Magnetic Stirling and other things

[fcheslop]

Hi,
   Just when I thought I had built enough of these engines I fell in love to this temptress designed by Jan Ridders
http://www.ridders.nu/Webpaginas/pagina_magneet_stirling/Magnet_stirling_frameset.htm
Why other things well as the last build was nearly finished I broke the hot end glass test tube and only had one spare left.
I normally cut them in the lathe using a diamond file a little risky as just as they cut through they tend to jam.So its time to make a proper glass cutting engine. I made a rough as in very rough lash up and it worked so its time to make a permanent one. I dont suppose it will do that much work in my life time but should at least make life easier.
I have seen a pic on Jans site of one he has made but cannot now find it so heres my take on his idea.
Please note anyone looking for tool room quality or of a nervous disposition LOOK AWAY NOW.
 My main criteria was that it has to be made from the scrap box other than the cutting bade. Yep tight wads
The cutter head was made from a lump of alloy as you can see its not cleaned up.
The spindle runs on three sealed bearing as I expecting lots of water splashing about


The depth stop again from a scrap lump of alloy nothing fancy


The V block was milled using a router bit and the frame slides on the two guide pins.This sets depth of cut


A mok up just to get some idea and to show what Im mumbling on about

The tail of the flexi drive is supported as on the rough lash up I made the weight of the flexi drive pulled out the plain bearings
I found a lump of polycarbonate that has laid round unloved and all the bits are now mounted to it as a base

The base has a few holes at 1inch pitch so that the depth stop can be adjusted.

Well thats me upto date now I need to think up an idea for a water drip feed or flood feed to the diamond wheel as the glass needs to be kept cool and I dont fancy breathing in that dust.
thanks for looking in
best wishes
frazer

[PStechPaul]

Or, you could just file a notch around the tube and simply snap it, as shown here. I think the dog is optional:
 
<a href="https://www.youtube.com/watch?v=pQKO1rJC2XI" target="_blank">http://www.youtube.com/watch?v=pQKO1rJC2XI</a>

[fcheslop]

Yeah right ,Try it and see how any times it dont 
I only had one chance on the lash up version as no one at the moment is selling 30mm test tubes in small quantities in the UK at the moment and the only alternative was shipping from Germany.
I have tried the method you mention and not had a lot of luck and a few other methods
The cutter will also be used to cut thin walled brass tubing and guage glasses

Cheers

[Nicolas]

Very neat I need to make one of those some time

I have seen a pic on Jans site of one he has made but cannot now find it so heres my take on his idea.

Here's the video if that is any help (probably a bit too late seeing as you have already made yours )

<a href="https://www.youtube.com/watch?v=xfYj-sq78DU" target="_blank">http://www.youtube.com/watch?v=xfYj-sq78DU</a>

Nicolas

[fcheslop]

Thanks Nicolas, thats the one youve no idea how long I looked for that video
I didnt like the idea of the Dremmel been so close to the water and have used the flexy drive as I dont want a curly perm although after seeing the video theres not a much water knocking about as I had thought.
Hope all is well with you
cheers
frazer

[PStechPaul]

Here's a way to do it on a lathe. I think he should have wrapped some PVC tape or rubber around the glass before chucking it, though. Also maybe a good idea for your setup:
 
<a href="https://www.youtube.com/watch?v=hYU3YXyAceI" target="_blank">http://www.youtube.com/watch?v=hYU3YXyAceI</a>

[fcheslop]

Thanks Paul, yep tried that one as well.
Iv had varying degrees of luck using that method and simply using a diamond file.
The tube tends to slip in the chuck or cracks.Have you tried the one with the burning string 
Honestly I have had a go a loads of different methods and Im a lazy soo and soo and wouldnt even think about making the cutter if I could cut to with .2mm and didnt waste too many tubes.
The first glass engine I made I thought was my last now 8 builds later Im still hooked and will build even more as Im now looking to go my own way and start on a 3 cylinder radial flame gulper and some mad ideas for a Stirling or two
cheers

[b.lindsey]

Nice job on the cutter frazer. Getting back to the engine itself...what exactly is the purpose of the magnet?

