Another Elmer's #5 Geared Engine

[Krypto]

Continuing with the cylinder, we are back at the mill cutting the exhaust ports with a 3/32" end mill. I'm holding that end mill in a stubby ER11 extension which is very handy as it gives you enough visual clearance so you can see what you are doing compared to holding the tiny end mill directly in the spindle.  I also have a longer ER11 extension for drilling holes in hard-to-reach places.



Drilling the exhaust passage from the cylinder face to the exhaust port which is always a tense moment.  The drilling angle suggested by Elmer worked fine and the small brass sheet is inserted into the exhaust port while drilling so you can easily feel when the drill breaks into the port.



Drilling the bolt hole circle for a cylinder cover using the DRO.



This is what the PCD function looks like on this DRO which I think is a bit more intuitive than the older displays that only feature a numerical output.



Awhile ago I milled the bottom of this Spindexer so it would sit accurately in the vise.  Here I'm using it to mill the cosmetic rounded part between the cylinder faces. It's not really made for this type of work, so take lights cuts and mill slowly as you don't want to spoil the work this far into the job.

[Admiral_dk]

Great setups - inspiring 

The Parts you are making looks good too 

Per       

[Krypto]

Thanks!  It's getting there...

[Krypto]

For the steam chest, a brass bar was held in the 4 jaw chuck at the lathe.  Made the round bit with a file on the outboard side and it came out good enough on the first try.



The proto steam chest was then flipped over, turned to length and the other end machined.  Drilled the 1/16" hole almost to the end of round bit on the other side which wasn't exactly fun.  Might have been better to mill out the inner part and then drill these holes at the mill.



The steam chest getting opened-up at the mill.



While the 4 jaw chuck was installed, the eccentric was setup and then machined.  I always enjoy making these as it seems somewhat magical while you are turning the offset.

[Krypto]

Working on the valve rod.  One thing I wanted to show is that it's usually difficult to turn such a long, thin rod without some form of support.  In fact, the first time I turned the rod down using multiple passes it snapped off from the parent stock.  This time I used a technique I seen described elsewhere which was to take it all in one shot.  So at first I just turned down the corners of the square bar to get a good measure and then the rest was removed in one pass.  It worked great with the valve rod measuring right on dimensions throughout it's length.



Using the Neil Butterfield inspired sliding tap/die holder for threading at 2-56.



The valve rod nut needs to fit nice and tight.



Working on the gear arm at the rotary table.  Tried out a new rotary fixture plate during this project and found it worth the bother of making it.



Some more clean-up of the gear arm at the lathe.  This will be soldered onto the orbiting gear.

[Krypto]

The orbiting gear needed a tiny bit of machining, so for some reason I decided to make a custom aluminum fixture to hold the gear. While I was machining the gear hub down, that expensive gear popped out of the fixture and one of the teeth got nicked a bit with the lathe cutter. 

Much profanity was issued! 

After I calmed down, the fixture was trashed and I just held the gear in a ER32 collet after straightening it with a ball bearing pusher and that worked great.  Sometimes I make unnecessary grief for myself!  I cleaned-up the gear with a file and hid the dinged tooth behind the gear arm so it's not really noticeable.  Whenever I setup the gears in the bearing holder, however, I noticed a slight tight spot while turning the crankshaft.



One would think the factory gears would be perfect, so probably the tight spot was my fault from the problem described above.  In any event, some lapping compound on the gears and less than a minute's work with a drill turning the crankshaft totally solved the problem.



I used the Timesaver lapping compound which is nice because it's guaranteed not to embed into softer materials. It comes as a powder that is then mixed with oil for use.  The test kit shown is an assortment of lapping compounds for both hard and soft metals and should last the average modeler a long, long time.  I tried to make the moving parts, like the eccentric / eccentric strap fit, a tad on the tight side and then used the lapping compound while working the parts for a perfect fit.  I think this is a more civilized approach than some of the madmen on Youtube who "break-in" their engines by turning them strapped to a lathe for hours on end.  Madness! 



Finishing off the valve.  Originally the valve was a bit too high to fit properly (assumed a dimension), but it was an easy fix as the bottom just needed a bit milled off.  The valve nut was installed so the nut wouldn't get squashed while being held in the vise.  By the way, that's a smaller vise held with the regular milling vise as the valve nut is under a 1/4" square.  You know when the ER11 collet looks big that the parts are getting small.



Getting parts attached to the cylinder. I'm using the Loctite thread sealer to "glue" the valve plate and steam chest to the cylinder in the proper location that way I can loosen the bolts to remove the valve cover and not have those parts loose their location.  Eventually I will switch to a clear acrylic cover to see the valve moving as shown in Inky's engine.  If you look closely at the valve plate you can see some polishing from the valve.  Looks like it's running right on the money!

[crueby]

Glad you were able to recover from the 'incident'!  Engine is looking great.   
I love that timesavers compound, the test kit just has small tins of each grit/type, but for our uses the tins are enough for many many models, I've been using it for years and the tins are still at least 90% full.
 

[Krypto]

Thanks!  I think it was worth it to splurge for the extra brass.

Yes, I used one tiny pinch of powder from one tin and that did everything.  A little bit goes a long way.

[Krypto]

Punching out the cylinder gaskets in one hit with a dual-head Mayhew hollow punch.  Bought this set used because it's made in France and somewhat salty here in the states.  Excellent kit if you see one.



More work on the gaskets.  I had bought one of those leather punch tools to try for the small holes but totally forgot about it.



Decided I wanted to round-off the end of the piston rod but didn't want to take it apart as the rod packing was set and everything was working correctly so I made a filing button.  Bit of work, but they are an almost idiot proof way of rounding parts like this.



Reaching the end of the build so I'm replacing the Phillip screws I was using during the build with studs which are just nuts loc-tited to a piece of threaded rod.  All the nuts I used on this model were 2-56 narrow-profile bought from McMaster-Carr.  I'll also be adding wood lagging to the cylinder.

I will be wrapping-up the engine build in the next post!

[Krypto]

The completed Elmer's #5 Geared engine.  Here you can see the doll house planking used as cylinder cladding for a cosmetic touch as shown in Inky's build.  I just used CA to attach the planking as I'm not planning on running this engine on steam.



The acrylic valve cover is yet another idea from Inky's build.  It's interesting to watch the valve working while the engine is running which nicely complements the trick gear arrangement on the other side.

<a href="https://www.youtube.com/watch?v=I2T6dQtQzho" target="_blank">http://www.youtube.com/watch?v=I2T6dQtQzho</a>

A short video composed of three different views of the engine running on air.

Overall it was a very enjoyable build without any major difficulties.  Elmer's drawings were spot-on and the engine ran well even at the first assembly.  Probably the most important new technique (for me) used during the construction of this engine was modeling the project in CAD and then using that model to produce shop plans or 3D printed components for reference. That definitely reduced the bone-headed mistakes.

[crueby]

A real beauty!  The motion of the crank/gear is just mesmerizing too.

[Krypto]

Thanks! It is interesting to watch while running.

[ShopShoe]

Congratulations on a beautiful engine.

I like the bling. I especially like the lagging: It definitely adds to the beauty of the whole engine.

As has been said, the motion while running is mesmerizing.

Thank You for posting.

ShopShoe

[RReid]

That's a really nice looking little engine. Well done!

I like the acrylic cover for the valve chest. I too did that when I built the #43 Mill engine; always like to see the "works"!.

[Krypto]

Thanks guys!  This forum was an incredible asset while making this engine.