Author Topic: Opposed Piston Twin, D.Kelley  (Read 32830 times)

Offline fumopuc

  • Full Member
  • *****
  • Posts: 3231
  • Munich, Germany, EU
Re: Opposed Piston Twin, D.Kelley
« Reply #30 on: January 07, 2018, 07:37:55 AM »
Glad to see some metal cutting underway  :ThumbsUp: :ThumbsUp: I will be following this one  :wine1:


Hi Roger, good to know you are with me.
« Last Edit: January 07, 2018, 09:58:20 AM by fumopuc »
Kind Regards
Achim

Offline fumopuc

  • Full Member
  • *****
  • Posts: 3231
  • Munich, Germany, EU
Re: Opposed Piston Twin, D.Kelley
« Reply #31 on: January 07, 2018, 03:44:40 PM »
Yesterday and today was the day of the CNC mill to drill all holes.
This little machine has done a proper job as always, but the Quality Manager has rejected the part in the early afternoon.
The complete hole pattern from the upper side is scaled down a bit over the whole length by 2 mm.
After two hours of failure analysis, I have realised that the Fusion DXF Export from yesterday is faulty. :Mad: :Mad: :Mad: :Mad: :Mad:
I. e. CAD Model shows 3,18 mm as dimension, DXF file 3,00 mm only.
No idea why, because done the same procedure today has given a proper result.
I will try to discuss this with the Autodesk people.
A new block of Aluminium is ordered and I have to remake the part.
What was learned, never trust a DXF Export in future any more without to recheck the dimensions and result of it.

Kind Regards
Achim

Offline dvbydt

  • Full Member
  • ****
  • Posts: 86
Re: Opposed Piston Twin, D.Kelley
« Reply #32 on: January 07, 2018, 10:16:49 PM »
Oh no! I feel your pain. Have you got a good Anglo-Saxon vocabulary? The air is usually blue when it happens to me!

Offline fumopuc

  • Full Member
  • *****
  • Posts: 3231
  • Munich, Germany, EU
Re: Opposed Piston Twin, D.Kelley
« Reply #33 on: January 14, 2018, 07:08:09 PM »
Hi Ian, thanks for the sympathy. In the meantime I have got a new aluminium block and the first machining steps are already done.
New block, new luck.


 
Kind Regards
Achim

Offline Admiral_dk

  • Full Member
  • *****
  • Posts: 3752
  • Søften - Denmark
Re: Opposed Piston Twin, D.Kelley
« Reply #34 on: January 14, 2018, 08:58:42 PM »
Was it impossible to plug the wrong holes Achim ?

I think I would continue with the "mangled" first try, if not for anything else, but to insure that no other errors has found their way into the design .....

Best wishes

Per

Offline fumopuc

  • Full Member
  • *****
  • Posts: 3231
  • Munich, Germany, EU
Re: Opposed Piston Twin, D.Kelley
« Reply #35 on: January 15, 2018, 05:49:43 AM »
Hi Per,
below a picture.
Black is the correct DXF export.
Red is the faulty one.
I have seen, that the radii at the two slots were replaced by straight lines, what I have corrected in the CAM program, but I did no realizes the scaling done of the whole thing.
So, putting the right lower corner as the reference for machining it was giving the totally wrong hole pattern as seen in the picture.
Until today I do not know what has caused the wrong DXF export at that specific day, because the 3D model is unchanged.
Fusion360 is in permanent contact with it´s home server and since X-mas we have a very bad network connection here in Munich, this may be could be a reason for that phenomenon.

Kind Regards
Achim

Offline Admiral_dk

  • Full Member
  • *****
  • Posts: 3752
  • Søften - Denmark
Re: Opposed Piston Twin, D.Kelley
« Reply #36 on: January 15, 2018, 09:52:06 PM »
Argh - it's not only the holes as I thought, but everything - what a bummer  :censored:

I hope this doesn't happen again ( but you will check for this the next many times I'm sure ) in the future.

