Bearings that will handle 10K rpm and 200lb?

[DennisCNC]

What type of bearings other than A/C, will handle 10k RPM and about 200 lb. of radial load? I don't need accuracy, just need them to handle the speed and load.

Thanks

[RICHARD ZASTROW]

You need more info. Is this an overhung load? If so, how far from the bearing? Is the load between bearings? It's kinda like grabbing a broom with one hand at the extreme end of the handle or both hands, one at each end.

[NC Cams]

Base upon the limited amount of input info (vague to minimal) and the specified durability requirement (none), the bearing size required to package the damn thing (none) and true/valid loading scheme (essentially, I dunno), pretty much ANY bearing or NO bearings willl work - take your pick.

I'd urge you to go to ANY bearing handbook and do a load life calculation. Input the varables that you've given here and see if YOU can run even an elementary load/life calc with ONLY the input you gave us. I'll save you the time - you won't be able to do so.

Call a bearing engineering dept and ask the same question and provide the same input. Chances are, they too, will NOT be able to answer your question - too vague an inquiry and too little input info.

Care to provide a bit more enlightenment as to EXACTLY what you have in mind and are trying to do????? And with WHAT, IN WHAT????

[DennisCNC]

Oh yeah about the size. Shaft around 2.5" diameter.


The bearings will be setup like a spindle in a mill. One bearing will at one end the other 7" away the load will be 2" away from the bearing.

It was late yesterday!

[the4thseal]

still a little vague......give yourself some limitations ..constraints ....tolerances ..... real performance expectations .....otherwise there are just too many variables. sometimes a clean sheet design can be hard because there are no limitations....impose some constraints and things might come into focus...

[307startup]

Maybe I can help bridge the gap...sometimes people don't know the right questions to ask, or the right answers to provide when they are asked a question in return...I see it all the time at work & also at school. So, if in addition to your constructive criticism you could provide him with a list of questions to answer (the variables), he would be able to provide them all & you would then be able to answer his original question. It's all a matter of not knowing what we need to know sometimes...

[DennisCNC]

limitations .... none: constraints ....?: tolerances ... very low: real performance expectations... the longer it lasts the better

I'm no engineer to know all the details that involve a design like this, I just need some basic info on style or type of bearings to look in to.

[NC Cams]

I am a former machine tool bearing engineer - and "not knowing the details involved in specing a design" like this makes it VERY difficult, impossible actually, to give you the SPECIFIC answers that you seek.

Sadly, bearings can't be chosen on vague, SWAG inputs like this and expect to work. Thre are simply too many "i dunno's" or undefined variables in your case.

Sadly, there are load life calcs that SOMEBODY will have to perform (engineer actually) to give you a viable bearing recommndation.

Remember, the load life calcs do not take "I dunno" or "very low: real performance expectations... the longer it lasts the better" as valid performance input calculation values.....

In the mean time, lets see what we do have to work with:

Per your "requirements" :

Quote: "none: constraints ....?: tolerances ... very low: real performance expectations... the longer it lasts the better"

I have NO clue as to what ???? represents so I'll hazard a guess - whatever the hell i choose to move the process along.

With that stellar input, sImple answer is: buy some 6313's.

These will "satisfy the "longer the better" requirement and fit the 2.5" approx shaft..

Oops: these are only good for 7500 rpm on the best day you'd ever hope for using your sketch and "data set" to spec from.

Sorry, you lose. Either develop more real input expectations or scale back or down what you're trying to do.

Go thru this process of iteration maybe 3-4 more times and you'll start to see what it REALLY takes to pick some "bearings that will handle 10K rpm and carry 200 lb load"

Seriously, when you or ANYONE chooses to design their own spindle, you or someone HAS to do some engineering in order for the thing to work - or even hope to work. SWAG's don't/won't work.

Basic info: find a bearing catalog. check out the speed and capacities and sizes of the bearnigs that MIGHT even hope to work/fit.

Then, either do or have someone do some rudimentary load life calcs for you.

