Author Topic: Bodging with Boris........  (Read 9917 times)

Offline Stilldrillin

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Bodging with Boris........
« on: September 29, 2016, 01:22:40 PM »
Hello, everyone..... I'm still around!  ;D

After another painful year, I'm managing to get into my workshop, once more.  :whoohoo:

The Doc put me on statins, three years ago. I've finally realised, just what has been causing me such grief, for so long.

I stopped taking them, a month ago, and now feel a new man! And, the walking stick has gone back into the cupboard......  :cartwheel:


Another needy orphan/ doorstop, arrived in July. I call him, Boris.........




Does anyone recognise the build?  Are there any plans out there?




The usual problem. Power cyl volume too large. Both cylinders, almost the same swept volume.




I turned up a better/ temporary crank assembly.........




No joy.......




So....... He's all in pieces, on my bench. Awaiting rebuilding materials.

It's nice to be back at it, once again! 

David.
David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

Online Jo

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Re: Bodging with Boris........
« Reply #1 on: September 29, 2016, 01:42:12 PM »
Hi David,

Please to hear you are feeling better  :cartwheel:

and now feel a new man!

Sometimes I think that I too would like to feel a new man  :mischief: but so far I have come to the conclusion that machine tools and castings sets are more reliable  :embarassed:

Jo
Usus est optimum magister

Offline Ian S C

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Re: Bodging with Boris........
« Reply #2 on: September 29, 2016, 02:35:51 PM »
David, I don't see how the displacer can operate connected to the crank the way it is. Does the vertical bolt with the acorn nut on top slide up and down in the L shaped  block on the crank, if so I would have thought there would be a lot of friction there.  I would be trying to loose a good bit of weight on the displacer linkage.  Also the displacer rod seems to be on the large side, but as long as the seal at the gland is OK, this should not cause any problem.
     The ratio between the displacer, and the power piston should be some where about 1.5 : 1, plus or minus a bit, a larger ratio will allow lower temperature.
     Minimum friction, no leaks, including the hollow displacer., and if it wont start remember that the displacer leads the power piston by 90*.
Ian S C

Offline sbwhart

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Re: Bodging with Boris........
« Reply #3 on: September 29, 2016, 03:20:14 PM »
Hi Dave

Good to see you back at it, been on those Statin things myself for about the same time I seem to so far .
Not posted much myself as I'm on a loco build and things  happen at a slower pace on that sort of project but I recon I'm long over due updating you Guys

Cheers
Stew
A little bit of clearance never got in the way

Offline b.lindsey

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Re: Bodging with Boris........
« Reply #4 on: September 29, 2016, 04:07:47 PM »
Welcome back to the shop Dave. Happy to hear you are doing better!

Bill

Offline Stilldrillin

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Re: Bodging with Boris........
« Reply #5 on: September 29, 2016, 10:18:24 PM »
Hi David,

Please to hear you are feeling better  :cartwheel:

and now feel a new man!

Sometimes I think that I too would like to feel a new man  :mischief: but so far I have come to the conclusion that machine tools and castings sets are more reliable  :embarassed:

Jo

Hello Jo.
 You keep an eye open, for that new feelable man.  :naughty:
I've been told, reliable is overrated. Just, not exciting enough.......  :(
David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

Offline Stilldrillin

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Re: Bodging with Boris........
« Reply #6 on: September 29, 2016, 10:30:00 PM »
David, I don't see how the displacer can operate connected to the crank the way it is. Does the vertical bolt with the acorn nut on top slide up and down in the L shaped  block on the crank, if so I would have thought there would be a lot of friction there.  I would be trying to loose a good bit of weight on the displacer linkage.  Also the displacer rod seems to be on the large side, but as long as the seal at the gland is OK, this should not cause any problem.
     The ratio between the displacer, and the power piston should be some where about 1.5 : 1, plus or minus a bit, a larger ratio will allow lower temperature.
     Minimum friction, no leaks, including the hollow displacer., and if it wont start remember that the displacer leads the power piston by 90*.
Ian S C

Ian.
 The displacer linkage is a scotch yoke, Giving slight dwell at, both ends of travel. Not much friction.
The displacer shaft is 6mm dia. About right, for the length of the assembly.
 The ratio, is 1.2/1. I have some 30mm dia graphite. Should make a 29mm dia piston. Also reducing stroke should give 1.9/1.

