What is the screwthread on the jets for MSR stoves?

[Imagedude]

Can anyone tell me which screw thread is used on MSR stove jets? I'd like to drill some kerosene jets out to 0.8mm (1/32") as part of my alcohol conversion project. I't be nice to hold and drill the jets in a mandrel on the lathe rather than doing it by hand with a pin vice.

Cheers

Bob

 

[Rabid]

I dont know but im sure if you emailed MSR they would tell you.

 

[bilmo-p5]

Most unlikely that you would get the info you want from MSR, IMO. Stove manufacturers aren't keen on users doing their own mods, no matter how well executed they might be. Not only is it doing them out of potential business, but if they can be shown to have helped you, it doesn't look very good in court.

I'd say you would stand a much better chance if you posed your Q. in the Fettling Forum at Classic Camp Stoves.

I can't help but think that 0.8mm might be a bit on the big side for a pressure alcohol system. The gas jet (0.48, IIRC) works fine with alcohol in the Omifuel but needs substantial air restriction. Pressure alcohol stoves also use fuel like it's going out of fashion.

 

[demographic]

Most unlikely that you would get the info you want from MSR, IMO. Stove manufacturers aren't keen on users doing their own mods, no matter how well executed they might be. Not only is it doing them out of potential business, but if they can be shown to have helped you, it doesn't look very good in court.

I'd say you would stand a much better chance if you posed your Q. in the Fettling Forum at Classic Camp Stoves.

I can't help but think that 0.8mm might be a bit on the big side for a pressure alcohol system. The gas jet (0.48, IIRC) works fine with alcohol in the Omifuel but needs substantial air restriction. Pressure alcohol stoves also use fuel like it's going out of fashion.

I know its not the same but for motorbikes that run on methanol they usually run jet sizes about twice the size (flow, not diameter) of the petrol version.
Good for power but not for tank range.

 

[Nomad]

Should be able to get close with a thread pitch gauge and the outside diameter. Work out the most likely candidate thread, and then get a tap to make a holder with.

 

[Grebby]

I've just measured the spare jet for my dragonfly and it's 9.3mm diameter or .366" and as far as I could make out about 24TPI. So could be 3/8" UNF?

Hope that helps. I know that the dragonfly uses a different sized pump from standard so may have different jets

Cheers

Grebby

 

[petrochemicals]

I've just measured the spare jet for my dragonfly and it's 9.3mm diameter or .366" and as far as I could make out about 24TPI. So could be 3/8" UNF?

Hope that helps. I know that the dragonfly uses a different sized pump from standard so may have different jets

Cheers

Grebby

Well there's a school of tought concerning brass as it's soft.
https://en.wikipedia.org/wiki/British_Standard_Brass

 

[Nomad]

Well there's a school of tought concerning brass as it's soft.
https://en.wikipedia.org/wiki/British_Standard_Brass

What does that have to do with it being soft?

 

[petrochemicals]

What does that have to do with it being soft?

Brass being brass has a standard due to the soft metal needing extra special care, thus you cannot just do as you like with it as steel!

 

[Nomad]

Brass being brass has a standard due to the soft metal needing extra special care, thus you cannot just do as you like with it as steel!

News to me.

 

[petrochemicals]

News to me.

Here's another chart

http://motalia.com/Html/Charts/bsb_chart.html

 

[Nomad]

Here's another chart

http://motalia.com/Html/Charts/bsb_chart.html

What's your point? 26tpi is the only pitch a piece of brass can be threaded at?

 

[petrochemicals]

What's your point? 26tpi is the only pitch a piece of brass can be threaded at?

Nope but the thread maybe something along these lines, or it maybe msrs own creation.

 

[Nomad]

It could be almost anything - there are lots of standard threads that could be used. It's extremely unlikely to be something that MSR developed on their own - there is no point in going to the expense of defining a new thread standard and getting custom tooling made when there are already plenty to choose from.

Any of the tap-and-die ranges here can be used to cut brass...

http://www.tracytools.com/taps-and-dies

There are 32 different threadform specs on that page.

Brass might be soft, but it is eminently workable with cutting tools to very fine detail. The fact that there is a threadform called "British Standard Brass" (or 26tpi brass on the above page) has nothing to do with whether brass is restricted to being cut to that standard. It could be either of these...

http://www.tracytools.com/taps-and-dies/UNF-taps/3-8-x-24-tpi-unf
http://www.tracytools.com/taps-and-dies/brass-cycle-special/3-8-x-24-tpi

 

[bilmo-p5]

It's extremely unlikely to be something that MSR developed on their own - there is no point in going to the expense of defining a new thread standard and getting custom tooling made when there are already plenty to choose from.

Stove manufacturers' use of 'in-house' threads on their products is by no means uncommon, although I think that MSR would probably use an established thread.

 

[petrochemicals]

Well that is true. When I had an omni I remember thinking that the burner attachment screw bolt (abover) had very large sharp thread on it, and being scared of threading or striping it, as it went into the base of the burner head. I think they used brass so as to not thread the burner itself andthe thread was so pronounced so as to make threading the bolt a no brainer, and give sereous hold over such a short thread. I think that was non standard. The nipples I would hazard aguess at being standard thread.