Author Topic: Another breath engine (Huff and Puff)  (Read 2996 times)

Offline Roger B

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Re: Another breath engine (Huff and Puff)
« Reply #30 on: May 07, 2019, 02:47:33 PM »
Alum is potassium aluminum sulfate KAl(SO4)2·12H2O.
Best regards

Roger

Offline Roger B

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Re: Another breath engine (Huff and Puff)
« Reply #31 on: May 11, 2019, 12:25:58 PM »
The holes in the valve rod were drilled with the Proxon drill and then this was exchanged for the mill. The flats were milled in the valve and the hole for the pivot was drilled 0.8mm and then 1mm. I have left the valve in the vice to cut the slot for the valve rod using the Hobbymat mill.
Next the excentric rod was milled to 1.5mm thick leaving about 10mm at 2mm thick so it could be held for profiling. The tongue was milled down to 0.8mm thick. To finish off the ends of the rod I could either make a fixture for the RT or some filling buttons  :thinking:  Probably filling buttons.

The broken tap has almost completely gone  :) 
Best regards

Roger

Offline Roger B

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Re: Another breath engine (Huff and Puff)
« Reply #32 on: May 12, 2019, 10:20:10 AM »
I decided to make two filling buttons to fit in the excentric bore so I could use them to hold it as well. A piece of 8mm silver steel was turned down to 5.5mm for 0.6mm and then parted off at 1.5mm. The 3mm hole in the middle in just to allow me to hold them for hardening but also makes parting off easier. The excentric rod was then filled to shape with a selection of small files.
Next up was the crank disc. The blank was turned from 11mm brass rod (I didn't have any 10mm) and drilled 1.4mm and reamed 1.5mm. It was them moved to the Proxxon drill, centred, offset 3.2mm and the hole for the crankpin was drilled and reamed. Finally the disc was Loctited onto the crankshaft.
Best regards

Roger

Offline Roger B

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Re: Another breath engine (Huff and Puff)
« Reply #33 on: May 12, 2019, 04:18:01 PM »
Good news  :) The broken tap has completely gone. I washed the cylinder with hot water, ran a tap down all the threads and gave it shot of maintenance spray.

The slot in the valve was cut with a slitting saw in the Hobbymat mill.  Next up I drilled the locking wire holes in the two pivot pins. They were placed on the drill table and picked up with the vice using an length of 1.5 mm ss to balance the load. The vice was centred with a 1.5mm spike, centre drilled  and then drilled 0.5mm. They are temporarily held together with some 0.2mm copper wire. I will use 0.5 mm wire for the final assembly.
Best regards

Roger

Offline Kim

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Re: Another breath engine (Huff and Puff)
« Reply #34 on: May 12, 2019, 04:33:39 PM »
Don't sneeze!    ;)  :popcorn:

Great work on all those fiddly little parts, Roger!  You've got to be getting close now...  how many more little parts could there be in an itty bitty engine? :)

Kim

Offline Admiral_dk

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Re: Another breath engine (Huff and Puff)
« Reply #35 on: May 12, 2019, 09:01:35 PM »
I know that what you are building in this small size isn't easy, but I can't wonder if it isn't almost like a walk in the park after the precision demanded in a small real diesel  :noidea:

I suppose that it can also be seen as another way of honing the skills demanded for doing the diesel ....

No matter what angle I choose to view this - you are doing just fine  :cheers:   :popcorn:

Offline Roger B

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Re: Another breath engine (Huff and Puff)
« Reply #36 on: May 15, 2019, 08:17:37 PM »
Thank you both  :)

Kim, The only bit left was the crankpin, just a little piece of 1.5 mm silver steel.

Per, there are several things behind making this little engine. Firstly I liked it  :) Then it was more practise and learning more about the little Proxxon lathe and mill. Finally it was something I could finish in a short time scale  ::) I think that the diesel will take another couple of years before I am happy with it and can move onto the Junkers.

So faced off the crank disc, Loctited the crankpin in place and put it together checking for free movement at each step. I used a couple of 1mm drills for pivots at this stage. I need to check the clearance between the valve pivot and the frame, it looks a little tight. The cylinder cover is just pressed in not screwed down. Obviously I had to try it and success  :whoohoo:  There is no lubrication other than residual maintenance spray on the cylinder and valve bores.


Happy  :)  :)  :)
Best regards

Roger

Offline Ye-Ole Steam Dude

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Re: Another breath engine (Huff and Puff)
« Reply #37 on: May 15, 2019, 08:46:55 PM »
Hello Roger,

The engine runs really well and a good job on your part. Hang in there with the diesel :ThumbsUp:

Have a great day,
Thomas

Offline b.lindsey

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Re: Another breath engine (Huff and Puff)
« Reply #38 on: May 15, 2019, 10:44:11 PM »
Very nice. Going to have to make one of these after finishing up some other projects first. Well done Roger :whoohoo:

Bill

Offline Kim

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Re: Another breath engine (Huff and Puff)
« Reply #39 on: May 16, 2019, 05:58:44 AM »
Wow!  Runs a treat!  Now to get rid of the drill bits sticking out the sides  :Lol:
Kim

Offline Roger B

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Re: Another breath engine (Huff and Puff)
« Reply #40 on: May 19, 2019, 06:48:33 AM »
Thank you all  :ThumbsUp:  :ThumbsUp:

I dismantled the engine to sort out a few details. I filled a small flat on the crankshaft to give better grip for the flywheel grub screw. Two small cutouts were filled in the frame and the cylinder cover to reduce the obstruction of the ports. The cylinder and frame were rounded off using a 1.5mm radius cutter with the fixed jaw of the vice as a location surface. I made a couple of 5mm filling buttons for the main bearing stands, using the clamp that held them in place to take the cutting load so as not to risk bending the stand.
Best regards

Roger

Offline Roger B

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Re: Another breath engine (Huff and Puff)
« Reply #41 on: May 19, 2019, 07:21:15 AM »
I reassembled the engine checking for free running at each stage. I will have to remake the two clevis pins, the valve one is too long and the cross hole is off centre in the piston rod one. I put a small amount of light oil on the crankshaft bearings and gave it a blow  :)


I have attached my drawing as PDF and DWG below if anyone is interested (note: they are more electronic back of an envelope sketches than professional grade drawings like Brian Rupnow's)
Best regards

Roger

Offline Jo

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Re: Another breath engine (Huff and Puff)
« Reply #42 on: May 19, 2019, 12:39:51 PM »
8)

Ideal engine to let the kiddies blow round to get them interested in our models  :)

Jo
Usus est optimum magister

Offline b.lindsey

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Re: Another breath engine (Huff and Puff)
« Reply #43 on: May 19, 2019, 01:48:03 PM »
Fantastic Roger!!  I love it  :cartwheel:

Bill

Offline Roger B

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Re: Another breath engine (Huff and Puff)
« Reply #44 on: May 25, 2019, 07:55:45 AM »
Thank you both  :)

Nearly there. I turned up a neater air connection from 6nn hex brass that takes a more sensible sized pipe and then started on new clevis pins.
Best regards

Roger