Major Diameter

[mcrump28210]

I have a piece of 6061-T6 aluminum tubing that has a 1" OD and a .060 wall (.880 ID). I will ID thread this to 28 TPI. I also have a 1" OD 6061-T6 round bar that I am going to turn down and thread to 28 TPI in order to make a cap for the tube. I will thread the cap first using the 3 wire method and then ID thread the tube to fit the cap for a smooth, snug fit.

My question is what diameter should my male threads (major diameter) be. I have been a job shop machinist but left the shop environment almost 30 years ago and can't believe how much I have forgotten. Even with my Machinery Handbook 23rd addition I cant seem to figure this out.

Any help would be most appreciated.

 

[Tony Wells]

One somewhat standard option:

 

[mcrump28210]

Tony,

Would you mind running this with a 0.880-28 threads? Thanks!

 

[4GSR]

THREAD TYPE STRAIGHT UNIFIED V
NOMINAL DIAMETER 0.8800
THREADS/INCH 28
LENGTH OF ENGAGEMENT 1.000

PRODUCT DIMENSIONS:
INTERNAL THD EXTERNAL THD

PITCH DIAM. - MAX. 0.8627 0.8554
PITCH DIAM. - MIN. 0.8568 0.8509
MAJOR DIAM. - MAX. 0.9032 0.8786
MAJOR DIAM. - MIN, 0.8800 0.8721
MINOR DIAM. - MAX. 0.850 0.8400
MINOR DIAM. - MIN. 0.841 0.8277
THD HGT - BASIC 0.0193 0.0219
FLAT ROOT WDTH - MAX. 0.0045 0.0089
ABS. MINOR DIAM. - MAX. 0.8360
THD RELIEF DIAM. - MAX. 0.8809
THD RELIEF DIAM. - MIN. 0.8800
BEST WIRE SIZE N/A 0.05774
ACTUAL WIRE SIZE - TBL N/A 0.02900
M.O.W. - MAX. N/A 0.91150
M.O.W. - MIN. N/A 0.90694

Not formatted as nice as Tony's but the same information.

Ken

 

[rick9345]

ID plus 2x the depth of cut(thread) = OD of(shaft/bolt/etc) to be fitted for uncommon or one off

 

[Tony Wells]

 

[mcrump28210]

Thank you all very much. Most helpful!