Balls!

[Digit]

As in bearings! All bearings have a speed limit, anyone no what the upper limit for run of the mill ball races is please?

Roy.

 

[Jonzjob]

Best thing to do is give the maker a bell. I had to find some gen on SPK (I think) bearings and the guy there couldn't have been more helpful. Plus you will get good gen on the bearings you are think of...

 

[Digit]

Ta! The reason I asked is for a router, if I recall correctly 'normal' bearings are rated for about 15/17K rpm. I started my table router today and the top bearing 'hunted'.
I'm having a bad week with bearings, found out yesterday that the big ends on the bike I've been building are shot! One of those weeks!

Roy.

 

[Jonzjob]

Sorry to hear your problem with the bike Roy, but that don't arf remind me of an old joke :mrgreen: :mrgreen: :mrgreen:

Good luck mate!

Is it my imagination, or is there a lot of balls being talked of on the forum at the mo? :? :?

 

[Digit]

I'm not flipping laughing John, this blooming bike has been one problem after another, I just hope the crank is ok. Fingers crossed.

Roy.

 

[Jonzjob]

Big ends, roller bearings and fixed I suppose?

 

[Digit]

Being a 'V' twin John both big ends share the same journal, so if a regrind is on the cards that will help with the cost, mains are also shells. At the moment I'm too busy to strip the engine and find out how bad it is.
Being a rare machine the shells may be difficult to obtain, time will tell. The previous owner must have been the worst mechanic I've ever come across. If it turns out that there is no oil pump in it I won't be surprised!
Meantime I've got to change the fork seals on my other bike! Then there's the wife's new kitchen, or at least there will be when I repair the router!
All go innit?

Roy.

 

[Jonzjob]

What bike is it?

I have seen shells reformed and cut to size with nothing more than a ruddy great hammer, a cold chisel, a vise and a ******* file. That was on a Healey 100/4 in a machine shop in Kuala Lumpa in 1968 and that bearing lasted all the way from there to Veintian, Laos and back to Singapore in the 1st Asia Highway Ralley.

BUT, what a pig awful car the 100/4 was to drive and ride in!

 

[Digit]

Honda VT250.

http://www.motorcyclespecs.co.za/Galler ... F%2083.jpg

I bought it as seen and it looked great. Most of the problems were hidden under the tank, seat etc. Like 7 out of 10 dowels were missing, several 'O' rings, carb inlet stubs were damaged, the rad frame was broken, a crack in the lower crankcase, the oil filter retaining spring was on the OUTSIDE of the sump and sealed with silicon, 3 stripped threads, heat shield between rocker cover and coils missing, one missing and one broken exhaust stud, twist of wire to replace 'R' clip on rocker shaft, rear brake seized, oil lost from one leg, seals wrongly fitted to rear shock so bearings shot, harness damaged, horn U/S, part of clutch cylinder missing, brake pistons siezed, 11 water and carb hoses gone hard, carb inlet rubbers gone hard, Choke cables U/S.
I think you get the picture.
I've made new hoses, new dowels, 'o' rings, welded the rad frame, had the crank case welded.
I've reached the point of either giving up or accepting that I've put too much effort into it to give up now, and I don't normally give up!

Roy.

 

[sometimewoodworker]

Honda VT250.

http://www.motorcyclespecs.co.za/Galler ... F%2083.jpg

I bought it as seen and it looked great. Most of the problems were hidden under the tank, seat etc. Like 7 out of 10 dowels were missing, several 'O' rings, carb inlet stubs were damaged, the rad frame was broken, a crack in the lower crankcase, the oil filter retaining spring was on the OUTSIDE of the sump and sealed with silicon, 3 stripped threads, heat shield between rocker cover and coils missing, one missing and one broken exhaust stud, twist of wire to replace 'R' clip on rocker shaft, rear brake seized, oil lost from one leg, seals wrongly fitted to rear shock so bearings shot, harness damaged, horn U/S, part of clutch cylinder missing, brake pistons siezed, 11 water and carb hoses gone hard, carb inlet rubbers gone hard, Choke cables U/S.
I think you get the picture.
I've made new hoses, new dowels, 'o' rings, welded the rad frame, had the crank case welded.
I've reached the point of either giving up or accepting that I've put too much effort into it to give up now, and I don't normally give up!

Roy.

I hate to tell you this but I've had either 3 or 4 of these and the engine died at about 50,000km on each one. As I recall it was big ends each time. I didn't bother to repair them as low milage second hand bikes are cheap here. My CBR250 however has an engine that won't die (it won't start at the moment but that is probably plugs)

 

[Digit]

If I give you my address could you send me one? :lol:
They are very rare over here due to the change in learner laws back in the 80s, sourcing parts has been a nightmare.

