Author Topic: Muncaster's Joys Valve Engine  (Read 159485 times)

Offline metalmudler

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Re: Muncaster's Joys Valve Engine
« Reply #195 on: January 28, 2014, 04:27:38 PM »
OMG Simon. That is comming along awesome. Thanks for posting m8.. Top stuff as always....
Yeah,  iv'e just pulled up a chair  :praise2:
It's not done, until it's DONE... Even then there is something else to do to it !..

Offline smfr

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Re: Muncaster's Joys Valve Engine
« Reply #196 on: February 03, 2014, 04:26:33 AM »
To take a break from finishing on those conrods, I did a trial run on a soldered crankshaft, making just one set of throws. This was very much an experiment: my first try at making a built-up crankshaft, and my first attempt at soldering steel, especially at this size (throw is 1", the shaft is 1/2" in diameter). So feedback on the technique is very welcome!

As recommended by others, I used O-1 (gauge plate/drill rod) for both the throws and the shaft and journal. Here's the material for the throws:



The two parts were milled to size, then drilled in increments up to 31/64ths:



then reamed 1/2" and chamfered slightly with a countersink to give the solder some room:



Both done:



Now I need to give the solder some room to flow between the parts. Ideally you need a few thou gap (exactly how much depends on the brazing alloy being used), but that makes it harder to keep the parts in line while brazing, so I cheated and filed 8 flats around the bar in the joint area:



A better option may have been to turn those areas down by a few thousands, and then use a diamond knurl to raise the surface enough to grip the reamed holes in the throws, but my knurls were all wider than the joint area. Another option would have been to turn down those areas, then make some pop marks with a punch.

Here are the parts prior to cleaning and assembly:



After researching brazing allows, and obtaining a few different ones, I chose to use Harris 45T for this, because it has quite a large range between solidus and liquidus, so is good at forming fillets. This is 1/16" wire, which seems a bit thick for this job, but was the only thickness I could get.



I wound some around a 7/16" rod then cut through the coils to form rings, then assembled with flux (Stay Silv white brazing flux) and set it up in the hearth:



I put the rings on the joints where I wanted to end up with a fillet. The white blankets are ceramic blankets, used by plumbers to avoid burning woodwork when soldering pipes! I'm using it here to try reduce heat loss from the shaft.

Brazing was a bit hairy; I just have a hand-held propane-bottle torch, which probably isn't really big enough for this. I tried to direct the flame onto the shaft and throws to heat the metal parts through, rather than onto the solder directly. Eventually the solder flowed, but I had to turn the part over and do a second heat to get the solder to flow on one side. Here's the result:



After a scrub in hot water to get off the flux, we can take a closer look.

Solder penetration on one side of the journal is obviously not great:



and after cleanup the gaps make this part a reject:



The other side looks really good though:



Neither joint near the shaft has a full 1/16" fillet all the way around, which is what I was aiming for, either.

So, not bad for a first attempt. I think next time I would:
  • Try turning the joint areas on the shaft down and using punch marks to locate the throws (or even use a locating pin).
  • Make the journal shaft long enough on each side to put a ring of solder on the outside as well.
  • Maybe use 1/32" brazing wire with a ring on each side of each joint (though this would have to be a different alloy).
  • Take more care to ensure the throws are in line before soldering. One is slightly askew.
  • Make the journals of thicker material to leave some to be turned away after soldering.

Is it reasonable to rely on a solder fillet to run against the bronze bearings to locate the crankshaft side-to-side, or is the solder too soft?

Now I have to decide on whether to try brazing the real part, or fall back to Loctite and pins.  :thinking:

Simon

Offline ths

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Re: Muncaster's Joys Valve Engine
« Reply #197 on: February 03, 2014, 06:49:34 AM »
Would more heat from a larger nozzle provide you with more success? Longer heat-ups can render the flux a bit u/s, meaning that the solder won't flow as you may like. It happened to me recently, and I had to hold two torches to gain heat quickly, put down the smaller, then wave a stick of solder in my then free hand.

Hugh.

