Barbed steam fitting.

[Tin Falcon]

As many of you know I posted a photo of a steam fitting that I use on my engines.
Bob has expressed an interest in using that design for the team build.
I promised him some suggestion of how to machine it. Not that it is a hard part but there are a couple of pitfalls to avoid . for instance if you drill the hole then thread with a die it is not hard to rip the newly threaded section off the end of the part.
Bob: rather than sending the info in a PM or e-mail decided to post it here for all to benefit from. Use this as a guide. hope it helps. then add to this thread with photos etc. so here is a sketch I did up. If you have questions just ask glad to help.

Be sure to de-bur /smooth all edges preferably in the lathe.
Tin

 

[Powder keg]

If I had to make many of those a form tool made on a surface grinder would be the trick. What! you don't have a surface grinder? How bout a mill? If you take it easy, you can do some grinding in a mill. Just make an arbor for your grinding wheel and mount it in your spindle. Dress the wheel to the shape you want and start grinding. You could probably do this in the lathe also if you thought it through.

We did a few jobs like this before we got our little grinder at work.

Have a great day! Wes

 

[Tin Falcon]

Wes:
If I were to make a form tool for this job I would carve it out by eye with diamond wheels in the Dremel tool. The way i typically do these is grind the required angle on a parting tool them make multiple cuts mostly by eye.
Tin

 

[Bogstandard]

i don't want to get involved, but maybe a little pointer on your barbed spigot.

if using silicon tubing for your connection it has a few properties that you need to know about.

it will grip like the proverbial s##t to a blanket on irregular shaped items, especially if it is stretched slightly. the problems occur when you 'nick' the surface. you will find it will just keep on tearing.

if i could make a suggestion. go over your barbs with emery, and knock all sharp edges off, it will grip just as well with nice rounded corners and won't have a tendency to keep splitting and tearing off.


john

 

[Tin Falcon]

John:
Most of us here in the states use plastic aquarium tubing and run low pressure compressed air. It does grip quite well sometimes you need to cut it off.
As far as knocking off the sharp edges absolutely. I may not have been totally clear here but I usually leave just a little flat at the top of the barb so it is not a sharp knife edge. I have used this type of fittings for 5 years at various ME shows and have not had a line tear yet.

i don't want to get involved, but maybe a little pointer on your barbed spigot.

Sure you do John you want to get your two pence worth in. But I do not mind helpful suggestions. ;D


Tin

 

[compound driver 2]

Hi
why are you even using plastic anything on steam?
Copper tube is safe reasonably easy to work and did i mention SAFE.

Plastic tube and steam at any pressure is a bad combination.


Cheers kevin

 

[Powder keg]

I think most people will be running these on compressed air at only a few pounds of pressure. Plastic is OK for that.

Wes

 

[Tin Falcon]

O.K I stand corrected. I DO NOT use plastic tubing on steam . I run my engines at shows on compressed air. If and when I run any of my engines on steam I will use copper tubing with the appropriate fittings. And likely add an oiler in the line. I used the term "Steam Fitting" because that is what it is called in the elmer plans . The correct term would be air fitting. Most ME shows I have attended provide air lines some do provide air and steam.
Tin

 

[mklotz]

Silicone aquarium tubing can be used quite successfully with live steam (although I wouldn't recommend it for high pressure steam). I've used it with my small (60 psi max) boiler many times and it shows no sign of deterioration.

Typically, the silicone aquarium tubing is green in color and translucent. The transparent plastic tubing is NOT silicone. I've never tried it with steam and would want to conduct some experiments before I did. I have no evidence but I doubt it would fare well though it works just fine for air.

 

[compound driver 2]

Hi

I watched a chap a few years ago trying to run a Burrell SCC on air using plastic tube. At the starting pressure all was fine (15psi) he then decided to try to compound the engine by opening the air regulator to 115PSI. The bang from the tube bursting was like a pistol going off! I couldnt be bothered to mention that no engine will compound on air, as I walked off muttering "dozy tit" under my breath.

Yup low pressure in plastic is fine, I run up most of my engines the first time on air. Not il admit with silicone tube I use reinforced PVC fuel line.

Cheers kevin

 

[compound driver 2]

Hi

Well Marv I guess your just lucky no one around you has been badly scalded with live steam.

Cheers kevin

 

[Bogstandard]

tin,

i chose the wrong word, it should have been interfere. the idea of a team build as far as i am concerned is that the team members themselves come up with their own ideas and ways of doing things. i just piped up because i could see a problem, but you already had that covered anyway.

but i do take an interest because there is a lot to be learned.

i have seen team type builds before, and it almost always produces a product that is much better than the original. the reason being, everyone steps up a notch, and produces astounding work, whereas if they were just making it for themselves they retain a 'that will do for me' attitude. in this case it is a team effort, and everyone puts in the best that they can achieve.

you should all end up with great and unique versions of this little engine.

john

 

[deere_x475guy]

Tin thanks for the tips. I hope to get started on those tomorrow. Right now I am trying to figure how I am going to get the raduis on the ends of the pipe plate so that they all look the same.

 

[Tin Falcon]

Bob:
If your three jaw is in good condition ie holds well on a small part and runs true it might be easier to part off after threading and flip the part and do the barbs as a second operation.
Tin

 

[zeusrekning]

Bob. Could you make a fixture to clamp all 12 bases together and machine them all together?
Tim

 

[deere_x475guy]

Bob:
If your three jaw is in good condition ie holds well on a small part and runs true it might be easier to part off after threading and flip the part and do the barbs as a second operation.
Tin

Tim I really like my 5c collet stuff so I am going to place and Enco order for a 1/4" hex collet and a collet stop. Plans are to cut a length of stock that is long enough to do all the 12 pieces. Thread the end, cut to approx length, part off, pull more stock off and begin all over again. Once I have all 12 threaded I will set the collet stop so all go back in to the same depth. Set my tool datum points for the first one and I should be able to repeat w/o re-setup for the rest (at least that's my hopes, will have to see how repeatable everything is). :

 

[Tin Falcon]

hey that is even better i was going to suggest a hex collet but not everyone has them . I recently got a hex set in 3C for my south bend also picked up a pot chuck for my part of the project.
Tin

 

[Bogstandard]

I thought I would just let you know.

I use hex in standard round collets and it runs as true as normal rod.
Just be careful that the edges of the stock are away from the collet grooves, and no really heavy depths of cut.
I was going to invest in a set of hex collets, but thought that the numbers of times they would be used, wouldn't justify the outlay.
But of course this depends on how many are in your collet set. Mine go up in 32nds and have never come across a hex that won't fit a collet (unless it is too large for the max size of collet).

John

 

[deere_x475guy]

John thanks for the info. Enco's price is pretty cheap actually and I can see me using this size enough moving forward that I don't mind putting it out. However, in light of you timely tip I think I will give that a try first. The cuts don't need to be to aggressive. BTW are you anywhere near London? There is an awful good chance I will be spending a week there during the month of May.