Roy.

 

[sometimewoodworker]

If I give you my address could you send me one? :lol:
They are very rare over here due to the change in learner laws back in the 80s, sourcing parts has been a nightmare.
Roy.

I would but the shipping is outrageous :lol: It might even be more expensive than getting stuff locally.

 

[Digit]

Always assuming that I can get the parts of course.
Ball bearings, my local supplier confirmed that the the rev limit for normal bearings is 16K rpm, the higher limit ones have greater radial clearance apparently.

Roy.

 

[kirkpoore1]

As in bearings! All bearings have a speed limit, anyone no what the upper limit for run of the mill ball races is please?

Roy.

Depends on the size. Small ball bearings will approach 20K rpm, bigger ones may only be good up to 12K rpm. Shielded bearings will usually have a higher rating than sealed, and open bearings will be faster yet. Here's a chart from SKF:

http://www.skf.com/skf/productcatal...ableName=1_1_1&presentationType=3&startnum=10

If you look for the rows with the 6203 bearings, which I used in a router I worked on last year, you'll see the plain 6203 bearing has a speed rating of 24K RPM. This is an open bearing, though, and you won't want that because routers don't let you grease the bearings. The 6203-2RS and 6203-2Z bearings are shielded and sealed on both sides (can't remember which suffix means shielded and which is sealed, though), and the 62032RSL and the 6203-2ZZ are both good to 19K RPM. You can overspeed bearings to a certain extent--they just won't last as long. Don't put a 12K bearing in a 20K router, though--it will heat up and kill itself quickly (been there, done that).

What you need to do is either go to a local bearing supplier or an on-line source. Have your old bearing with you if possible, and measure bore, thickness, and outer diameter, and whether it has seals (plastic or rubber) or shields (metal). If you go local, you'll pay more, but you'll be able to talk to the guy at the desk and describe exactly your situation. He'll be able to check the RPM rating in his catalog. You'll also be able to tell him that you DON'T WANT Chinese bearings.

On line, you'll save money, but you're at the mercy of the site's search function and whatever they have in stock from whatever source. If they have different brands, stay with a known reputable brand like SKF, Nachi, Fafnir, or NTN.

In any case, router bearings are cheap. Don't buy bottom-end bearings unless you like to change them. Everything I've seen on Chinese bearing quality control is that it's all over the map and you don't know what you're getting. US, Japanese, and European bearings are much more reliable.

Kirk

 

[Digit]

Thanks for the info Kirk, I've changed numerous bearings in my time but till I got to routers the speed limitation was a matter only of acedemic interest.

Roy.

 

[Benchwayze]

As in bearings! All bearings have a speed limit, anyone no what the upper limit for run of the mill ball races is please?

Roy.

The speed limit for a ball-bearing depends on the strength of the (CAT)apault Roy!

yes, I know. It's against the law to frighten cats. I am only joshing of course.

John

 

[Woody Alan]

When I replaced my Elu bearings the lower bearing is a type "c" rated for radial thrust as opposed to the top bearing which handles any axial float. As I understand it. http://www.kaydonbearings.com/typesACX.htm

 

[Jonzjob]

As in bearings! All bearings have a speed limit, anyone no what the upper limit for run of the mill ball races is please?

Roy.

The speed limit for a ball-bearing depends on the strength of the (CAT)apault Roy!

yes, I know. It's against the law to frighten cats. I am only joshing of course.

John

Did you realise that a cat that has just had a pebble go past its ear can accelerate from 0 to about 40 mph in about 1/4 second. I don't think it's agin the law here :twisted: :twisted: Unless you get caught :roll:

Sorry, this has no 'bearing' on the thread. Hijack over

 

[Digit]

The obvious solution of course is to replace like with like, assuming that you can still read the info! Which I couldn't, but once I knew the RPM limit then I could fit a suitable replacement, of which I have now noted the number!
And talking about cats John, (who says we have to stick to the thread?)...

http://news.sky.com/home/uk-news/article/16147397

Roy.

 

[kirkpoore1]

And talking about cats John, (who says we have to stick to the thread?)...

http://news.sky.com/home/uk-news/article/16147397

Roy.

"There have been thousands of reported sightings of large felines on moorland and in woods and fields across the UK for centuries"

Hasn't anyone hit one with a car or shot one or something? They get hit by cars over here from time to time. Probably scare the cr*p out of somebody, though.

Kirk
who thinks anything that eats deer can't be all bad...