Thread Bar Project, nothing is going right and I need help

[bfd]

nice threads. 3/4-11 that's an oddball. 3/4-10 is standard. where is the nuts. some of my apprentices made a table lamp out of the completed project. bill

 

[jlsmithseven]

it's probably 3/4-10, i just took a guess.

 

[netfences]

One such formula is: 0.750 / TPI. In this instance, 0.750 / 11 = 0.0682", so you would incrementally feed in with your compound a total of 0.0682" to create a full depth thread.

Noted, so with a 3/4" x 24tpi thread case, the measure will be 3/4" on the male part and 23/32" on the female part (ie: .750/24)?

 

[mikey]

Noted, so with a 3/4" x 24tpi thread case, the measure will be 3/4" on the male part and 23/32" on the female part (ie: .750/24)?

.750/24 = 0.03125" = the depth of cut taken with a threading tool to reach final depth of a 24 tpi thread. It appears you are looking for the diameter of the work piece at the bottom of the thread; this is called the minor diameter and is listed in any table that lists the specs for a given thread. The major diameter is the OD of the work piece, in this case 3/4".

 

[netfences]

mikey
I think I've finally got it. Continuing the 3/4" x 24tpi thread example, a bolt will have a 3/4" O.D. and the nut will have a 23/32" I.D., the major diameter in each part being the same 3/4".

 

[mikey]

mikey
I think I've finally got it. Continuing the 3/4" x 24tpi thread example, a bolt will have a 3/4" O.D. and the nut will have a 23/32" I.D., the major diameter in each part being the same 3/4".

The depth of cut (0.750/24 = 0.3125" = DOC). DOC is taken on the radius so at the base of the thread (the minor diameter) the dimension is theoretically 0.750 - 0.03125 X 2 = 0.6875". So, you are feeding in a total of 0.03125" but it is cut all the way around the work piece so at the bottom of the final cut the diameter of the work piece is 0.6875". This is all theoretical because there are tolerances involved but this is the concept.

 

[jamby]

When in tech school in 1965 I had to make V threads, Square threads, Acme and Double Acme threads and then the cruelist twist, had to make the nuts to screw on them. If your thread form is not right they will screw on one way but not the other... errrr
I still have the samples I made back then, thanks to my Dad. When I cleaned out his house I found them in a box in the basement. Thanks Dad!

Jim