CHUK " V "

[Alyn Foundry]

CHUK " V "

The Vee Twin, my liking for them possibly inherited? Dad drove and competed with Morgan three wheelers through the late 40's and early 50's fitted with engines from Anzani, JAP and Matchless, he loved them.

As a natural progression my CHUK range developed starting with a vertical then an inverted vertical and onto a horizontal. The engines were conceived on a modular basis so the same patterns and castings could be used over and over keeping production costs to a minimum. CHUK 4 ( an inverted vertical twin cylinder ) is still in part built form and will be finished when it's finished.

The Vacuum, flame licker/gulper engine is one of the simplest to build and equally easy to run. This was the main reason for its choice as a build project aimed at novice entry level to model engineering.

I mentioned the concept to Jason Ballamy whilst he was helping me with some patterns for my long term project, the Brayton Readymotor. Within a couple of days I received 3D images of my concept via email. Several more interchanges later and CHUK " V " became a reality. To see a pencil sketch become wood then metal in a fraction of the time it used to take shows the amazing power of CAD and CNC . CHUK " V " ? Well the Roman numeral for five is the letter " V " quite an obvious choice really. Whilst the concept is mine due credit must go to Jason who has virtually designed the rest of this engine.

The number 5 will predominate in this particular build and my choice of using Aluminium instead of good old cast Iron is based upon a chance sighting of a Stuart Turner " bottle " steam engine. I was really taken by both the shape and nicely polished surfaces. Cast Iron is still in predominance as both air cooled cylinders, pistons and heads will be made from it. The engine will also use my recently improved " rotary " valve and
" Chipmaster " exhausts.

What will follow is our documented collaboration of a new engine from the Alyn Foundry stable. Some Iron castings are still on order but the Aluminium crankcases arrived yesterday from my dear friends at Madeley Brass. Hopefully we'll see a working Vee twin vacuum engine for our efforts or perhaps a nicely polished door stop? Time will tell....

Now over to Jason....

[Jo]

 

[Alyn Foundry]

I know, Jo....

Who'd have thought? Jason making patterns?

He's damn good at it too!

Oh, I forgot to mention the flywheel.... It's a rather " pretty " IRON one too.

[Jo]

I know, Jo....

Who'd have thought? Jason making patterns?

He's damn good at it too!

Jason is irrelevant    I am thinking about if a Vee twin flame licker would feel right  .


I don't like the Stuart Vee twins: They seem to be a model designed to meet a current trend of men who wished they owned a big Vee twin motorcycle. Having owned Vee twins I can confirm I sold mine and kept the Norton 

Jo

[Alyn Foundry]

Well....

If I'd have been the remotest bit interested in motorcycles it would have been a Brough for me Jo.

A tangle between me a Honda CD175 and a rose bush on my garden path put me off two wheel transport, permanently. It didn't stop me acquiring a rather nice 1925 350 cc BSA flat tank though. The riding was always undertaken by Martin when taken to the Steam rallies.

I'm sorry you feel the way you do about the model but I happen to like Vee twins.

Cheers Graham.

[Jasonb]

It's all Grahams fault, he made me do it honest

At the end of August Graham sent me that napkin sketch with a very basic spec, I liked the idea and asked him for a few dimensions of the cylinder castings and while waiting had come up with a basic design using enlarged 3D models of many of the parts from my version of the CHUK range "CHUKY"



After several exchanges of e-mails sending screen shots of the evolving engine to Graham for comment a final design had been agreed by the end of September with a one piece crankcase that would carry the overhung crank on one side and have a cover plate on the other side bearing the CHUK V name with the intention that this could be buffed up to look like the Stuart BB that Graham had seen. It will use a modified version of the existing cam profile that will be housed within the crankcase with tapped guides set into the top of the crankcase. The builder will have the option to machine 5 holes in the flywheel side of the casting to make it possible to watch what is going on inside.



As Graham mentioned the existing cylinder castings can be used with some machining of the end to allow them to be fixed to the crankcase flanges with yes you guessed it 5 studs and nuts. The head castings will incorporate a boss to house the exhaust spring and may be retained with studs and nuts or with counterbored holes for screws



The plate that closes up the crankcase will have recessed letters allowing the builder to buff up the surface and inlay the writing with their chosen colour of paint, red or black seem likely candidates. Once again the cover will have 5 fixings and Graham likes the idea of the recessed screws to match the look of that bike engine that Graham lusts after.



