CHUKY - Build One Yourself

[Jasonb]

I remember seeing the CHUK range of engines when Graham first posted them on the Alyn Foundry website and quite liked the look of them but as I was engrossed in building my Fowler traction engine at the time did not have the need for more engines.

With the demise of Alyn Foundry I had put the engines out of my mind until Andy started a build thread on his set of castings which got me thinking about building a flame licker. There are a few designs about but they do all look as though they were made from bar stock which in fact they are! I still liked the look of the CHUK and was able to borrow the build notes that came with the engines, these combined with looking at Andy's engine photos and a bit of artistic license allowed me to come up with the design shown below. Despite what some people said in Andy's build thread if you want to make an engine enough you don't need dimensions on every feature to copy



I have made a few engines recently with a 24mm bore which I find quite a nice size as they are not too big to handle or display and there are no large bits of metal needed that will break the bank. So this engine also has a 24mm bore which makes it about 2/3rds the size of the original CHUK, stroke is 32mm and the flywheel is 102mm dia and also the only casting used but at that size could be fabricated quite easily. I have tried to add a bit of shape to the parts so that they look like they were made from castings rather than make just another barstock engine.

The work is mostly milling or turning from solid although there are two items that will require silver soldering, even then one could probably be done with some small CSK screws if you don't fancy soldering. There are also several parts that need lapping, the flat ones can be done easily enough on a flat surface with fine wet and dry but the cylinder also needs lapping as does the piston.

A big thanks to Andy for posting his original build and help with the build notes and also to Graham Corry for coming up with the engine in the first place and also giving me permission to share my design drawings with the membership so lets start making swarf.

I have also attached the 3D pdf which should allow you to look around the engine design in detail

[Jasonb]

BASE

Drawing #1

This can be made from a slice of 75mm or 3" dia aluminium or could even be done from some 12mm plate. I started with a slice of round bar, held in the 3-jaw to face off and then bore the 28.5mm hole right through. I also removed some of the waste by turning a 60mm dia spigot.



The spigot also made it easy to hold the base the other way around to face off the bottom.



The base can then be mounted on the rotary table and clocked in true to the spindle to start shaping the raised area. I used an old 10mm dia milling cutter with the corners ground off to a small 1mm or so radius so that it left a fillet as you tend to see on castings but it could be left square if you prefer. Start by cutting in from one side until the face is 21mm from centre.



Next cut the two sides, I have shown the point where the 10mm cutter should stop at 22mm in the Y axis and 13.86 in the X axis.



The table can now be rotated to reduce the rest to 42mm dia



Next add the decorative moulding to the edge, an old 6mm dia cutter can be ground by hand either on the corner of the bench grinders wheel or with a dremel which will give an acceptable shape.



While held like this the Hole for the chimney can be drilled 9mm and then tapped M10x1, if you don't have fine pitch metric taps then 3/8" ME threads would do.

The base can now be held upside down in thevice with teh flat edge against the fixed jaw, clocked central to teh spindle and the four M3 clearance holes drilled, I tend to use 3.0mm drills for this as teh socket head CSK screws tend to come in at about 2.8mm OD. I won't keep mentioning it but ease the edges of all holes either with a CSK bit or a lathe tool ground at 45degrees, you will often see these tools in the photos as it it the last op before taking the pic.



To mill the exhaust passage I dusted off the swivel base for my vice which was the first time I have used it in the 10yrs since I bought it, set the vice to 45degrees and then with an 8mm cutter cut the slot 3mm deep . If you don't have a swivel vice base then the base can be clamped directly to the mill table and the angle is not critical.



Thats the first part out of the way

If anyone spots any errors on the drawings please let me know and I will update them, also feel free to ask any questions.

[Gas_mantle]

Thanks for taking the time to upload this build, it's the kind of thing I may be interested in having a go at making 

[crueby]

Excellent start, going to be following this one. Thanks for posting it!