Online Jasonb

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Re: Muncaster's Joys Valve Engine
« Reply #198 on: February 03, 2014, 07:43:47 AM »
Simon why do you feel the need for a fillet on the inside, it just means you have to either machine or clean it all away or put a large CSK on the bearings to clear it. Myself I would only CSk the webs on the outside and only place the solder on this side ( I actually prefer to feed in teh stick). If you look at my Galloway build you can see the CSK on one side only.

Also with the best will in the world a drill will wander slightly and the reamer will follow this hole, finish the holes with a boring head which will also allow you to play with the hole size.

A bigger torch will help to get things upto temp faster. Place the solder on the opposite sides to what you had it and apply the heat to the opposite side to the solder which will draw it towards the heat once it becomes liquid

J

Offline smfr

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Re: Muncaster's Joys Valve Engine
« Reply #199 on: February 03, 2014, 04:52:26 PM »
Thanks for the advice, Jason! I was going for a fillet to replicate the fillet on a part turned from solid (or a forging), but I agree that it's a pain to adjust the bearings to fit.

I'll make the other set of throws with your suggestions  :cheers:

Simon

Offline Admiral_dk

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Re: Muncaster's Joys Valve Engine
« Reply #200 on: February 03, 2014, 08:12:04 PM »
Sorry no experience in this, but ....

I can't help thinking that a very shallow and narrow groove placed in the middle of the throws + one or two of your file "cuts", should do the trick. The file cut allows the solder in and the groove distributes it all the way round the axle.

Offline Florian Eberhard

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Re: Muncaster's Joys Valve Engine
« Reply #201 on: February 03, 2014, 09:18:53 PM »
Hey Simon

I think its not a bad attempt for the first try!

Though I have no experience with soldering crankshafts, here some Ideas:

- I would propose you turn the ends of the crankpin to a smaller diameter so the distance between the throws is given by that.
- Then turn a groove (width in about 1/3 of the throw width, in about)) into the shaft and the crankpin where the throws will get. This will allow solder to flow all around (you will need to apply enough solder of course)
To get the solder into the groove you can still use your method but you wont have to file eight flats, two or three will do. (For better contact of the solder with the throws and the shaft, you could aswell mill away most of the surface where the throws are and just leave 3 or more "high spots".)

For the fillet, you could make the throws wider than they have to be and then turn them smaller after soldering and making your fillet on the edge to the shaft.
Or, alternatively, you could add small rings to where you want a fillet and then turn them off again once everything is soldere. But thats not really making the soldering easier (because of more parts...)

However, Im looking forwart for your next steps, as always its very interesting!  :ThumbsUp:

Regards Florian


Offline NickG

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Re: Muncaster's Joys Valve Engine
« Reply #202 on: February 03, 2014, 09:19:59 PM »
I tried this recently with similar results too but feeding the wire in. Unfortunately I had to grip my crankshaft I. The lathe which was probably have some heatsink effect. The other thing I think would help most is to have gravity on your side - difficult I know unless it's pinned as well but if doing 2 heats would it help standing on its end to help the solder to flow down to where you want it?

Offline tvoght

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Re: Muncaster's Joys Valve Engine
« Reply #203 on: February 04, 2014, 01:58:20 AM »
Hi Simon,
Where do you get the plumber's 'ceramic blankets'? Is that the search term I should be using? I don't recall seeing the stuff at the local big-box hardware stores.

--Tim

Offline smfr

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Re: Muncaster's Joys Valve Engine
« Reply #204 on: February 04, 2014, 06:50:58 AM »
Where do you get the plumber's 'ceramic blankets'? Is that the search term I should be using? I don't recall seeing the stuff at the local big-box hardware stores.

Hi Tim!

I got it on eBay. Search for "ceramic blanket" and you'll find lots of huge rolls (it's used to insulate around fireplaces, furnaces etc). It's also called "Kaowool" or "Cerablanket". If you're lucky you'll find someone selling offcuts. I would think that a fireplace installation place or builders yard might have it too.

Simon

Offline smfr

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Re: Muncaster's Joys Valve Engine
« Reply #205 on: February 09, 2014, 07:23:20 AM »
After getting the conrods done, I'm itching to get enough of the moving parts done to see some motion, so next are the crossheads.

