Author Topic: Machining a bearing housing clearance  (Read 3803 times)

Offline Spurry

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Machining a bearing housing clearance
« on: December 22, 2020, 05:34:26 AM »
This started out as a Could-You-Just sort of job for one of my neighbours. He mashes up apples to make juice and bottles it.
The apple machine has two bearings, one on either side of a rotating drum. They are sealed ball bearings 47mm diameter x 14mm with a 20mm bore for spindle.

Two new bearing housings are required, which have to be welded to an 8mm thick backplate.

There are no instructions, nor handbook as the machine is so old.

Would anyone have any idea what sort of fit to make the housings to the bearings? I was thinking of a tight push-fit, so that they could be replaced when needed, so housing would need to be ?? diameter.

Just to make it interesting, I cannot fit the bearings to the housings then weld them up as the seals would not like the heat. Not sure if welding would distort the housings either...

Any pointers would be gratefully accepted.

Offline mattinker

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Re: Machining a bearing housing clearance
« Reply #1 on: December 22, 2020, 05:47:34 AM »
Spurry,

Couldn't you use a flange mount bearings, 8mm would be plenty thick enough to tap and bolt to.


https://www.bearingboys.co.uk/Round-4-Bolt/FYC20TF-SKF-20mm-4-Bolt-Round-Flange-Bearing-with-Grub-Screws-90145-p

Cheers, Matthew

Offline Spurry

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Re: Machining a bearing housing clearance
« Reply #2 on: December 22, 2020, 06:36:07 AM »
Thanks for your thoughts Matthew. If it was my machine, it would be a good idea. The bearings have already been given to me by the owner. The other difficulty with the job is the construction of a gearbox casing on one side; it would have to be increased from the 60mm x 8mm to 100mm x 8mm for that type of bearing.
So my first hurdle is these bearing housings, and then hopefully onwards.

Offline MetalMagus

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Re: Machining a bearing housing clearance
« Reply #3 on: December 22, 2020, 07:02:22 AM »
SKF have a good handbook on all things related to bearings that can be downloaded for free as a pdf.

https://www.skf.com/binaries/pub12/Images/0901d1968013be94-SKF-bearing-maintenance-handbook---10001_1-EN%281%29_tcm_12-463040.pdf

Should have the info you need on clearances.

Offline John Rudd

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Re: Machining a bearing housing clearance
« Reply #4 on: December 22, 2020, 07:05:40 AM »
Pete,
I'd go for 47mm,( 1.8500 inches)  then deduct 1-2 thou from that ( 1.8498 ) for a press fit for the bearings into the housing....maybe warm them up a bit to make the bearing easier to fit....or if the hole is a bit slack, a bit of Loctite bearing retainer?

But cant the new housings be bolted in place rather than weld?  Make up a housing with a flange to bolt to the plate...3 bolts should be plenty enough ?

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Offline Pete.

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Re: Machining a bearing housing clearance
« Reply #5 on: December 22, 2020, 07:37:03 AM »
I'd make them a light press fit. If you mess it up then use bearing retainer it's good for a couple of thou and that's a very loose fit for a bearing.

Offline Muzzerboy

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Re: Machining a bearing housing clearance
« Reply #6 on: December 22, 2020, 09:15:19 AM »
Something like this https://www.arceurotrade.co.uk/projects/truloc/Truloc-271-Retainer.pdf

Use a torch or heat gun if you ever need to remove the bearing again.

Offline Spurry

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Re: Machining a bearing housing clearance
« Reply #7 on: December 22, 2020, 11:21:56 AM »
Thanks to everyone for their thoughts. I may end up having to use loctite to retain the bearings, it all depends on how accurately I make the housings, but that depends on what diameter I should aim for, as stage one.

Having read oodles of technical data from various (bearing) manufacturers, the amount of info is considerable, so I was rather hoping someone may have had a similar job to give an initial diameter to aim for. At present, choices are limited. If slightly too small and welding distorts things a little, it will never rebuild, so trying for a press-fit is beyond reach.

They say a thread is worthless without pics so, here's a some pictures to show the starting point...

Offline Sea.dog

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Re: Machining a bearing housing clearance
« Reply #8 on: December 22, 2020, 12:16:04 PM »
The first thing I notice is that you've a problem boring the gearbox bearing housing. Perhaps it would be easier to bore it out, from the outside, then make a sleeve, which you can weld in, then bore to it size. You could make a cap plate for the outside if the bearing doesn't have a seal.

Offline Pete.

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Re: Machining a bearing housing clearance
« Reply #9 on: December 22, 2020, 02:28:25 PM »
I would fit a new big bearing, and ream the hole round then fit a bronze bush and re-make the arm to suit.

Offline vintageandclassicrepairs

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Re: Machining a bearing housing clearance
« Reply #10 on: December 22, 2020, 02:51:29 PM »
Hi Spurry,
I would aim for size for size , 47mm, this should give a tight push fit plenty good for such a device,
and as said a drop of loctite if it turns out to be a bit slack
It looks like there was a lot of "juice " around turning the grease to mud ?? I would try some outboard motor water proof grease ??

John

Offline Spurry

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Re: Machining a bearing housing clearance
« Reply #11 on: December 22, 2020, 06:13:13 PM »
Thanks again for all the comments. The up/down play in the gearbox side bearing was 3 to 5mm. This meant that the plastic gear did not last long at all. The other shorter side was not quite so bad. The visible odd-shaped holes were caused by using the machine with really clapped out bearings, so one of my first difficulties was trying to locate the centres. All in all, I decided to start from square one, hence the question about bearing housings.

This was a slight understatement "It looks like there was a lot of "juice " around turning the grease to mud ?" Sums it up exactly! There is a photo of the contents, but to post would not be in good taste. :)

These pix show the story so far.

Offline Spurry

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Re: Machining a bearing housing clearance
« Reply #12 on: January 26, 2021, 03:24:33 PM »
Bit of an update.
A start was made on the new case. Unfortunately my metal bender had a max capacity of 50mm, but 60mm was needed. The only thing I could find to do the job was the log splitter, so that was 'adapted'. Fortunately both of the bends ended up quite square with almost no twist. (2&3)
(5) Shows the bearing housing, average of 4 readings on mill DRO showed undersize by 0.001mm. The other size was 0.019mm under. If the latter caused a problem, it would easier to remake that side. Main problem is that I did not want to risk the bearing fits, as they would have to be removed before welding the housings.
(6) Last dry fit before inserting bearing.
(7) Finally in place.
Still a few parts to sort out before completion.
Pete

Offline Sea.dog

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Re: Machining a bearing housing clearance
« Reply #13 on: January 26, 2021, 04:15:43 PM »
That looks like a nice job  :clap:

Offline vtsteam

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Re: Machining a bearing housing clearance
« Reply #14 on: January 26, 2021, 08:15:53 PM »
It does.  :clap:
I love it when a Plan B comes together!
Steve
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Offline John Rudd

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Re: Machining a bearing housing clearance
« Reply #15 on: January 27, 2021, 05:15:58 AM »
Great job Pete...nice touch adapting a log splitter... :bow: :bow: a bit of lateral thinking..
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Offline vintageandclassicrepairs

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Re: Machining a bearing housing clearance
« Reply #16 on: January 27, 2021, 03:01:09 PM »
Full marks for ingenuity  :clap: :clap:

John

Offline Spurry

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Re: Machining a bearing housing clearance
« Reply #17 on: February 25, 2021, 12:50:31 PM »
Thanks to all for the advice and comments. The job was finally finished today....good job I'm not on piecework.  :doh:
Picture shows completed assembly, but with all the safety/operating coverings removed.