Ask an Engineer

[husaberg]

Any good ways to glue nitrile rubber to aluminium for long term use exposed to fuel?

http://jbmindustries.com/aboutus.html

[bogan]

So, what the fuck is up with BSP? I've been contracted in to help out with a bunch of pipework, and different suppliers seem to have a different idea of what the S bit in BSP means.

And is there a decent alternative to stilsons? sick of seeing fucking stilson marks on the pipework coming out of that workshop.

[speights_bud]

So, what the fuck is up with BSP? I've been contracted in to help out with a bunch of pipework, and different suppliers seem to have a different idea of what the S bit in BSP means.

And is there a decent alternative to stilsons? sick of seeing fucking stilson marks on the pipework coming out of that workshop.

My 2 closest resources tell me that the S means standard. Which is what I have always understood.

Though it took me over a year to convince our manager that there is a difference between a BSP taper tap (starting type tap) and a BSPT tap.

We use 1/4 inch BSPT plugs for water galleries in injection moulds and they always leaked. He kept buying tapered BSP taps. Grrr.....

(Sorry if the images are huge. Using the phone and Tapatalk)

[husaberg]

So, what the fuck is up with BSP? I've been contracted in to help out with a bunch of pipework, and different suppliers seem to have a different idea of what the S bit in BSP means.

And is there a decent alternative to stilsons? sick of seeing fucking stilson marks on the pipework coming out of that workshop.

I always though BSP was British standard pipe?

edit that's what google says but not so standard in the best of British traditions. (it has different threads lol)
https://en.wikipedia.org/wiki/British_Standard_Pipe
As for the Wrench no doubt these just leave a different kind of mark.

[schrodingers cat]

I always though BSP was British standard pipe?

edit that's what google says but not so standard in the best of British traditions. (it has different threads lol)
https://en.wikipedia.org/wiki/British_Standard_Pipe
As for the Wrench no doubt these just leave a different kind of mark.

The 'S' in BSP is certainly 'standard'

However, since there are tapered and non tapered versions, the tapered gets referred to as BSP tapered (BSPT) and the non tapered version is sometimes called 'straight' leading folks to confuse themselves by referring to BSPS - which is incorrect. The non tapered (parallel) is actually BSPF.
The 'F' refers to 'fitting'
Reason being that usually, sockets are BSPF and nipples are BSPT.

This colloquial use of 'straight' may be the cause of confuzzlement

[bogan]

Yeh I know the S stands for standard, but some suppliers BSP fitting only get like 2 turns into another suppliers ones, and some go right over the top and are still sloppy as shit. Ie, in what fucking world is that standard.

And yeh I know there's BSPT and BSPP and BSP can mean eaither of those things, especially in sizes around 1-2in

Though it took me over a year to convince our manager that there is a difference between a BSP taper tap (starting type tap) and a BSPT tap.

We use 1/4 inch BSPT plugs for water galleries in injection moulds and they always leaked. He kept buying tapered BSP taps. Grrr.....

(Sorry if the images are huge. Using the phone and Tapatalk)

This makes sense, the guys I'm working for don't use any taps though, any female thread is purchased as a fitting. Do the BSPT taps leave a nunga on the thread when you bring the tap back out? or does the backside of the previous tooth clean that up pretty well?

[speights_bud]

Yeh I know the S stands for standard, but some suppliers BSP fitting only get like 2 turns into another suppliers ones, and some go right over the top and are still sloppy as shit. Ie, in what fucking world is that standard.

Yep i'm with you now. Probably shitty suppliers that are machining to different tolerances. Are the differing parts being locally made? or are they chinese shit/good euro quality?
It doesn't take much to go from tight to sloppy on a parallel thread. My guess is that a CNC just spits them out and no one gives a damn.

As you can see in the previous photo's, the 'standard' dimensions allow for no clearance on the threads.

This makes sense, the guys I'm working for don't use any taps though, any female thread is purchased as a fitting. Do the BSPT taps leave a nunga on the thread when you bring the tap back out? or does the backside of the previous tooth clean that up pretty well?

It cleans them up pretty well, but then again we only use the small taps. 1/4 and 1/8 for plugging off 12mm waterway galleries. Nothing big like 1-2inch.
I would expect most female threads above 1 1/2" would usually be turned in a lathe?

Your guys would be cutting their own male threads though wouldn't they?
Not that this makes any difference as the problem you are having is the "same shaft, sloppy in some holes but not others"

[bogan]

Yep i'm with you now. Probably shitty suppliers that are machining to different tolerances. Are the differing parts being locally made? or are they chinese shit/good euro quality?
It doesn't take much to go from tight to sloppy on a parallel thread. My guess is that a CNC just spits them out and no one gives a damn.

As you can see in the previous photo's, the 'standard' dimensions allow for no clearance on the threads.



It cleans them up pretty well, but then again we only use the small taps. 1/4 and 1/8 for plugging off 12mm waterway galleries. Nothing big like 1-2inch.
I would expect most female threads above 1 1/2" would usually be turned in a lathe?

Your guys would be cutting their own male threads though wouldn't they?
Not that this makes any difference as the problem you are having is the "same shaft, sloppy in some holes but not others"

It's a good brand name stuff, but perhaps they outsource down a little bit. The good news is it's all low pressure anyway. Anzor or S&T fittings seems to be the good shit, it'll only on the expensive stuff we attach to this (pumps, valves etc) that we have a few clearance issues.

Some appear to just be cast, the rest machined, but given the imbalance around that axis, it might be CNC thread milled.

Yeh, that's one thing I'm going to have to fix though, big tolerance in what they make, and what I spec them to make. Sure is, good thing the goop fills em up all the same...

[speights_bud]

You might have to make them some go-no go gauges. I've made a few up for the production dept. Made a big difference in overall quality

[bogan]

You might have to make them some go-no go gauges. I've made a few up for the production dept. Made a big difference in overall quality

Yeh that's a good idea, cheers.

[Grumph]

Yeh, that's one thing I'm going to have to fix though, big tolerance in what they make, and what I spec them to make. Sure is, good thing the goop fills em up all the same...

I used to call that electricians tolerances...1/2in hole to put a small wire through...the fact that plumbers use so much joint packing as routine will always count against better quality control.

[Ocean1]

Yep, if they don't fit at least one of 'em is out of spec. Go/No go guages is a good idea.

What rips my nightie is fucking plumbers and suppliers insisting on calling them "15mm BSP"

[bogan]

Yep, if they don't fit at least one of 'em is out of spec. Go/No go guages is a good idea.

What rips my nightie is fucking plumbers and suppliers insisting on calling them "15mm BSP"

Fuck I reckon, specially since most still have the 1-1/2" cast into the bloody side.

[F5 Dave]

The B stands for British. This probably goes a long way to explaining the tolerances and why some bits have to be matched to selected other bits. Its part of the standard and part of the licencing agreement, which is incidentally why the Germans didn't get accredited and begrudgingly had to follow the French lead which as you can imagine caused much grumbling and probably lead to the first and second world war.

[schrodingers cat]

Dear Bogan, now I understand.
Your questions aren't really questions are they? It's just a thinly veiled whinge.
Next time try a. Friday night rant thread b. Expressing yourself clearly
Here's a clue: starting by asking ' what the fuck...?' Is never going to open the door wide to positive and proactive communication.
But then, that was never the point anyway as per my initial observation.