Is 1" x 14 t.p.i. antenna mounting thread just BSP?

[jdc]

I want to make some extension pieces to my comms post and need to get the appropriate stainless steel pipe, die and fittings.

Antennas are usually described as having a "standard 1" x 14tpi thread". I think the thread might be 3/4" BSPT but can not confirm this after a bit of Googling. 3/4" BSP, is, according to Wikipedia, 14tpi with a major diameter of 1.04" and a minor diameter of 0.95" so there's a good chance.

Does anybody know and/or have successfully built a comms post themselves?

 

[earlybird]

1" x 14tpi is not BSP.
AFAIK, it is a 60 deg. thread sometimes referred to as UNS, ie Unified Special series.
A 3/4" BSP tap might enlarge a 1" female thread to make a bodge job though!

 

[rogerthebodger]

As earlybird said antenna mounting thread is not BSP but it is quite close. I have used a 3/4 inch socket to plug up a spare antenna mounting and it has worked OK so far but the mounting is quite loose so would not have the strength of the correct thread.

You can get antenna extension from Shakespeare like one of these

http://www.ebay.com/sch/i.html?_odk...extension&_nkw=antenna+extension&_sacat=26443

 

[jdc]

UNS

1" x 14tpi is not BSP.
AFAIK, it is a 60 deg. thread sometimes referred to as UNS, ie Unified Special series.
A 3/4" BSP tap might enlarge a 1" female thread to make a bodge job though!

Thank you, that's very helpful. I do not want to make a bodge of it, hence the question on here! Where one gets a UNS 1-14 die from heaven knows; it begins to seem that I'll have to abandon doing it myself and get what I need made up by a specialist, unless a standard part exists.

What I need is a sort of Y piece with a female thread on the bottom and two vertical sections with male threads on the top. This is to get two antennas down the one hole since I've now filled all the existing mounts on the comms post. The two antennas would need separating by about 20cm (not critical) and it should be as short as possible consistent with being able to thread the cables down (one's a GPS receiver at ~1.5GHz and one a Navtex receiver at ~500kHz, so there should not be any issue with RF coupling).

The Y needs to be 316 stainless. I've not seen such a part for sale by Glomex or Shakespeare for instance. I guess I could alternatively get a completely new comms post with space for 4 rather than 3 antennas, but had hoped for an easier and possibly cheaper solution.

 

[prv]

Last winter Colin (Colhel on these forums) kindly machined me a small part. The thread on that was simple metric (M10, I think), but during conversation he happened to mention that he cuts threads on his lathe rather than using taps and dies, and can set up any size required. I don't know whether that extends to completely arbitrary choice of thread form, but it seems like it may do.

Worth a PM?

Pete

 

[Hugh Foulis]

Where one gets a UNS 1-14 die from heaven knows;

I once took an unknown size screw for which I had no metric or Imperial tap into our local proper tool/ steel stockist. Took them 20 minutes with a range of catalogues to identify the thread, so I said I could be whistling Dixie as far as getting a tap is concerned. Guy says, no, we have 6 in stock.

Just cos its not a common thread doesnt mean taps and dies will not be available.

 

[Bilgediver]

Tracy tools supply 1" UNF 14 TPI taps dies etc

http://www.tracytools.com/1-x-14-tpi

 

[DinghyMan]

Last winter Colin (Colhel on these forums) kindly machined me a small part. The thread on that was simple metric (M10, I think), but during conversation he happened to mention that he cuts threads on his lathe rather than using taps and dies, and can set up any size required. I don't know whether that extends to completely arbitrary choice of thread form, but it seems like it may do.

Worth a PM?

Pete

I do the same - you can get better choice of custom threads and a better fit that way as they can be made under or over sized, for a lot of the dive stuff I make I make one half and then cut the thread to the fit required rather than to a standard size.

Choice of threads is just down to the gear set that you have and as I cut mostly metric I can just set the lathe up for the pitch I want and diameter is irrelevant.

 

[rogerthebodger]

If it's only the male thread you need there is an fitting available that hast a male thread that fits onto a 25mm o/d pipe.

http://aaaworld-wide.com/product_info.php?cPath=7&products_id=774

The Y could be made from standard pipe fittings or fabricated.

 

[PKDJ]

Hi,

I know this is an old post but have just spent a while trying to find a fitting with a 1-14 UNS thread to use to mount an Airmar wind speed transducer. After much searching I found out that ORFS fittings have a UNS thread (UNS is an american thread and now more commonly known as ORFS.

ORFS fittings are fairly common and available from Hydraulic companies (in stainless as well) and you can get various adaptors etc that will convert from ORFS (UNS) to other threads.

ta

PKDJ