Tooling/Fixture - Press Fit Tolerance

Question

Tooling/Fixture - Press Fit Tolerance

rc0213 (Mechanical)

(OP)

27 Jul 20 15:56

I am re-learning manufacturing engineering skills.

One of my latest task is to create a tooling/fixture which will have a Press Fit Tolerance for a pin and a hole.

The pin is 4.5" diameter.

So, what is the industry standard in making the hole that the pin should go in.

I looked at the Machinery Handbook, and, wasn't quite sure how to apply it.

Does anyone have a link or a PDF of a chart I can print?

Thanks!

EdStainless (Materials) · Answer 1 · 2020-07-27 16:55:14

So are you fitting one of these or a bunch?
And is the pin 4.5000" and is it very round?
Which material is softer?
What are the alloys and strengths involved?
Are you looking for some interference or just a snug fit? Might it ever need to come out?
Can you make a round hole (jig bore) or will this just be drilled?

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rc0213 (Mechanical) · Answer 2 · 2020-07-27 18:47:16

I am fitting one pin to the hole.
Yes, the pin is very round.
The hole will be the softer material.
Both are A50 steel.
I am looking for a snug fit.
The hole will be drilled. But, for a non-fractional dimension, I am looking at laser cutting.

hendersdc (Mechanical) · Answer 3 · 2020-07-28 16:59:27

Laser cutting is not a good option. The hole will not be nearly round enough for a good press fit. Of course, if this is just a locating pin or something that might now matter

mfgenggear (Aerospace) · Answer 4 · 2020-07-29 18:07:59

@rc0213

the machining is depending the accuracy positioning & diameter of the hole and assembled pin.
if true position .0005 inch then it will require roughing & jig ground.
if true position is .005-.010 inch it can be drilled and reamed or bored by a vertical machining center. the new machines are very accurate.
and that is if no heat treat is required.

pull out the machinist hand book and review press fits. & post what exactly what you don't under stand.
or google metric press fits like H7 EG

if its a tool I use the pin to locate a part for orientation and location I will just make it a .0005 inch press fit.
if there is no safety issues. for accuracy and ease of assembly try to keep the press light.

more exact insight of what the form, fit function is will give better answers.

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Tooling/Fixture - Press Fit Tolerance