1/4F to 3/8M UNC Adapters

[daveintheshire]

Hello All,

This isn't going to bring about a revolution in binocular astronomy, but I hope it's worth recording for anyone Googling along these lines.

I like to use my Helios Apollo 15x70 on a generic Chinese trigger grip ball head and Amazon Basics monopod.  The monopod has a male 1/4 UNC thread, while the ball head has a 3/8 UNC female, necessitating the ubiquitous adapter.  I found that the 1/4 UNC to monopod top surface interface was not sufficiently recessed to accommodate the lip found on the most common type of adapter.  The result was that the lip was sandwiched between the top of the monopod and the bottom of the ball head.  This means that all of the weight of the binocular and trigger grip is being borne through the threads, adapter and thread/plastic interface of the monopod, rather than the bottom of the ball head bearing on the top of the monopod with the thread acting as a locator.

I had considered cutting a washer from something like a plastic milk bottle, but it seemed to be a cure rather than prevention.  The answer lies in a different style of adapter:

The one on the left is the one - please excuse the photo quality.  As it has no lip there is nothing to be sandwiched between the ball head and monopod (or tripod). A screwdriver can be engaged from the inside or outside, but fitting it onto the 1/4 thread first ensures it does not go to far into the 3/8 thread, which would loose you some purchase when attching the monopod.  It is also much more tolerant of screwdriver width as it is slotted across the full width of the adapter.  The adapters are available for cheap on the usual big auction site.

Clear Skies,

Dave.

[NGC 1502]

 

Thanks for the post.  Sometimes it’s tiny accessories like this that get the job done.  If the exact part cannot be found anywhere, I’ve often raided the  “come in handy sometime” box in the shed and adapted something or scratch built it from raw materials.  Hours of fun on a wet afternoon ?

Ed.

[Alan White]

Thank you Dave,
An interesting and improved over the basic cheapies as on the right in your image.
Almost all monopods or tripods need this adaptor at some point, for Astro or otherwise.

[BinocularSky]

On 29/08/2018 at 20:57, Alan White said:

Almost all monopods or tripods need this adaptor at some point, for Astro or otherwise.

Not the Manfrotto 679B - it has a spring-loaded 3/8" sleeve that just pushes down out of the way if you are using something that needs 1/4".

Small(er) point: I'm pretty sure the photographic threads are Whitworth (BSW), not UNC. Not usually a problem except at 1/2", but the thread profiles and angles are slightly different. (Would be delighted to be shown to be wrong, if I am)

Edit: I do sit corrected. Early RPS standard was BSW, but ISO 1222:2010 now specifies UNC.

[daveintheshire]

You are quite right, Steve.  There seemed to be enough “compatibility” at least on the 1/4 inch to more or less get away with it. My first L bracket was a piece of wall plate strap bent through 90 degrees with a vice and a 2lb hammer. This was secured to a borrowed Bushnell 10x42 NatureView with a scrounged Whitworth bolt ?