16mm IDRIS

Hi

I have decided to try and give this lil 16mm IDRIS model a go.
Metal for the Boiler ordered tonight.
It's going to be interesting cos I was brought up in Metric. This ( like most other ME Models) is all in imperial. I'm just hoping I can use metric equiv Threads. BA Taps and Dies seem to be somewhat costly compared.

Is anyone else going to try this model ? it'd be great to work and learn together.....

It looks a nice little project although I won't be making one myself.

Just watch the imperial threads for fittings on the boiler etc. If you are going to buy in any fittings such as pressure gauges then they will not be available in the UK with metric threads unless you buy from the continent as they do them in metric but they are metric FINE not the commonly use metric Coarse so you wil need taps and dies in either case.

This is a table I drew up for when I'm making american casting kits to convert their threads to BA but you could also use it to convert BA to metric.

Edited By JasonB on 19/03/2015 19:28:45

Hi Jason.
Good point re. The Boiler Fittings.
Maybe I will buy some BA / Imperial taps n dies.

I would not rush out to buy a load of BA stuff at this stage if you already have ISO metric *.

The 6 or 4BA temporary bolt for the gauge glass block can be M3

The bolt on the end of the burner M4 as most people don't have M3.5 in a set

The 7BA valve screw on the jet carrier would be M2.5

The only one you may need is the1BA tap for the gas jet

J

* I put ISO metric before some bright spark chipps in and says that BA is based on metric measure.

Well I've read the article but it doesn't seem to explain why it is called Idris when there has been a 16mm design called Idris around for years. I thought it was going to be that design.

Hi All.

Metal Arrived for the Boiler.

Made some Progress tonight.
Plug and Screw for the RH end of the Burner made.
Gas Valve screw made - turning M2.5 stainless studding I had is a challenge to make the .050" point.
Nice knurled brass end made. Locktite setting as I type.

No 3/8 or 10mm square brass for the gas valve body. I have 7mm Hex or 10mm Round.
I can make it from 3/8 X 1" bar as 1 bit but that's a lot of chips.

3/8 Tube for the burner pipe sourced.

Need to buy some Imperial taps n dies.
Suggestions for a good supplier welcome. I'm after quality, not always the best price.

Alex.

Hi John.
Certainly an interesting and worthy idea.
Dremel mount added to the job list.....

Hi All.

Not sure where to ask these. If here is not appropriate please point me in the correct direction.

This will be my first Boiler but I have done a fair bit of silver (and soft) soldering before.
It'll no doubt be a challenge and I have enough metal for a 2nd attempt.....

Couple of Q's for you.

Am I better off Pilot drilling all the Bushes then Drill / Tap them to size later ?

I'll make a former to make the boiler end plates. I also have access to a press.
How high up should the Fire tube be ? It's not shown on the drawing.

And Lastly. The water gauge bushes.
I guess they are drilled through and outside hole plugged.
The drawing shows that they are not drilled through.

Thanks

Alex

With the tapped bushes it is best to machine and drill on the lathe and while they are still in the chuck start the thread with a taper tap but don't go all the way. Once soldered in you can complete the tapping and there is less risk of scorching the crests of the threads and as you started the thread square in teh lathe it will still be square when you finish the cutting.

I'll have a look at the other bits and get back to you

Probably best to keep all questions about the Idris in this thread

Right can't give an easy answer to te other two except for what I usually say when a project is being published and that is don't be in too much of a rush to cut metal until at least a few installments have been published.

You are right that teh water gauge blocks should connect to the main boiler space and I'm not sure how Martin intends to do that. Also if you look at pic No 11 there is an additional part soldered onto teh block which suggests a hole goes through front to back but don't drill one yet.

I'll see if Diane can throw any light on it or better still get Martin to post a reply.

J

Hi Jason.
Rest assured I don't intend to start cutting £40 worth of copper until I can see and understand 100%where I need to get to.
Tomorrow I intend to complete the Burner pipe. Waiting on Dies for the gas valve which is otherwise complete.

Thanks for your answers.

Hi All. Got a little more workshop time today.
Made the Burner tube.
My Myford Lathe made this very easy. (8 TPI Lead Screw)
I used a 0.5 mm Slitting saw mounted in the lathe chuck to make the cuts.
3/8 Copper Tube in my vertical slide with a small milling vice.

Set the Lead screw dial to zero, Engage the lead screw and take up the lash.
Line up the first mark, make a 3.5mm cut.
1 full turn on the lead screw and make the 2nd cut. Rinse and repeat until you have all 16 slots.

Deburred the inside with a suitable size drill.

Just sussed out the photo thing....

Making good progress Alex.

Just for future reference its better to remove the chuck and put the tapered saw arbor into the spindles tapered socket. I would say you were lucky this time but on a heavier cut you could come a cropper if just holding on a threaded rod. If its a different tape and won't fit then bringing up the tailstock centre will add support

Hi Jason. The taper fits exactly as it should (MT2) in the spindle.
However there is not clearance to make the cuts. The pipe fouls the headstock. A larger (4" saw would resolve this.
I'm aware that this setup is less than ideal and agree that for heavier work this would be unsuitable.
I like your Tailstock idea. Noted for future ref.

Taps n Dies turned up yesterday .
I made a clamp to stop the (now soft from soldering) copper tube from expanding as I threaded it.
Put the Gas Valve back in the 4 jaw. Drilled and tapped the Gas Jet. Tapped the outside to fit the tube.

At the weekend I made the formers for the End Caps and made the 2nd end cap tonight.
They are a really nice fit in my Boiler tube.
All looking rather good.

Another Q for you all.

I notice brass is not used for Boiler Bushes and Fixings. It's all Phosphor Bronze on this and other Models.
I guess there is a reason for this ?

The Water Level glass bushes call for Square Phosphor Bronze and I have little desire to buy some.
I do however have suitable Square and Hex Brass. I suppose I can make square from Round .......

Can I use Brass for the water gauge Bushes soldered to the Boiler ?

Thanks

Alex.

Yes there is good reason for using PB and not Brass.....

brass is an alloy of copper and zinc, when used for boiler bushes over a period of time the zinc will come out of the alloy......a process called leaching....or de- zincification.....it's caused by galvanic process....

So best stick to PB.....

Hi Alex,

You must never use Brass for boiler bushes etc. where it is in contact with the copper and the water.

Brass will slowly decompose (de-zincification) and your boiler will eventually fail. (In fact a boiler inspector may fail the boiler if submitted for testing)

Therefore you must use Bronze for the Water-Gauge bushes.

Dave