Trying to identify a bird-feeder thread.

Hello guys,

I would like to make a pole top (ferrule) for a bird-feeder but the female thread in the feeder appears to be a strange size.

Holding digital calipers against the thread across the two crests of what I imagine to be the male thread that would fit into the feeder, I get about 20.8mm.

Using a thread gauge the nearest I can see is that it's 1.75mm (the largest I have) or possibly 1.8mm pitch.

Using an online calculator this all works out to be 13/16" by 1/16" pitch.

Is this a standard thread or maybe a pipe thread of some description?

The inner most crests of the female thread are turned quite flat.

Thanks,
Ed.

1.8mm pitch is close to 14tpi, 1/2" BSP is 20.995 OD so could be that

Try 1/2 BSP

Rgds Simon

edit Jason types faster n' me

Edited By Simon Williams 3 on 17/09/2023 13:56:16

Jason just beat me to it - BSP 1/2". common in tube or pipe work. Noel. I got the bronze medal

Edited By noel shelley on 17/09/2023 13:58:34

Thank you guys.

Ed.

It looks like an American feeder that we have, so likely to be made to Imperial dimensions, rather than Metric dimension..

1/2 BSP is 0.825 (20.955 mm ) OD with a core of 0.734" (18.644 ) and is 14 tpi.

American pipe threads usually differ from BSP by 1 pitch, but in this case both are 14 tpi. but will be 60 degree rather than 55 degree Whit form.

So a wild guess suggests 1/2 NPS as close to your measurements (1/2 NPS is 0.840" (21.36 mm) OD, with a core diameter of 0.747 - 0.759" (18.97 - 19.23 mm  )

Howard

Edited By Howard Lewis on 17/09/2023 14:52:48

This is the cast alloy bottom of an old feeder I threw into the scrap metal bin a few weeks ago. Tap would well in just by hand

It might be worth measuring other dimensions if there is a concern that US threads may be used. If the rest of the product is metric, the thread is more likely to be BSP / G, the "metric" standard.

Brian G

Grip fill of similar came to my mind, but I am a Philistine with to many jobs to get on with. lol

Pete

I found and tried a 1/2" BSP tap and it starts to screw in a bit but it's too long for the blind hole. A bottoming tap would be better and I might have one in work. I can check tomorrow.

The feeder was purchased here in the UK.

Ed.

Hi Ed,

Good look with finding a solution. I couldn't resist commenting as follows...

The notion that the thread of your bird-feeder moulding conforms to a standard, I’d suggest the odds are in favour of the thread having little to no relationship with any standard.

Unless I've missed something, there would be no particular reason to conform.

Ask me why.

Cheers,

Sam

Any manufacturing facility will try to work to standard threads, for costv reasons, unless aiming to capture a niche in the aftermarket.

So a non standard thgread will only be used for a very good reason (Exclusivity being one )

If the feeder is of American origin, *As are some sold in UK ) the thread is most likely to be 1/2 NSP.

If it is UK manfactured, might well be 1/2 BSP. Both are 14 tpi, but different thread form. So one may screw into the other.

Probably won't matter too much, since no sealing or great tensile loads involved.

If Continental might well be what they call Gas, (Or Gaz ) but actually BSP.

The main thing is to be able to secure the feeder to post withot fear of it falling off, or spinning in the wind.

Howard

Edited By Howard Lewis on 18/09/2023 13:22:40

If I understand the situation, my approach would be minimally sophisticated. Assuming I wanted it mounted on a pole, I would get a broom handle of slightly greater diameter than the thread OD, then plane or sand a shallow taper on the appropriate end to a bit less then the thread ID. Then screw on the feeder to get a witness of the thread, trimming the length back if necessary. This may achieve sufficient retention, but if not, resort to a triangular file to form a deaper and longer thread until it is judged adequate.

If the feeder is plastic, be careful not to split it, so perhaps resort immediately to filing the thread. Araldite enthusiasts could use glue instead of making a thread, assuming a full H&S assessment was completed first.

Fully agree, on this spendid forum, with load of very techincal help, things are very often over thought sometimes?

My referance to Gripfill, have a look on Screwfix or wherever, to my my mind was a realistic solution, especially with ragging up the pole. As I said, to me there are far more important things to do than whittle about what the tread is, its a support for a bird feeder, plastic or ali, we dont know. As usual we are asked to find a solution without the full facts, its still a bird feeder support.

Pete

Double post, think the micro wave oven took the wiffi out? 

Edited By Pete White on 18/09/2023 19:41:31

If someone produces a table of bird feeder threads and other useful standards like watering can rose tapers, outside tap connector threads (there are at least three) and pea netting mesh sizes, we could produce a pull out for MEW.

Neil

Considering the many possibilities Neil, it would be some pull-out.

There was a booklet available years ago that provided 108 (one hundred and eight) thread-profile variations for glass bottle-thread finishes.

I can't recall the title, and my copy probably went out in one of my rare 'tidying up' exercises.

Cheers,

Sam

Clearly, Ed’s intention is to erect his bird feeder on a pole.

The need to measure and therefore determine whether thread pitch, profile, and diameters, conform with a particular (engineering) standard is understandable. It offers a simple solution to the perceived home workshop limitations and available tools. Howard’s point too is also valid as far as ‘design economy’ is concerned.

This however, is where things come unstuck and why I couldn’t resist a bit of superficial nit-picking. After all it’s ‘only’ plastic not an exotic material, so who cares?

Well, after years in TS often analysing a plethora of design-related product failures, I do for one!

Fully respecting Ed’s plastic ‘bird-feeder-on-a-pole’ issue, my comments are more a message for readers led into the impression that engineering standards are equally applicable to plastics. That is not necessarily true!

Choosing an off-the-shelf mechanical engineering standard can invite failure. Thus we see yet another product assigned into the bl***y plastic category.

While looking up suitable thread standards for plastics materials, and especially responding to Neil’s suggestion, take a squiz at this one.

DIN 6063-1 - Threads, mainly for plastic containers - Part 1: Buttress threads, dimensions.

**LINK**

At least that’ll be a start.

Good luck to all who sail in her.

Sam

Ah but you also need to consider the commercially sold poles which tend to be supplied in reasonably short lengths for easy postage and screw together often with threaded connectors and you can also buy extension poles. Keeping these to both a standard thread and also one that works with metal tube makes it better to use the same thread for the bird feeder at the top of the pole too.

I am not sure that it matters what the thead is, Ed has measured the internal size and the pitch can be carefully counted, thread form can be estimated? So there is enough information to start screwing until a nice fit is achieved to my mind?

We are not needing high precision engineering and with a bit of glue the job would be a good un....or could it be a 3D printing project?

Pete