Bill

[fcheslop]

Hi Bill, the magnet moves the displacer.So no shaft or bushing to leak.
Iv a few other mods for her some via Huib Visser and some just to enable me to use materials I have
cheers

[fcheslop]

Hi and thanks for the interest shown
The lash up continuous after a trip to Boys store a little stainless pot followed me home.This was mounted and a leaky valve from the scrap box used to control the flow of water


A few trial cuts.Im getting a little chipping but at least Im hitting the lengths unlike when I cut them in the lathe
The one on the right was with the dremel running flat out and as Mr Ridders shows on his video the central one cut at about 15000rpm and is good enough for me

So a start has been made cutting the displacer .
Was the effort making the cutter worth it I dont know the jury is out and time will tell.
Im looking at building some very small flame lickers below 8mm bore using glass for the cylinders within a finned alloy cylinder to my own design as its time I at least try to go my own way with these toys.
Will it work Iv no idea but cannot see why not any help gratefully received.
Ultimately I would like to build a micro flame gulper below 5mm bore but have my doubts if it would work she will be a multi 3 cylinder radial.
My thinking  is 3 cylinder give me 120 degrees between cylinders so one cam should fire all 3 cylinders. The cam will be a face cam to get rid of the usual linkage.Pipe dreams at the moment but it keeps me going.
So thats all for now
OOps


A start

Best wishes to all
frazer
 

[Bluechip]

Slice my tubes off in the lathe.

Tubes poked on a plastic mandrel, gripped by the  O-rings ....

Piccys here :

http://s359.photobucket.com/user/Bluechip_mech/library/Tube%20Cutter%20Saga?sort=3&page=1

Dave

[fcheslop]

Thanks Dave, food for thought
Is that a nice Ringbom??
Do you know of any specific hot air engine builders forums
cheers

[Bluechip]

Hi Fraser

Nope, sort of stretched HR-25, to suit 24mm tube.

And other bits re-designed ( boasting !! ) to fit bits of ally plate in the bit box.

BTW It's not obvious but there is an axial hole thro' the mandrel to let the air out otherwise the tube pops off.

The only Stirling Forum I know is this:

http://stirlingengineforum.com/

Ian S C probably knows a lot more as he posts fairly frequently, I just nip in occasionally .. 

Dave

[fcheslop]

Hi Dave, I like the HR25 on steroids
Thanks for the link it maybe a better place to ask my questions
cheers

[fcheslop]

Hi,
    You know how it is?? just when you're ready to start another niggle had to be put right
This little drill attachment has driven me up the wall for a while as you don't know how deep you've gone so some graduations were put onto the spindle.Just though I would mention it for any one making such a contraption


The main body is from 30mm brass with the power cylinders bore straight through, Well I couldn't get the old boring cutter to give a good finish shouldn't complain its lasted a long time.
So a bit of 1/4 stubs was set up in the three jaw with a 1/8 packer to throw it out

The end is filed as per Mr Thomas instructions and I only harden and temper the tip should a mishap occur the cutter bends and can simply be straightened up not that we have any mishaps

Just a few shots of the tool Iv found it very useful for over 20 years and the best bit it only costs a few coppers to make OK its no fancy bit of kit but this tight wads wont spend the pounds they ask and can the commercial ones bore down below 3mm and not cost an arm and a leg



Iv machined the body with a 1mm allowance all round  as Im not sure where Im going with it yet
The same applies to the upright Im looking at Huibs video to see how he has changed a few things I want to incorporate into the toy.


The gears are next up Mr Ridders used some old clock gears on his built.There is a dimension between the displacer and the magnet that has to be adhered to so 40 teeth 0.5 mod gears have been made luckyfor me I had made a batch for a futur build when I find some info on the Cracker T
These gears just needed thinning down and have been held in a split ring to save damaging the teeth.I was going to mark them out for tapered spokes but decided life's to short and anyhow couldn't find my tin of pins for my marking out jig they will be some where safe no doubt


A simple jig just to make sure the gears run absolutely free as drag will kill this little toy. I did round up the dimension by 1/2 a thou just to be sure

Next up the actual bearing housing and gears


Thats me up to date so thanks for looking and best wishes
frazer