Bearing fit

This topic has 18 replies, 8 voices, and was last updated 19 October 2019 at 08:29 by Michael Gilligan.

Viewing 19 posts - 1 through 19 (of 19 total)

Author

Posts
18 October 2019 at 16:41 #433840
IRT
Participant
@irt
I am staring to build the Myfordboy's hacksaw.

My first proper project. Expect quite a few questions to come…

My first one regards the fit of a bearing – both into a housing and onto a shaft.

I far as I can understand, the published tolerances are in a few um for small bearings. I cannot even measure down that small.

Would an acceptable approach be to machine to allow an easy press fit by hand then fit with a retaining compound like Loctite 641 or is there a better way?
Advert

18 October 2019 at 16:41 #9895
IRT
Participant
@irt
18 October 2019 at 16:46 #433842
David Noble
Participant
@davidnoble71990
Yes Ian, that's certainly the approach I would take.

David
18 October 2019 at 16:48 #433843
Michael Gilligan
Participant
@michaelgilligan61133
641 ‘Bearing Fit’ is wonderful stuff !!

MichaelG.
18 October 2019 at 16:51 #433844
IRT
Participant
@irt
That was fast!

Thanks.
18 October 2019 at 16:59 #433846
old mart
Participant
@oldmart
Loctite 601 or 638 are quite fast curing, but if you need more time to assemble things, then 620 is your best bet.
18 October 2019 at 16:59 #433847
Michael Gilligan
Participant
@michaelgilligan61133
It’s an easy answer !!
18 October 2019 at 17:02 #433848
Michael Gilligan
Participant
@michaelgilligan61133
Posted by old mart on 18/10/2019 16:59:22:

Loctite 601 or 638 are quite fast curing, but if you need more time to assemble things, then 620 is your best bet.

.

Be that as it may … but why wouldn’t you use ‘Bearing Fit’ for fitting bearings ?

MichaelG.
18 October 2019 at 17:02 #433849
IRT
Participant
@irt
I will start you off easy – they will get harder.
18 October 2019 at 17:08 #433854
Michael Gilligan
Participant
@michaelgilligan61133
18 October 2019 at 17:11 #433855
old mart
Participant
@oldmart
Loctite 601, 620 and 638 are part of their extensive range of BEARING FIT PRODUCTS.

Edited By old mart on 18/10/2019 17:11:41
18 October 2019 at 18:28 #433864
David Noble
Participant
@davidnoble71990
Posted by Ian Thomson 2 on 18/10/2019 17:02:11:

I will start you off easy – they will get harder.
18 October 2019 at 18:56 #433868
JasonB
Moderator
@jasonb
Posted by Michael Gilligan on 18/10/2019 17:02:02:

Posted by old mart on 18/10/2019 16:59:22:

Loctite 601 or 638 are quite fast curing, but if you need more time to assemble things, then 620 is your best bet.

.

Be that as it may … but why wouldn’t you use ‘Bearing Fit’ for fitting bearings ?

MichaelG.

If you had a high temperature requirement then 638 will retain its strength for longer than 641 and 648 will be even better at higher temps.

638 will also tolerate a larger gap than 641 which may be handy for poorly fitting parts or where a housing has become worn.

Or like a lot of people who may not need to fit bearings very often they may just reach for what they have on the shelf rather than pay for a bottle if it is a one off job. 638 is also less likely to need an activator on passive materials then 641 so no need to buy activator.

Edited By JasonB on 18/10/2019 18:57:29
18 October 2019 at 20:24 #433879
Michael Gilligan
Participant
@michaelgilligan61133
Thank you for not ‘shouting’ Jason

I agree that, according to the circumstances [*] all of the products you mention may be viable alternatives to ‘Bearing Fit’ … but for the job that Ian is contemplating, it does seem the obvious choice.

MichaelG.

.

[*] BMW for example specifies 638 for retaining certain bearings on the Superbikes.
18 October 2019 at 21:19 #433886
Ron Laden
Participant
@ronladen17547
I am a big fan of 638, it cures quite quickly probably too quick if you have adjustments to make but in some assembly situations the speed can be a bonus. It has good gap filling up to 0.25 mm if I remember correctly and the cured joint is extremely strong. For permanent fixing and retaining of parts 638 is the one I always use.
18 October 2019 at 21:38 #433888
Michael Gilligan
Participant
@michaelgilligan61133
Posted by Ron Laden on 18/10/2019 21:19:23:

I am a big fan of 638, […] For permanent fixing and retaining of parts 638 is the one I always use.

.

Likewise, Ron [for several decades]

But I maintain that ‘Bearing Fit’ is generally more appropriate for fitting bearings.

MichaelG.

.

Edit: Quoting from the 641 Technical Data Sheet:

“LOCTITE® 641 is designed for the bonding of cylindrical fitting parts, particularly where disassembly is required for service operations. The product cures when confined in the absence of air between close fitting metal surfaces and prevents loosening and leakage from shock and vibration. Typical applications include retention of bearings onto shafts and into housings.”

Edited By Michael Gilligan on 18/10/2019 22:03:46
19 October 2019 at 03:44 #433901
Hopper
Participant
@hopper
Treacle works too. But takes a bit longer to set than Loctite.
19 October 2019 at 06:59 #433904
not done it yet
Participant
@notdoneityet
The area of the inner and outer surfaces can be considerable. Clearly a properly operating bearing requires “support” so needs a gap-filler when shafts/housings are out of spec.

Some consideration of this and the need to dismantle might be far more sensible than reaching for the strongest, most permanent offering available as the ‘dumb’ option for any and every instance a problem may arise?
19 October 2019 at 08:29 #433911
Michael Gilligan
Participant
@michaelgilligan61133
Well-said, ndiy

MichaelG.
Author

Posts