A Very Simple Corliss Engine

[Captain Jerry]

This will probably be the slowest build log but today, It officially Started.

[Johnmcc69]

 
 Sweet! I've got time!

 What are the specs of your new engine??

 john

[Captain Jerry]

John, I spent about an hour writing an answer to your question but the post process failed and I lost the text.  I have learned this lesson several times in the past but I didn't learn it well enough.  Future lengthy post will be composed offline in Word  and copied to the posting page.  The engine is partially shown in the attachment.


Jerry

[Johnmcc69]

Yep. Been there & done that, I save my posts in "Notepad".

 Looks like a sweet design! I like the dash pots & linkage. Will the dash pots be functional?

 John

[crueby]

I don't bother to compose them in another app, but do select-all and copy the contents of the text window before hitting post. Not often that it fails, but it does happen. Sometimes it gives an error, and hitting the refresh button in the browser makes it try again and it goes through. Hitting the back button will take it back to a blank compose window!

[Captain Jerry]

John:  Thanks for taking the time to look at the design.  I'm glad you like the older style dashpots but the disappeared last night.  It seems that my shop time may be more limited than I had anticipated.  My health and strength are up to it but I need to spend most days providing care for my wife who suffers from Parkinsons.  I only get a few hours per week in the shop and that id on weekends when there is someone else in the house.  But I do get plenty of design time with Alibre". 


Last night I threw the old dashpots out and designed a spring type dashpot that is mounted to the face of the cylinder between the inlet valves. I have no experience with this type of dashpot and I haven't found any plans of the internals on other builds so if anyone can point me to some, please do so.  This one is a simple cylinder with an internal spring.  I was surprised how easy it was to fit it into the design.  I had to slightly modify the knock-off pin linkage to give some clearance.  That is what is shown in the attachment.


One other design situation is needing some attention.  Driving the governor requires either a pair of bevel gears or a twisted belt.  I did find a pair of bevel gears of about the right size that I made a few years ago when I was learning to use a rotary table.  The are of the single pass design and maybe a little rough.  I even found the cutter that I ground for them but To make a new pair will take more work than I want.


The other option is a belt drive with a ninety degree twist but that requires some guides to keep the belt aligned.  That will add some friction that I would like to avoid but it might be smoother than a poor set of gears.  Any pros or cons?


Jerry

[Johnmcc69]

Hello Jerry, don't worry about the progress on the engine, take care of things at home first. We've been getting hammered on with snow the past few days here in the north, close to a foot here & even more like 3Ft. in Crueby's neck of the woods. Good time for some design time.

 I like your idea with using springs on the dash pots, I really think that will work.

 I'm not sure what size or scale your engine may be, but when I designed my governor for the Corliss, I spec'd these gears from PM research, maybe they might work. Cheap & off the shelf.

 John

[crueby]

Hello Jerry, don't worry about the progress on the engine, take care of things at home first. We've been getting hammered on with snow the past few days here in the north, close to a foot here & even more like 3Ft. in Crueby's neck of the woods. Good time for some design time.

 I like your idea with using springs on the dash pots, I really think that will work.

 I'm not sure what size or scale your engine may be, but when I designed my governor for the Corliss, I spec'd these gears from PM research, maybe they might work. Cheap & off the shelf.

 John

I'm about 50 miles east of where they got the deep snow south side of Buffalo, 4 feet and still coming down. Only a half inch last night and that melted today.
Very interesting work on the Corliss!

[Captain Jerry]

Its cold hear too.  Didn't reach 70 deg until afternoon but we had about 2 feet of boredom.


Thanks for the heads up on the gears.  It looks like they will work out great.  I ordered a pair.


Jerry

[Captain Jerry]

I got a little more done today. I now have the three pieces that make up the quick release linkage. The central rocking actuator and the two push links that operate the valves.


Jerry

[Admiral_dk]

To me it looks like you have made the middle part from two different materials - is that just a trick made by the camera or .... 

Per

[Captain Jerry]

No camera tricks.  The center part is actually three materials.  The plate is aluminum. The top insert is cast iron which is secured with Locktite and a brass screw.  The screwhead was then filed to provide the center divider.  The two links are cast iron so the actual wear faces are CI to CI which should give smooth operation and good wear.


Jerry

[Admiral_dk]

Thank you for explaining - glad it wasn't my Eyes or my Head Brain that had a problem 

Per

[Captain Jerry]

I haven't posted much but due to limited shop time I havent done much. I had some time today and decided to attack a part that has been on my mind. It looks easy but it is a bitch.It is the link arm that pivoys on the intake valve shafy with equal length arms that connect with the push action bar and the dashpot link. It is a small part with overall length of about 3/4 inch  and their are many ways to design such a part but my armchair design decided on the traditional spherical hub method.


What a pain in the cheeks.  Three small spheres closely spaced on a single bar, the milled flats with drilled holesin the resulting faces. the center sphere is .25" diameter with a .125" hole and the two outer spheres are .200" dia. with .094" holes.  The spheres are the problem.  If they are less that perfect they really look crappy when the faces are milled. Their position on the shaft is also critical because the holes must be perfectly centered and must be .305" from the center.  The material is plain BON steel.


Give it a look and offer any suggestions if you can.  I don't plan to exhibit this model anywhere but here so if necessahr, I can resort to plain flat bar but I really like the appearance of the spherical hubs.


Thanks for looking,
Jerry


Oopa. the attachments are Alibre' Part and drawing files.. I'll try to get them converted to images so everyone can see.

[Admiral_dk]

Flat-bar and form-tool springs to mind here .... if you're lucky the later can be a Wood-Routerbit (but they are probably all too big).

I'm sure I don't need to tell you to use a too long bar supported by a 'Live Centre' ....
Also sure that this can be done in many other fasions. Happy hours in the Shop 

Per