Muncaster's Joys Valve Engine

[smfr]

Thanks Jason, I did pein the pins over. I can feel and see the crank end rotating around the pin; I'm going to see if I can work in some Loctite by wobbling, then set it up on some V-blocks to harden.

I found that I don't have a bit of 1144 big enough, so will have to order some ($32-$60 + shipping depending on supplier  )

Simon

[Hugh Currin]

Simon:

That is a beautiful build. As I look at it I keep identifying parts I remember you building, and all the work that has gone into each. Really stunning.

Locktite makes a penetrating version for assembled parts. From MSC I think its their 290. I've used it for loose bearing presses (bicycle hub) and it worked well. You might give that a try.

Thank you for posting the build.

I've discovered that one of the pinned joints on my crankshaft is loose now (must have become loose when fitting the flywheel) 

I'll try treating with Loctite 603, but the penetration won't be good so this would be a temporary fix. I don't think I can bash out the pin and re-glue without damaging the parts. Since I have some big sticks of 1144SP kicking around, I'm back to thinking about a turned crankshaft.

Simon

[smfr]

Gosh, over a month since that last update  Travel, work and the garden have been taking time, and, to be honest, a couple of issues with the engine put me off a little bit.

I seem to have rescued the crankshaft. I soaked it in denatured alcohol for a while to try to get the oil out of the loose joint, then applied some Loctite (619 I think?) and set it up on some V-blocks overnight. Now everything seems rigid, but I'm going to be careful hammering the flywheel on and off in future (which I think is what loosened the joint).

The second issue that I haven't dealt with yet is tightness on one of the piston rod glands. I think one of the cylinder covers is not quite square, so I'm considering making a new pair.

As a gentle re-introduction to the workshop, I attended to the bearing covers. When we last saw these they looked a bit like this:



and while they were still attached to the parent stock, I tidied up the top profile around the oil box, using the rotary table:



and ball-end mill:



Some pockets were milled to take the stud pads:



and I milled out the oil cavity:



Next they were cut off from the parent stock, held upside-down in the vise with a bit of packing on each side, and the bottom surface milled to size. After a bit of cleanup, we're ready to J-B Weld in the pads:



which gives us this:



A trial fit shows that we need a bit more clearance around the bearing flanges:



Now for the oil well caps. I wanted a pyramidal tap, and computed the two required angles. The material here is, I think, naval brass; it's harder than normal brass, and makes bright yellow chips.

I used my usual technique to get the angle (some trig, and an adjustable parallel next to the vise jaws). Here both caps are still attached, and I'm cutting the second side of one cap. I marked the center line, and just milled to that.



Now the caps have been separated, and I'm holding them side-by-side in the vise with the second angle set:



again milling to the marked line. If the angles are right, the faces should join at the corners, which they do 



Holding them for the remaining ops is a bit tricky. Here's how I trimmed down the sides:



and I had to use some 1/8 key stock packing for the remaining sides.

They still need some spit n' polish, but I'm quite pleased with the way they turned out:





Don't worry, I'll be making studs for these!

Simon

[fumopuc]

Hi Simon, good to see you back in the shop again.

[Kim]

Hi Simon,
Glad to see you moving forward on this beautiful engine!
It can be hard to get back in the swing of things when you've been out of the shop for a bit.  And it can be hard to push through with the finishing work that needs to be done once you've got an engine running!  Put these two together and I'd say you're doing great!
Kim

[Coopertje]

Very nice work Simon, really like the square caps you have made. I admire your skills and dedication, I have never been able to work so long on a single project. I hope you are able to find the energy to finish this engine, it deserves it!

Regards Jeroen

[Don1966]

Simon glad your over coming some of your hurdles. You continue to do some impressive metal carving and this engine is a fascinating engine to see come together.nice work all the way around bud.


Don

[Roger B]

Still following along    I do like your oiler caps 

[smfr]

Thanks for the comments everyone 

I had a bit of time over the Thanksgiving break to work in the shop. First order of business was a to fix the sticking piston rod. One side was fine, but the other side had some binding when the cylinder cover was clamped down. Initially (before a logical investigation) I thought the cylinder cover bore wasn't perpendicular with the flange face, so I turned a mandrel in situ to the diameter of the piston rod, clamped the cylinder cover on it and saw from the indicator about 6 thou of "runout" on that face:



I took a skim of the flange with a sharp tool:



Alas, on reassembly, that didn't help 

After a bit of I knew I had to check that the piston and crosshead were correctly aligned. I checked the horizontal alignment with a bit of ground bar across the two piston rods, with an indicator above the rod on the troublesome side. Sure enough, the rod dipped about 3-4 thou over the range of piston travel. This indicated that the crosshead was low (I was pretty sure my crosshead guides were horizontal, since they were milled out in the same setup as the "good side").