Once YOU see some of the published limitations that bearing selection involves, you'll surely come back with more answers than "I dunno's".

if that is too complicated,

Pick something that at least has a viable size and speed capability that is at least close to what you hope to achieve.

Finally, get real with the loads and speeds you hope to run achieve.

Your SWAG, pie in the sky values preclude the development and/or selection of valid, viable bearings for for your application.


When you finally do all that background "engineering" you'll hopefully see why Duplex'd A/C's are used pretty much exclusively in the application that you so vaguely describe.

[307startup]

simmer NC Cams...simmer I have pet peeves too, and I know you have a LOT of knowledge in this area. This site has helped me immensely in planning and designing a workable machine. That being said...sometimes responses get heated or answered off-the-cuff and become a flaming issue long before they need to be, if ever they do. Frustration leads to one of two things, resolve to see something through, or throwing ones hands up and walking away. Does this mean I think you're out of line or DennisCNC is doing his best to help others help him? No. It just means that I don't believe you need to invest this much energy in being frustrated & venting, and that I do believe DennisCNC needs to realize that while this is a FREE source of valuable info, that there are real, live human beings on the other end of the comp who spend their limited free time trying to help him...for FREE. DennisCNC...do all of us a favor and try to give us the information we need to help you...if you can't, that is fine, if you can, good...but please don't come back later with a post that we haven't tried to help you.

[NC Cams]

My prior replies may seem like "rants" but they are "nice" compared to what was said to me and how it was said by some of the old time engineers that I grew up/was taught by/under.

Those SOB's were NOT nice and they didn't care if they hurt your feelings when they told you to go back and do your homework when it came to "asking for help". Especially, when it was in an area that you had NO background in or knowledge of. Rest assured, when they got thru with you, you DID have a much better background and/or knowledgeo f the particular techology.

At the time, they told you to "go figure it out" and there wasn't an internet or readily vailable message boards handy to learn from/ask of. They also usually put you thru at HORRIBLLY uncomfortable witch and/or scavenger hunt to find every concieveable piece of info needed to spec out the bearings and/or do the load life calcs.

You can bet that you NEVER asked vague or poorly defined questions EVER again - and more importantly, YOU LEARNED how to do the proces RIGHT the next time. You at leaste cam armed with the necessary info needed to do the calcs - they would should show you were the formulae could be found but they NEVER did the calcs for you.

Frustrated? perhaps. Venting? maybe. But when people ask for highly technical help with non-specific and/or poorly defined input, how do you show/tell them how to do it?

Sometimes niceties can help. Sometimes, absurdity speaks volumes. Sometimes, malicious banality works wonders.

Sometimes, the "student" will even ask "HOW TO I DO THIS?" as oppoed to "what is the answer?????"

The "how to I do this?" gets a TOTALLy different set of responses with a totally different attitude than the " what do I use???" inquiry.

Some learn faster one way and other learn quicker the other.....

Care to try again, albeit with more design input data?????

[martinw]

Originally Posted by DennisCNC limitations .... none: constraints ....?: tolerances ... very low: real performance expectations... the longer it lasts the better I'm no engineer to know all the details that involve a design like this, I just need some basic info on style or type of bearings to look in to.

Dear DennisCNC,

I am absolutely no expert on bearings, but some people who have posted on this thread most certainly are. NC Cams incidentally gave me some really handy advice a while back, and told me where to look.

If you have a limited knowledge of bearings, like me, the first step is to tell everyone what you are trying to do in as much detail as possible. You may be surprised at the helpful responses from everybody. Otherwise, it's rather like asking...

"How big is a circle?"

End of lecture (LOL)

Best wishes,

Martin

[the4thseal]

being a mechanical engineer i need more 411 to help...... .....when you do not understand the complexities of your question "from our point of view" it does seem that it can't be that hard to get a simple answer"from your pint of view". you see we can not see what is going on in your head....if we could, it would not be a big deal.....but we cannot ......so we ask all these questions.......So the more you define your needs....the more help we can be...hopefully.....it is true "whatever" is hard to calculate...:-)