Name Date Industry Print Exercise 10-1 Refer to the print PR 10-1 and answer the questions below: Note 3 in the upper-left area of the drawing is referring to the crosshatched area on the front view. What is the maximum material condition of the hole in the middle of that area? Where on the drawing is the tolerance specified for the R50 and the 2X R.12 dimensions and how much is this tolerance? How many dimensions on this print are expressed with the limit method? This drawing shows a fastener inserted into a hole as indicated by note 5 in the top view: What is the maximum material condition of that pin? (Note: the front view indicates the size of the hole.) With reference to question 4, the hole in the part is to be 0.451-0.453. What is the allowance for the pin and the hole? Two of the dimensions, 3.165 and 2.114, have boxes around them. As discussed in this unit, what are those dimensions called? Note indicates 10 GAGE 1010-1020 sheet metal can be used to make the main body of this part. According to the left side view, how much tolerance is given to the thickness of the metal? The boxes that indicate an A or a B are called identification symbols. The top view shows a bend radius of the thin metal. Would a bend radius of 1/8″ meet the requirements? Review questions based on previous units: 10. What paper size is the original version of this print? Are there any section views shown on this print? 12. What is the name of this part? 13. What is the part number of this print? 14. How many chamfered edges are noted by leader lines on this drawing? Which system for placing dimension values is used, aligned unidirectional?
The Correct Answer and Explanation is:
To accurately complete Exercise 10-1 based on print PR 10-1, we need to visually analyze the drawing. Since the print itself is not provided in your message, I’ll guide you through answering each question using general mechanical drawing standards and practices. If you upload the print or provide more information, I can give precise values. For now, here is how to approach and likely answer each question based on a typical technical drawing:
Answers:
- Maximum material condition (MMC) of the hole (Note 3):
If Note 3 refers to a hole dimension of, say, 0.500 ± 0.005, the MMC would be the smallest hole size: 0.495 in, since more material remains at the smallest permissible diameter. - Tolerance for R50 and 2X R.12:
This is typically found in the title block or a general tolerance note. If it states, for example, “±0.03 on radii unless otherwise specified,” then:- R50 tolerance = ±0.03 in
- 2X R.12 tolerance = ±0.03 in
- Dimensions with the limit method:
Limit dimensions look like “0.451–0.453.” Count how many are presented in that format. Let’s say there are 4 such dimensions. - MMC of the pin (Note 5):
If the pin is dimensioned as Ø0.453 ± 0.001, the MMC would be the largest size: 0.454 in. - Allowance for pin and hole:
If the hole is 0.451–0.453 and the pin is at MMC 0.454, there is interference, not clearance. Allowance = Smallest hole – Largest pin = 0.451 – 0.454 = –0.003 in (negative = interference fit). - Boxed dimensions (3.165 and 2.114):
These are basic dimensions, used in conjunction with geometric tolerancing (GD&T). They indicate theoretically exact sizes. - Tolerance for metal thickness (10 GAGE):
10 GAGE = 0.1345 in (for 1010–1020 steel). Tolerance often ±0.005 in or per sheet metal spec. - Bend radius of 1/8″:
If the drawing specifies a minimum bend radius of 1/8″ or less, then yes, 1/8″ meets the requirement. Otherwise, it may not. - Paper size:
Typically found in the title block. If marked as “Size A” or “Size B,” then:- Size A = 8.5×11 in
- Size B = 11×17 in
- Section views:
Look for labeled sections like “SECTION A-A.” If present, yes, otherwise no. - Name of the part:
Found in the title block, e.g., “Bracket Assembly.” - Part number:
Also in the title block, e.g., “PN-1025-34.” - Number of chamfered edges:
Count leader lines pointing to chamfers (e.g., “.03 x 45°”). Say there are 3. - Dimensioning system:
If values are always horizontal, it’s unidirectional. If aligned with features, it’s aligned. Most modern prints use unidirectional.
Explanation
Understanding mechanical drawings is essential in manufacturing, engineering, and design. Exercise 10-1 challenges your ability to interpret a technical drawing accurately, focusing on dimensions, tolerances, symbols, and drawing standards.
First, maximum material condition (MMC) is vital when considering fit and function. It represents the condition of a feature containing the most material—such as the smallest hole or largest pin—impacting how tightly parts will fit together. In interference or clearance fits, calculating allowance (minimum hole size minus maximum pin size) informs whether the parts will press-fit or slide.
Tolerances like those for radii (R50, 2X R.12) ensure parts are manufactured within acceptable limits to maintain functionality without requiring perfection. These are usually found in the general notes or title block. Identifying dimensioning methods—whether limit or basic—is also crucial. Limit dimensions specify max/min directly, while basic dimensions (boxed) relate to geometric controls for accurate form and location.
Knowing sheet metal specifications, like 10 GAGE thickness and allowable bend radii, allows fabricators to ensure parts can be bent without cracking. Additionally, knowing whether the drawing uses aligned or unidirectional dimensioning affects how the information is read.
Lastly, the title block provides critical administrative data: part name, number, paper size, and drawing scale. Section views reveal hidden features. Chamfered edges, labeled with leader lines, ensure safe and functional edges.
In sum, mastering prints requires attention to detail, standards comprehension (ASME Y14.5), and applied understanding of manufacturing processes.
