Duplex Vacuum, (Heinrici type stirling)

[Deanofid]

Zee, Doc, Joe, Kevin, Bogs, Dennis, Arnold;
Thanks very much for your remarks. Very encouraging, and they're really appreciated!

Zee, sorry to be so pokey. Most of my day is taken up with eating and sleeping, you know. What a struggle!

Doc, thanks for the tips on the 17-4. I'll get a piece and play with it sometime. Looking at the cutting charts for it, could be a little tough for my small machines, but I'm all for a new (machining) experience!

Joe and Dennis, sometimes those darn recut marks are caused when I blow out a slot and I've left the mill running. That's often how I do it, and if I would take the time to shut off the mill beforehand, it would cut down on it some. I use canned air with a long nozzle to reach in and give it a puff, and sometimes can hear a chip going past the cutter edge. It makes a little "tic" as it goes through, pushing the end mill over against the other side of the cut, and you get that little nick.
I rarely get those nicks when cutting a wide slot or profiling an edge, since the chips have somewhere to go.

Arnold, sometimes those marks that look the same as recuts can be from a blunt tool. That will often leave a kind of "fuzzy" surface, too, or a rippled effect that is more pronounced than usual. If your tool is sharp though, it's probably from recutting chips. If you have room for a finish pass you can get rid of much of it. Vacuum out all the chips and run your last pass.

John, thanks. I surely agree, much of the end result comes from what is done after the piece comes out of the mill vise. I want the machine to do the needed accuracy part, (as long as I do my part!), but don't expect it to put on the paint and polish. ; )

Kevin, do you have some fairly good files? Just your average well made brand will do, and you don't need to spend a fortune. Nicholson, or something like that. A 6" single cut (mill bastard), and a single cut mill smooth in the same length will be a good start. Shorter files give a finer finish. Watch for pins, a real finish killer.

Dean

 

[Deanofid]

Hello all;
Today, lathe work!
Made a good start on the cylinder, and though not quite finished, here are the progress shots, so no
one thinks I'm just kickin' back, eatin' bon-bons.

Kind of a long piece of aluminum square stock sticking out of the four jaw, but it has to be what it is.
Faced off the end, then centered drilled for a live one.

Bringing down the mid section of the cylinder was done in two steps. It was done this way to
accommodate the use of the 1" travel of the dial indicator that tells me the position of the carriage.
Cut an inch, lock the carriage, move the DI down the bed to zero it out, and cut the rest.

This shot shows the flat nosed tool used to cut out the mid section. It's ground just like a parting tool,
flat on top, both sides narrowing down toward the bottom of the tool for side clearance either way.
Makes a decent finish.

Now that the OD of the middle of the piece is to size, it's time to cut the cooling fins.

Since the base and top of the cylinder are square shaped for mounting things on top and bottom, I
need a flat edge on either side of the tool to cut the top and bottom fins without running into the
square ends. Right and left hand tools were ground up, and I'm groovin'.

I didn't take any stills of the process used for making the fins, but did a video instead, thinking maybe
one person would like to see it being done. Each fin is cut in one plunge.

The lathe is running at 100 rpm, and each cut is dialed straight in .257". As soon as the tool reaches full
depth, it's backed out just a touch to let the tool pull off any chatter marks. When I'm satisfied that the
bottom of the groove is clean, the tool is backed completely out of the cut and onto the next one.

There can be a fine line between cleaning up the bottom of a groove, and making things worse, when it
comes to chatter marks. I don't know how to explain the feel of it. I guess the best teacher in this
case is practice.

Here's the vid:


[ame]http://www.youtube.com/watch?v=P6zeRmx0Rjk[/ame]

After the cooling fins are done, the piece is drilled through and the bore is cut.

Here's the bore shot. Came out okay enough.

Nothing more for today. If I can get to it, there will be a few more pics finishing this up tomorrow.

Thanks again for checking it out.

Dean

 

[zeeprogrammer]

Made a good start on the cylinder, and though not quite finished, here are the progress shots, so no one thinks I'm just kickin' back, eatin' bon-bons.

You thought the pics would help eh?
What kind of bon-bons are you eating?

I didn't take any stills of the process used for making the fins, but did a video instead, thinking maybe one person would like to see it being done.

Yeah...I'm one person who likes seeing it done. These kinds of videos are very helpful. I remember when I first joined and asked about threading...someone was kind enough to show a video of them doing it. This forum is great.

Thanks Dean!

 

[arnoldb]

That cylinder surely came out better than "good enough" Dean. It does not look like you will have too much lapping to do, if any!
Thanks for the tips on the milling; I think I need to invest in some new cutters when I have a bit of loose cash.

Kind regards, Arnold

 

[Deanofid]

Zee and Arnold, thanks guys, for the comments!

You thought the pics would help eh?

Sorry Zee. Just my meager attempt to make you happy. I'll try to do better.
Oh. M&M flavored bon-bons, of course.

It does not look like you will have too much lapping to do, if any!

Arnold, it's getting a liner, so no lapping this part, at least!


Just a few things done to finish up the cylinder today.