 

[10KPete]

 

I like this one. There's something about the exhaust note and it will also run pretty slowly. Not too big and not too small.

Yep, gotta do this one!!

Thanks for bringing this to us.

Pete

[Jasonb]

Sub Base

Drawing #2

Start by cutting a piece of 6mm aluminium a little larger than the 110mm required, locate the middle and dot punch. Mark out a 110mm circle with a pair of dividers, roughly mark 45degree lines and saw off the corners.



Clamp the plate to the mill table with some packing underneath then proceed to drill the four M3 clearance holes and the four 4.0mm holes which will be used to mount the engine to a wooden display base. Then with an 8.0mm dia milling cutter counterbore the 4.0mm holes 3mm deep and also cut a flat bottomed hole 2.0mm deep in the middle of the plate to locate the valve spring into. If you have a larger spring then make the hole to suit. Once removed from the mill table the underside can have the M3 clearance holes countersunk so your screw heads sit just below the surface.



Screw a piece of ply or MDF to the lathe faceplate of if you have a large enough 4jaw then the board can be held in that, use the tailstock centre in the dot punch mark to hold the plate to the board and then screw it on through the 4.0mm holes and turn the outside down to 110mm diamater.



Blue the plate in a couple of places and then offer up the base using a couple of screws in the M3 holes to line things up and scribe on its diameter.



Swing the topslide right round and set to about 4degrees then taper the edge of the plate until the cut runs out where the scribe marks are.



The last turning job is to add the decorative moulding to the edge which can be done by grinding up a small HSS form tool.



Finally back to the mill, pop two drill bits into the 4.0mm holes and locate them against one of the tee slots then locate the middle of the plate. Using the 8.0mm cutter again cut the other half of the exhaust passage 3.0mm deep



And a quick picture of the two parts together, I will give details of the spring later.



J

[crueby]

Great step by step - nice work!

 

[NickG]

Watching with interest, nice looking engines they are, and your CAD model looks good.

I have to say I've made 3 flame lickers now and the pistons and cylinders do require a good fit. I tried lapping at first but was unsuccessful, what worked for me was just focussing on making sure the bore and pistons were parallel. So I used an adjustable reamer with plenty of oil for the bore and just a finely turned finish cast iron piston to keep things nice and square. So it can be done without lapping - my lapping failure was probably due to my poor technique, tools and lack of patience though.


Sent from my iPhone using Tapatalk

[crueby]

Can they work with a viton o-ring as a seal? How much friction can they take and still run?

[awJCKDup]

Looking good, I'm following along, and downloading plans. Keep up the good work, and thanks.

John

[wagnmkr]

Jafa Cakes and coffee in hand for this one. Just LOVE the sound ... we have Harleys around here that don't sound that good.

Tom

[Jasonb]

Thanks Chaps, good to know you are enjoying the build.

I think using O rings would add too much drag on such a small engine, you may get away with it on a larger version where there is a bigger volume of gas to cool and more momentum from the flywheel. Also not an adeal combination of flame and vitron. As you will see later it is not to hard to lap the piston into the bore so worth having a go.

Maybe Graham could comment on the use of o rings if he is looking in.

[Alyn Foundry]

Maybe Graham could comment on the use of o rings if he is looking in.

Hi Jason.

Indeed, reading with great interest. I wish we'd have had this form of communication back in my heyday!!

http://www.modelenginemaker.com/index.php/topic,7187.msg150758.html#msg150758

The engine mentioned above was made from some of the last Iron to leave the Rhuddlan foundry.

The grade was about 17 , meaning it could be brought to a mirror finish, literally you could see your face in it! Martin and I both had the Delapena system of honing and were able to get both finish and parallel cylinder bores.

CHUK 2 being an inverted vertical meant that two forces were working, gravity and atmospheric pressure. That's the reason why out of the three styles CHUK 2 ran the best.

Patience is the key word, as Andy pointed out, a lot of lapping involved. I too found that music aided the process immensly.

Kind regards, Graham.

