Spindle bearings

Download the pdf and then open it and go to page 218. I mistakenly saw page 48 of that particular section. Go to page 218 and then you'll find the bearing, you'll also note my mistake. Apologies, I'll change my earlier post
 
Download the pdf and then open it and go to page 218. I mistakenly saw page 48 of that particular section. Go to page 218 and then you'll find the bearing, you'll also note my mistake. Apologies, I'll change my earlier post.

I've made a double post, how do you delete these?
 
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No need to appologize.... looking around through there I did find the exact number of the bearing I removed it is on page 56 of the pdf I'm wondering the difference maybe the abec rating
 
That one would do the trick considering its the same number. It has a lighter thrust rating than the 7204W, you can tell by the angles of contact.
The 204WI looks like a 20 degree contact angle, meaning its capable of higher speeds with light thrust capabilities.
The 7204W has a 40 degree contact angle so it is capable of absorbing greater axial thrust or has greater precision in maintaining axial position of the spinning shaft.
I think the 7204W has more precision and is no doubt good for 20000 rpm. What spindle speeds is your machine rated at?
 
Thats a good question but I would have to say well with in that range! Thanks
 
The 204WI bearings are the high precision ABEC9 type, and they have a different contact angles. With a quick and not exhaustive search, I did not see any of the 204WI bearings for sale other than at retail. They will be very high priced, my guess is at least $100 each, maybe more, maybe MUCH more unless you get lucky. The ones you ordered, 7204W, will do the job. The shim stack needed may be different with those lower precision bearings due to different tolerances, but the shim stack must be chosen for the desired preload anyway. The other dimensions are also tighter on the 204WI bearings, and so they probably run somewhat smoother, but they will be a lot better than what I could see in the races of the ones you removed from the machine, and you probably would not know the difference unless somebody told you or showed you with a sensitive vibration tester. The price is right and they will work. I suggest you give them a try.
 
For example a 100mm pulley on a motor doing 3000 rpm will give you a spindle speed of 5000 rpm if the spindle pulley is 60mm diameter
 
My surface grinder uses 7" wheels and has a spindle speed of 3200 rpm, and the wheels are rated to 3600 rpm. That small grinder may use smaller wheels, and that would likely increase the spindle rpm, but probably not over about 5000 rpm at most.
 
That's a very relevant point to bring up Bob. NG needs to calculate his final spindle speed so he can select suitable wheels to use.
So he needs to ckeck the speed rating on his motor nameplate + measure his driver pulley and driven pulley.
But we're getting ahead of ourselves here, and need to focus on getting his spindle back together.
 
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