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Tolerance a profile to become a fit

Tolerance a profile to become a fit

Tolerance a profile to become a fit

(OP)
Good afternoon, back again with my stupid but necessary questions! smile

We have some pins which are shown on the attachment, these fit into a bush head, shaped the same way (so the bush is slotted) How, or should I say what is the best way to tolerance this piece in order to give it a H7 g6 type fit with the bush? I've never done it before, as you normally put those sorts of things on a hole/shaft. I've experimented with line profile etc. but it just doesn't look right.

Any help would be great!
Cheers

RE: Tolerance a profile to become a fit

For pins in slotted bushings, typically diameter control is all that's required to meet the majority of the function. The straightness of the pin will further secure function and prevent lack of fit.

RE: Tolerance a profile to become a fit

I don't quite understand your picture.

Do both your pins and your matching slots have obround shape?

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

RE: Tolerance a profile to become a fit

(OP)
Yes checkerhater, they are both that shape. So the image is the pin part and the Bush is the female of that shape

RE: Tolerance a profile to become a fit

First, to get our terminology straight.

According to the text of the stahdard, "For the purpose of ISO 286, only features of size type cylinder as well as type-two parallel opposite surfaces, defined by a linear dimension, apply."

That is, only simple features are subjects to "fit" and not compound ones. So, the best you may expect, is fit similar to H7/g6

H tolerance zone is extending from theoretically exact Nominal (formerly BASIC) feature into the body of the part, similarly to Unilateral profile.

g tolerance zone goes even further into the body of the part, being unequally disposed, but in the same direction - the condition that is not very well defined for Profile tolerance.

If you are willing to go there, we may consider the possibilities.

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

RE: Tolerance a profile to become a fit

(OP)
I think I get what you are saying smile

I was thinking of using, although didn't think it 'looked right' the profile of a line and having the tolerance one sided with the 'U' and using a mid range tolerance of the fits. So for example it would look like the attached image, being mid range of a g6 fit. You know? At least that way I know it's all going one way, and then I BASIC all the dimensions in question?

RE: Tolerance a profile to become a fit

It could be profile of a surface, this way the form will be controlled.
Adding datum(s) will also control orientation and location.

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

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