Do not attempt to recut a thread with a different die. That is an incredibly dangerous thing to do.
When you run a die with a different "pitch" over an existing thread it cuts through that thread at a shallow angle and now, instead of a continious thread from top to bottom, you have a thread cut into segments from top to bottom and the only part that holds is that shallow angle cut.
Plus, like Schurkey said, cut threads are much different than rolled threads.
Get yourself a thread pitch gauge.
They come in standard (sae) and metric.
An SAE thread gauge will not fit on any metric bolt
A metric will not fit on any SAE bolt.
The thread gauge will fit exactly to the thread space on the bolt in question
No gaps
Once you find the proper gauge fit, you know if its a standard bolt or a metric and you know the pitch.
Now, you need to know the "major basic diameter" of the bolt
The outside dimension of the threads
In this case .306
So, because of tolerence and cheap ass bolt at .306 it could be a M8x1.25
But it isnt
It is a 5/16-18 because a metric thread gauge would not fit but the SAE 18 thread fits perfectly
The next part of the puzzle is a thread chart
Most hardware suppliers have pocket reference books for a couple of bucks that will show commonly available thread sizes.
There are online calculators that will convert decimal to fraction but they are mainly useless.
It doesnt help to know that your decimal converts to 122/177
You just need a bolt.
When you run a die with a different "pitch" over an existing thread it cuts through that thread at a shallow angle and now, instead of a continious thread from top to bottom, you have a thread cut into segments from top to bottom and the only part that holds is that shallow angle cut.
Plus, like Schurkey said, cut threads are much different than rolled threads.
Get yourself a thread pitch gauge.
They come in standard (sae) and metric.
An SAE thread gauge will not fit on any metric bolt
A metric will not fit on any SAE bolt.
The thread gauge will fit exactly to the thread space on the bolt in question
No gaps
Once you find the proper gauge fit, you know if its a standard bolt or a metric and you know the pitch.
Now, you need to know the "major basic diameter" of the bolt
The outside dimension of the threads
In this case .306
So, because of tolerence and cheap ass bolt at .306 it could be a M8x1.25
But it isnt
It is a 5/16-18 because a metric thread gauge would not fit but the SAE 18 thread fits perfectly
The next part of the puzzle is a thread chart
Most hardware suppliers have pocket reference books for a couple of bucks that will show commonly available thread sizes.
There are online calculators that will convert decimal to fraction but they are mainly useless.
It doesnt help to know that your decimal converts to 122/177
You just need a bolt.
You must be registered for see images attach
You must be registered for see images attach
You must be registered for see images attach
You must be registered for see images attach
Last edited: