needle roller bearings

[Douglas JohnstonParticipant @douglasjohnston98463]

[Douglas JohnstonParticipant @douglasjohnston98463]

I have been reading the latest copy of MEW (217 ) and on page 9 in the article about updating the universal pillar tool the auther mentions having to increase a bore from 0.551 " to 0.554" in order to fit a needle roller bearing.

I seem to remember reading that needle roller bearings should be a press fit so that they then provide the correct internal diameter once fitted. If this is correct the bore should have been left at 0.551" and the bearings pressed in.

Does this make sense or am I talking rubbish?

Doug

[Clive FosterParticipant @clivefoster55965]

Press fit is more to ensure that the bearing is properly supported than for adjustment of internal diameter. The thin outer race provides next door to no support for the needle rollers under load so press fit lets the forces go straight through the outer race into the main body. Any slackness or uneven fit will let the outer race distort as the needles move past it which will eventually walk the bearing out.

For best results you have to go by makers data for bore and shaft size. Which is why its always best to go for a decent, branded, bearing rather than generic. However tempting the price. Even small enough differences to be within generic specification can have considerable impact on performance and life.

That said most of the applications we put them to will be of the looks right variety and, from the viewpoint of aprper bearing engineer, ridiculously conservative in bearing rating relative to actual loads. The silly optimistic designs (bin there, dunnit) tending to be qietly ignored and not mentioned outside the shop.

Clive

[Ketan SwaliParticipant @ketanswali79440]

Douglas and Clive,

I have yet to read the article properly, but in principal, you are right Douglas. I think that the author may have made a mistake, but I am not a 100% sure. I am not an engineer, so it will take me some time to read and understand what he is saying.

I think he is referring to a Drawn Cup Needle Roller Bearing (D.C.N.R.B) HK1010 – which is a metric bearing – 10mm x 14mm x 10mm. if so, many people make the mistake of measuring the OD of such bearings and opening up the housing to accommodate.

1. A D.C.N.R.B. gets its support from the housing in which it sits. As is, before fitting, the outside diameter is likely to be greater than 14mm. This type of bearing has to be press fit into a housing, using an appropriate mandrel. the housing diameter has to be between half a thou to a thou smaller than the outside diameter of the D.C.N.R.B., depending on how hard or soft the housing material is.

2. to prove point 1, take the bearing and put it onto a 10mm shaft, and you will see/feel it rattle. You make a 10mm diameter mandrel T shape/top hat to suet hole diameter, for the purpose of press fitting. When you press fit the bearing into the housing, the needles will 'compress' onto the shaft of the mandrel, to get correct fit. After the D.C.N.R.bearing is fitted correctly into the housing, you will find that a 10mm shaft will go through it with a perfect fit.

3. one should not open up the housing to the outside diameter of a D.C.N.R type bearing. One should not use loctite for fitting these specific type of bearings – unless it is a 'bodge'.

4. All good D.C.N.R.bearings and one way clutch D.C.N.R.bearings are stamped with a bearing number. When inserting such bearings into a housing, the 'pressing' should be done on the side which has the bearing number marked, as this 'end' of the drawn cup 'plate' is hardened, specifically for the purpose of 'press' fitting.

I have often come across this problem/mistake, especially with lubricators where one way D.C.N.R.clutch bearings are used, and the user complains of 'slippage' over time.

Hope the above information helps.

Ketan at ARC.

[Ian S CParticipant @iansc]

Some time ago  ME ran an article on bearings / needle rollers, fitting and type of shaft etc.

2004 Vol 193 no. 4237

2005 Vol 194 no 4249 / 4250

                           4241 / 4250

There are quite a few references to needle rollers, and others.        Ian S C

Edited By Ian S C on 03/06/2014 14:29:00

[Ketan SwaliParticipant @ketanswali79440]

In MEW 218, page 42 – the author (Updating the Universal Pillar Tool) refers to bearing dimensions in Table 1. He also talks about the supplier but doesn't wish to advise the suppliers name. This is fine, as the matter is between him and his supplier. I am reasonably confident that he did not buy from ARC, and I don't know in which country this author lives.

However, it would be good if authors – now and in the future – at least write the bearing numbers relating to the sizes mentioned, and advise/confirm if the said bearings have shields (zz) or rubber seals (2RS). This would help the reader to source the correct bearings from where ever they wish. It also helps the bearing supplier to identify and supply the correct bearings quickly. I am sure that the authors supplier would have mentioned bearing numbers on the invoice/delivery note.

For those who are interested, 'I think' that the bearing numbers the author is referring to are:

1pcs x 608-zz or 2RS – 8x22x7mm – Metric Ball Bearing

2pcs x 6203-zz or 2RS – 17x40x12mm – Metric Ball Bearing

2pcs x HK1010 – 10x14x10mm – Metric Drawn Cup Needle Roller Bearing

These are 'common' bearings which any bearing dealer around the world will recognise. It is irritating/difficult for bearing dealers to identify what the buyer is asking for if an inquirer just asks by measurements – quoting both metric and inch measures for what ends up being a metric bearing, and please be aware that if you approach certain dealers with sizes alone, it gives them the opportunity to name their price…which could end up costing you more, because you don't know what it is!…the more you know, the more the price comes into line.

The prices for above bearings are listed on ARC's website. Current prices from ARC:

1pcs. 608-zz x 80p, or 608-2RS x £2.20 each – so which one would you use?..It does not really matter for this application.