For those that are wishing they had not sold their old bike I did sketch out a possible alternative head and exhaust option



Or there may even be other possibilities using the same crankcase casting



What will follow is a few posts showing the pattern making process and if you are good boys, girls and elephants Graham may then show you some shiny castings

[Twizseven]

This looks interesting. Need to get few others done first.

How long before Surus asks for a set.

Colin

[Dave Otto]

Interesting project guys!
Will be fun to watch.

Dave

[Jo]

How long before Surus asks for a set.

He is more interested in the boxes of Snickers that turned up the other day at the moment 

Jo

[Jasonb]

He is more interested in the boxes of Snickers that turned up the other day at the moment 

I doubt he will have any problems finishing them

I thought you liked V twin's Jo, does not seem long ago that I drew this out and you said "You know how much I love Hoglets, its on my build list along with another couple" At least you seem to be able to get the flame lickers running unlike any four-strokes.

[Alyn Foundry]

Good morning Jason.

I hadn't thought about alternative uses for the crankcase myself but obviously with the CHUK range the
 " overhung " crank might be a little flimsy. We would have to incorporate an additional boss in the front cover to accommodate a bearing so a more conventional " full " crank could be used.

The five holes in the rear of the crankcase serve a way more important function than just observation, without them the case would be effectively sealed. Because these types of engine function using the power of atmospheric pressure if a vacuum was created in the cylinder with a sealed case you'd get equilibrium.

Cheers Graham.

[Jasonb]

I was thinking more along the lines of machining the whole end off and then having matching covers each side, not sure if the cam would stay inside of have to be exposed like the Hoglet is at the moment. Only a couple of engines to go before you can join 4 crankcases together for CHUK Version8

Talking of alternate uses for castings don't you think a couple our nice new iron ones would be about the right weight and diameter for a Heinrici

Will post a bit more about the pattern making tonight.

[Alyn Foundry]

Hmmm, I don't particularly like repetition of components Jason so no, two is enough.... However a 5 cylinder " rotary " would be an interesting challenge wouldn't it?

Although our " Iron ones " are very pretty to look at I think they'd be totally inappropriate for Jo's Heinrici as it's meant to be a replica. I recently found the original flywheel patterns but they've gone astray after a recent " tidy " session. I do, however have a pair of fully machined flywheels on a disassembled Reeves version. These could be used as patterns at a pinch.

Looking forward to your next instalment.

Cheers Graham.

[Jo]

I thought you liked V twin's Jo, does not seem long ago that I drew this out and you said "You know how much I love Hoglets, its on my build list along with another couple" At least you seem to be able to get the flame lickers running unlike any four-strokes.

There was a time when liked the idea of being married as well   

The only engines that I have built that have not run when tried have been ones that had a liking for damaging thumbs 

Jo

[Jasonb]

Now that I had the engine drawn out it was time to start converting the drawings to ones that could be used as patterns. Starting with the crankcase I made a copy of the file shown in my post above and then suppressed all the features that I did not need such as bearing hole, holes in the flanges for the cylinders to locate in, etc. I then added machining allowances where needed as well as draft angle so that the patterns could be pulled from the sand.



I decided it would be easiest to start by cutting two matching "halves" and then add the endplate with bearing boss as a third part so did a simple "extrude - cut" which left me with half a crankcase. I find that sometimes Alibre can have problems adding fillets to some internal corners once you start having more complex shapes joining at odd angles so left most of the fillets off the pattern file but will make use of the shape of the cutter to include them on the actual pattern.



The file was then exported to Fusion 360 to do the CAM, I ended up with 3 separate strategies to produce the shape. Firstly an adaptive clearing one which is basically a roughing out pass leaving 0.5mm stock which was done with a long shank 4-flute carbide cutter at 5000rpm with a feed of 450mm/min taking most of the material off with a 5mm high by 1mm deep cut then just stepping up 1mm for the fine roughing which can better be seen on the next but one photo. The blue lines are the path that the centre of the end of the tool follows when cutting the yellow are where it is moving between cuts



Next using the same tool and speeds but with a 4mm stepover the flat face had the final 0.5mm removed. you can see the stepped finish that the adaptive cuts left better in this photo as the tool paths don't get in the way.



