acme thread gage??? 2

[CandCQC]

We have to machine a 5.50-4 acme 2G internal thread and have no gage to check the part. My boss wants me to calculate the dimensional criteria to machine a check gage. Where do I the information needed to do this? We have made gages in the past to get by until a gage could be ordered and received by using the internal pitch diameter min/max info to make a plug thread gage to check the internal thread. I have in front of me a 3/8-16 2B thread plug gage and the pitch diameter info is correspondant to the internal specifications in the machinist handbook, but what do I do when the thread in question is not listed in the handbook? Any help would be appreciated. Just to squelch any discourse from my post, I fully understand that gaging is a separate entity and we should not be undertaking this venture, however that is not within my control. I am just the guy that has this put in his lap and now has to deal with the situation. Thanks in advance.

 

[unclesyd]

The first two sites are list of some dimensions with their derivation.
We have used Keystone for special feed type screws, though
mostly on smaller sizes. I would give them a call about making a part to your specifications. We actually used their bar stock for wear gauges in Acme Bushings.

http://www.landisthreading.com/ThreadCutting/Library/TC_Acm

eThreadforms.pdf

http://www.unionmillwright.com/2884.pdf

http://keystonethreaded.thomasnet.com/item/all-categories/specialty-forms/item-1013?&forward=1

 

[tr1ntx]

5.50 - 4 ACME - 2G Internal (from GageMaker)
Pitch Dia MAX = 5.4041
Pitch Dia MIN = 5.3750
Major Dia MAX = 5.5400
Major Dia MIN = 5.5200
Minor Dia Max = 5.2625
Minor Dia MIN = 5.2500
Thread Height (Ref) = 0.1350
Root Width = 0.0875

Plug Gage (Class X tol)
Pitch Dia (Go) 5.3750, tol = +0.0011
Pitch Dia (NoGo) 5.4041, tol = -0.0011
MOW (Go) 5.61248, tol = +0.0011
MOW (NoGo) 5.64158, tol = -0.0011
Major Dia (Go) 5.5100, tol = +0.0020
Major Dia (NoGo) 5.4375, tol = -0.0020
Minor Dia (Go) 5.2400, tol = -0.0020
Minor Dia (NoGo) 5.2400, tol = -0.0020
Half Angle tol = +/- 0deg 8min

 

[KENAT]

A different idea to avoid using a gauge that a previous employer used on some large acme threads...

Use dental molding material - the same stuff they use when creating an impression for a crown - to take an impression at various points around the part.

Then put it up on an optical comparator to inspect it.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[mrainey]

5.50 - 4 ACME - 2G Internal (from GageMaker)
Pitch Dia MAX = 5.4041
Pitch Dia MIN = 5.3750
Major Dia MAX = 5.5400
Major Dia MIN = 5.5200
Minor Dia Max = 5.2625
Minor Dia MIN = 5.2500
Thread Height (Ref) = 0.1350
Root Width = 0.0875

Plug Gage (Class X tol)
Pitch Dia (Go) 5.3750, tol = +0.0011
Pitch Dia (NoGo) 5.4041, tol = -0.0011
MOW (Go) 5.61248, tol = +0.0011
MOW (NoGo) 5.64158, tol = -0.0011
Major Dia (Go) 5.5100, tol = +0.0020
Major Dia (NoGo) 5.4375, tol = -0.0020
Minor Dia (Go) 5.2400, tol = -0.0020
Minor Dia (NoGo) 5.2400, tol = -0.0020
Half Angle tol = +/- 0deg 8min

What does "MOW" mean? If "Measurement Over Wires", what wire diameter and constant were you working with?


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