2pcs. 6203-2RS x £2.00 each – (ARC does not do zz in this size)

2pcs. HK1010 x £3.64 each

Total cost for these bearings: £12.08 (if 608-zz) + £3.95 = £16.03 (~US$27.25) to U.K. Mainland destination.

Total cost for these bearings: £13.48 (if 608-2RS) + £3.95 = £17.43 (~US$29.63) to U.K. Mainland destination.

The same package cost the author US$45.00. I do not know if he imported the bearings. If so, international shipping cost for 'secure-registered' airmail are not cheap!…but then again, we have no idea about what method was used by the seller to send him goods, nor do we have any idea of what origin/brand of bearings were supplied. However, I do agree that the seller should have clarified the shipping costs (as ARC does), before the buyer confirms the order and pays. Then it is up to the buyer if he accepts the costs, even if they are 2/3s of the price of the goods…as can be the case.

For the current stocks of bearings supplied by ARC, the ball bearings are or Chinese origin – for which we are very happy with the quality, and the HK1010 are Torrington manufacture of German/Japanese or US origin.

The reader will find different quality/origin/brand/price from who ever they wish to buy from, but my point is that the authors should really try to state bearings numbers where ever possible, to allow the reader to source the correct bearings from where ever they wish. Generally, these are not hard to find bearings in any country, provided you know the bearing numbers.

Ketan at ARC.

[JasonBModerator @jasonb]

Postie must get to you early Ketan, 218 is not yet available online let alone paper?

I think the Author is American hence why he talks about using metric bearings in the predominantly imperial US and his thread sizes would back that up

 

Edited By JasonB on 28/06/2014 13:52:04

[Neil WyattModerator @neilwyatt]

> Postie must get to you early Ketan, 218 is not yet available online let alone paper?

All together… "OH YES IT IS!!!!"

Seriously, David is in the US, which is why he added the inch measurements. I'll bear in mind the idea of including bearing codes – applies to things like belting and some pulleys as well..

Neil

[Ketan SwaliParticipant @ketanswali79440]

Posted by JasonB on 28/06/2014 13:47:22:

I think the Author is American hence why he talks about using metric bearings in the predominantly imperial US and his thread sizes would back that up

Edited By JasonB on 28/06/2014 13:52:04

Ok then that would make sense, along with Neil's confirmation.

thanks, Ketan

[JasonBModerator @jasonb]

Posted by Neil Wyatt on 28/06/2014 13:59:47:

> Postie must get to you early Ketan, 218 is not yet available online let alone paper?

All together… "OH YES IT IS!!!!"

 

On No its Not or does MEW come out in print before online?

Edited By JasonB on 28/06/2014 16:28:12

[Michael GilliganParticipant @michaelgilligan61133]

Received my paper copy in today's Mail.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 28/06/2014 13:59:47:

… including bearing codes – applies to things like belting and some pulleys as well..

Neil

.

Please do, Neil

Listing the standard codes for any generic components used in a design would be a great help.

MichaelG.

[John Stevenson 1Participant @johnstevenson1]

You must have an old computer Jason

[V8EngParticipant @v8eng]

Clicking the magazines link on the green banner at the top of this page only goes to issue 217.

Perhaps I have an old computer as well!

[Michael HornerParticipant @michaelhorner54327]

Posted by John Stevenson on 28/06/2014 17:18:35:

You must have an old computer Jason

John

What are those dotted lines at the bottom of the mag outline?

[martin perman 1Participant @martinperman1]

I recieved my magazine in the post this morning but electronically 217 is the latest.

Martin P

[John HinkleyParticipant @johnhinkley26699]

My magazine link and the digital app on my iPad still only gives access to MEW 217, too. Can't understand how this can be, though, as John S has a screenshot of 218 – or is he a time-traveller?

John

[JasonBModerator @jasonb]

Posted by Michael Horner on 28/06/2014 17:48:27:

What are those dotted lines at the bottom of the mag outline?

Looks like John cut along the wrong dotted line when he was cutting and Pasting, another bodge job that can't be hidden with a big bead of weld

[John Stevenson 1Participant @johnstevenson1]

Jason,

No idea ? The lines are not there on the screen but appear when you do a screen grab ?

Just taken this shot with my phone.

No lines ?

Probably the weld has had time to dry ?

[Neil WyattModerator @neilwyatt]

It's a good job our designers can do a better job of retouching!

The print one definitely hit many doormats this morning. This is the first time I've received my paper copy before people have seen the digital version.

The digital issue release date is set as 4/7./14, but i think that's just the archive version. The subscription version should be out already, but i suspect it's been delayed as they are moving the MTM offices to Sevenoaks and the server (with the master copy on it) is still offline.

I hope that the digital editions will all be made available ASAP, but I have no way of checking when this will be.

Neil

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, mine copy arrived this morning also at about half nine.

Regards Nick.

[Chris TriceParticipant @christrice43267]

Going back to the original topic, I’ve had needle roller bearings that have had instructions included stating what diameter the hole needs to be bored and also explaining that once pressed in, the bearing assumes the correct size for the shaft it’s nominally designed for. As someone previously stated, if you slip the bearing over a correct sized shaft before pressing it in, it’s a slack fit but once pressed in to a correctly sized bore, it holds the shaft perfectly.

[Ian S CParticipant @iansc]

Either the place that sells you the bearings, or a site you find on line will be able to tell you the size required for bear hole, and shaft sizes, the catalogues I,v seen will have all the information and procedures for fitting each type of bearing. Ian S C

[Author]

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