Offline fumopuc

  • Full Member
  • *****
  • Posts: 3231
  • Munich, Germany, EU
Re: Opposed Piston Twin, D.Kelley
« Reply #37 on: February 04, 2018, 07:41:42 PM »
Hi everybody, some more progress.
Gear train in motion.


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


The stands and the water inlet is done.


Kind Regards
Achim

Offline b.lindsey

  • Global Moderator
  • Full Member
  • *****
  • Posts: 13860
  • Dallas, NC, USA
    • Workbench-Miniatures
Re: Opposed Piston Twin, D.Kelley
« Reply #38 on: February 04, 2018, 10:18:32 PM »
That is a  real bummer Achim, but glad to see that you have it all sorted out now. The gear train looks fantastic too!!!

Bill

Offline Art K

  • Full Member
  • ****
  • Posts: 1761
  • Madison, Wisconsin USA
Re: Opposed Piston Twin, D.Kelley
« Reply #39 on: February 05, 2018, 03:50:50 AM »
Achim,
Great progress. I hope you sorted out the glitch.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline fumopuc

  • Full Member
  • *****
  • Posts: 3231
  • Munich, Germany, EU
Re: Opposed Piston Twin, D.Kelley
« Reply #40 on: February 11, 2018, 05:06:26 PM »
Bill, Art good to know you are still with me.


Today I have started the liner story.
First cutting some bar stock in pieces, 4 plus one set up part.
The usual process including the final honing was done with all five pieces.
My piston rings are 24 mm, that was the target. I get it managed to get 3 pieces with 23,99 mm, one with 24,00 mm and the set up part with 24,02 mm.
Honing seems to be successful too.
Next to do, a mandrel for the liners. Target is to get them 0,04 mm bigger than the bore in the cylinder block.
My first attempt with the "set up" liner in the messed up cylinder block was o.k.
So hopefully next week end I will be able to repeat this procedure 4 times with my real new cylinder block.
Kind Regards
Achim

Offline fumopuc

  • Full Member
  • *****
  • Posts: 3231
  • Munich, Germany, EU
Re: Opposed Piston Twin, D.Kelley
« Reply #41 on: February 18, 2018, 05:22:24 PM »
All liners are in the block now.
Some measurement and machining of the relevant outer diameter in accordance to the bore in the aluminium block was done.
Unfortunately #1 get stuck 2/3 of its way.
I took a chair climbed up at it and tried it with the weight of my half body, no chance.
A medium propane torch and some heat in the middle of the block has given the necessary clearance for pushing the liner into the block.
The other 3 liners could be press fitted without any further problem.
Some red high temperature sealing was used also, to avoid any coolant  later in the combustion chamber.
Kind Regards
Achim

Offline Roger B

  • Global Moderator
  • Full Member
  • *****
  • Posts: 6133
  • Switzerland
Re: Opposed Piston Twin, D.Kelley
« Reply #42 on: February 19, 2018, 07:50:55 AM »
Good progress  :ThumbsUp:  :ThumbsUp: Are those CNC cut gaskets?
Best regards

Roger

Offline fumopuc

  • Full Member
  • *****
  • Posts: 3231
  • Munich, Germany, EU
Re: Opposed Piston Twin, D.Kelley
« Reply #43 on: February 19, 2018, 10:38:38 AM »
Hi Roger, I do own this little plotter since a couple of years, brilliant for gasket cutting from a dxf file.
https://www.hobbyplotter.de/shop/pi.php/Hobbyplotter/silhouette-portrait-2-organizer-buch-bundle.html
Kind Regards
Achim

Offline fumopuc

  • Full Member
  • *****
  • Posts: 3231
  • Munich, Germany, EU
Re: Opposed Piston Twin, D.Kelley
« Reply #44 on: February 25, 2018, 07:10:13 PM »
Some progress with the crank shaft bearings.
7075 Aluminium for the bearing blocks, RG7 (similar to 660) bronze for the bearing bushes and SS for the fitting sleeves.
Bearing bushes are press fitted with 0,05 mm oversize.
« Last Edit: February 26, 2018, 12:14:22 AM by fumopuc »
Kind Regards
Achim

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal