5/8" - 11 Threaded Shank Adapter

5/8"-11 to 5/16"-24 Adapter for DA Polishers

The Buff & Shine DA5816 is a 5/8"-11 to 5/16"-24 adapter: a double-ended stud with male threads on both ends. The 5/16"-24 end threads into the spindle of a dual action polisher, and the 5/8"-11 end takes a backing plate with a female 5/8"-11 insert, so a plate built for a rotary or a drill runs on an orbital machine instead. Buff & Shine pairs it with its 3" rigid backing plate (part 358), and the two ship together in Buff & Shine's 3-inch small buffing kit, which it lists for orbital, rotary, and drill use. Detailers and body shops use the combination to put a 3-inch spot-repair plate on the DA they already own.

Its look-alike, the SP5814 drill shank adapter, has the same 5/8"-11 end but swaps the 5/16"-24 thread for a 1/4" shank that a drill chuck grips. Check your polisher's spindle before ordering: this adapter is 5/16"-24 only, and machines with an M8 spindle need a different part. Buff & Shine's own parts list for its 3-inch kit (TP-4), sold here as the 3" buffing starter kit, includes the 358 plate, both adapters, and 3-inch wool and foam pads.

What Makes it Great:

🔩 Male Threads on Both Ends: The adapter becomes the plate's spindle. Thread it into the DA, then spin the plate on exactly as you would onto a 5/8"-11 rotary.

🎯 3-Inch Spot Work on a DA: With the 358 rigid plate on top, a dual action polisher works a single scratch, chip repair, or sanding mark instead of the whole panel.

🔁 One Plate, Three Machines: The 358 plate runs on a rotary's 5/8"-11 spindle, on a drill with the SP5814, or on a DA with this adapter. Only the adapter changes.

📏 Inch Thread for Inch Spindles: Made for the 5/16"-24 spindle common on North American dual action polishers, not metric M8.

Frequently Asked Questions

Is 5/16-24 the same as M8?

No. The diameters are close, 7.9mm against 8mm, but 5/16"-24 has 24 threads per inch, about 1.06mm per thread, while M8 runs 1.25mm. Forcing one into the other cross-threads it and can damage the spindle, so this adapter is for 5/16"-24 spindles only.

Can you put a rotary backing plate on a DA polisher?

A plate with a female 5/8"-11 insert can go on a 5/16"-24 DA with this adapter in between. Buff & Shine builds that setup around its 3-inch rigid plate and lists the kit for orbital machines.

What is the difference between the DA5816 and SP5814 adapters?

Both have a male 5/8"-11 end for the backing plate. The DA5816's other end is a male 5/16"-24 thread for a dual action polisher's spindle, and the SP5814's is a 1/4" shank for a drill chuck. Pick the one that matches your machine.

Specifications:

Installation (Best Practices):