Author Topic: Another MEM Corliss (in .40 scale)  (Read 3220 times)

Offline kvom

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Re: Another MEM Corliss (in .40 scale)
« Reply #30 on: July 10, 2018, 11:49:46 PM »
I'd have had to buy a pack of 3/64" dowel pins from McMaster as there's no way I'd ever get a paper clip straight.

Offline crueby

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Re: Another MEM Corliss (in .40 scale)
« Reply #31 on: July 11, 2018, 12:00:29 AM »
Now we have to get him to make us all paperclips with tiny nuts threaded on the ends, back in the shape of a paperclip of course!

Offline Craig DeShong

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Re: Another MEM Corliss (in .40 scale)
« Reply #32 on: July 11, 2018, 02:22:38 AM »
Your work is just amazing George  :ThumbsUp: :ThumbsUp: :ThumbsUp:
Craig

Offline gbritnell

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Re: Another MEM Corliss (in .40 scale)
« Reply #33 on: July 11, 2018, 04:38:30 AM »
First of all thanks everyone for the gracious comments.
The flywheel scales down to 2.90 inches diameter. The spoke cross section is .100. The full sized flywheel is a fabrication of the hub, spokes, inside outer rim that the spokes mount to then a finish ring on the outside.
To fabricate the flywheel would have meant silver soldering .094 spokes into the hub and rim. Even with careful fixturing there is a possibility of warping. On the larger wheel that wouldn't be too much of a problem because the flywheel would be rigid enough to chuck and cut true but with this little one there is no good way to correct any out of true condition.
With that in mind I decided to make it from solid steel. I increased the spoke cross section from .100 to .135. With larger wheels I start with the blank in the chuck and cut the recesses in the part but with the radius in the corners of the hub and rim it takes several tools changes to finish it. One tool is needed to rough to depth (trepanning) then the other tools for finishing the inside and outside radii.
I decided to mill the whole wheel. I chucked it in the lathe and faced both sides to size. I also drilled and reamed the center hole. (.156 diameter) I set up the rotary table and indicated it true. I then clamped an old aluminum fixture plate to the rotary table. I milled a center hole into the plate and drilled and tapped for some small clamps. I turned up a plug for the center hole that would locate the wheel blank perfectly on center.
I left extra material on the outside edge of the rim to clamp to. I milled to depth leaving stock for finishing the fillets in the corners.
Talent unshared is talent wasted.

Offline gbritnell

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Re: Another MEM Corliss (in .40 scale)
« Reply #34 on: July 11, 2018, 04:46:30 AM »
The part was then turned over and the same machining completed. The next step was to center drill and drill out the inside corners. I stayed away from the tangent point so this could be finished with a .187 end mill. With the pilot holes complete I started roughing the spokes staying about .006 away from the finished dimensions. Once the material was roughed out I went to my finish dimensions. The hardest part of this process is cutting the inside of the rim. If you leave even .001-.0015 stock then it's really a lot of work filing and finishing to blend it in. If you go the other way by the same amount it leaves a step in the part.
Talent unshared is talent wasted.

Offline crueby

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Re: Another MEM Corliss (in .40 scale)
« Reply #35 on: July 11, 2018, 04:50:48 AM »
More stunning work...


 :popcorn: :popcorn: :popcorn: :popcorn:

Offline gbritnell

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Re: Another MEM Corliss (in .40 scale)
« Reply #36 on: July 11, 2018, 04:52:16 AM »
I was more than happy with the way everything blended so the part was then mounted in my 3 jaw chuck and the extra material that I had left for clamping was reduced leaving about .005. The chuck isn't accurate enough to take the part to the finished size so I put it back on the fixture plate that was still set up on the rotary table. Using an end mill I cut the remaining material off the wheel.
Talent unshared is talent wasted.

Offline gbritnell

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Re: Another MEM Corliss (in .40 scale)
« Reply #37 on: July 11, 2018, 04:53:43 AM »
All that remains is to put a radius on the edges of the spokes and drill and tap for a set screw.
Talent unshared is talent wasted.

Offline Ramon

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Re: Another MEM Corliss (in .40 scale)
« Reply #38 on: July 11, 2018, 05:28:14 AM »
Just caught up George but all very much worth waiting for  :ThumbsUp:

Thanks for the heads up on the tap. That type is new to me. Though never used I have a couple of fluteless forming taps from work days which require a larger hole and power feed which look similar -  I guess these ones are designed mainly for through holes in thin material - do you need to keep withdrawing to clear any swarf ?

Super machining on the flywheel - at sub 3" those spokes would have need a delicate touch for sure, a lovely result indeed.

Love the use of the paper clip too  :praise2:- I've used wire coat hanger material to make 8BA studs in the past but this takes it all to a new level  :o.

Yep, it's going to be a little 'Gem' for certain  :ThumbsUp:

Regards - Tug
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline gbritnell

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Re: Another MEM Corliss (in .40 scale)
« Reply #39 on: July 11, 2018, 12:41:53 PM »
HI Tug,
Thanks for the reply. Usually with any small tap, fluted or otherwise, I back them out repeatedly to clear the chips. As most builders have found the taps go in very nicely, it's when you're backing them out that they start binding up. I use my headband magnifier when using the small taps. It gives me better control at keeping the tap square.
gbritnell
Talent unshared is talent wasted.

Online b.lindsey

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Re: Another MEM Corliss (in .40 scale)
« Reply #40 on: July 11, 2018, 12:52:38 PM »
Lovely work as always George on the flywheel !!

Bill

Online steamer

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Re: Another MEM Corliss (in .40 scale)
« Reply #41 on: July 11, 2018, 01:09:53 PM »
 :popcorn:
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline gbritnell

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Re: Another MEM Corliss (in .40 scale)
« Reply #42 on: July 11, 2018, 07:42:03 PM »
Corners radiused and polished. Just the set screw remains.
Talent unshared is talent wasted.

Offline zeeprogrammer

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Re: Another MEM Corliss (in .40 scale)
« Reply #43 on: July 11, 2018, 07:58:07 PM »
I've been  :popcorn: from the beginning. I just don't know what to say.

Amazing work!
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline Craig DeShong

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Re: Another MEM Corliss (in .40 scale)
« Reply #44 on: July 16, 2018, 12:57:55 AM »
Lovely George, just lovely.
Craig