Jump to content

Another day...Another GD&T Question ¯\_(ツ)_/¯


---
 Share

Recommended Posts

In regard to the "in between" Profile callout as shown in the capture below, how do we determine which direction the engineer is talking about? Is it based on the basic dimensions given, or is there an unwritten/written rule in the standard of the direction?


2725_24b768edae45fbea55d85ecad98cfef9.png
Link to comment
Share on other sites

The way that I've always interpreted them is the shortest distance between the two. I've seen a lot of custom designed inverted tooth sprockets that use Profiles to define the teeth geometry, and this is how I've always measured it.

Think of it this way, it is in-between those start and stop locations, if you went the other way you wouldn't be measuring in-between.

It doesn't matter if you go a clockwise to b or be counter-clockwise to a; as long as you stay in between those two start/stop locations.
Link to comment
Share on other sites

Also, since this is a spline, it looks like someone got extremely lazy and didn't want to fully define the spline tolerances. Now you have this Profile tolerance that is controlling not only Orientation, Location, Roundness, but the nominal Involute, Helix, Pitch, Major Diameter, and Minor Diameter.

Lazy drawing... Lazy.

Now when it is out of specification, you get to do the extra homework of showing them what exactly is out.
Link to comment
Share on other sites

I know this particular drawing isn't a great example because it is very clear based on the basics and where the Profile leader line points to but I've seen some awful drawings with the in between and just wondered what the correct direction may be.
Link to comment
Share on other sites

That seems like a lot of tolerance for teeth.

If those surfaces/teeth aren't defined anywhere else on the drawing, then I am ¯\_(ツ)_/¯
Link to comment
Share on other sites

It's not to the teeth, all the of the basics are called out for the outside and the teeth have a data set in a table with a different profile tolerance.
Link to comment
Share on other sites

Howdy gents,

We make this same part, or at least we farm it out. I made a program for this not long ago.

I interpreted it as A to B around the back avoiding the gear teeth.

( I also had to inspect pitch lead and profile on all teeth with a 0.5mm )

Good luck!
Link to comment
Share on other sites

Please sign in to view this quote.

Yeah I've had a program for this bad boy for about two years now, just wondered about other instances. I also use a 0.5mm on the teeth, great minds think alike bud!
Link to comment
Share on other sites

 Share

×
×
  • Create New...