Bearings

[bob58o]

I need 3/4" pillow block bearings for a jack shaft.
I bought these.

ucp204-12
http://www.ebay.com/itm/like/141751...7290-0%26rvr_id%3D1100277423178&ul_noapp=true

4 shipped for under $20 total.

Can't find the RPM rating.
I need about 5500 RPM.

I found McMaster Carr has 5800 RPM pillow block bearing for like $35
And high speed 12,000 RPM IIRC for $100 each.


The ones I bought are probably not good Nuff.
Anybody know max RPM for these?
I will probably get the 5800 rpm $35 ones unless I hear of something different.

 

[mckutzy]

Im not too sure on the rating for cheaper bearings.... Most good bearings( *** NTN NBR ect) will go about that fast, its just you need to keep them lubricated often...
Id almost go to a local bearing shop... and ask to see what they have for just the bearings, get the housing cheap, then spend for a known high speed version......

Is you selected speed rating a sustained speed or for short while?

 

[bob58o]

I suppose I will try the cheap ones out.
When they go bad, I got a spare set.

When those go bad, I'll upgrade.

I guess I'll just maintain the crapola out of these?

 

[Bbqjoe]

I suppose I will try the cheap ones out.
When they go bad, I got a spare set.

When those go bad, I'll upgrade.

I guess I'll just maintain the crapola out of these?

Keep 'em well greased, and just remember to open them up once in a while to let the smoke out.

 

[mckutzy]

Noooo.... Don't let the smoke out.....

Oh wait... Are We're talking bearings here... Or electric motors...
If bearings are smoking... There was problems long before the smoking began...

 

[68sportcoup]

Not sure what rpm you turn your engine but it would have
To be more than 20,000 rpm for the axle to spin 5,000 rpm
I would try those
Good luck

 

[mckutzy]

Well it does depend on ratio....

Check this link out, it has a few other interesting facts in its calculations...a pretty good calc.
http://www.compgoparts.com/TechnicalResources/JackshaftRatioCalculator.asp

And for the wheel circumference....
http://www.mathgoodies.com/calculators/circumference-calculator.html

 

[chancer]

Not sure what rpm you turn your engine but it would have
To be more than 20,000 rpm for the axle to spin 5,000 rpm
I would try those
Good luck

NO. It is a jackshaft, So it could be potentially turning the same Rs as the motor, and Bob's building a motor to turn 5800Rs.

If it were for his Axle at 4:1 you would be correct.

 

[bob58o]

Yep.
Crank shaft 5800
Jack shaft 5800
40 series 1:1 ratio.
60:11
1000-1100 aXle RPM

 

[OzFab]

$12 for two pillow blocks & bearings does sound a little on the cheap side, most likely chinese; I would expect to pay more than that for one set...

 

[68sportcoup]

Jack shaft I read that but guess it didn't register

 

[machinist@large]

All bearings technically have a break in period. There are a lot of variables for that: the best advice I can give is to start off slowly, and for only a minute or two. Then stop, get off the kart and check the bearing temperature with your bare hands. If they're warm, let them cool down for several minutes. Repeat the same cycle.

If at any point they get extremely warm or worse, something is wrong. If things are OK, you should be able to work up to a half hour run without things getting hot.