Machinist (MAC)

Third Period Package (25 Modules) Comments

Date: 5/25/2021 3:15:25 PM
Module: 150302c
Version: 21
Page: 11
Comment: In the module Bevel Gears on page 11 all the formulas are unreadable. The font didn't come in properly?
Status: Declined

Date: 5/25/2021 3:16:48 PM
Module: 150302c
Version: 21
Page: 11
Comment: The formulas on this page are not readable
Status: Update in Progress

Date: 5/25/2021 3:14:21 PM
Module: 150302e
Version: 21
Page: 3
Comment: In the module Gear Manufacturing Methods Page 3 the end of the third paragraph reads "2mm (M = (20+2)/44mm" It should be M = 44/(20 +2). This is derived from transposing the outside diameter formula on page 5 from OD=(N+2)M to OD/(N+2)=M.
Status: Update in Progress

Date: 5/25/2021 3:14:40 PM
Module: 150302e
Version: 21
Page: 10
Comment: In the module Gear Manufacturing Methods page 10, the end of the very last paragraph is (OD=8.120 inches + 20.0625 inches). It should read (OD = 8.120 inches + 2 x 0.0625 inches).
Status: Update in Progress

Date: 5/12/2021 9:11:25 AM
Module: 150302f
Version: 21
Page: 7
Comment: Page 7 first paragraph, second sentence "The table is swiveled to the lead angle of the worm". I believe if you are using a rack milling attachment the lead angle of the worm is achieved by swiveling the rack milling attachment.
Status: Approved for Review

Date: 5/12/2021 1:59:58 PM
Module: 150302f
Version: 21
Page: 26
Comment: Question #13 page. 26 "What is the approximate lead angle of an 8DP worm gear with a pitch diameter (PD) of 1.75 inches?" The answer on page 29 is "B) 3.5 degrees" Are you using PD as your diameter? If so the answer is 4.08degrees...if you are using root dia. it is approximately 4.7 degrees.
Status: Approved for Review

Date: 5/12/2021 2:21:36 PM
Module: 150302f
Version: 21
Page: 27
Comment: Question #18 page 27 "What is the minor diameter of 2 - 0.25P -0.75L (3-START) UN 2A thread? Answer page 29. "D) 1.676". I believe it is 1.693" D-(2 x straight depth). Straight depth is .6134/4 in this case.
Status: Approved for Review

Date: 5/12/2021 2:21:51 PM
Module: 150302f
Version: 21
Page: 27
Comment: Question 23 page 27 "How far must the compound rest be advanced when turning a 1-0.625P - 0.25L (4START) UN thread?" Answer Page 29 "A) 0.0625 inches." First of all the pitch in the callout should be 0.0625P Second assuming you are asking about advancing the tool for the 2nd thread (and so on) answer A is correct. (My mind went to slant depth).
Status: Approved for Review

Date: 5/12/2021 2:54:52 PM
Module: 150302f
Version: 21
Page: 28
Comment: Question 26 page 28 "Which of the following threads can not be cut using the thread chasing dial on a lathe with a 4 TPI lead screw" Answer page. 29 "B) 1-0.125P -0.25L (2 START) UN" To start I found this information very confusing. According the the chart on page 24 B will work...even lead yes 4TPI, 2 start yes. Answer A) page 28 makes no sense "1-0.167P - 0.133L (2 START) UN". 2 times pitch equals lead so 2 x .167 = 0.334L Thanks
Status: Approved for Review

Date: 5/25/2021 3:13:57 PM
Module: 150302f
Version: 21
Page: 26
Comment: Module 150302f Version 21 Question 13(p.26) asks; "What is the approximate lead angle of an 8 DP worm with a pitch diameter (PD) of 1.75 inches? Unless I'm missing something this should be a simple Tan function. (pi / DP (8) ) / (pi x 1.75) = 2nd fc tan = lead (linear pitch) p.11 / circumference = 2nd function tan = I get 4.085 degrees. The answer p. 29 is 13)B 3.5 degs. I think 13)C is closer, 4 degrees.
Status: Update in Progress

Date: 4/29/2021 12:33:28 PM
Module: 150302g
Version: 21
Page: 17
Comment: Second last line, last bullet on page the word "verified" should be "vitrified".
Status: Approved for Review

Date: 5/5/2021 1:19:39 PM
Module: 150302h
Version: 21
Page: 46
Comment: Question #1 the self test answer "B" is incorrect, it should be "C". The self test question is on page 43.
Status: Approved for Review

Date: 5/25/2021 3:15:45 PM
Module: 150302h
Version: 21
Page: 43
Comment: self test question 1 The answer “C” your answer is “B” page 46. The correct information is found on page 2.
Status: Update in Progress

Date: 5/11/2021 12:13:20 PM
Module: 150302k
Version: 21
Page: 16
Comment: The first sentence under the heading Milling Fixtures uses the word "tenons". Is this referring to a strap clamp? Could you choose another word?
Status: Approved for Review


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