Author Topic: Bijou. Something for the small guys.  (Read 15295 times)

Offline Dean W

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Bijou. Something for the small guys.
« on: July 21, 2012, 07:27:34 PM »
Hi everyone.  Thought I would do my first build for the new forum starting with something small.  Quite small, really.

This is a small oscillating engine designed by Dr. James R. Senft.  Dr. Senft did some work for NASA, and also did a fair
bit of R&D on the Low Temperature Differential engines, like the kind you can run off the heat of a coffee cup. 

Dr. Senft called this engine Bijou.  It's pretty small, though not the smallest he has demonstrated.  One of his designs
is much smaller than the one I will be building here.  (You could fit a number of his smallest design inside a sewing thimble.)





I started with the standard.  This is the piece that all other pieces are mounted on.  It also serves as the port face for
the cylinder.  Here, the pivot bearing has been turned on a small piece of brass.  The hole in the round bit is where the
pivot piece on the cylinder comes through.  The hole diameter is .086".







This is the cylinder, along with my little finger.








Here, the cylinder has been re-mounted in the four jaw for reaming the bore.  The round bit under the upper chuck jaw
is a piece of tubing placed over the pivot shaft so the jaw does not damage it.
The cylinder is the "trunk guide" type.  The trunk, the lower part where the piston goes in, acts as a cross head.







A little mill work on the standard.  The drill bit is .093" diameter, making the hole needed for the main bearing,
which will be pressed into that hole later.







A 1/16" end mill is used to cut away all the un-needed metal.
Once the standard and cylinder were fairly well done, the piston was turned from stainless steel.







These are the pieces so far, next to your standard M&M candy.  Piston, cylinder, and standard.
The ports will be drilled later, if I can find a small enough drill bit.  :)

I'll put more up later.  Thanks for looking in!
Dean
In beautiful N. Idaho, U.S.A.

Shop Projects:
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Offline lazylathe

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Re: Bijou. Something for the small guys.
« Reply #1 on: July 21, 2012, 07:38:13 PM »
Hi Dean,

Chair has been pulled up nice and close! ;D
Looking forward to following along with you on this build.

I will have to look this one up to see what the end result is going to be!

Andrew
A new place to hide my swarf!

Offline dsquire

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Re: Bijou. Something for the small guys.
« Reply #2 on: July 21, 2012, 07:43:08 PM »
Dean

If that is a regular size M&M candy then they must make them a lot bigger in the US than in Canada. Haha.

Nice work Dean. I've got the glasses on and will be watching.

Cheers  :)

Don
Good, better, best.
Never let it rest,
'til your good is better,
and your better best

Offline Dean W

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Re: Bijou. Something for the small guys.
« Reply #3 on: July 21, 2012, 07:58:29 PM »
Thanks guys.  Won't take long to get all the pics and text up for this one, as it's all written and ready.
So, you will see the finished result in a couple of days.  Appreciate your comments!
Dean
In beautiful N. Idaho, U.S.A.

Shop Projects:
http://www.deansphotographica.com/machining/projects/projects.html

fcheslop

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Re: Bijou. Something for the small guys.
« Reply #4 on: July 21, 2012, 08:28:18 PM »
Hi Dean,nice build when are you doing the Thimble ;D
only kidding

Offline Alan Haisley

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Re: Bijou. Something for the small guys.
« Reply #5 on: July 21, 2012, 08:39:22 PM »
I love it, Dean. Just the right size for my Sherline. And so inexpensive in material too. I'm looking forward to the rest of the story.


Alan

Near Raleigh, NC, USA

Offline ksouers

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Re: Bijou. Something for the small guys.
« Reply #6 on: July 21, 2012, 08:39:53 PM »
Nice one, Dean.
That teeny tiny stuff is really tedious. (Sorry for all the "Tees")

I knew there had to be an M&M in there somewhere...




Kevin

Offline Dean W

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Re: Bijou. Something for the small guys.
« Reply #7 on: July 21, 2012, 11:13:21 PM »
I knew there had to be an M&M in there somewhere...

Kevin
You got it, Kevin.  That's my international scale reference for most small things!  ;)

Thanks all for the comments!  As Alan says, this is a project that is sure to fit on even the smallest
lathe.  And, of course, it costs very little to build.


So, on with a bit more progress:



This is the cylinder, standard and piston assembly.







I set up for cutting the main bearing using some 660 bearing bronze.  In the shot above the piece has been
roughed out and a center spot put in the end for drilling the bore.  The bore was drilled a thou under size
to allow cleaning up with a reamer.







I don't have a store bought reamer in .047" (1.2mm), which is the size needed for the crankshaft bore, so I made up
a little shop reamer using hardened pivot wire.  These are usually called "D" reamers, or D-bits.  Normally,
for a larger size it would be made up from drill rod, the end machined to make the cutting edge, then hardened.
For this one I made it in a kind of half lozenge shape using an india stone to grind away the basic shape.








Then to finished it off and make it sharp, it is stoned on a hard white arkansas stone.  I think it's called
slip stone in other parts of the world.  Since it is already hardened to begin with, there is nothing more
to do to make it ready for use.  Pivot steel is hard enough to cut brass, bronze and aluminum just the way it is.








Now the reamer is run down the bore with the lathe running.  Since this is a no clearance/no flute cutter, it can only
go in a tiny bit at a time, then has to be withdrawn to clear the tool and hole of shavings.  Once the reamer
has cut the length of the bore, it's finished and the part can be cut off the parent stock.








Parts shot.  The bearing is a press fit in the engine standard.








