Surface for Needle roller bearing

[Alex CollinsParticipant @alexcollins55045]

Hi All
My nice motorcycle dealer​ supplied me a nice 18mm bore SKF needle roller bearing and a lump of rough and rusty mild steel as the center.

As the bit of Mild steel was like £30 I suggested that they can have it back. They agreed.

1 Length of 18mm Silver steel bought, Drilled and cut to length.

Do I need to Harden the Silver steel ?
Do I then need to temper it ?
Or can I use it as is ?

The bearing is part of the suspension linkage. High Load but very little movement.

Thanks

Alex.

[Alex CollinsParticipant @alexcollins55045]

[Boiler BriParticipant @boilerbri]

 

The liner that they run on is very hard usually, I use them in trip clutches to engage ball bearings. If you put them on anything medium hard it will wear quickly. 

As they are small I could let you have one etc?

It he bore is 18mm what could you go down to, to accept a sleeve?

Bri

Edited By Boiler Bri on 07/08/2015 19:00:39

[Neil WyattModerator @neilwyatt]

There was much discussion of using plain silver steel as a loco axle with roller bearings in ME some years ago. As I recall the definitive test was a loco which had used this arrangement for donkey's without detectable wear.

Obviously if you have to turn it down, avoid a sharp inside corner and go for as good a finish as you can get.

Neil

[JAParticipant @ja]

What happens if it fails? Could you be dead?

It strikes me that silver steel is very much the wrong material. Perhaps use it as a hardened sleeve but better still would be case hardened mild or low carbon steel. Mild steel generally bends before it fails unless a crack is present. As Neil says, no sharp fillet radii (fatigue cracks readily start from such corners).

As someone on this forum said recently silver steel (actually he was referring to gauge plate) is a tool steel.

JA

[Boiler BriParticipant @boilerbri]

Yep if travelling at high speed your dead because stopping kills you😈

[duncan webster 1Participant @duncanwebster1]

you can buy rod specially made for running bearings on from

http://www.bearingboys.co.uk/Linear_Shaft-3782-c

it's pretty hard so depends how much machining you need to do. I seem to remember that it's surface hardened only

[Alex CollinsParticipant @alexcollins55045]

Hi.
The insert is 25 mm long. 18mm OD 10 mm ID. 10mm bolt through the middle. Total Failure would be interesting but certainly not cause for major concern. ​

No turning down involved. Drill 10 mm hole. Cut it off and tidy up.

Loco axles rotate full turns. This will only ever rotate about 1/8 of a turn.
The worn original is hard – file bounces off even in the worn areas. That leads me to think it wasn't case hardened.

The replacement was that rough it looked like rebar – seriously it wasn't fit for the job in my book.

I'm going to drop it in raw. See what happens. If it gets loose I can put a hardened and tempered one in.

Thanks

[BowberParticipant @bowber]

I know the exact part your talking about.

I've hardened and tempered them just to take the edge of the hardness, quick scim over with wet n dry, take note of the polishing in the lathe thread, and then used them for years.

My bikes have been used off road so the bush is getting a lot more hammer than it would on the road.

Steve

[AjohnwParticipant @ajohnw51620]

Needle rollers usually run on a hardened surface – they can be bought with the inners or the inners can be bought separately as here

**LINK**

They are made to rather tight limits.

John

–

[Alex CollinsParticipant @alexcollins55045]

Hi All.

None of the web links are able to supply a suitably sized inner.

It's gone in Raw for now. I'll see what it looks like in a few weeks.

I'll make another, Harden and temper it if need be.

Thanks to all who responded. ​

[OuBallieParticipant @ouballie]

Talking about silver steel reminds me of the time my Dad raided my steel supply stock to make axles for the luggage trolley he was building, prior to Mom and he going on their European jolly.

Beautiful job he made as usual, much to my 'annoyance' as I was never that capable, but the moment he loaded the trolley, both axles snapped.

We look at each, then the penny dropped when I saw he had welded the axles on.

"What steel did you use?"

"Some of that nice shiny stuff in short lengths"

"Bad move, it's silver steel and hardened when you cooled it after welding, did you?"

Yep he did, and I burst out laughing, much to his annoyance.

Lesson learned, he never touched the stuff from then on.

Geoff – I was over the moon, as I for once, was able to teach him something.

[Tim StevensParticipant @timstevens64731]

What you need to avoid (to give one example) is a bearing inner surface which is not hard, after some miles the rollers dig in, and the bearing ceases to turn. Then the load comes on the end of the suspension damper, and after a few more miles it snaps off. The suspension unit then digs into whatever is around, – perhaps the wheel, and the back end locks up. Is your dealer the only possible source of a genuine replacement?

Regards

Tim

[Alex CollinsParticipant @alexcollins55045]

Moto-Guzzi supplied me genuine Guzzi parts through my dealer.

The original Inner has worn. I wanted to replace the bearing (which was probably fine) and the inner.
The bearring supplied is SKF and of fair quality. More than adequate.

The inner should have a smooth and hardened surface. The inner supplied had neither. It was rough as hell, rusty and very poorly made.

That is why I returned it and made one myself. More and more people are suggesting it should be hardened and tempered ( to straw colour I guess).

Looks like i'll be pulling it apart again and replacing the inner with a hardened and tempered one…….

​

[duncan webster 1Participant @duncanwebster1]

you can get 18mm OD, 25.5mm long, 15mm ID from

http://simplybearings.co.uk/shop/Bearings-Needle+Roller+Bearings-Needle+Roller+Inner+Rings/c3_29_35/index.html

just make a 15mm OD 10mm ID bush and press it in If you really can't cope with the excess 0.5mm on length someone with a surface grinderv will be able to take a bit off.

[Author]

Posts