Awaiting tubing, bearings, 6" flywheel casting, inspiration etc.......
David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

Offline Stilldrillin

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Re: Bodging with Boris........
« Reply #7 on: September 29, 2016, 10:33:41 PM »
Stew, Bill.
 Thanks for your replies. 

Updates and pics, as n when.  ;)

It's good to be back!  :)

David.
David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

Online kev

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Re: Bodging with Boris........
« Reply #8 on: September 29, 2016, 11:20:42 PM »
good news indeed, and you have me thinking about those statins myself now !

Offline tvoght

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Re: Bodging with Boris........
« Reply #9 on: September 30, 2016, 12:02:01 AM »
Good to see you back. I've  heard a lot of bad things about those statins, including significant short-term memory loss. Did you experience that?

That's an interesting way to implement a Scotch yoke. If you had not described it as such, I wouldn't have thought of it that way.

If you got the swept volume ratio to 1.9, I bet the engine would have a very sweet disposition!

--Tim

Offline Stilldrillin

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Re: Bodging with Boris........
« Reply #10 on: September 30, 2016, 10:40:41 PM »
Thanks Kevin.
 I won't go back on them again! I never had a need for cholesterol reduction, in the first place!

Tim.
 Mrs Drillin thought I had early dementia signs. I was "vague", and didn't remember, what she swore she told me. Read that, whichever way you wish.  ;)

Though, I was making plans, how to dispose of the workshop and contents........  :(



Anyway! Enough!

I did attend a few shows. Here's a member's random video. My table, after 30secs.......

<a href="http://www.youtube.com/watch?v=pW_fZnx0aRA" target="_blank">http://www.youtube.com/watch?v=pW_fZnx0aRA</a>



Also..... I came away from STL, with "Best in Show". For the second year running........




Happy!  :whoohoo:

David.
 
David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

Offline Oldboy

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Re: Bodging with Boris........
« Reply #11 on: October 01, 2016, 12:22:10 AM »
Welcome back David.  Great to hear you are feeling better and back in the workshop.

Barry.

Offline b.lindsey

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Re: Bodging with Boris........
« Reply #12 on: October 01, 2016, 12:32:06 AM »
Congrats David. Great picture and video.

Bill

Offline Stilldrillin

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Re: Bodging with Boris........
« Reply #13 on: October 16, 2016, 01:54:35 PM »
Barry, Bill.
 Thanks Chaps! 

So.... The initial rebuild begins. With the displacer.  :thinking:

I really, don't like copper pipe for this purpose. Too heavy. Too much heat absorbtion/ conduction.  :ShakeHead:

Lots of handy diameters and lenghths, of s/s exhaust available on Ebay. This is 42mm......




Bored out, to lighten. Now, around 20 thou' wall thickness.......




8mm thick, s/s offcut, friction turned, to slide in the displacer's bore.......




Chopped the inside away, to give 1mm wall thickness......




Drilled through boss. Silver soldered in, a 12mm long extension. Then drilled to spigot depth, and tapped M5.

Rough cut end cap, in background Awaiting friction turning........




Silver soldered in, both end caps. Cleaned up.

That looks better! Even though, it will not be seen........




Next up.... Reducing the power cylinder bore. From 35mm to 29.5mm.  :headscratch:

I used two more lengths of s/s exhaust pipe. They have very accurate and consistant, bores and o/d's.
 A couple of thou' removed, allowed two to be sleevelocked together.
Topped to just below original bore size. Then bore opened out to 29.5mm.

Lots of time spent oscillating, to achieve a decent finish, and remove the 1 thou' taper.......  ::)





Looks ok, I think! The joint can just be seen, at 10 and 4 o'clock positions. close to the bore's chamfer.......




Frankly..... I'm not impressed by the little end's arrangement.......  :o




And, there's only poverty, holding the big end in place........  :facepalm2:




Guess, we now need a new conrod!  :shrug:

Thanks for looking in.....  :cheers:

David.



David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

Offline Roger B

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Re: Bodging with Boris........
« Reply #14 on: October 16, 2016, 06:18:34 PM »
Looks like another rescue well under way  :ThumbsUp:  :ThumbsUp:  :wine1:
Best regards

Roger