A Robinson from rejects.

[Alyn Foundry]

Hi Richard.

Not wrong but things are on hold at the moment.

Sadly with the passing of certain volunteers Geoff has been having to focus on the more pressing museum matters at the moment.

We’re hoping to move the Gardner patterns to a foundry that’s a little closer and a lot cheaper than present and expand the range to include the R.L.E. and Robinson “ X “ type.

Cheers Graham.

[Jasonb]

Bit of an exhausting day.

The cooking of the exhaust block did the trick and it machined up nicely though I did have to deviate from the drawings in a few places to make my worst of the rejects casting work. Also made the Exhaust valve, spring collet, tappet, Eccentric rod guide pin and end plug.

One item that did give me problems was the hole for the pin that stops the gearbox rotating, barely managed to drill it and blunted the drill good and proper, took a few more teeth off an old 2BA tap trying to cut a thread and then found the hard spot had made the drill wander so the pin did not line up with the hole. So ended up plunging the hole with a 1/4" carbide slot drill which still struggled and made a pin with a spigot to fit this hole and a small flange to locate it and will JB Wled that in place.

[Jasonb]

I decided to do the conrod next. Squared up the ends and ctr drilled both then drilled and tapped for the bolts before sawing off the cap and cleaning up the cuts.



Bored the big end and reamed the little end



Bit of turning using a round insert in a MGEH holder which gives a nice 1.0mm radius to the internal corners



Job done, big end bronze has just been soldered up so that will be ready to machine next time.



J

[Alyn Foundry]

Hi Jason.

Getting closer now! That's pretty much the way I used to make them.

I do however see a slight flaw....

The Robinson has a tapered connecting rod. 

Cheers Graham.

[Jasonb]

I could not decide what was drawn as the view from above looks parallel, but looking again it does mention a taper but my drawing has a black blob over part of the writing.

All is not lost as I turned it 5/16 parallel so easy enough to taper it down to the 1/4" at the little end

[Jasonb]

Graham will be pleased to know that I now have a tapered conrod and it seems to have also aquired some bearings.



With that done I could not resist seeing what the engine turned over like. No rings but it sounds rude promising and sorry that the camera moved so the loctite is more in focus than the inlet valve.

<a href="https://www.youtube.com/watch?v=S4Vnfcvv7bU" target="_blank">http://www.youtube.com/watch?v=S4Vnfcvv7bU</a>

J

[Alyn Foundry]

Hi Jason.

The “ rude “ noise is just what’s needed, not much more to do now!

Spring 2018 is seeing new life to old castings!   

Cheers Graham.

[RayW]

By sheer coincidence, I too was playing with the Robinson yesterday and producing that amusing noise (the engine that is, not me!).
I still have a couple of little jobs left to do - drilling the hole for the gearbox locating pin and drilling out the hot tube to accept the 11mm burner.
Last thing is the flywheel keyway. I have cut it parallel, and now need to file the slight taper in it to match the key. To my annoyance, it looks at the moment as if there is a slight wobble on the flywheel despite me having set everything up on the lathe to run true to within a thou or so before boring the centre.I will check on the lathe that the crank is running true and see if the key pulls the flywheel true once the keyway has been tapered. Failing that, I will have to consider boring out the flywheel and bushing it before re-boring and re-cutting a keyway.

[Alyn Foundry]

Hi Ray.

Before you go a boring, put a piece of 1/2" Silver Steel in the lathe, clock it for truth and slip the flywheel on. It might be that the crankshaft has a slight warp not the flywheel itself.

Cheers Graham.

[Alyn Foundry]

Hello All.

I've attached a photograph of the sight feed lubricator that's fitted to my full size Robinson XP.

Note the extra long thread that's used to hold the front of the crank guard down.

Overall length is 6 inches and the glass is approximately 2" diameter at the top and approximately 1" diameter at the bottom. Glass length is 2 1/4 ".

I know Jason is going to make a replica using Acrylic, this is something I've never done and I will be very interested in seeing the final outcome.

Cheers Graham.

[Jasonb]

Thanks for that Graham

While you are on are the "trumpet" shaped main bearing oil cups you show on teh drawing original? I was thinking of knocking a couple more like these as the shape would complement the wine glass one.

[Alyn Foundry]

Hi Jason.

I had to go back to page 13 to look at the original engine!

No, is the best answer. I used a little " license " and came up with those oil cups myself. Looking at the original they seem to be simple " screw cap " greasers.

Feel free to " license " your own version.   

Cheers Graham.

[Jasonb]

And for your evening entertainment here is a half finished lubricator



Started with some 20mm dia acrylic bar, drilled it out and then bored it using a router cutter to get the internal radius



Quickly ground up a form tool for the external radius



Then worked my way down through the grits with some Micro-Mesh



Came out quite nice and clear



J

[Gas_mantle]

Wow that turned out nicely, I'm suprised how clear it machined 

[Ian j]

That's superb Jason. Must have another "play" with my engine now the workshop has warmed up a touch!