Element Threads

[Blue Zulu]

I see on the Hayden Website that the thread on their Kettle Elements are M40 x 1.5 and that a KM8 Lock Nut has a M40 x 1.5 thread and hence why they are used to secure these Elements.

I also see on the Backer Website that the thread on their Kettle Elements are 1 9/16" (No T.P.I Given)

I see on various posts that people are using the M40 x 1.5 KM8 Nuts on the 1 9/16" Backer elements.

Are the threads simply a close enough match (Metric and Imperial thread sizes are never completely compatible) and it is a bodge job or is in fact the Backer Elements actually an M40 thread?

Cheers
Neil

[Normski]

Hi Neil
Can you post the links to the elements you are quoting.
I had problems getting M40 nuts to fit, Will give more detail when i can double check against your links.
But in general, i found the Imperial and metric were not compatable.
Norm

[Brighteyebeer]

Hi Neil

Can't answer your question about the 19/16" and M40 x 1.5 threads being the same, but, like you, I've often seen those thread sizes quoted for elements and lock nuts.

What I can say is that I've used slimline M40 lock nuts successfully (I rejected the KM8 bearing nuts as too 'clunky'). I posted about it here:

viewtopic.php?f=6&t=59259

Since then, I've used the same lock nuts on both Millers Vanguard and Backer elements in a s/s boiler - no leaks or problems . AND it leaves enough thread to fit a shroud.

Cheers,
Chris

[chastuck]

I've used the Backer elements with KM8 lock nuts with no problems. Some KM8 nuts are better than others. Try and find ones made from stainless steel. Some are only made from mild steel and rust behind the nut where you can't see it. I bought my SS KM8s from here: http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0121950446.

[angelHomeBrew]

This is interesting as I am just having stainless steel shrouds/fitting nuts manufactured to fit the backer elements now

I have sent elements off to a few places and several people have been scratching there heads trying to identify the thread for a few weeks and finding it doesn't match any of their extensive range of thread gauges

It's not M40 x 1.5 although this may just about provide enough of a fit. Apparently it is an old imperial thread which has stuck and a nearly impossible to find anything for or reproduce

However, having correctly threaded fitting nuts/shrouds made for these now

[chastuck]

It's more than "just enough fit" in my setup - it's a perfect fit.

[Ben711200]

Likewise. I use KM8 locknuts on Backer elements and the fit is good enough that I would never have identified it as being wrong or a forced fit. The 1 9/16 threaded elements sold by Peco (the Electrim people) also come supplied with KM8 locknuts. More than close enough, a happy coincedence and not a bodge, IMO

[angelHomeBrew]

Ok, sounds like the KM8 nuts fit fine

Maybe I'd be better just get them all M40 x 1.5 threaded so would fit Haden and backer

Anyway, I've left it in hands of people who know a lot more about this threading stuff than I do

[mrlard]

i believe the threads are m40 and din32

[angelHomeBrew]

The guy did tell me the name of the backer one but I forgot, will see him on weekend but it was some imperial 1- 9/16" thread that was more commonly used by british gas some time ago

He was comparing it to the story about threads used on scaffolding clips. Apparently these are mostly still an old unusual imperial thread that hasnt changed but you can get a metric nut/spanner close enough that will fit

[Blue Zulu]

Thanks for all the replies - they are much appreciated.

The reason for asking is that I am machining some shrouds out of Delrin/Acetal and to avoid stripping the threads I need an exact match. You can see from the picture below that the diameter is exactly 1 9/16" and not 40mm so they are not an M40 thread. I know a KM8 locknut with an M40 thread will fit, but it is not an exact match.

[IMG]http://i470.photobucket.com/albums/rr62 ... dlpbu8.jpg[/IMG]

It does look like it has a 1.5mm pitch but it could also be 18T.P.I

[IMG]http://i470.photobucket.com/albums/rr62 ... 1evroi.jpg[/IMG]

[IMG]http://i470.photobucket.com/albums/rr62 ... lj21kk.jpg[/IMG]

So it could could be a 1 9/16" UNEF thread.

http://mdmetric.com/tech/thddat9.htm#uef

Anyway, whatever it is, it is certainly an unusual thread form that I have never heard of before.

Will post some pictures of the finished articles.

Cheers
Neil

[Blue Zulu]

Hmm... looks like there is some restriction on me posting my photos as I have just done a test post on some other forums and working ok on there????

[Horden Hillbilly]

Thanks for all the replies - they are much appreciated.

The reason for asking is that I am machining some shrouds out of Delrin/Acetal and to avoid stripping the threads I need an exact match. You can see from the picture below that the diameter is exactly 1 9/16" and not 40mm so they are not an M40 thread. I know a KM8 locknut with an M40 thread will fit, but it is not an exact match.



It does look like it has a 1.5mm pitch but it could also be 18T.P.I





So it could could be a 1 9/16" UNEF thread.

http://mdmetric.com/tech/thddat9.htm#uef

Anyway, whatever it is, it is certainly an unusual thread form that I have never heard of before.

Will post some pictures of the finished articles.

Cheers
Neil

[Horden Hillbilly]

Hmm... looks like there is some restriction on me posting my photos as I have just done a test post on some other forums and working ok on there????

Yes, I've posted your pics for you. There's a restriction on new posters as part of the anti spam measures.

[Blue Zulu]

Thanks HH, much apreciated - figured it would be something like that.

Cheers
Neil