attempting a project need help

[Suzuki4evr]

I would do as Mike mentioned, and mount the back plate to a faceplate, get it centered up, then bore to your required ID.

Next, you would need to set up a threading tool and get it properly 'registered' with the existing thread so that you can cut it deeper to achieve the new, larger thread.

According to Machinery's Handbook, you would want an ID of 2.115" to 2.1297" (class 3B thead) then cut your thread deeper until you reach the thread major diameter of 2.250". Since measuring the major diameter of an internal thread can be a bit difficult, I believe you could safely cut the thread deeper until it fits properly on the spindle thread, or plug gauge if you go to the trouble of making one.

What he said.

 

[Asm109]

You need to clock your work so the thread cutting tool exactly follows the helical path of the existing threads. Then it is a simple matter of cutting them deeper to the new size.

 

[jbalp]

You need to clock your work so the thread cutting tool exactly follows the helical path of the existing threads. Then it is a simple matter of cutting them deeper to the new size.

I guess I wouldn't know how to do that..