NPT vs BSP thread type in a new set-up

[Ducatiboy stu]

You couldn't pay me to use a carbon steel tap. It might only be 22 bucks but it'll cost you a minimum of 100 to get the ******* spark eroded out if it picks up and jams or you could just junk the bit you're tapping into and buy a new one.

Buy a HSS one and use it properly and you won't have a problem. It'll last you a lifetime too, and you can probably pay for it in beers from your mates tapping out their threads.

I write this advice as someone who made a lot of money out of removing broken taps from expensive parts in a former life.

I was yelling your name this morning

 

[Fat Bastard]

Did it get the broken tap out?

 

[TidalPete]

One would hope so FB & as an ex fitter\welder I endorse your earlier post.

On another thread-related matter ------------- Has anyone ever noticed that 3\8" BSP lock nuts are as scarce as hen's teeth?

Quite easy to buy 3\8" BSP ss hardware such as 3-piece ball valves, nipples, barbs, etc, but try to get a couple of the above lock nuts then you're doing the hard yards. Even when you do find a (rare) seller then they want an arm & a leg for a lousy ss nut. <_<

Any links to 3\8" BSP ss nuts at a reasonable price appreciated.

 

[pk.sax]

http://pages.ebay.com/link/?nav=item.view&alt=web&id=331214877221

?

 

[billygoat]

http://pages.ebay.com/link/?nav=item.view&alt=web&id=331214877221

?

You've linked to 3/8 UNC, Pete was after 3/8 BSP, no match.

Pete,
I got 3/8 BSP lock nuts/backing nuts, but in brass, from Enzed.
They said they could get SS but I settled for the brass as it wasn't in contact with wort and they had them in stock.

 

[Ducatiboy stu]

Did it get the broken tap out?

Well it took a lot of patients, some punches, small chisel, fencing pliers. and a hammer

Just took it nice and easy

 

[Fat Bastard]

Been there done that! Somewhere in my tools is a tin full of carbide and HSS rods with ground ends expressly for the purpose of slowly chipping broken taps out of valuable parts. Takes a while, but you can eventually get there.

I miss having easy access to a spark eroder though!

 

[TidalPete]

Thanks for your help billygoat & PF.
I reckon Enzed is just about the only place I haven't tried so far. Pirtek down the road couldn't help & Ebay was far too expensive.

I'll give Enzed a go next week.
I was looking at filling up a few nuts with silver solder & re-tapping. PITA.

 

[Ducatiboy stu]

I have always kept punches and chisels...come in very handy

 

[mofox1]

Thanks for your help billygoat & PF.
I reckon Enzed is just about the only place I haven't tried so far. Pirtek down the road couldn't help & Ebay was far too expensive.

I'll give Enzed a go next week.
I was looking at filling up a few nuts with silver solder & re-tapping. PITA.

Was it just 1/2" that shared a pitch with bsp, i seem to recall it was two sizes?

I've got a couple of 3/8 NPT lock nuts I can part with. Don't know off the top of my head if it's bsp compatible like the 1/2" (mostly) is.

 

[Camo6]

Been there done that! Somewhere in my tools is a tin full of carbide and HSS rods with ground ends expressly for the purpose of slowly chipping broken taps out of valuable parts. Takes a while, but you can eventually get there.

I miss having easy access to a spark eroder though!

Reminds me of the Ford 5.4l 3 valve engine. At higher kms the lower half of the spark plug would carbon up and snap off in the head on removal. The trick was to de-carbonise and get the bugger red hot (a solid roadtest with the thermo fans unplugged helped). When they snapped it was a case of chipping away the ceramic insulator with a centre punch until you could tap the shell and remove it with a puller...or pull the heads off.

 

[TidalPete]

Was it just 1/2" that shared a pitch with bsp, i seem to recall it was two sizes?

I've got a couple of 3/8 NPT lock nuts I can part with. Don't know off the top of my head if it's bsp compatible like the 1/2" (mostly) is.

Thanks for the offer mofox1. It's much appreciated. :icon_cheers:

You're probably referring to both 1\2" & 3\4" BSP & NPT that are compatible in a no-pressure situation like ours.
3\8" BSP is 19 TPI & 3\8 NPT is 18 TPI more's the pity.

 

[mofox1]

Thanks for the offer mofox1. It's much appreciated. :icon_cheers:

You're probably referring to both 1\2" & 3\4" BSP & NPT that are compatible in a no-pressure situation like ours.
3\8" BSP is 19 TPI & 3\8 NPT is 18 TPI more's the pity.

Came across these guys: http://www.kingfittings.com.au/collections/stainless-steel-fittings/products/lock-nut-stainless-steel-bsp

3/8" lock nuts for $5.45, + $20 postage... although if you're in the brissy area you might be able to pick up.