Vega 9cc v twin

[Mo deller]

I started to build this engine when it was published in Model engineer magazine in the 80's. I am now going to try and carry on where I left off. I have to work on a tight budget but have ordered the three gears it needs. I managed to find in my box of aluminium the piece for the timing case so thought I would make a start only to discover the first operation is to drill and ream a 5/32" hole and I dont have a reamer that size. I got a shock when I found prices around £16 for one. I have read about making D shaped reamers but can't decide if it would be more trouble than it was worth.
Anyway here are the photo's of work so far.

Crankcase

crankshaft

Anyone here built one?

Mo.

 

[Maryak]

Mo,

For reaming, get a hold of a piece of 5/32" HSS or make a 5/32" shaft from drill rod. Grind diagonally across the diameter such that it goes from below centre tapering out to the diameter at say 15 deg. Grind a small lead in on the round section on the end.

Hope this helps ???

Best Regards
Bob

 

[Mo deller]

Thanks Bob,that seems easy enough. How would one use a reamer like that? Is it hand use only?

Peter.

 

[Maryak]

I hold mine in a drill chuck and machine ream.

Best Regards
Bob

 

[Speedy]

hi Mo.
could you please keep us up to date with your build
looks great so far.

 

[gilessim]

Bob, that looks like a great and easier way to grind a D-bit than the parallel ,stepped type,I've never seen one like that, I always find it a little tricky trying to grind them to just a few thou over the radius, looks like it would work better too!

Mo, looking good so far!

Giles

 

[Metal Mickey]

I do not have any link to them, other than a customer in the past, but Arc Euro Trade (UK) sell HSS 5/32nd reamers for £2.75p! Their link and order code is below.

http://www.arceurotrade.co.uk/Catalogue/Cutting-Tools/HSS-Reamers/HSS-Imperial-Hand-Reamers-H8/532-HSS-Hand-Reamer-H8

060-040-10125 5/32" HSS Hand Reamer (H8) £2.75


MM

 

[Mo deller]

Hi MM, had a look and they all seem to be hand reamers. I only know hand reamers have more taper but can they be used in a lathe?
Just to update things I decided to sort out some of my stuff as I couldn't get on with anything and surprise surprise I have found a 5/32 reamer!!! No idea where it came from but I had marked it as a need to get on my original list so perhaps I got one, I just don't remember.
I will have a go at making one though next time I need a size I don't have.
I have ordered some silver steel,stainless and bronze from Cronos now and my gears have arrived.

Bob, I have also found where the photo of the reamers come from.I have the book

Mo

 

[Mo deller]

At last I have made a little progress. Turned the timing case to size,then drilled and reamed the hole for the drive shaft and turned the diameter to fit the crankcase.

It was good to make some swarf again,it has been far too long.

Mo

 

[cobra428]

Looking Good Mo!,
I'm not famiiar with this engine. Is it gas, glow or steam (comp air)??
TonyR

 

[Mo deller]

Hi Tony,
It's a glow.

Peter.

 

[cobra428]

I should have known with the drain in the bottom of the case!
TonyR

 

[steamer]

Very Nice job on that crankcase!


Dave

 

[kustomkb]

Fantastic work!

It's going to be a great looking engine.

Keep at it.

 

[Mo deller]

Hello folks,
I started the cylinder heads yesterday but struggled a bit. I managed to break a parting tool :-[ because I tried to go too deep without enough clearance. At least the work survived and I finished with a hacksaw.
I have ended up with two blanks that should be ok but as I said I struggled and kept having to set up and start over trying to get them machined to size and the top fin/groove put in.
I found that I had no way of measuring the length when they are in the chuck like this

Now I think the penny has just dropped as when I came to put the groove in I had to make a ring to push the work out far enough like this

That is perhaps what I should have planned to do in the first place as it would leave just enough to get the verniers in :
Any comments or constructive criticism welcome
My heart also sank somewhat when a mistake with the crankcase became apparent. The holes for the conrod/piston should be central in the face but clearly are more to the front. Not sure if this is a big setback as it depends on where the crank lines up. It could be that I had machined too much of the front face as this is wider than shown on the drawing.
I am running out of turning jobs now and need to get the mill sorted asap.

Mo

 

[rklopp]

A groove micrometer is useful for measuring lengths like you showed. Another approach is to stuff an adjustable parallel between the back of the work and face of the chuck, and measure with a depth gage.

 

[Mo deller]

I have made a little progress this week on the timing case. Boring the rear face for the three gears. Had a few difficulties chasing it round in the four jaw trying to get it centered. Started with the small centre hole and that went ok. I had the depth set on a stop and all other points noted.I then found that I couldn't move it across as the centre of the face in the chuck came up against the edge. Changing the jaws round wouldn't work either because of the depth of things so I ended up machining a support ring which is needed for milling ops next anyway. I was annoyed because I lost all my settings. Anyway it was a good exercise and I got there in the end.

Boring for the first camshaft gear with the centre already done.

Getting it centered for the next one

All three completed

I did notice a fair amount of vibration while working but couln't work out what I could do about it so pressed on with no ill effects. I know you should use counter weights on a faceplate but not sure of what should be done when offsetting in a four jaw.

Peter.

 

[Mo deller]

After finishing my oscillating engine I was keen to get some more done on this engine.
I decided to have a go at the conrods. I am following the build article in M.E. magazine and have drilled and reamed the blanks big and little ends and turned and fitted the bottom end bushes.
Here is the setup for drilling/reaming done with packing as I dont have a verticle slide.

On the first one I noticed that the big end was off centre. Due to too large a drill too quickly. Another two sizes first and all was well.

It was at this point I made an extra pair.
Now I have four blanks fitted with bushes that need to be reamed inside. So a question. Can I ream these somehow without having to centre up each one again?

Peter.

 

[Maryak]

Now I have four blanks fitted with bushes that need to be reamed inside. So a question. Can I ream these somehow without having to centre up each one again?

Yes, IMHO you can hold them in a vise with soft jaws and hand ream them. Depending on what reamers and/or tap wrenches you have to hand, you can reverse the process and hold the reamer in the vise and rotate the blanks. Option 2 works better for me if the reamer is horizontal as you are more able to see how square you are keeping it. ( Saves rushing out and buying another reamer)

Hope this helps.

Best Regards
Bob

 

[Mo deller]

Got the reaming done, thanks for your input Bob, and made a jig to hold them and milled to width.

Then onto the rotary table to radius the ends.

These were my first proper milling job and the results were not as accurate as I had hoped. Even though I had them located on fixtures things seemed to wander a bit. I think I will have 2 out of 4 that should be ok but I do feel I could have done better.

Carried on and put the slit for oil in the big end and a c/sunk hole in the little end.

Not sure what bit I will do next but I do need to get better with the mill before I do more to the timing case. I have got som EN8m steel for the cylinders now so maybe I'll get back on the lathe to start those.

ttfn Peter.