Finally a long shank 4-flute 6mm carbide ball nose cutter was used with a "steep and shallow" strategy that was set with a fine 0.33mm stepover or "scallop" between cuts again running at my max speed of 5000rpm but feeding a bit faster at 550mm/min



This image shows how F360's simulator will leave the finished part, the bright green areas are where it has cut to the drawn surface, the blue is material it has not removed which you can see is basically all the places where I wanted an internal fillet. This method works well on the easily cut wood but you do have to watch when doing it on metal as the percentage tool engagement can go up a lot and chatter is possible, in these cases it is better to try and draw in teh fillets with a radius say 10% more than the radius left by the tool.



A couple of mouse clicks and the thousands of lines of G-code that F360 created were on a memory stick that could be transferred to the mill.

It was now time to cut some brown stuff, however I was wary that the flanges and particularly the feet could be broken off easily if the grain was not in the right direction. So rather than cut from a solid block of timber I laminated some thin boards of Sapele together which would have a similar effect to using plywood with it's grain that runs in two directions. I glued my blank to a piece of MDF with Titebond placing a sheet of copy paper in the joint which makes it easy to separate afterwards. Sorry No video of the crankcase being machined but this is after the final cuts with the ball nose tool and I also added a 6mm hole for later alignment.



Early on Graham had suggested that the crankcase could be cast without the need for a core which would save me time having to make a core box and also keep casting costs from the foundry lower. By having the external draft angles going each way from the split line but the internal angle being constant through both haves from the open side of the crankcase this is possible. So the next thing to do was glue the outer face of one half to another MDF clamping board and then glue the two mating faces of the pattern together both again with the sheet of paper.

The inner cavity could then be roughed out with a long shank 10mm cutter and finished with a long shank 10mm ball nose cutter working it's way around the inside in a steadily lowering spiral. I also used the same cutter to form the inside profile of the end plate.



After separating the case from the clamping board and shaping the outside of the end plate the two were glued together and a fillet of filler added and sanded smooth. The actual surface of the wood needed hardly any sanding at all and came out far smoother than any of the hobby 3D printers would have done.







That's enough for tonight, flywheel pattern next.

[Jasonb]

Needless to say the flywheel was always going to have 5 spokes right from the start although it was chopped and changed quite a few times, originally i thought that it would need something about 7" dia due to there being two cylinders which meant it would extend below the crankcase but Graham felt a smaller one would do so we settled on a of about 120mm dia with a wide rim and tapering oval section spokes. Like the crankcase the 3D model was enlarged to allow for shrinkage, draft angles and machining allowance added and a model of the half pattern exported to F360



First operation was to face the stock taking it down to the finished height of the edge of the rim. I've put the all the cutter details on the video so won't repeat them again here.



The bulk of the waste material was removed with a pocketing path leaving 0.5mm for finish cuts. While the 6mm tool was in the collet a finish cut was taken to bring the hub to height. As well as the blue and yellow paths mentioned in the last post there are some red ones which are where the tool ramps down into the work in a spiral which is kinder to the cutter than just plunging straight down.



Changing to a ball nose cutter the inside was finished with a "steep and shallow" path



Finally the tapered outer edge was finished with a "ramp" cut which has the tool gradually dropping down as it follows the profile, in this case I had it drop 0.75mm over one rotation which was approx 400mm length of cut.



I'm pleased with how it turned out, there was a bit of splintering of the top edge that can be seen on the video as I had used up some offcuts of boards that had a bit of snipe at the ends so that left a slight void not helped by the top layer ending up about 0.5mm thick. Nothing a bit of Upol filler could not sort out. This is the finish straight off the mill which needs almost no sanding.



<a href="https://www.youtube.com/watch?v=yh5zggx_Xfc" target="_blank">http://www.youtube.com/watch?v=yh5zggx_Xfc</a>

Here are the two halves together with the crankcase pattern.

[Jasonb]

The final pattern required was the cover plate to enclose the open side of the crankcase, Graham had said that it would be nice if the writing could be engraved allowing the builder to fill it with paint and buff up the surface if they wanted to rather than his usual raised "CHUK" that can be found on the other engines in the series.