[NickG]

Yes, the lower the friction the better so I would say any kind of piston ring would be a no no. The power output is tiny by comparison with a steam, ic or even Stirling engine, relying only on the difference between atmospheric pressure and the under pressure caused by cooling of hot gas in the cylinder.

I used graphite for the pistons on both poppin engines to good effect, was very easy to obtain a good fit and self lubricating.


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[Jasonb]

Cylinder

Drawing #3

This is probably the most involved part of the engine but if you take it one stage at a time it should not present too many difficulties.

It is just possible to squeeze the cylinder out of a piece of 50mm dia cast iron bar, anyone in the States thinking of making this will have a little more to play with by using 2" stock.

Start by sawing off a piece a few millimeters longer than needed and then lightly face to clean up the ends. Blue the end of the bar and then lay it  onto a flat surface and scribe a line at centre height, roll it 1/4 of a turn and mart a cross line 3.5mm below ctr height. Accurately punch where the two lines cross.



Set the punch mark to run true by holding the bar in the 4-jaw chuck.



Then spot drill followed by drilling out most of the material with several drills of increasing size until you get to about 18mm when the rest can be bored out.



I like to do the last couple of cuts with a HSS boring bar as I find that springs less but even so take a few passes at the final setting to let any spring work its way out and hopefully you will get a parallel bore. Aim for something like 23.90mm which will allow for honing and lapping but as the piston will be made to fit the bore the turned finish is what to aim for not the exact size.

Talking of sizes I did not use a micrometer once on this engine all measurement was with a digital calliper.



Take a finishing cut across the bar and then take another 0.5mm deep cut to leave the small raised area 28.5mm dia, this raised area will make it easier to lap the end of the cylinder later.




The work can now be reversed in the 4-jaw and the bore set to run true, make sure you can machine down to the top of the valve face which will probably mean the work is away from the chuck face. You may just be able to see that I have a piece of 1" material between chuck and work so it can't get pushed back by teh tailstock. NOTE this must be prevented from flying out for which I have used hot melt glue. Bring up the tailstock ctr for support and rough out to about 43mm dia.



Then with a tool that can get into a corner turn to 42mm finished dia and to leave 16mm for the port area.



Now form the spigot on the top of the cylinder to leave the 42mm dia section 50mm long.



Continued in next post.

[Jasonb]

Next put your parting tool in the toolpost, set the front edge to touch the work and zero the cross slide dial. Then with the topslide touch the edge of the tool against the end of the cylinder, retract and move half the width of the cutter towards the headstocjk and then zero the topslide handwheel. This will make it easy to set the spacing of the fins as they are all dimentioned to their ctr from the top of the cylinder OD.

First make a central cut on each 5.5mm deep.



Then increase the width of the slots to 4mm by taking a equal cut off each side of the first grooves.



Then swing the topslide around to 5degrees and cut the taper down one side of each fin. Swing to 5deg the other side of zero and make a similar set of cuts down the opposite sides.





Grind up a 4mm square HSS tool bit to a half round profile and then round out the bottoms of the grooves, a slow speed will be needed to avoid chatter.



Then with a file the external corners can all be rounded over whith the lathe running.



Remove the tailstock and trim the spigot back to its final 5.0mm length.



With the largest part of the lower cylinder uppermost mill it back flush with the edge of the fins or just a fraction proud. Use a nice sharp cutter as we want a good finish here to save excessive lapping later on.



Centre up the port face and drill two 4.0mm holes 10mm each side of ctr into the bore, then another four holes will remove most of the material from the inlet passage. Finish up by cleaning out the slot with a 4.0mm milling cutter.



The cylinder can then be held bottom up on the rotary table and the two sides of the port machined as was done to the base.



Then again like the base round the rest to 42mm dia



Then add the four holes but this time thay are tapped M3.



Finally for now the five M2.5 hole scan be drilled and tapped in the top but make sure you drill them in the right place unlike me the one above the port face should be left out.



