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Converting torch head to threaded fitting

Posted: Tue Nov 26, 2013 1:04 pm
by Biopyro
Torch head
Torch head
So I have this blowtorch head which allows me to get gas from my MAP-Pro cannister. It's great but as you can see below it's not very elegant, because it needs a long, thick hose to prevent kinks.
Fuel meter
Fuel meter
I remember when I built it I had a terrible headache trying to go from cannister > BSP as I am in the UK but I wanted to revisit this 5 years later since I thought there might be a new part I could use to neaten this somehow.


Ideally everything except the fill hose would be small and compact, using perhaps 8mm copper or similar to achieve this.

Does anyone know of any examples of fuel meters built by UK spudders? I am open to a total redesign.

Re: Converting torch head to threaded fitting

Posted: Tue Nov 26, 2013 1:16 pm
by jackssmirkingrevenge

Re: Converting torch head to threaded fitting

Posted: Tue Nov 26, 2013 1:24 pm
by Biopyro
I wish, alas I need it to convert to schrader and have the pressure to fill when I press the tyre-fill fitting to said schrader valve.

I am just thinking about cutting off the torch head and using a die to make a 1/4 BSP thread. This is something I've not done before - what diameter do I need my torch to be for this to work?

Re: Converting torch head to threaded fitting

Posted: Tue Nov 26, 2013 1:51 pm
by jackssmirkingrevenge
It needs to be 0.518" dia to be able to cut a male thread.

Alternatively: http://www.ebay.co.uk/itm/BRASS-BSP-Tap ... 3a6563deb1

Drill out the torch head, epoxy the hose barb to it.

Problem solved ;)

Re: Converting torch head to threaded fitting

Posted: Tue Nov 26, 2013 1:56 pm
by Biopyro
Awesome, was that number from a public resource or from memory?

It's only 11.1mm (0.437") so I think I might have to consider something along the lines of #2.

Re: Converting torch head to threaded fitting

Posted: Tue Nov 26, 2013 2:36 pm
by jackssmirkingrevenge
Memory, I've cut more 1/4 BSP threads than I care to remember ;) plenty of lists online though.

Nothing wrong with option two, use decent epoxy and you'll be fine.

I would still use syringe fuelling though - simple, easy and precise!

http://www.spudfiles.com/how-to-databas ... 22301.html

Image

[youtube][/youtube]

Re: Converting torch head to threaded fitting

Posted: Tue Nov 26, 2013 2:38 pm
by Biopyro
The other issue with the syringe option is that one of my chambers is rather large and I calculate it would need more than 100 mls of fuel. So it's inelegant and a pain in this case.

Re: Converting torch head to threaded fitting

Posted: Tue Nov 26, 2013 3:03 pm
by jackssmirkingrevenge
http://www.ebay.com/itm/Sealey-Oil-Suct ... 589dcf06c9

In the words of Arthur Smith, I'm determined to carry on ;)

Re: Converting torch head to threaded fitting

Posted: Tue Nov 26, 2013 3:37 pm
by POLAND_SPUD
You do know you can get such syringes in almost any drug store/pharmacy ??

Re: Converting torch head to threaded fitting

Posted: Tue Nov 26, 2013 5:01 pm
by jimmy101
You could just use a couple of right-angle barbs. As you said, the problem with the original setup is the large radius you need to get the hose bend without kinking. Replace all that hose with right angle barbs (or right angle fittings) and short straight pieces of hose.

http://www.smarthome.com/31018/Orbit-67 ... -20/p.aspx
http://www.ebay.co.uk/bhp/barbed-elbow

Or, just get cooper tubing of the appropriate OD and use your blue pressure hose to make the connections.

Re: Converting torch head to threaded fitting

Posted: Tue Nov 26, 2013 6:46 pm
by Biopyro
jimmy101 wrote:You could just use a couple of right-angle barbs. As you said, the problem with the original setup is the large radius you need to get the hose bend without kinking. Replace all that hose with right angle barbs (or right angle fittings) and short straight pieces of hose.
There must be some good reason why I never did this. :oops: I think because I needed an asymmetrical reducing tee and therefore had no call to order from a place with barb elbows.


I will get some and see if the neatening is to my taste, then go from there. Thanks for the suggestion.

I might thread the tip anyway, because I can drop a tee and do some neatening like that too.

Re: Converting torch head to threaded fitting

Posted: Wed Nov 27, 2013 8:52 am
by Biopyro
Does anyone know what the thread is which screws the aerator(?) onto the torch head?

I destroyed the threadlock and unscrewed the pipe but it's the same thread at both ends, neither NPT or BSP. PArallel thread with OD of 11.05mm

Re: Converting torch head to threaded fitting

Posted: Wed Nov 27, 2013 9:18 am
by jackssmirkingrevenge
If you're not comfortable with epoxy, you can always drill the inside of the head to 8.5mm, tap it for 1/8" BSP (all you need is this, female threads are much easier to cut that male threads: http://www.ebay.co.uk/itm/New-G-1-8-28- ... 25747e9738 )

Then use one of these to attach to your fittings: http://www.ebay.co.uk/itm/1-4-Bsp-Male- ... 19e2a25c4a

Side note, this turned up on google, ouch: http://bernzomaticinjuries.com/index.html

Re: Converting torch head to threaded fitting

Posted: Wed Nov 27, 2013 9:58 am
by Biopyro
Yeah I might tap the inside to a female thread but I don't know if there is enough material to do 1/8"

I've just found this: (How-To) Basic Propane Meter which is useful, it suggests that there is a compression fitting which will screw in... decisions.

Re: Converting torch head to threaded fitting

Posted: Wed Nov 27, 2013 9:22 pm
by PeteS
Another option is to find a fitting a suitable size and solder it on. I typically turn a part on the lathe or drill one out if I don't have something that fits properly. If the fit is close soldering it together is really easy, just like sweating copper pipe.