Installing a '31 Roadster passenger side stanchion mounted mirror

[bogiediver]

Got conflicting information from various sources...

Marco indicated the driver's side is supposed to drilled with a nut on the inside of the stanchion, as I found on mine. I asked him because I was taking the driver's side mirror off to check the thread and discovered there is a nut that appears to be somewhat loose inside the stanchion. I was able to pull out on the stem while turning and got the nut to tighten back up and then also tightened the jam nut - so I think the driver's side is good again. But, he didn't really address the passenger side.

I wasn't expecting a nut inside - I thought the stanchion was drilled and tapped. I was planning to do the same for the passenger side.

I sent the following request to two of the vendors who sell the mirror...

*****

1930-31 Post Mirror

How is this mounted to the passenger side of a '31 Roadster that does not currently have one?

Is it simply drill the 25/64" hole, tap with 7/16-20 thread?

Is there enough metal for the threads to
hold?

I've heard others say a nut inside the stanchion is required... if so, how does one do that?

Thanks for the advice.
*****

One reply said:
The stanchion has enough metal there for the threads to hold (with the jam nut) and is just drilled at 25/64ths and tapped at 7/16-20.

Second reply said:
There is not adequate metal thickness to just "drill and tap" the stanchion.

You will need to backup the area with a taped 7/16-14 nut plate. The other small modification is the area where the mirror mounts should be flattened for the mirror to mount securely and match the drivers side.

The inner post liner will need to be removed to access the inside of the stanchion. You will need a thin abrasive wheel to cut through the welds without damaging the stanchion. The liner will need to be re-welded when you reinstall it.

Not an impossible task, just time consuming and patience is needed.

One makes it sound easy - the other not so much (also note they mention different tap sizes. - my using the jam nut to size it comes in at the 7/16-20...)

Anyone done the simple drill and tap? How's it worked out over time?

Don't like the wind-wing mirror - have one, can't see anything out of it - too much vibration and just more weight for the brackets to have to support - so that's not a viable alternative.

Thanks!!