I have not found a way to get lettering in Alibre to follow a curve so ended up manually placing each letter using a couple of guide circles and tilting & spacing the letters so that they looked right. The 3D model was then exported to F360 which has an engrave function that produces some nice crisp corners to the letters rather than the rounded ends you would get if the a milling cutter just followed a single line. It does this by ramping the Vee shaped cutter down into the letter and up each of the corners. This video of part of the simulation shows it better than I can explain it.

<a href="https://www.youtube.com/watch?v=tvnde64xjcU" target="_blank">http://www.youtube.com/watch?v=tvnde64xjcU</a>

I thought I would do a test run first to see how the lettering looked so slipped an off cut of 6mm melamine faced MDF into the mill as this gives a good contrast.



A wooden pattern may have been prone to damage so I had some 10mm clear acrylic of some unknown parentage so decided to see how this cut. I was a bit worried that I may end up with a glob of molten plastic wrapped around the end of the tool but it cut nicely at 5000rpm and a feed of 200mm/min using a carbide chamfer mill. I actually ran the path twice giving an undersize tool height so that the second pass would cut slightly deeper but just leave a slight rounding to the corners of the letters so the sand would not get stuck.



The 10mm material was too thick for the pattern so I cut out a rough circle on the vertical bandsaw and stuck it to some MDF using the two layers of easy peal tape and superglue sandwich method. The MDF was then held in the 4-jaw and the test letters turned off as the thickness was brought down to 6mm and the edge turned round with a slight draft angle.



It was then just a case of clamping the MDF to the mill table, locating the middle of the disc and running the cut again

<a href="https://www.youtube.com/watch?v=FxdaV9fjsdo" target="_blank">http://www.youtube.com/watch?v=FxdaV9fjsdo</a>

The tape separated quite easily and there was hardly a burr to be removed.



Here it is up against the crankcase, you may be able to see a couple of blind holes at 3 & 6 o'clock these were drilled in from the back so the pattern can be pulled from the mould with a couple of screws.

And if you look really hard you can see two filled holes in the edge of the crankcase at 1 & 7 o'clock. These were holes drilled in past the joint line which had brass dowels located in one half to help line up the pattern halves when moulding them up.

[Alyn Foundry]

Here are the " shiny " results of Jason's labours....

[Jasonb]

You could make a nice alarm clock out of one of those

[Twizseven]

Graham,

Will you be going into production with these at some point in the future??

I assume you and Jason will do test builds first of all.

Colin

[Alyn Foundry]

Graham,

Will you be going into production with these at some point in the future??

I assume you and Jason will do test builds first of all.

Colin

I think it's highly unlikely at this point Colin.

Judging by the sound of " Crickets chirping " both here and at Model Engineer I would say it's a " non starter "

Obviously this is a concept engine, yet to be proven but I have every confidence in my abilities that a successful runner will result.

The design calls for a different " physical " cam than the normal flat disc with profile. It resembles more of a " Top hat " shape to be able to clear the front bearing housing. This will be fabricated, as a pattern is probably a waste of time.

The only " tricky " parts to make will be the cam followers, a few ideas are swimming around at the moment.

If nothing else it will make a nice Christmas present for the two of us.   

Cheers Graham.

[Jasonb]

It resembles more of a " Top hat " shape to be able to clear the front bearing housing. This will be fabricated, as a pattern is probably a waste of time.

What's the world coming to, first me making patterns and now you talking of fabricating parts, next thing you know Jo will be throwing all her (his) castings out and finishing a barstock engine

I'm sure you must have a spare bit of CI to cut it from, maybe a reject casting for the X-type gearbox/cover would be deep enough?

[Alyn Foundry]

Hmmm....

I do have a sack of Robinson hot air engine piston castings left over from the 90's. Plenty of meat in the crown end.

I'm thinking that the usual crank web can be glued to the 10 mm Silver Steel and make the cam to slip over the crank web boss.

Cheers Graham.

[Jo]

What's the world coming to, first me making patterns and now you talking of fabricating parts, next thing you know Jo will be throwing all her (his) castings out and finishing a barstock engine

Strangely enough we had been discussing making an engine out of bar stock earlier this morning when Polly Wobbles told us they did not have the set of castings Surus wanted for his Christmas present in stock and they could not tell us when the foundry would actually get round to doing them Its going to be a nightmare before Xmas 

Jo

[Jasonb]

Which one has he got on his list?

