Tug's Corliss Tandem Compound Project

[Ramon Wilson]

'Morning Guys, Thanks for looking in and taking the time to post - always appreciated

It's been far too long since I was working on this but I am pleased with this latest progress so maybe it will act as a catalyst to pay a bit more attention to than of late.

Thanks for the PM David - be in touch later.

Hope you are well Vince - nice to see your Corlisss on MEW 

Per - wheres that year gone - I guess you and your brother in law won't be over here this year due to the virus but when you do again do call in for a for a cuppa and a visit to 'tha ol shid' if you are this way. Sue and I are fine - hope you are too.

The engine, despite all the potential for binding, runs quite freely - I can 'run' it by turning it by hand holding the big end but whether all the timing is right and the valves work as they should remains to be seen - if they don't it's going to be one big paperweight  .

Thanks again guys, always good to hear from fellow members - back sometime with a further update

To coin a good friend from Tennessee

Y'all stay safe now ya' hear 

Ol Tug

[Admiral_dk]

I'm not sure John and I would have gone to the UK this year if it had been an option ....
But his mother is in the extreme high risk group with regards to Covid, so not even his sister that live close to their parents are allowed to visit them ... 

I was sick with all the symtomps off the worst version off Covid last week (except it only lasted 72 hours), and I was just released from home quarantine yesterday afternoon and back to work today. Other than that things are improving - I got my first mill just about exactly a year after we meet. It hasn't touched an engine part yet - the closest have been a few parts for the Off-Roader and T-Nuts for itself. Most time since it arrevid has been used to transform the workshop to make space for it - but it's in place now 

[Ramon Wilson]

Hi Per, hope you are as well as you sound - I believe having this virus can leave you with some unpleasant after affects that can hang around for some time.

Good news about your mill  - you're well on your way now to making that David Anderson eh

Regards to John - offer's open whenever you are this way again

Tug

[Admiral_dk]

Thank you very much Ramon, both for your concern and the open invitation

As all the symptoms were the same as Covid - I was tested, and it was not Covid - so beside the annoyance of being sick and the following quarantine (until the test result came back), there are and will be no after effects

Per

[gary.a.ayres]

Hopefully you are correct, Per.

The tests are not infallible though. My daughter and her flatmate are both nurses. Earlier in the pandemic they both had direct contact with patients who had covid, with inadequate or no PPE (I shall refrain from getting political about this here in the forum!).  They share a kitchen and bathroom in the flat. They both developed the same clear covid symptoms. Shortly afterwards they were tested for antibodies. He tested positive; she tested negative.

That was antibody testing. It may be different  with the test for actual covid itself - I don't know without looking it up.

[Ramon Wilson]

Good to hear Per lets hope it stays that way

We have been doing our best to be as cautious as possible but despite the easing of sanctions it's still ever present. Given my age the last thing I want to do is spend one minute of it staring at the ceiling of a Covid ward wondering if I'm going to make it!  Perish the thought - I have an engine to finish (besides 'one or two' other things I'd like to do) before I fall off the end of my perch

Regards - Tug

[Ramon Wilson]

Hi Guys,

Had a busy week making the governor parts ......



.. and very pleased with the result

Yes it has been assembled and tested but it's now stripped to paint the column and the rebuild and fit destined for tomorrow. Next up is to start on the inlet side of things.

Regards - Tug

[crueby]

Great job on the governor parts, watching along!

[deltatango]

Those bits look good, hope it works as well!

Is the column a casting or a fabrication?

David

[gary.a.ayres]

Beautifully crafted components.

[Ramon Wilson]

Hi Guys - thanks for looking in 👍

David - the pedestal is a fabrication of the two parts as drawn but with a slight modification of the top part to suit myself. It's machined from cast iron so I guess it's as near as you can get with the help of a smidgeon of JB Weld (what else  ) The main spindle is supported top and bottom by bronze bearings



Here it is all in situ but it may have to come apart again for an improvement.....



.... As drawn the spindle make up allows the spool to be pressed against the top of the pedestal by the pressure of the spring which creates a fair degree of friction. It would be better to have the spindle stepped so that the spool has something to register against without causing this situation. As it stands here I have had to weaken the spring considerably - I will try it as is but have a feeling that in the long run I will need to make a new shaft and open the bearings.

Bit of a red letter day today - I'm pretty certain I have just machined the last part that requires to be made from cast iron 

Regards - Tug

[gary.a.ayres]

Looks immaculate!

 

[Ramon Wilson]

Thanks Gary 

David - further to that thinking, this morning I gave it another thought.

I have now reduced the shaft to 3.5 diameter above the pedestal and fitted a sleeve over it - 24 mm long 4 OD x 3.5 ID with a 5.5 diameter 0.8 thin shoulder at the bottom. This gives 5 thou running clearance between the shaft and pedestal and the spool bottoms out on the shoulder. The correct spring has been refitted and the whole thing works much much better - no friction as such and the weights much more smoother and positive in their movement

Hope that's of interest to you

Regards - Tug

[deltatango]

Hi Tug,
Definitely of interest! I haven't got a CAD model of the governor as drawn, I think I modified it as I went to get rid of interferences etc, I'll put together an "as drawn" version shortly for future reference. I think that minimising friction is the only way to go for something like a governor and then you are in to watchmaking methods to keep friction down whilst limiting lost motion. I guess I'll learn a lot about this when I get to actually make one  . I wonder if anyone who has completed one of these engines has made the governor work - does Bob Potter know?

You may well be correct that the engine will run well enough even if the governor isn't really working but it would be cool to actually see the Corliss gear working as it should to control speed. MJM's electronic governor might find a place here!

BTW, I think you used a drive belt for a turntable for the governor belt, can you remember a part number/source? I don't think there's much chance of finding 1/16(?) scale cotton drive rope and I don't fancy making the splices anyway.

David

[Ramon Wilson]

Hi David

I haven't had any contact with Bob for some time but maybe if he reads this he'll comment.

I wouldn't say I've done anything to reduce friction except as mentioned other than making all working surfaces nice and smooth and bind free. As it is at the moment the governor responds quite quickly to an increase in RPM (hand driven of course) but how it will react once the linkage is complete is another matter.

A search on ebay for turntable belts will soon bring something up - the one fitted at the moment is approx 285mm end to end  when laid flat. Though it works okay it is probably a tad on the slack side so I intend to search for something about 260-70 to increase the tension a bit

Not much done today but maybe tomorrow eh

Regards - Tug