1/2 x 28 UNF

[mattthemuppet2]

I've got a whole bunch of those taps up on eBay for not much money. Link is in my thread in the for sale section

 

[nuturner]

Lost in this rabbit hole. Rebuilding a vintage motorcycle engine and task with making various unobtainable threaded fastners.
I've searched the internet and am able to find data on 1/2 x 28 UNEF taps and dies. For reference I have been using;

1/2 - 28 UNEF : Thread Dimensions (Machining Doctor)

1/2 - 28 UNEF : Basic Thread Dimensions (Pitch, minor & major diameters, depth, lead), Tolerance range for all applicable classes and much more

www.machiningdoctor.com

&

Thread Pitch Chart (UNC / UNF / UNEF / UN)

amesweb.info

I search for; 1/2 x 28 UNF taps and dies on Ebay or Amazon .................only UNEF flavors display.
I cut 1/2 x 28 threads on my mill........... and my 1/2 x 28 UNEF tap is reluctant to thread into this hole.
No data on 1/2 x 28 UNF or does it exist?

Thank you forum!

Vloeisn New HSS 1/2"-28 UNEF Right Hand Thread Tap and Die Set (1/2 X 28) 313032292290 | eBay

Find many great new & used options and get the best deals for Vloeisn New HSS 1/2"-28 UNEF Right Hand Thread Tap and Die Set (1/2 X 28) at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[Ischgl99]

Using this cutter and program. Yes, I'm getting it. I don't know what I don't know. I should have stated that I wanted a 1/2 x 28 UNF to
check the threads I cut using the machine. 1/2 x 28 UNF only exist when I force it by a program

Where are you coming up with needing a 1/2-28 UNF thread? Was that on a drawing for the part you are looking to make?

When you are threading your part, are you compensating for the point on your threading tool? If the tool comes to a sharp point, you need to cut to the theoretical vee of the thread and not the design depth of the thread. The major diameter of an internal thread assumes there is a flat across your tool 0.125P wide, P is the pitch. If you programmed your mill to thread to the stated major diameter in the specs, then you might not be threading your hole deep enough and would cause your tap to not thread in easily.

 

[OTmachine]

ON EDIT: I responded to this thread earlier this morning when the only post was from the OP. There were 4 new responses when I returned, but mine was not one of them. I refreshed the page several times and my response finally appeared. It appears the forum is having several problems with access from different devices and posting responses from members. In addition, the links I posted to information about thread classes and thread types aren't active.

It seems that Apple devices were having problems and some Windows.

 

[OTmachine]

Do you have Thread Mics, Thread Wires, Thread Triangles, or a comparator mic to measure P.D.? Sent you a shot from H-28 Handbook. HTH, Keith

 

[WobblyHand]

Where are you coming up with needing a 1/2-28 UNF thread? Was that on a drawing for the part you are looking to make?

When you are threading your part, are you compensating for the point on your threading tool? If the tool comes to a sharp point, you need to cut to the theoretical vee of the thread and not the design depth of the thread. The major diameter of an internal thread assumes there is a flat across your tool 0.125P wide, P is the pitch. If you programmed your mill to thread to the stated major diameter in the specs, then you might not be threading your hole deep enough and would cause your tap to not thread in easily.

Quick and dirty test if you have a micrometer, measure the tap diameter and the screw diameter. If you don't have clearance between the measurements, there's no way the screw can get in the hole. Screw diameter + clearance needs to be greater than the tap diameter.

If you don't have a micrometer yet, you ought to get one. Even a cheap one (plain mechanical with vernier reading to 0.0001") is pretty good. It's an invaluable tool.

 

[mofosheee]

Do you have Thread Mics, Thread Wires, Thread Triangles, or a comparator mic to measure P.D.? Sent you a shot from H-28 Handbook. HTH, Keith

I received it thank you!

 

[OTmachine]

Quick and dirty test if you have a micrometer, measure the tap diameter and the screw diameter. If you don't have clearance between the measurements, there's no way the screw can get in the hole. Screw diameter + clearance needs to be greater than the tap diameter.

If you don't have a micrometer yet, you ought to get one. Even a cheap one (plain mechanical with vernier reading to 0.0001") is pretty good. It's an invaluable tool.

For clarification, According to what I see, he is thread milling an external thread on a CNC milling machine. Works good if you have the measuring tools to verify size and the dimensions required. HTH

 

[OTmachine]

I received it thank you!

I have a 0 - 1 and 1 - 2 interchangeable anvil mics to check threads. Just need a known P.D. thread to calibrate them to once you install the anvils. Usually, I use a similar thread that I have measured using the 3 wire method, ( man, how I miss Mecco Gages), to get a standard.

 

[Woodfab]

Could it be MF 12 1.0 metric