Distance from the outer diameter of a shaft to the flat?

[renasis]

Hello,

What is the correct terminology for the distance from the outer diameter of a shaft to the flat? Dimension "R" on the attached sheet. I believe it is flat height, but I am not sure.

Thanks,

-ren

 

[renasis]

Here is the link.

 

[desertfox]

I would call it "to base or bottom of key way" , I checked our key way standard and this doesn't dimension isn't given any special name or title as far as I can see.

 

[MikeHalloran]

I think the customary term is "dimension over flat".


Mike Halloran
Pembroke Pines, FL, USA

 

[tbuelna]

It would "keyway depth" or "key slot depth". The keyway depth is dimensioned this way because it is the easiest way to measure it.

 

[Artisi]

I have always used "keyseat depth". Not too dissimilar to the prior post.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[electricpete]

I think you guys are describing U minus R
(where U is diameter)

Looking in NEMA MG-1, they call U minus R depth of keyway at the crown
(the "at the crown" part clarifies that is it not the easy measurement from bottom corner of keyway along side to top corner of keyway)

NEMA calls R "Bottom of keyseat or flat to bottom side of shaft or bore", but that sounds ambiguous to me.


=====================================
(2B)+(2B)' ?

 

[renasis]

Guys,

Thanks for the replies. In this particular case I am asking about a dimension to a flat on a 3/8 shaft diameter. I should not have appended the picture with a keyway, it made the question a little bit confusing(see how it notes "FLAT" for dimension "S" on the drawing, that is the case to which I am referring to). Not sure if this would change any of your replies or not. Maybe they both would be referred to using the same terminology.

Thanks,

-ren

 

[ornerynorsk]

Dimension across flat would pretty much sum it up.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[electricpete]

Where flat is annotated, I believe the shaft is cut flat (rather than a keyway or groove) for a setscrew. I think you knew that, but just wanted to clarify for the thread.

=====================================
(2B)+(2B)' ?

 

[renasis]

electricpete,

Right, the "S"=FLAT is the case I am referring to. In those cases, for a 3/8 or 1/2 shaft diameter, what is the "R" dimension called?

Thanks,

-ren

 

[ornerynorsk]

Dimension across flat is the correct call-out.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.