# Interpretation of dimensions

Continuing through my practice examples I came across the following diagram and I have a question on how to interpret the depth of the part.

I have the part drawn up in inventor, but when I went to do my extrusion I started interpreting the spacing between the plates in different ways. What is throwing me for a loop is the note "BAR DIA.70 x 76 LONG" and the 28 dimension.

I have interpreted it these ways:

• 9.5 sticking out the front.
• 19 thick front plate.
• 12 thick rear plate.

Option A)

From the face of the 9.5 protruding 66 dia. cylinder (assumed machined down to) to the back of the cylinder is 76 mm and there is a 28 mm space between the plates.

Option B)

There is a 76 mm cylinder between the plates and it protrudes 28 mm beyond the back of the back plate.

Option C)

There is a 76 mm cylinder starting at the back of the front plate that is 76 mm long and a 28 mm space between the plates.

What is your interpretation for the setting the various depth?

Option D) being something I have not considered and please provide details.

• You need a section cut through the link to see how is the transition from the 70 mm dia. bar down to 66 mm dia. bar, how deep is each bar sitting on the respective bore. I read the thickness of the back bar is 12 mm.
– r13
Commented Oct 15, 2021 at 22:12
• All I have is the sketch to follow. Thank you for pointing out my typo. that 20 will be corrected to a 12 Commented Oct 15, 2021 at 22:13
• If I zoom in, it looks like 28 (units?) between plates, but hard to tell. I'd hate to rely on a drawing like this for anything. Commented Oct 15, 2021 at 22:34
• if it were not for the fact its from an example exercise book, I would be requesting clarification from the designer. Commented Oct 15, 2021 at 22:35
• My guess is the 76" bar extends 36" from the back of the 12 mm bar (76-12-28=36). It at least has to provide the length of the 66" bar to be correct.
– r13
Commented Oct 15, 2021 at 22:57