Press fit bearing hole size?

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Well, I've recently started working at a shop. I'm operating a VF-1. I'm trying to make some parts which will have bearings pressed into them. One bearing is 1.181 OD (Best I could measure)

I usually mill the hole with a G13, then at fairly high speed, and leave about .0002 for the finish pass. That I run at a really low feed.

Seems to work ok for getting repeatable results. However, I'm having problems figuring out what size to make the hole.

Anyone have any tips?

[motomitch1]

What kind of bearings?
What is the application?

[Geof]

Well, I've recently started working at a shop. I'm operating a VF-1. I'm trying to make some parts which will have bearings pressed into them. One bearing is 1.181 OD (Best I could measure)

I usually mill the hole with a G13, then at fairly high speed, and leave about .0002 for the finish pass. That I run at a really low feed.

Seems to work ok for getting repeatable results. However, I'm having problems figuring out what size to make the hole.

Anyone have any tips?

There is a member on the forum under the I.D. NC Cams. Do a search on his posts and you will find everything you need about bearings and more. Also links to information about bearing fits and things like that. Either that or suggest you are going to simply drive them in with a sledge hammer and NC will descend on you breathing fire and brimstone

[HuFlungDung]

Interpolating bearings seats can be tricky in the mill unless the machine is in excellent shape and the servos tuned with equal excellency. The possibility exists that the hole may be irregular and difficult to measure accurately with a micrometer. Best to check the absolute roundness of the hole with a dial indicator mounted in the spindle, and sweeping the bore.

Once you have determined that the hole is round, then you can begin to believe your micrometer. If the hole is not round, then a boring operation may be the better option for finishing. Also, tool wear will have less effect if the boring tool is saved for only a final cut.

Beware of the effects of clamping pressure if holding a relatively flexible part in the vise when machining this hole. The shape could change when the part is removed.

BTW 30mm = 1.1811" , in case you're wondering what is the basis for the strange figure that you measured

[NC Cams]

Thanks Geoff for the advance billing. I've worked hard to nurture that 'no bull' sort of reputation with regard to the dissemination of technical information

Today, I'm simply NOT in the mood for hellfire and brimstone - stomach flu.

Go here:

http://www.jp.nsk.com/app01/en/catal...gi?ec=bearings

EDIT
The site has apparently been changed recently and won't load unless you d/l the Japanese characters. It used to load just fine without Japanese language support.
END EDIT

Download the various catalogs for industrial and machine tool bearing applications for the info you seek.

They are quite easy to read and to figure out what sort of ISO fit tolerance to use. Too lazy, no time to d/l the data use an H6.

What's H6? Simple: download the catalog and learn.

HINT: not all bearings want to be or should be pressed into a housing.

[scappini]

1.181" equals 30.mm. Make the hole size = 1.1807mm
But really you should ask the customer what his preferred fit is, as we have a couple that would like size = size or even .0005" clearance.
I guess you could not go wrong making the hole size 30.0mm +/- 0.01mm (1.181" +/- 0.0005")
Hope that's what you were asking lol.
Ciao all

[fkaCarel]

Scappini: you can't say you were'nt warned. See post #3. Dive! Now!

[scappini]

I posted another comment but my wireless stuffed up. As motomitch says:
I was intending to say it does depend on the bearing and that some bearing like to float on the shaft etc. Your bearing company should be able to provide you these details unless of course the are as stupid as work experience boys, but they are there to help you of course.
It is 4:30 in the morning here. I do apoligise motomitch !! lol

[scappini]

I think I just got excited when I saw the closest size measured was 1.181" as that was one of the 1st imperial sizes was embanked in my memory bank, and that most of US use emperial jumped on it rotflol.

Cheers.
Have a good night USA

[fkaCarel]

I think you just made one the narrower escapes of your life. I estimate your chances 50/50 now.

[scappini]

If I keep sending post to explain why my wireless keeps stopping on me, I might not be a CHIP SWEEPER, lol
Question: Why does my wireless broadband decide to stop??? Not really related to bearing fits and limits but most of us are usefull outside bearing sizes!!! lol

[fkaCarel]

35/65