Mike's P.M. Research No. 6 Steam Engine

[ErichKeane]

That optical flat method is interesting... though I guess I would have just found the split-line by removing the cap, using an edge finder, then re-adding the cap back.

 

[macardoso]

That optical flat method is interesting... though I guess I would have just found the split-line by removing the cap, using an edge finder, then re-adding the cap back.

Yup, probably a sane person would do that. I don't trust my edgefinders much better than 0.001". If you don't drill and bore right on the split line, you end up splitting the cap on a chord of the circle. With such little clearance between the parts, it doesn't take much for you to not be able to assemble the parts. The indicator method is as accurate as your indicator (0.0001"). The optical flat can be replaced with any good and flat surface (carbide insert, gage block, etc.) but I have a small flat for stuff like this ($20 on ebay).

 

[macardoso]

Here is the engine as it stands today.



The connecting rod now links the crankshaft with the piston side and allows you to manually cycle the engine. Even though a good alignment fit hasn't been done yet, everything slides really smoothly and there is not any appreciable rubbing or binding.

There are no seals installed in the packing nuts and the piston has no rings installed. Only some computer paper head gaskets were made. Even still, the whole thing is nearly gas tight. You can hear the air being pumped in and out of the cylinder through the steam inlet port, and blocking this port with your finger makes it so you cannot turn over the crankshaft.

I have technically made all the remaining parts, but they require a fair bit of hand fitting. The next steps will be to bend the valve rod, pin it to the linkage joint, and set the valve throw and timing. With that complete, the engine should be ready to run on shop air.

My buddy (who I have been making this for) took it home to mess around with and show his father. I'm going to get it back from him before I move so I can put the finishing touches on it. Specifically, the frame needs a hole drilled for an oil cup, the cylinders need drain bung holes drilled and tapped (necessary if the engine would ever be run on live steam), and we came up with a plan to add oiling provisions to the eccentric and connecting rod (crankshaft side). I'll then tune it up and run it in for several hours to make sure it works well. I'll also install all the seals and proper gaskets. I also want to adjust the fit of the crankshaft bearings, and the inboard head of the cylinder as these are the locations of the most rubbing. My friend plans to clean it up, polish it, and paint it with a classic green enamel.

Here is a list of machined parts and my status:

Crank Disc (Qty. 2): Done (4.5 hours)
Cross Head: Done (8.5 hours)
Crank Pin: Done (4 hours, 1 Scrap)
Lower Valve Head: Done (2 hours)
Piston Rod Packing Nut: Done (1.5 Hours)
Lower Linkage: Done (2.25 Hours)
Upper Linkage: Done (2.25 Hours)
Eccentric Hub: Done (8 Hours, 1 Scrap)
Wrist Pin Bolt and Nut: Done (1 Hour)
Outboard Valve Head: Done (2.75 Hours, 1 Scrap)
Valve Rod Packing Nut: Done (1 Hour, 1 Scrap)
Oil Cup (Qty. 2): Done (1.75 Hours, 1 Scrap)
Piston: Done (5 Hours)
Lower Valve Rod: Done pending final fit (0.5 Hours)
Pillow Block & Cap (Qty. 2): Done (17.5 Hours)
Valve Eccentric Ring and Cap: Done (10 Hours, 1 Scrap)
Upper Valve Rod: Done pending final fit (0.5 Hours)
Valve: Done (3 Hours)
Crankshaft - Short: Done (0.75 Hours)
Crankshaft - Long: Done (0.75 Hours)
Piston Rod: Done (4.5 Hours, 1 Scrap)
Connecting Rod and Rod Cap: Done (13.5 Hours, 1 Scrap)
Base: Done (5.5 Hours)
Flywheel: Buddy did this one, I just skimmed it true. Done (1 Hour)
Frame: Done pending drip oiler selection (10 Hours including repair)
Cylinder: In Process, drain port needed (9.5 Hours)
Inboard Head: Done (3.5 Hours)
Head: Done (1.5 Hours)


Recorded hours to date: 126.5 Hours (probably close to 140 including cleaning, bench work, and planning)
Estimated Completion: 95%

 

[Manual Mac]

Thanks SO much for taking us on The Grand Tour of this build.
I’ve thoroughly enjoyed it so far and appreciate your documenting it for us.
Good luck with your move.

 

[macardoso]

Thanks SO much for taking us on The Grand Tour of this build.
I’ve thoroughly enjoyed it so far and appreciate your documenting it for us.
Good luck with your move.

I love this community and sharing here has helped me get the kicks in the tush that I need from time to time to keep moving on longer projects. I've also learned a ton here and hope I can contribute a little bit back.

 

[wachuko]

As a newbie, the scary part of these kits is the amount of jigs that have to be made to just work a part... This is very intimidating for me...

I am so grateful for you taking the time to share the process... all of it, the good, the bad, and the ugly...

Good luck with the move!!

 

[macardoso]

As a newbie, the scary part of these kits is the amount of jigs that have to be made to just work a part... This is very intimidating for me...

I am so grateful for you taking the time to share the process... all of it, the good, the bad, and the ugly...

Good luck with the move!!

I think the workholding is absolutely the most difficult thing about working with castings. Mill vises are great for bar stock but suck at holding oddly shaped parts. I'll say that ~75% of the time I have spent on this engine has been setup and fixturing. Lots of time with an indicator making sure things are lined up. Really gets you thinking about the best way to do things, any ways you can do more operations in one setup, etc.

I'll say that this project has single handedly pushed my machining skills and knowledge further than anything that came before. Kinda cool.

My only aversion to picking up another one would be the time commitment. Being 27, between work and family, I don't get much shop time at all in a week. So a 150+ hour project just drags on forever. I also am uncomfortable with outstanding projects, so I am always wanting more time to get it done.

 

[Lo-Fi]

As a newbie, the scary part of these kits is the amount of jigs that have to be made to just work a part... This is very intimidating for me...

You'll get to appreciate that making jigs, fixturing and workholding is actually the fun part

I've been making a tool and cutter grinder from castings myself. Had a few "lessons" (mishaps) as it's my first time working with rough castings.
My top tips would be:
Watch Joe Pie on YouTube. His lathe project in particular, though his approaches in general tend toward using fixtures and jigs to make life easier for yourself regardless.
If the grip is smaller than the chip, the part will slip.
Order of operations is key. Set yourself up so you've got access to do all the things you need to do in a specific orientation in one setup if you can.
Think carefully about how you can used the features you're machining to register features that come later.

Don't be afraid of stuff you can't just sling in the vise! It's really rewarding to set up a jig and absolutely nail some parts. Certainly more than doing something quick but sketchy and getting a mediocre result or failing altogether. Joe Pie is an absolute master of this and the best content I've seen for consistently inventive, effective setups that get excellent results. Taught me a lot about how to think about setups.

Loving your work, @macardoso