Questions on pinion runout 1

[SeasonLee]

Runout questions on pinion:

1.No matter the perpendicularity or runout callout, the reference datum is B-A on the pinion print (page 1), however the reference datum on the assembly drawing (page 2) is A-B, are there any differences between them (A-B and B-A)?
2.What is the meaning of runout callout on a wire size Ø.0864?
3.The bench center is around $700, it’s very expensive, I am trying to save the money, are there any other open-setup ways to measure the perpendicularity or runout?

Thanks for all your comments

SeasonLee

 

[MechNorth]

1) B-A is the same as A-B; there is no precedence / priority between the two, and are in fact the exact same.
2) They are trying to verify that the opposed tooth valleys are symmetrical (high school symmetry); i.e. they average out at Datum C.
3) Set the piece up on a lathe / turning centre. You might also be able to find a commercial runout stand that you can just put a pair of conical mandrels in instead of collets.
Btw, you don't actually have a Datum A or a Datum B callout, just two boxes with letters in them. Put the anchor triangle on the angle dimension line.

Jim Sykes, P.Eng, GDTP-S
Profile Services

http://www.profileservices.ca

TecEase, Inc.

http://www.tec-ease.com

 

[pmarc]

Ad 2) This looks like standard method of gear runout verification with the use of cylinders contacting the gear at its pitch diameter.

 

[MechNorth]

Pmarc,
more like trying to verify pitch diameter?

Jim Sykes, P.Eng, GDTP-S
Profile Services

http://www.profileservices.ca

TecEase, Inc.

http://www.tec-ease.com

 

[SeasonLee]

Jim and pmarc : Thanks for the reply, may I ask m+ (or mt) is short for what as shown on the attached.

Thanks

SeasonLee

 

[DanStro]

I think that is an 'mt' not 'm+'. From the context it looks like it is meant to be an abbreviation for 'measurement', though I have never seen it abbreviated this way.

HTH,
Dan

Han primo incensus

 

[pmarc]

I do not have access to ISO standards on allowable deviations of gear parameters (e.g. ISO 1328-1 & ISO/TR 10064-2), but looking to a handbook I have, it is just written that:
- balls or cylinders of precisely calculated diameter can be used in inspection of gear runout error (thus runout FCF). There is however a mathematic relation between runout and pitch diameter error, so knowing one makes possible to calculate the second;
- the same balls or cylinders can be used in controlling tooth thickness by determining "dimension over balls or cylinders" (thus mt parameter, I believe).

 

[SeasonLee]

Thanks for your comments, Dan and pmarc.

I am figuring out how to measure the gear runout, pmarc, would you mind tell more details about the mathematic relation between runout and pitch diameter error. Thanks

SeasonLee

 

[pmarc]

SeasonLee,
Not sure whether this isn't against the rules of the forum, but here is a document you may be interested in.

http://www.docin.com/p-299801160.html

The relation is pictured in Figure 11 of the doc.

 

[SeasonLee]

Thanks, pmarc. Excellent.

SeasonLee