TA Rear Trunnion

[Monoxidemanor@aol.com]

Dear Kimberites: We erred. Dave Dwyer pointed out that the threads for the large retaining nuts on the ends of the rear trunnion housings are left hand threads on both sides of his J2 and TA. We took a second look at the ones on our car as well as the replacement parts from Sports & Vintage and found that they to were both left hand threads. Our mention in our earlier message that they were L/H and R/H threads was in error. The trunnion housings themselves are both left and right since there is a slot to slide the rear spring ends through the housing which faces forwards on both sides. So, the question of which replacement end goes where is resolved with ease. Question. Neither Dave or nor we know why they are left hand threaded. Does anyone else on the list have any incite on this? Kindest regards, Alan & Victoria Campbell

[C. Knight]

Monoxidemanor@aol.com wrote:

> Question. Neither Dave or nor we know why they are left hand threaded. Does > anyone else on the list have any incite on this?

I think the reason for the LH thread is to simplify the manufacture of the nut. Cutting a RH thread right into the blind hole of the nut would have been very difficult on a conventional screwcutting lathe. The swarf would be forced ahead of the tool to jam against the blind base of the hole giving a very high risk of tool breakage. The LH thread allows the machinist to cut the thread from the base of the blind hole outwards. The design appeared on the very first MG designed chassis in 1930 and remained unchanged on all Midgets from C type to TB. Best wishes Cliff

[C Sherriff]

Message text written by "C. Knight"

>The LH thread allows the

machinist to cut the thread from the base of the blind hole outwards. The design appeared on the very first MG designed chassis in 1930 and remained unchanged on all Midgets from C type to TB. Best wishes Cliff