Undercut for bearing housing 3

[WardHollowayPE]

I am designing a bearing housing. The housing will hold the bearing plus a spacer ring on either side to prevent movement. The spacers apear to have square edges, so I need to design in clearence in the corners of the housing. Is there a standard design or tool for an undercut? I believe the same standard should apply to shaft design when there is a ground finish in both the diameter and a shoulder. There needs to be clearence for a grinding operation.

Thanks

Ward Holloway, Jr, PE

 

[MikeHalloran]

OR, you could chamfer the OD of the spacer rings, so you didn't need to undercut the housing bore.



Mike Halloran
Pembroke Pines, FL, USA

 

[Tmoose]

I tried to define undercuts that could be generated with the nose radius and goemetry of our standard tooling inserts.
If the face of the housing or shaft shoulder is to be finish ground then the grinding wheel's radius will create a new corner radius, unless the undercut is into the bore AND face. That almost requires a parting tool fed in at an angle, or worse. I'd chamfer the spacer rings heavily on both sides for universal installation.

 

[JamesBarlow]

My first stop would be the machine shop.

Show the guys the housing and they will proboably tell you that they will be using a certain size boaring bar that takes a specific insert and then your done. Use the insert to form the cut, based on the machinist input, and your all set.

Standards are great for engineers but they often just cost more money they doing what the machinist would like.

As an aside I agree %100 with Mike's suggestion to chamfer the spacer. Your could spend 100's or 1,000's of dollars to do something that could be done in 30 seconds on a belt sander. If I understand your question, though, you have to grind the housing which would require an undercut anyway so chamfering the spacer dosn't save you anything.

 

[WardHollowayPE]

It's not so much the fitting of the spacer ring, but how to finish machine the two surfaces. A grinding operation on one should not effect the other.

Ward Holloway, Jr, PE

 

[MikeHalloran]

Okay then, first you need to decide if grinding is actually required to meet your tolerances. If it is, then yes you need some kind of undercut adjacent thr ground surface(s). If the housing is cast, you can cast in the undercut. If you're machining the housing from billet, then you may have to make up some odd tooling to get in there.

I agree that your first stop should be the oldest, crankiest machinist in your shop.



Mike Halloran
Pembroke Pines, FL, USA

 

[Tmoose]

Depending whether

 

[EdDanzer]

For lowest cost use a .032” radius in the corner and chamfer the spacer .045”. It would be wise to ask the grinding people if they can live with the .032” radius. It is possible to under cut the shoulder with a radius nose grooving tool, but this step will cost more than chamfering the spacer and you may need to look at stress if the housing sees high loads.