Actually that is probably a silly question as I expect he has all that are not already in his collection on the wanted list. So what's top of the list?

[Jo]

Top of his list is the double sized Williamson, next he fancies a Bee  .

Jo

[Jasonb]

Who does the big Williamson?

I'm not keen on the Bee, if I were to pick one of the hot air engines from them it would likely be the Denny Improved Ericsson but the Eisner is a better size at about 450mm tall plus I have the drawings.

[Jo]

Who does the big Williamson?

A friend, you wouldn't like it the drawings are in metric   

The Denny is too similar to the Rider Ericsson and we have done one of those.

Jo

[Alyn Foundry]

Special thanks to to Colin ( Twizseven ) who was " out and about " yesterday....

They've come out reet nice eh Jason?

Cheers Graham.

[Jasonb]

Not bad the two halves look to have lined up well, surface is down to sand and method of moulding Airset?

How many did they cast?

I meant to ask did you paint any of the patterns or just send them as the bare wood ?

[Alyn Foundry]

Not bad the two halves look to have lined up well, surface is down to sand and method of moulding Airset?

How many did they cast?

I meant to ask did you paint any of the patterns or just send them as the bare wood ?

Hi Jason, so many questions....

I've just tried ringing them but the boss wasn't available until later on today.

I'm guessing " Airset " too but you can improve the surface finish by gently compressing the sand around the pattern.

The picture shows how they were run to eliminate shrinkage. The " sprue " direct on to the hub.

I asked for six flywheels initially but if I can wangle a better price will try for 10 in total.

I was in such a rush to get the pattern proven I totally forgot to protect the wood with paint. Back in the heyday we just used the primary master once to make Aluminium masters that were machined to a bright, polished finish.

Cheers Graham.

[Twizseven]

Perhaps I should have interrogated Chris when I collected my castings and asked him for some details as to how your castings were done.

I know as I pulled up to the foundry there were sets of castings still in the moulding sand blocks (they were out of the cope and drag) cooling down out on pallets on then pavement.  Had a good warm of my hands whilst I waited to see Chris.

My castings were for die filer parts.  Another set gone out to a customer.  Two sets left to go.

Colin

[Alyn Foundry]

Thanks again Colin.   

Ok, the deed is done. I've ordered 10 flywheels hopefully ready before Christmas. They're done in an 80% Virgin 20% reclaimed mix of medium grade " airset " sand.

They had just done the one to evaluate the pattern which they were clearly happy with. Well done Jason.

I'm hoping my health will return so that I can get an engine together.

Cheers Graham.

[Twizseven]

Graham,

Depending on how the timings run, if you want these collected I am happy to do so.  You could then either collect from me or we could meet up.

Colin

[Alyn Foundry]

Whilst the Beef was a'roasting....

 

It wouldn't be Christmas Day without an hour or so in the workshop!!

Merry Christmas, Graham.

[Jasonb]

Is that all you are going to show us

As for beef on Xmas day I suppose it's a Welsh thing

[Jo]

As for beef on Xmas day I suppose it's a Welsh thing

Wouldn't touch Turkey over priced and wrong time of the year to get a good one, a joint of Roast Steak or rib of Beef is much better 

Jo

[Alyn Foundry]

Is that all you are going to show us

As for beef on Xmas day I suppose it's a Welsh thing

Yes, that's all for this year Jason, merry Christmas.   

None of us like Turkey here so we rotate between roast Pork or Beef.

Thanks again for your immense help with this project, all the very best, Graham.

[Twizseven]

Looking good Graham.  Just waiting to hear it running.

Colin

[Jasonb]

well it's been a little while waiting for the flywheel castings but with the help of Colin the van driver Graham was able to send me the full set of castings for engine number two of two plus a few extra flywheels that I will now need to design an engine or two so they can get used.

[Alyn Foundry]

Hi Jason.

Pleased to see they arrived in one piece, albeit a little later than advertised.

I don't know what Colin had to use but I was ready to dust off the Dynamite !! However.... Many thanks Colin ( Twizseven )   

Cheers Graham

[Admiral_dk]

I'm not particular into castings (sorry Jo) - but these look great - hope that they machine just as well 

[Twizseven]

Just friendly persuasion