Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

The Regular Stuff: Chat, Buy, Sell, Off Topic, etc. => General Discussion - Model & Toy Steam Engines – Stirling Cycle – Flame Lickers – Small Antique Originals => Topic started by: Nu2modlin on September 07, 2020, 03:29:17 pm

Title: Re: Checking out my Stuart 5A
Post by: Nu2modlin on September 24, 2020, 02:14:51 pm
I've spent a little time going through this engine, getting to know it and cleaning it up a bit. It sure seems to be well made.
Very little wear as I said before. I have taken off the reversing lever to remove the rust, I am going back together with the linkage. Much better I think.
I think I will just clean it up and set it aside for now. Once I build my PM#7 I'll look into a method of providing steam. I would love to see the Stuart 5A run on steam.
Lots to learn first
Title: Re: Checking out my Stuart 5A
Post by: txlabman on September 24, 2020, 06:09:33 am
A nice restoration thread.

Looking forward to the next chapter. 🤠
Title: Re: Checking out my Stuart 5A
Post by: Steam Technology on September 08, 2020, 04:53:53 pm
He has some good stuff on his channel.
Title: Re: Checking out my Stuart 5A
Post by: Nu2modlin on September 08, 2020, 04:35:04 pm
I just watched a David Richards Youtube video. I think it was #6 or 7. He was talking about this exact thing, adjusting a bit of float in the valve.
I love his channel.
For those of you not familiar with him, he operates a 1925 environment, line shaft, full machine shop on steam.
Title: Re: Checking out my Stuart 5A
Post by: Steam Technology on September 08, 2020, 04:25:05 pm
the valve shoe should 'float' so the steam pressure in the valve chest can press the shoe to the face for a good seal.
If it is securely attached to the valve rod the shoe can lift as the rod moves giving a poor seal to the face.
Title: Re: Checking out my Stuart 5A
Post by: Stoker on September 08, 2020, 09:22:05 am
Air and Steam are very different things to be sure, but if it does run on air okay, then the slide valve must be seated in the correct position and maybe okay. The jam nuts are supposed to be jammed against each other, but in such a way as to allow the actual valve the slightest amount of free movement to let it "seek" its seat on the port face. At least that is how I've always understood slide valve theory. Steam admission does change temperature of the metal drastically, and could change a slip fit to an interference fit under some conditions. But if the slide can in fact "float" some, then expansion of a rigid setup should not be a problem.
Title: Re: Checking out my Stuart 5A
Post by: Nu2modlin on September 08, 2020, 09:09:07 am
Parts are sitting in Evaporust. I'll get it back together and apply some air pressure for our viewing pleasure..

Mr. Stoker sir, I see what you mean about the jam nuts. I ran this on air just to see what happens. I oiled it first of course. It runs very smooth and quiet.
Do you think it would be different under steam? meaning the valve play.
I've heard they run different-better under steam. I'm just wondering what motivated the last owner to lock the nuts?
Title: Re: Checking out my Stuart 5A
Post by: Steam Technology on September 08, 2020, 01:19:28 am
Firstly you aquire the engine for an absolute song, and now you make us wait to see it running.
What next already. ::) :) 8)
Title: Re: Checking out my Stuart 5A
Post by: Stoker on September 07, 2020, 11:52:43 pm
There is one thing that gives me pause for thought in looking at the photo of the steam chest with the missing stud at 4 o'clock. It looks like the jam nuts are cinched down tight on the slide valve flange, and if so, then the slide valve can't "float" over the ports using the steam pressure to seat it against the port face. If in fact the slide valve can "wiggle" and is not held rigid by the jam nuts, then all is as it should be, but if there is no wiggle room available and it is clamped tight as it looks in the photo, then I don't think that is right. It needs to be able to move free, not much, but enough so that it can find its own seat against the port face when under steam pressure.
Title: Re: Checking out my Stuart 5A
Post by: Tadfafty on September 07, 2020, 10:37:53 pm
Built well and taken care of then.
Title: Re: Checking out my Stuart 5A
Post by: Nu2modlin on September 07, 2020, 08:55:47 pm
What’s amazing to me is the movement feels like it’s on greased bearings
Each revolution is buttery smooth.
A mark of a true artist. IMHO
Title: Re: Checking out my Stuart 5A
Post by: Nu2modlin on September 07, 2020, 08:51:40 pm
I’m getting to know this beautiful work of art.
I put the linkage and  Several parts in Evaporust.
Tomorrow I’ll pull everything out, I have some polishing to do on the brass.
This may take a week or two. I’m in no hurry.
Title: Re: Checking out my Stuart 5A
Post by: Jim on September 07, 2020, 07:59:12 pm
Very nice looking Stuart there.
Title: Re: Checking out my Stuart 5A
Post by: Hero on September 07, 2020, 06:30:55 pm
A veritable work of art.
Title: Re: Checking out my Stuart 5A
Post by: Steam Technology on September 07, 2020, 04:32:59 pm
The 5A is a great engine and yours is a very good example.
Title: Checking out my Stuart 5A
Post by: Nu2modlin on September 07, 2020, 03:29:17 pm
I introduced this engine on the new members thread.
I had some time today and decided to do a bit of cleaning and inspection.
First off, the machinist who built this engine is very good.
The fit and detail, in my novice opinion, is outstanding.
Take a look.