How to Correctly Dimension This drawing

[zetnie]

I thought I had it right before but now I'm supposed to do something with the auxiliary views, what is it?

[kencaz]

That's good but we can't tell how wide the part is or the edge radius. Add a top view with dims.

 

Have you tried using projected views. It makes it simple to project off of a single view.

 

 

KC

[zetnie]

Well the views on the bottom are the top views and my instructor wanted me to put in the auxiliary views shown.

 

Well, what I really need to know is how to dimension the auxiliary views.

[kencaz]

Some more info your going to need to make this part...

 

 

Also, for this kind of part your going to need a flat pattern...

 

KC

[pinco pallino]

that's how i would do

[kencaz]

I would dimension more like this:

 

 

Now it can be cut, drilled, and bent.

 

KC

[JD Mather]

kencaz

 

If you turned that drawing in to me you wouldn't get a very good grade.

 

JD

Certified Machinist

[kencaz]

kencaz

 

If you turned that drawing in to me you wouldn't get a very good grade.

 

JD

Certified Machinist

 

I could make this part in 15min with that information and do it every day.

 

Maybe that's why the schools are in so much trouble.

 

KC

[kencaz]

No! Your probably right JD, it is full of holes, however, in my defense.

 

I have submitted similar layouts to major construction companies, recently, Perini Building Company and Tishman Contruction for the City Center Project in Las Vegas, and they did not have any problems with my drawings.

 

 

 

 

KC

[shift1313]

you wouldnt get any grade with no title block:) I would say the issue is the dimensional references. Measuring to edges especially on the bent part, but different people like to see different things. I used to work with a machinist that told me exactly how he liked to see drawings for him to make and it was a little off the standard. Knowing what works best(in small industry) for the guys who make the parts can go a long way. However that doesnt mean its by the book

[kencaz]

I would say the issue is the dimensional references. Measuring to edges especially on the bent part, but different people like to see different things.

 

Yeah! I see what your saying, however, the critical dimension are on the Flat Pattern. If you bend in the right location at the right angle then the part should end up very close to the bent part dimension references, but there will be tolerances.

 

I used to work with a machinist that told me exactly how he liked to see drawings for him to make and it was a little off the standard. Knowing what works best(in small industry) for the guys who make the parts can go a long way. However that doesnt mean its by the book

 

I see this a lot as well. In my case we do have a designer, however, he does not know anything about fabrication, so I end up having to re-due a lot of the drawings for myself so I can make them.

 

We are considered (under 100 employees), a small company so we can get by not worrying to much about standards.

 

KC

[JD Mather]

I could make this part in 15min with that information and do it every day. KC

 

Take a look at the way you have dimensioned with respect to datums and tolerances. (we can ignore actual values of the tolerances for this discussion)

 

The information to make a part might be there but in the real world parts cannot be made to exact dimensions. There are tolerances associated with each dimension.

 

Real questions would arise if you sent this drawing out for bid, dimensioned as you have. Worse yet, if a large number of parts are made with some or all pushing the limits of the tolerance (whether known or in this case not given) simply because of the way it is dimensioned.

 

You said you could make the part in 15 minutes from your information on the drawing, but now take a look at it from the perspective of an inspector signing off on delivery of thousands of this part as delivered from a vendor. Some vendors will deliver questionable parts and take the money and run.

 

Granted, the tolerances for sheet metal parts are generally fairly loose compared to machined parts, but I think I would dimesion a bit differently.

[kencaz]

The information to make a part might be there but in the real world parts cannot be made to exact dimensions. There are tolerances associated with each dimension.

 

True! However, I addressed that in post #11 and am aware of it. That information would be in the title block which I removed as it was not needed for the OP's question.

 

Yeah! I see what your saying, however, the critical dimension are on the Flat Pattern. If you bend in the right location at the right angle then the part should end up very close to the bent part dimension references, but there will be tolerances.

 

 

You said you could make the part in 15 minutes from your information on the drawing, but now take a look at it from the perspective of an inspector signing off on delivery of thousands of this part as delivered from a vendor. Some vendors will deliver questionable parts and take the money and run.

 

Again true, however, if thousands of parts were going to be made most likely using a die form. Tolerances could be made very tight and all parts would be the same. The issue then would be making the die form accurately enough.

 

 

KC