I made up a shim to go between the body of the crosshead and the lower plate from a bit of 0.004" feeler gauge:



That fixed the dipping problem. When I put the crosshead back together, I was careful to check for sideways movement, adjusted by leaving those two screws not quite tight, and tapping the crosshead on the side until there was no sideways deflection of the piston rod over its travel. Then the screws could be tightened.

Now there was still binding when the cylinder cover was clamped down, so I put the cylinder cover back on that mandrel (which I hadn't disturbed), and took another measure (it was now low on the flange where I skimmed it before!) followed by a skim. On reassembly, the piston now moves without binding. Very satisfying!

Now that I had a smooth-running motion, I played with the valve timing for a while. I'll probably write more about that later, but did find that if adjusted well in forward, it's a bit lumpy in reverse, which I'm pretty sure is an artefact of the valve gear geometry.

Now, slowed down by a cold, I decided it was best that I stick to easy stuff like making studs, so the valve chest now has a full complement:



(those side ones are still a bit long), the bearing covers also:



and I've replaced the screws on the crosshead guides with studs:



Those obviously need some length adjustment, which will have to wait until l tear down the engine so I can make sure they are fully seated before trimming them down. I need to make nicer washers for those, too (and maybe elsewhere).

I've mostly complete the fitting process for this engine now, but I've been wondering if there's a treatise on "fitting" that anyone knows about: how to logically fix issues with non-smooth-running machinery?

Thanks for following along!

Simon

[Jo]

You are doing and excellent job Simon  ,

Did I mention: Nice Studs 

Jo

[smfr]

Thanks Jo! 

I haven't been getting into the workshop as much as I should, but I've been getting bits and bobs done.

The valve guides thingy needed the ends taken down to the correct length, which required a rare trip out for the steady rest:



Then I made the exhaust pipe, with a gland on the bottom of the cylinder block, exiting through a hole in the base. A couple of bits of scrap brass were silvered soldered to make the gland:



and friction-turned to clean up the fillet:



with the flanges squared off in the square collect block:



Then it could be held at a angle to cut the 45deg end of the pipe:



with a matching angle on another bit of 3/8" brass pipe. While writing this up, I realized that I should probably have put a bit of a downslope on the exhaust  so that water runs out 



Those were then held for soft soldering.



This is actually the second attempt at this part. In the first attempt, I got this far and tried to silver-solder this joint; however, the solder didn't take, I think because the thin pipe didn't retain enough heat, so for the second try I used soft solder.



That cleaned up quite nicely:



and after drilling and tapping 6BA in the cylinder block:



it's affixed with some studs:



Then I needed a hole in the base for the exhaust, so, after a bit of head scratching, I figured out how to hold the base in the vise on the milling table via a sturdy cross-member. The vise was raised 1/2", and an adjustable parallel used to bring the part to the correct height. A wobbler shows that I got the maths right



This was then drilled in stages, pushing on the base using the tailstock:



which was uneventful.

And it fits (the exhaust was not fastened down here):



After that was a very tedious couple of hours taking some deep scratches out of the flywheel, but I'll save that until I have a final beauty shot.

We're getting really close to the end now. The only major hurdle left is to figure out how to re-attach some bits of cast iron to the cylinder block to fit drain cocks, and then to make the drain cock mechanism. I need to "put back" some bosses to have enough material to thread for the drain cocks. I know I can use J-B Weld for this, but that wouldn't be a great solution since it would be subject to cylinder pressure, and I'm not sure how well it adheres to cast iron. I think the heat required to braze or silver solder would distort the part, and I'd have a really hard time getting that cylinder block up to silver-solder temperatures. Soft solder might be an option; I need to do some testing to see if it's possible to tin a cast iron surface. Any other ideas?

Thanks for following along 

Simon

[Roger B]

Coming along very nicely      Is there enough material in the cylinder wall to fit some screw in bosses?

[Jasonb]

Simon are you going to run on steam or just air? as the temperatures will affect what you can use. Have you got a drawing of where the bosses need to go?


J

[smfr]

Thanks Roger and Jason. Roger, the cylinder wall is about 3/16" thick (minus a bit if I mill a flat), which seems a bit thin to take threads.

Jason, I do plan to run it on steam (eventually!). I presume that eliminates the soft solder option?

Here's the underside of the cylinder block:



and here is my plan for the drain cocks:



I don't think there's another route for the drain hole (e.g. out of the side), given the position of the stud hole, and the various flanges.

Simon

[Jasonb]

I think rather than D shaped bosses I would go for round ones which can be screwed into fine pitch threaded holes (such as 40 TPI) these can then be tapped for the drain cocks.

If you cut the thread on the boss with a die and do it on the end of a decent length of bar you will have something to get hold of so it can be screwed in tightly and will wedge itself in a bit like a taper pipe thread, the JB Weld will seal any gaps and make sure it does not come loose.

J

PS on those drain cocks what will stop the tapered spindle working its way loose, you probably want a nut on teh small end to keep the spindle pulled into the taper.