DA Backing plate washer and adapter

[FPEvo]

Two quick questions.

When using the DA Adapter that let's you use a rotary backing plate on a DA, do you need a washer?

Second, where can you get the washers that go on the back of the standard DA backing plates?

Thanks

[BobbyG]

To be honest I've never seen one of these. I'm not implying they don't exist but backing plates are pretty inexpensive so I've opted for dedicated plates.

All rotary machines use a 5/8-11 thread and dual action polishes a 5/16-16. The 5/8-11 is a female design and 5/16-18 a make design.

If I were to design such an adapter it would need to fit snugly in the larger threaded hole and somehow lock in place. This design would need to incorporate a 5/16-18 set screw that would allow the assemble to mount on the dual action polisher...

The dual action washers function as a spacer to keep the plate away from the machine housing. Any washer should do the trick but looking at the gap to ensure clearance is maintained is about all that's required. I have a Porter Cable 7424 and although it did come with one of these it disappeared long ago and I don't use one to this day..

[FPEvo]

Thanks for the reply Bobby. The adapter I'm referring to is this one below.

D.A Adapter 5/8" X 11 (http://www.autogeekmobile.net/daadapter58x11.html)

The one I bought is the same however it did not include the washer on the 5/8's thread side. I bought this to use with the 2 7/8 rotary backing plate for the MF 3 inch discs

[C. Charles Hahn]

I've got one of those adapters and have used it a few times when I have two DAs in concurrent use; I've never used a washer between the spindle assembly of the DA and the adapter, and it's been fine.

You'll need either a pair of pliers or a deep socket and the DA flat wrench to remove the adapter from the spindle afterward though.