J

[Jasonb]

Although I'm not a fan of them myself I was asked on ME forum about a Bill of Materials so here is one you can download.

Bill of materials

[Dave Otto]

Continues to be an interesting build Jason.
Thanks for the update.


Dave

[Jasonb]

Bearing Support

Drawing #4

I mentioned at the start that there were two pieces that are silver soldered fabrications, this is one of them and it is the one that if you are not able to silver soilder too well could probably be done by machining the vertical part into a "+" section and then tap this top and bottom for a couple of M2 CSK fixings each end. Though it would also be a good thing to get the hang of silver soldering on as there is not much material in it and if the worse came to the worse it could be melted apart, cleaned up and another go at soldering attempted.

I have shown the finished sizes on the drawing but strongly suggest that the top piece is made of something thicker than 3mm material and also left ovesize in the other two directions. It is unlikely that you could solder it all in exactly the right position but by leaving the top oversize it can me treated like a casting and machined exactly right once soldered.

So make a start on the lower ring. Chuck a piece of 45 or 50mm dia bar, turn down a short length to 42mm dia, face the end and then drill and bore out to a nice snug fit on the 28mm spigot left on teh top of the cylinder. Saw or part this off and then face back to the finished 5mm thickness



For the curved part of the upright I used a short length of scaffold pole skimmed inside and out to clean it up and then faced both ends to bring it to 32mm long. It could be cut from solid or even bent up from some 3mm flat, the exact curve is not really that critical.



The cross shape is made with a halving joint so mill a 5mm slot half way up.



Then mark out a pleasing shape. I drilled 5mm at the top to leave a nice fillet shape and then drew the two larger curves by scribing around a roll of masking tape. Saw and file to your chosen design.



The other part of the cross is cut from a bit of 5mm flat plate and has the other half of the having joint milled in it a 3mm wide. Finally cut and file to shape. I would suggest the face that the valve rod guide screws to is also left overside at this stage.



Another bit of the 5mm stock forms the top plate, these are the 4 parts prior to soldering.



Give them a good coat of HT5 or Tenacity5 flux and place on the hearth, a couple of bits of scrap metal can be used to help steady things. Put a bend in your solder rod before starting to heat as it makes it easier to apply the first bit of solder under the top plate then chase the heat down with the flame watching the solder flow as you go adding more as needed.



Once cooled give the part a soak in your chosen pickle I tend to use brick cleaner now as it shifts all the black scale from soldering steel as well as the HT5 flux.

The part can now be held on the mill either using a chuck or clamped to the table. If holding in a small chuck as I have shown add a clamp or two to hold it down because the leverage from milling the top can pull it about a bit and result in a chip to a nice new milling cutter With it held in place locate the centre of the hole and from there the 4 sides of the top can be machined to the drawing dimentions and the two M2.5 holes drilled & tapped. Then mill the top down until the 40mm height is reached.



Now with the bracket upside down in the mill vice locate centre and drill the five M3 clearance holes on as 35mm PCD, support the overhanging edge so it does not move under pressure from the drill.



Holding by the round ring and with the long side of the top on the flat of the vice the surface for the valve rod guide can be milled back until the cutter just skims the edge of the ring which will put the surface 21mm from ctr. Don't mill right upto the top plate but feather out the cuts and afterwards file to a pleasing radius. The two M2 holes can also be drilled and tapped at this time to complete another part.



J

[crueby]

Nicely done! Watching along....     

[Jasonb]

Piston and Associated Parts

Drawing #5

Before starting on the piston it is best to hone the cylinder, this can be done quite easily with one of the cheap brake cylinder hones. I run these in the bench drill at about 750rpm and just move the cylinder gently up and down making sure not to let the stones stick out too far and risk a bell mouth end, a little paraffin will help stop the stones clogging.

