Author Topic: JC attempts the MEM Corliss  (Read 10990 times)

Offline crueby

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Re: JC attempts the MEM Corliss
« Reply #135 on: November 15, 2021, 04:45:56 PM »
Woohoo!  Just wait till the rest of the links are on and moving....  Watch the link... Watch the link.... You are getting sleepy...!

Offline astroud

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Re: JC attempts the MEM Corliss
« Reply #136 on: November 15, 2021, 05:11:34 PM »
When I did my MEM Corliss I thought the valve rod to valve disk connection looked  a little Mamodesque and went with a threaded rod end and threaded clevis to allow final adjustment.
Andrew

Online Kim

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Re: JC attempts the MEM Corliss
« Reply #137 on: November 15, 2021, 06:45:51 PM »
Great looking linkage there on your Corliss, JC!   :popcorn:

Kim

Offline JCvdW

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Re: JC attempts the MEM Corliss
« Reply #138 on: November 18, 2021, 08:57:51 PM »
Thanks guys for the feedback.

Andrew, please share a picture of your linkage. I am curious to see how it looks.

The valves were finished yesterday, and were made from 6mm drill rod. As always I first had a look how Vince made his, and more or less followed his lead.

First a slot was milled with a 6mm ball nose cutter in a piece of scrap aluminium, to securely hold the valves when milling the flat section.



An M10 and M6 bolt were used to make a stop for the MT2 ER25 collet holder. The M10 bolt screws into the drawbar thread of the MT2 shank. The M6 bolt then screws into the M10 bolt. The stop ensures that the four valves are held at exactly the same depth in the collet, for turning on the lathe.



The final result:



A 1mm ball nose cutter was used to mill a line and a small hole on the end of each valve, to mark the orientation of the flat section of the valve. This will hopefully later assist when setting the valve timing.



The original plans for the Corliss show a valve consisting of two separate pieces. What would be the advantage of a two piece design compared to a solid valve?
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Offline astroud

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Re: JC attempts the MEM Corliss
« Reply #139 on: November 19, 2021, 10:11:42 AM »
Hi JC
here's a picture of my linkage. I Have always thought cranked valve rods don't look right so laid out to allow straight rods

Offline JCvdW

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Re: JC attempts the MEM Corliss
« Reply #140 on: November 20, 2021, 04:24:13 PM »
Thanks for the pic Andrew! That straight linkage looks really good! Too late for me to now make a change though. Can't wait to see my Corliss running!

I made a start on the valve bonnets.

First a piece of 22mm brass round stock was milled into 15mm square bar.



After drilling the 2mm holes for the rear bonnets, four of them were sawed off on the mill.



The four front bonnets were then also drilled and sawed off one by one.



The four rear bonnets were then milled to 1.5mm thickness, and finished off with a bit of sanding.



I now have to make a small jig to finish turning the front bonnets, ala Vince.
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Offline Don1966

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Re: JC attempts the MEM Corliss
« Reply #141 on: November 21, 2021, 03:25:57 AM »
Nice work JC been following quietly and enjoying the built.

 :cheers:
Don

Offline vcutajar

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Re: JC attempts the MEM Corliss
« Reply #142 on: November 21, 2021, 07:52:37 AM »
Great progress JC.  Not long to go before you put some air in it and see it turning.
Thanks for mentioning my build log but I would like to add that I took some  ideas for my build from Arnold who did the same Corliss before me.
Just curious but how can you follow my build log?  I thought that the photos in my log were not visible anymore.

Regards
Vince

Offline JCvdW

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Re: JC attempts the MEM Corliss
« Reply #143 on: November 21, 2021, 08:09:52 AM »
Thanks a lot Don!

Just curious but how can you follow my build log?  I thought that the photos in my log were not visible anymore.

Vince, thanks again for your detailed log. Your photos are certainly (fortunately!) still visible. Since you have already incorporated Arnold's ideas, I only have to consult your log  :D.

A small mandrel was made to hold the front bonnet in the three yaw chuck.



The four front bonnets could then be turned in quick succession. I decided not to use o-rings for now, as the bonnets can easily be bored later if needed.



Now for the fiddly bits. Cannot decide yet how to fasten the valve levers and still have them easily adjustable. I would like to keep the shape of the levers as shown on the plans, as this matches the originals more closely, as shown here: http://www.wkinsler.com/technology/corliss/figures/index.html

Maybe a sholder on the valve stem with an M2 bolt to clamp the lever will do.


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Offline JCvdW

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Re: JC attempts the MEM Corliss
« Reply #144 on: November 24, 2021, 08:28:45 PM »
Another idea (similar to how Arnold did his) how to clamp the valve lever to the valve stem, seeing that I do have these small M1.4 bolts and nuts from Knupfer:



Anything is possible in a CAD model. Let's see if it can be made from 303 stainless steel...
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Offline derekwarner

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Re: JC attempts the MEM Corliss
« Reply #145 on: November 25, 2021, 01:26:49 AM »
JC...thinking that you have 4 of the linkage adjustments to achieve......

I have zero knowledge in the installation of Corliss valving, so does the geometric orientation provide correct timing?, or does each of the 4 valve spools require any +/- positioning?
 
If you used the same bolt pitch  [0.3P] as the M1.4 diameter bolts as the linkage rod, would 0.3P [x .5= 0.015mm per 180 degrees] allow sufficient alignment?....or would you have slip fit & solder both ends of the connecting rod to ensure absolute accuracy in the timing of the arm?

Derek

« Last Edit: November 25, 2021, 01:44:51 AM by derekwarner »
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Offline JCvdW

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Re: JC attempts the MEM Corliss
« Reply #146 on: December 03, 2021, 09:22:47 AM »
Derek, I would think that if all components are accurate, that geometric orientation should provide correct timing. But I expect that in my case I will have to make small adjustments.

On real Corliss valves, the linkages are adjustable, and your suggestion makes for a more realistic model. In fact, this is also how it is shown on the plans. But making adjustable linkages seems really difficult. Hence the attempt to make adjustable valve levers instead.

I started off the adjustable levers by squaring off two pieces of 303 stainless steel.



The ears were milled, drilled and then rounded off on the rotary table. The four yaw chuck on the rotary table allows for easy adjustment of the pivot point.



The M3 holes for the valve stems and the M2 threaded holes for the connecting rods were then drilled and tapped, and rounded on the rotary table.



The 0.5mm slots for the ears were then cut on the lathe. The lever was clamped in a tool holder, with the slitting saw in the four yaw chuck. This way the saw could be accurately centred using the lathe DRO.



The angled sides were then set and milled on the rotary table.



The levers were then separated and the connecting rod side also rounded on the rotary table.



The final result is not perfect, but will do for now. Next time I will rather use the M3 hole as reference point for all operations, rather than the end of the ears.



Only the connecting rods now, and then the engine should hopefully move under its own steam!














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Online Kim

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Re: JC attempts the MEM Corliss
« Reply #147 on: December 03, 2021, 02:29:36 PM »
Very nice work, JC!  :popcorn:
I found it interesting how you used the slitting saw and held the part in the tool rest on your lathe. I've never seen that done before.  Pretty interesting!

Kim