Muncaster's Joys Valve Engine

[smfr]

Excellent flywheel    You also like to see just how far you can push your lathe  Still following along 

She's an old Emco, older than me, and she has her limits but she's a workhorse and gets the job done! After this build I'll give her a treat by realigning the headstock and make some gibs to fix the nodding milling head.

Simon

[fumopuc]

Hi Simon, nice flywheel and a very good build report, as usual.

[Jasonb]

Simon, I use the "superfine white" which is easier to work and also seems a bit more sticky. The surface really neads to be degreased and you want to push the putty well into the surface first.

J

[smfr]

Thanks Jason. I was quite surprised to see Milliput in a hobby shop here in the US, though I don't know if I'll be able to find superfine white.

Anyway, here's a beauty shot of the flywheel:



Putting a good finish on the outside surface is a bear with this steel; I got bored and gave up for now.

Simon

[ths]

Great post Simon, and a lovely result. Hugh.

[Dave Otto]

Beautiful work on the flywheel Simon!

Dave

[Stilldrillin]

That flywheel, is a thing of beauty....... 

Well done Simon! 

David D

[Don1966]

Oh yea! That's a nice flywheel Simon and I need to finish building mine up. Great job bud. 

Don

[smfr]

Thanks Hugh, Dave, David and Don!

I snuck that flywheel on you all by skipping some steps since the last time it was shown, so, quickly, here are the last few operations on it.

The curved rim was done with a step-off chart, generated in a spreadsheet based on the equation for a circle and using the Glanze 6mm circular cutter. I actually made a small boo-boo and wound in about 3 thou too much on one of the early cuts, so re-did the numbers with a slightly larger radius to take the middle down a bit. It's interesting that the plans show the curve to be a 6" radius, which equates with the diameter of the flywheel. I suppose it just makes drafting easier

Here's the profile when almost done with the left side (working from the center outwards):



I had an indicator for left-right travel (done using the topslide), and just used the dials for tool advance, doing some two-handed knob twirling to try to interpolate between the steps in my chart.

The finish left by the tool was pretty poor, and of course the steps needed to be evened out, so I spent about an hour and a half with various files and coarse emery, trying to get rid of the gouges so I could start the emery stepping. Some marker shows the high and low bits:



Part of the reason this was so laborious is because the lathe is running quite slowly, so you have to keep the file in the same spot for a what seems like a long time to cover the whole circumference. At times, I stopped the lathe and did some draw-filing to target specific areas. Something else I tried was rubbing with 120-grit emery in a circular motion.

After a while I got bored and decided to drill, bore and ream the hub while in the same setup.



Normally I'd do this first, then put the flywheel on a mandrel for the final pass over the rim, but there's no way I could do another pass over that radius! I know the reamer is a snug fit for my crankshaft, so runout should be minimal.

Finally, we need a 1/8" keyway, so out came the nice broach set, and two passes of the broach (the set came with a shim) and we have a nice keyway:



There, I think that that sits much better on the engine than the temporary cast flywheel 



The other bit I got done today was to finish off the crosshead pins. I'd already turned the pin shafts to a close 0.250" on a bit of drill rod. This was set up in the vise with a V-block to hold it, and the conrod+washer used to find the location of the hole for the taper pin.



I started the hole with a sharp spotting drill:



then drilled through with a 0.063", half-way with drill a couple of steps up, and then just touched the top of the hole with the larger drill. On the right you see one of the spiral pin reamers I got for this job:



I go this nice collection of taper pin reamers from eBay for about $25, with the hope that they'd work better than the straight taper pin reamer I broke trying to pin my crankshaft 



Well, it worked like a dream!



Slow speed, cutting fluid and very gentle downward pressure, and I got nice fine spiral chips. I should probably have marked the reamer for depth, but I just went down until I could not longer see the step created by the larger drill. Both crosshead pins were done without incident.

Back in the lathe, I set over the topslide by indicating on one of the reamers (a shim between the indicator point and the reamer evened out the bumps), then cut some taper pins from 1/8" drill rod.



That'll do 



Thanks for stopping by!

Simon

[Jo]

  Looks like you have sussed those tapered pins.

Jo

[Jasonb]

Simon, next time you have  a curve to blend try some of the small 2" abrasive discs in a cordless drill or airtool. They tend to cut across the ridges as the work turns in the lathe and get through the job very quickly. I tend to stop at 400g as I like the satin finish rather than going to blingy.

http://catalogue.3m.co.uk/en_gb/gb-asd/Roloc_Quick_Release_System

[gbritnell]

Beautiful work as usual Simon. In my experiences with spiral reamers they give a much nicer finish than the straight flute ones.
gbritnell

[Kim]

Couldn't agree more Simon, beautiful work!
Kim

[Roger B]

Good work, as ever    Rather than marking the taper reamers it is easier to make a washer with an appropriate size hole and put that over the reamer to act as a depth stop.

[smfr]

Thanks for the comments folks!

I've been doing various bits and bobs over the weekend. Moving the attachment point for the control arm went OK; I turned a button with a fillet on it already to avoid having to do the fillet on the rounding table (not enough headroom with the complete base on the rotary table). The old boss was milled off, and a plug Loctited in and peened:



I milled away the plug and cleaned up with sandpaper, and you can't see a trace of the old hole. This shot also shows me using a center finder for a change:



Now we can mill a pocket for the button:



and it was Loctited in. The button was a bit deep, so I had some blending with files to do:



and then it was drilled through, and the surface taken down:



One side of the control arm needs turning down to suit (using an expanding mandrel that I happened to have of the right size):



I also fashioned a hand wheel from some earlier hand wheel experiments (it's a bit small, so temporary), so now the control arm can be fitted correctly:



The control arm has two pins with taper pins, so I got a bit more practice with the taper pin reamers.

I cleaned up everything and put the engine back together today, after milling clearance in the oil wells for the linkage parts. It's running OK, but there are a few tight spots that need some attention, and one of the valves isn't seating quite right 

Simon