extent necessary to go to tolerance after treatment?

 

[320i S]

I know that you can take more or less precise bearings, but I don't think they can be taken with positive bin tolerance
and if I put a bigger support by interposing a ring between this is the tree? the ring would do it with the hole with interference so that it does not move while the outer diameter would be as from project

on a combined bearing, the other is mounted internally to the structure, I would not be able to mount the inner ring blocking it on the tree.

 

[320i S]

but it is not clear if the round is 40 from trade.
Can't you take it bigger and work it to the extent necessary to go to tolerance after treatment?

the round is a 40 commercial reclaim, I hoped that in tolerance h11, it allowed me to "absorb" the thickness of the nickel, but this can happen, as not to happen and in production can not have a discontinuous adjustment, it goes of the times of assembly and saturation of the post.

the idea would also be the working of the round, but it is costly because of the final length of the piece, among other things I lose part of the reclamation.

 

[marcofor]

you could estimate centerless grinding, the material to be removed is a few cents probably more the cost of placing than processing.
In the past I used to make mould rods of a ø32 nitriding material even 1500 long and remove 1 mm of less expensive centeless than turning them, with precision results and straightness not thoughtable in turning.
the reclaimed round undergoes treatment at heart is not a problem you can find differences according to the diameters but are minimal, unless you mean tempered bar then the induction hardening part is about 1 mm deep.
you could also evaluate the chrome bar is in tolerance f7/h7 the problem is that the 2 faces would remain untreated

 

[320i S]

I finally bring back the choice made:
- the measure with tolerance to be achieved, can only be achieved with rectification, so the round of the lever is too expensive as processing seen numbers (200 pieces year)
- Faster and less expensive result to resume hand bearings with abrasive grinding (no cylindrical precision required) with a few minute processing time
- for rapid control, I designed a "pass/do not pass" check pad where I decided the measurements of the pads, based on a sample of 8 hand-crafted bearings, which fit perfectly with 2 test rounds.