Basically, you are trying to find how how "tight" a fit you want between 2 mating parts.

"Shaft Basis" means the shaft is your nominal dimension.

Look up the fit tables for a free running type fit and you can calculate the tolerance for the shaft and then what the corresponding hole and tolerance should be for the mating part.

When I first started out tolerancing and what should be done was a mystery to me. These types of tables are great way to achieve the fit you need without all the guesswork.

Maha Nadarasa wrote:

If one can look at the table and answer this question, it is not an challenging question.

Good!

It is not supposed to be a challenging question.

You are supposed to look it up in a table.

The challenge is - "Has you instructor taught you how to use the table?"

Has your instructor taught you realistic tolerances for the machining processes to be used in manufacturing the parts?

Watch out - beginners forget to move the decimal places in that table and return ridiculous answers that make no logical sense if they took the time to model at min/max they specify.

What is the title/author of the textbook you are using?

Do you own a Machinery's Handbook (or whatever is appropriate for the standards in your country)?

(And actually, this stuff in built into SolidWorks now.)

Yep.

I've found that "imperial" based tables like in the MH give you good guides as to what the fit combos mean and will do for you.

If you look up an ISO tolerance chart, you get a ton of fit classes but not a real good explanation of what fit means what. Just a bunch of F8/f8 so on and so on.

There are a few good tables I've found for the ISO charts that give some good combination assistance.

In my MH 23rd edition, you'll find it all under "Fits" in the index.

ISO shaft/hole preferred fits

https://mdmetric.com/Ch6.8wGO.pdf

ANSI Fits calculator and charts:

Unfortunately, they don't mention material, nor do they mention the standard by which they base themselves. I know that the standards are similar, but they are not exact.

This is a standard style question of which I ask candidates for internship here. It is not that they have to memorize a table. It is can you open your machinery handbook, then find and apply the appropriate fits to 2 mated parts.

This is related to solidworks in the fact that drawing a picture on your screen is not good enough. What you draw has to be made by someone and there are other parts that will need to work with it.

It is a basic question regarding the understanding of mechanics and how to apply them at a project level.

If we have a machine with 15 operation stations and I have a designer working on 1 station I don't want him coming over and asking me every 15 minutes on how to apply fits between a shaft and a hole. I want them to be able to take the criteria for the job (shaft diameters, load applied, length of motion etc...) & calculate what the fits are and where and how to apply them.

Just like I expect someone coming in as an intern to be able to detail a shaft with the input of what the fitment is to apply tolerancing to the print to get the part made correctly.(Which is in essence what this question was) You were given the basics(what type of fit and nominal size).

If I answer and you get the job, what do I get, a yearly or monthly commission ?