The MGA With An Attitude
MGA FASTENERS, Original Threads - RT-104A

Michael, At 10:20 AM 1/5/06, Michael Sloan wrote:
>"I have to provide a lot of nuts and bolts. Is there any rule of thumb as to what is course or fine thread? I don't want to order individual pieces out of the catalogue if I can help it."

Since the car was designed well after WW-II, nearly all of the fasteners are Unified Thread Standard, fine or coarse. Most are UNF, which is functionally interchangeable with SAE fasteners. There are a few UNC threads on the bottom end of double threaded studs, particularly in the engine block (head bolts) and transmission case (soft alloy casting). Virtually all of the body and suspension bolts and most of the drive train fasteners have UNF threads.

So head off to the local hardware store, or auto parts store, or visit the McMaster Carr web site, and stock up on inch size fine threaded nuts and bolts. Get lots of them in 5/16-24-UNF, some in 1/4-28-UNF, and some in 3/8-24-UNF. Get flat washers, lock washers, and hex nuts in boxes of 100 for 1/4-28, 5/16-24. and 3/8-24 (all UNF).

You can often buy fine/coarse threaded studs at a local auto parts store, but fine/fine threaded studs may need to come from a Brit parts supplier. They are not expensive, and you don't need to replace them very often, so just buy a couple spares for each size for inventory.

There are a few odd threads (pre-WW-II era design parts) on the MGA, but not needing replacement very often. Such are the SU carbs, SU fuel pump, and Auster windscreen frame, which all use British standard BA threads. There are also a few BSP straight pipe threads in the sides of the engine block and oil drain plug.

Early on I bought a few small hang on the wall cabinets with lots of little plastic drawers for the fastener inventory. Anything special is in little envelopes or baggies stored with the related mechanical parts.

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