Spindle Thread Damage on NOVA Lathes
When approaching this problem, unless the threads have little or no vestige of usability left, the best answer is to use what is called a chaser (also called a re-threading die).
This step (chasing the threads) is the first thing that our Service Team attempts when a DVR Headstock comes in with this problem. Our Service Team reconmends to attempt it with the help of a machinist.
While the rotor/spindle can be removed, it is not a simple task. In general it is better to ship the whole DVR Headstock to us. When shipping your DVR Headstock to us, it will require special packaging as it needs to be double packed (think of it like packing 100lbs of eggs). Please note that in addition to any parts and labor charges incurred, there will also be a return freight charge. Our Service Centre is located in St Petersburg, FL (see our FAQ Guide for Shipping Items to our Florida Service Center).
The following list are places in the USA to acquire the correct sized re-threading die. For NOVA lathes that size is 1-1/4" x 8TPI UNC, with the exception being the NOVA Comet II, which is 1" x 8TPI UNC.
Gyros (92-98008) 1-1/4 - 8 Carbon Steel Hex Rethreading Die
Gyros 92-40108 High Speed Steel Die 1-8
The following are some DIY videos that may help with this procedure
How to use a tap and die - FIXING STRIPPED THREADS
MACHINE SHOP TIPS #1 Taps tubalcain
MACHINE SHOP TIPS #4 Dies/Threading
MACHINE SHOP TIPS #5 Dies/Threading