To make sure the bearing goes in straight I cut and bored a small aluminum piece to back up the bearing against
the lathe chuck, then pressed on the standard using a brass rod to push against the standard with the tailstock.
Sorry for the fuzzy pic.  It happens.








I wanted to check that the bearing was pressed in straight.  If it's not, the engine won't run.  I put a pivot wire
the same size as the crankshaft into the crank bore and put some more eyeball on it.  It's good.  I'm glad!

More later, folks!
Dean
In beautiful N. Idaho, U.S.A.

Shop Projects:
http://www.deansphotographica.com/machining/projects/projects.html

Offline Alan Haisley

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Re: Bijou. Something for the small guys.
« Reply #8 on: July 22, 2012, 03:15:31 PM »

Dean,




I don't have a store bought reamer in .047" (1.2mm), which is the size needed for the crankshaft bore, so I made up
a little shop reamer using hardened pivot wire.  These are usually called "D" reamers, or D-bits.  Normally,
for a larger size it would be made up from drill rod, the end machined to make the cutting edge, then hardened.
For this one I made it in a kind of half lozenge shape using an india stone to grind away the basic shape.


Is this "pivot wire" the same as the "piano wire" that I'd find in a local hobby shop?


Alan
Near Raleigh, NC, USA

Offline smfr

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Re: Bijou. Something for the small guys.
« Reply #9 on: July 22, 2012, 05:26:54 PM »
My eyes hurt just reading this post! Good stuff.

Simon

Offline Dean W

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Re: Bijou. Something for the small guys.
« Reply #10 on: July 22, 2012, 06:50:48 PM »
Dean,

Is this "pivot wire" the same as the "piano wire" that I'd find in a local hobby shop?
Alan

Alan, pivot wire is what watch and clock makers use for making shafts for a time piece.  It is a hardened and
tempered wire.  It's quite similar to piano wire, and yes, you can use piano and music wire for making cutters
for soft metals, same as I showed for the pivot wire.


A bit more progress on this build:



To setup for drilling the crank disc, a piece of steel rod is dialed in on the four jaw to show .125" runout.  That
will give the crank pin offset of 1/16".  Then the piece is drilled .031" for the pin.  Next, the steel rod is
dialed in for no runout and an .047" hole popped down it's center.







Here you can see the hole for the crankshaft, and the offset hole for the crank pin.







Once again, I used the tailstock on the lathe to press in the two shafts, and crankshaft is done.







The flywheel is a simple turning and boring job, then it gets drilled and tapped for the 00-90 crank set screw.







I turned up a piece for the base, too.  Here, it's having a slot milled with a 1/32" end mill.








Made a couple of little screws.  The fasteners in this engine are 00-90.  That's about 1.2mm for folks on the
sillimeter system.  I don't like making very small screws so much.  The failure rate on them is about 50%.  They
tend to break off in the threading die, even with the die opened up all the way.  I made five to get two good ones.







One goes in the flywheel to lock it on the crankshaft. 







Made a little spring from steel guitar string.  This spring keeps the cylinder pressed against the port face.
You can use any solid steel guitar string for making various size and strength of spring.  They are music wire,
which is what commercial springs are made from.







This little thing is a washer made with two steps.  One step larger than the OD of the spring and the smaller
step fits inside the spring.







You can see it better here.  This is the second one I made.  The first one rolled away at the moment it was
parted off.  I had put a thin wire inside it while parting, but the last bit of brass caught on the wire that
was supposed to keep it from getting lost, and the wire flicked it away.  Usually, putting a wire down the
center of something you are parting off will keep it from getting lost as it comes off the parent stock.  This
time it backfired. 







Here are the parts just made.  Spring, washer, and screw.

That's it for this post.  More to come.  Thanks all for having a look!
Dean
In beautiful N. Idaho, U.S.A.

Shop Projects:
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Offline arnoldb

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Re: Bijou. Something for the small guys.
« Reply #11 on: July 22, 2012, 10:17:10 PM »
I've got your fingerprints now Dean  ;D

Seriously, that's good going on really small work! Thank you for showing it  8)

Kind regards, Arnold
Building an engine takes Patience, Planning, Preparation and Machining.
Procrastination is nearly the same, but it precludes machining.
Thus, an engine will only be built once the procrastination stops and the machining begins!

Offline Bearcar1

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Re: Bijou. Something for the small guys.
« Reply #12 on: July 22, 2012, 10:29:36 PM »
Good gosh! Dean, that is small. Terrific work but way too fiddly for me. Do you use any kind of magnifying devices when you are doing this type of stuff? It would seem one would have to. Gonna be a nice looking little thing when you're done.

BC1
Jim

Offline Mel Larsen

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Re: Bijou. Something for the small guys.
« Reply #13 on: July 22, 2012, 11:20:36 PM »
That is great work!  I would have to have a big magnifying glass for something like that, My eyes are getting too weak.   What if you dropped a part, you would have to build another. 
I hope there is a video of it running planned for the future.
Mel
Hi from Wet, Wild, and Windy Waldport,OR.

Offline Dean W

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Re: Bijou. Something for the small guys.
« Reply #14 on: July 23, 2012, 12:17:54 AM »
'

Thanks for the further comments, fellows!

Do you use any kind of magnifying devices when you are doing this type of stuff?

Sometimes Jim, for the tiny things.  Though I wear glasses, my vision is fairly acute once corrected.  I do use an optivisor
for the really small stuff.  I think it's a 1.5x lens.

Mel, yes, there will be a video in a few days.  :)
Dean
In beautiful N. Idaho, U.S.A.

Shop Projects:
http://www.deansphotographica.com/machining/projects/projects.html