First, cut a recess in the bottom of the cylinder that will take the large flange on the displacer cylinder,
or hot cap. Then the piece is parted/sawed off, flipped end for end, and the top end faced off for a flat
surface to mount the bearing supports.

Then to the mill to drill the mounting holes and a couple of threaded holes. These holes need to be
pretty well "on" so the bores in the bearing supports line up well. I found the edges and used table
coordinates to locate the holes.

Another piece down for the count. Almost. It still needs a cylinder liner. That's for another day
when I'm feeling spot on, 'cause it won't tolerate my usual goofs.

The group shot, then, and since there are now enough parts to put a few things together,





an assembly shot:

It's starting to look kind of contraption-ey. I like contraptions!

Thanks again to all who are so nice as to follow along.

Dean

 

[4156df]

Dean,

Enjoying this thread. nice work.

It's starting to look kind of contraption-ey.

Great word. My tool collecting friends would refer to it as having a "high gizmocity factor".

Dennis

 

[kcmillin]

Looking great Dean. (As always)

This is going to be a fun engine to watch.

Kel

 

[ksouers]

Looking great, Dean.

Parts are starting to go together. That's a good sign, isn't it?

 

[zeeprogrammer]

Looks great Dean.

Wish I had time to say more. But you know my signature! "To work. To work."

 

[b.lindsey]

You are making great progress Dean and the the cylinder looks perfect. Its nice when you can start putting some of the bits and pieces together ...if you look hard enough you can almost see it running. Looking forward to more !!

Bill

 

[Deanofid]

Thanks all, for your comments.

So, I haven't posted to this thread for 10 days. I've been ailin', and the doc has me on some kind of
antibiotics trying to get rid of what's slowing me down. Haven't done much of anything in those 10
days but sleep and come here to read the forum. Man, it's boring!

Today, I thought I felt somewhat better, so decided to spend a short time in the shop. I figured about
an hour in there would do me good.
I need a cutter to counter bore a couple of the holes in the bearing supports that will hold the main ball
bearings. I make these cutters all the time.

Turn a pilot on the proper sized piece of drill rod, and then start cutting flutes. You guys who aren't
fuzzy headed will see something wrong with this already.

I didn't notice until I took the blank out of the jig to re-position it for cutting the clearances. The flutes
are backwards. They'll be going the wrong way when the mill is turned on. I make these things all the
time.

Not a big problem, just go cut a pilot on the other end of the piece and start again. So, that's what I
did.

Second try, and now I really know I'm not fit for the shop, even if I "make these things all the time".
I ran the cutter up and started the cut, and the whole thing pulled out of the jig. The peck marks along
the length of this thing are where the end mill flutes grabbed it and ran it out like a gear rack. I'd
stripped a jig screw the last time I'd tightened it down and didn't realize it. No way that would have
gone un-noticed, normally.

'Course, totally ruined this beautiful Atrax end mill, too. Only had a few hours on it.

Nothing came flying out, but could have. I use a shield to keep chips localized, but it also keeps other
things in. Like those things I make all the time.

That's it for today, and probably for a few days to come. If I get the urge to go into the shop
tomorrow, I think I'll just turn on the radio, have a seat, and wipe the grease off something.

For the guys who want to see the goofs along with the good'uns, this is for you.

See you soon.

Dean

 

[doc1955]

Sorry to hear you feel a little under the weather.
Rest up and take it easy.

 

[mklotz]

Tomorrow might be a good day to sort screws. That's what I do when I know I'm unfit for normal shop work. If I don't have screws to sort I polish my hammers or sharpen my Allen wrenches.

Get well soon.

 

[zeeprogrammer]

Get well soon. We need you at top performance.

But we'll tolerate you any way you are. ;D

 

[ksouers]

Get well soon, Dean.

Don't need any more broken tools, or worse. I don't like to operate anything more complex than a paper towel when feeling poorly. Even a broom can be dangerous if you aren't careful about the free end.

 

[b.lindsey]

Feel better soon Dean. Bummer about the end mill but they can be replaced, unlike fingers, etc. Glad thats all that suffered damage.

Bill

 

[Deanofid]

Dennis, Marv, Zee, Kevin, and Bill; Thanks for the well wishes.
Seems like it's taking a long time to get better!

Dean

 

[Noitoen]

Why not use the cutter running backwards? Doesn't your mill have reverse?

Hope you feel good soon.

 

[ariz]

perhaps when you cut the blank in the 'wrong' way you were doing conventional milling (so the work was perfect) while when you tried to cut it in the 'right' way for the rotation of the mill spindle, you were doing climb milling indeed... and this fact caused the disaster :-\

anyway, everyone of us sometimes do this type of errors, so don't worry too much
hope you feel better soon Dean

 

[Deanofid]

Noitoen, no, it only runs one direction.
Ariz, the main problem with the way I did these had to do with trying to get a job done when I wasn't thinking clearly. I've made a lot of these things, really. Just shouldn't have gone into the shop that day. I'll show it properly done in a day or two.

Thanks for the well wishes, both of you.

Little ways from well, yet, but getting there! Did manage to make up a few bushings from 660 bronze. Just enough to keep this thread from dropping to page two, (again!).

That's all today, folks! Thanks so much for all your comments and "wellness thinkings".

Dean