While I had the Emco set up for turning, I churned out a couple of piston rods from precision-ground 303 stainless, leaving the piston end unfinished (for length adjustment later), and putting a bit of thread and a landing on the other end to fit to the crosshead.

The plans show the crosshead and piston rod as a single forging, but I didn't fancy turning both from solid, and without grinding ability, I didn't have the confidence to get a good even diameter on a rod the length of the piston rod. So I'm doing a fabrication. I haven't yet decided whether to silver-solder or use Loctite to hold the parts together.

So here's some material for the crossheads and the slide plates (which bolt onto the underside of the crosshead). The crossheads are 1144 stressproof, and the plates are O-1 gauge plate.



The first operation on the crossheads was to drill the corners of the bearing opening:



after which I opened them up with an end mill:



leaving a little spare for later filing. After that, each crosshead had three 5BA threaded holes made: two to hole the slide plate, and one for the bearing wedge:



Initially I was going to do the piston rod recess in the 4-jaw chuck, but then thought I'd get better alignment by doing it in the mill. First I drilled through for tapping size,



then went part-way through with a larger drill. Then I could tap:



and finally bore to fit the piston rod end with a tiny boring bar:



This joint is critical to get the piston rod lined up with the crosshead, so it was worth some care to get a good fit. I did have to do quite a bit of fiddling to get the pistron rods to screw all the way in.

The final operation while the vise was set up was to mill away some of the material to reduce the amount of interrupted turning later:



Then it was time to set up each crosshead in the 4-jaw, using the piston rod to center:



which allows the radius to be turned:



I was getting a bit of chatter there, but it should clean up with a file.

Both done:



This is a mockup that shows the arrangement of the screw that pushes down on the bearing wedge:



What I don't see on the plans is anything that locates the bearings in place; are they just held in by the wedge?

Now the bearing openings need to be cleaned up, and the only way I have to make square holes is by filing! To get the corners nice and square, I made up a couple of L-shaped guides from gauge-plate, and hardened them. Then, by clamping them on either side of the part to be filed, I can be sure that my filing is square.



Setting up these guides was a bit fiddly, but a toolmakers vise helped. The strategy here was to find a drill bit of the right thickness to line up the bottom edge to be filed, snug up the vise, then tap the part to align the perpendicular edge. Then tighten the vise, and apply a toolmakers clamp to hold things together for transfer to the bench vise, for filing:



A triangular file helps get into the corners. Four setups per part, and the bearing openings are reasonably square and sharp-cornered  :cartwheel:

Final steps are to mill the slight taper on the back face of the crosshead, and to take it to thickness, using the screwed in piston rod to make sure the sides are parallel with the direction of travel. A bit of draw-filing removes the milling marks, and we're here:



What I didn't show was the hour spent struggling to get the slide plates moving smoothly in the slides, which involved lots of filing, rubbing on stones, some TimeSaver, and milling off the odd thou here and there. My fingers still hurt from the sharp edges  :(

All was rewarded, however, with a test-fit with the cylinder covers on the cylinder block. Everything seems to fit  :pinkelephant:



Next I think I'll do two sets of bearings: those for the conrod, and the crosshead ones.

Simon

Offline fumopuc

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Re: Muncaster's Joys Valve Engine
« Reply #206 on: February 09, 2014, 08:50:29 AM »
Nice job Simon, I am always watching your progress.
Kind Regards
Achim

Offline NickG

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Re: Muncaster's Joys Valve Engine
« Reply #207 on: February 09, 2014, 10:18:43 AM »
Yes looks pretty spectacular  :ThumbsUp:

Online Jasonb

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Re: Muncaster's Joys Valve Engine
« Reply #208 on: February 09, 2014, 10:23:34 AM »
Looks good Simon, what size thread is that on the rods? looks a bit light for a large engine

Offline zeeprogrammer

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Re: Muncaster's Joys Valve Engine
« Reply #209 on: February 09, 2014, 12:51:05 PM »
Beautiful! That was a real interesting post Simon.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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