The piston will come out of a length of 25mm cast iron bar, face it off then turn the outside until it just enters the cylinder bore. Check against both ends of the bore, if one is smaller then use the hone some more to remove any taper. Once you have a push fit into the cylinder stop working on the outside and bore the inside followed by drilling and tapping for the M3 thread.



Saw or part off the piston and then face off to 20.5mm finished length being careful not to distort or crush the now hollow piston. Face off and tap a bit of say 12mm bar to take an M3 screw and this can be used as a mandrel to hold the piston while it is lapped into the bore.  This is easily done at a slow speed with a small amount of 1000g silicon carbide powder and a liberal amount of oil. Just work the cylinder onto the piston from the top until it is a close but friction free fit. Clean off all traces of SiC powder.



The lug for the gudgeon pin can first have the end reduced down to 3mm and then be threaded M3



Then mill it to a square section if you have not started with square bar. This can then be cut off the main bar and milled to length and a 3mm slot cut into it.



Followed by the drilled and reamed cross hole after which the end can be rounded off by filing or machining.



The gudgeon pin is a simple turning job. Onec done blue the end, put it in teh hole and mark off the position of the split pin holl. Then drill for a 0.8mm (3/32") split pin.

This pic shows the finished parts along with the conrod which is still to be descibed.



J

[crueby]

For the paraffin to prevent clogging the hone, is that the solid type paraffin wax, or kerosene liquid?

Following along, nice work!

 

[Jasonb]

Just the liquid Kerosene, I put a few drops on at the top and let it run down and out the bottom taking the dirt with it.

[Gas_mantle]

Looks great Jason 

What sort of soldering equipment are you using ?  I like idea of fabricating parts rather than using castings but wonder if my simple Mapp gas set up will cope

[Jasonb]

I have an old Bullfinch torch that runs off a 3.9kg propane bottle with about a 22mm burner. A mapp torch would probably do this bracket OK as the bits are reasonably small so you don't need as many Kw as a big burner puts out. Mapp would certainly be OK for the other part that must be soldered and that is the shutter.

As a half way measure "Comsol" could be used which has its melting point between soft and silver solder.

[Gas_mantle]

Thanks, I quite fancy having a go at making one of these engines once my new lathe arrives.

I've silver soldered a few parts in mild steel using a small Mapp torch to fabricate something but they were quite small.

[Alyn Foundry]

Hi Jason.

Proceeding nicely.

Insulation.... A key word. For Silver soldering we used Ceramic fibre wool surrounding the object. It matters not how big the heat source is, if you let that heat escape the object won't heat up.

The wool is so reflective that objects quickly get up to the required temperature, I also recommend Tenacity 5. It works really well on the Ferrous range of materials, still working even with prolonged heat exposure.

All my " homespun " furnaces  were lined with Ceramic fibre, we cast most prototypes at home before moving on to the foundry.

Another well known tip, particularly useful if you're a bit shaky, is to cut pieces of solder, fluxed, and place them strategically around the object. My technique was to play the heat around the outer area and get it hot before going into the joint proper. This method ensured that the whole object expanded and, in theory contract without twisting.

Kind regards, Graham.

[Jasonb]

Crankshaft Parts

Drawing #6

I made a start with the crank web and to make it easier to hold actually machined it on one end of a short length of 40mm dia steel bar and the cam on the other end.

Start by facing the end of your stock, then using a tool with a small radius on the corner turn the 3mm long spigot and also the 38mm OD. Followed by drilling and reaming the central 5.0mm hole.



Transfer to the mill, locate centre and then use the handwheel dial or DRO to move 16mm and then drill and tap M3.



Saw or part off and then holding by the spigot clean up the other side but leave the web about 0.5mm over thickness at this stage. Mark out the two straight edges, saw off the waste and then mill back to the lines.



A bit of simple file work will round off the edges.



The crank shaft can be made from precision ground mild steel (PGMS) or silver steel, stainless would also be OK if it is a good fit in your bearings. Face it off either end but leave it 1.0mm longer and then turn the spigot also 1.0mm over length. The crank web can be used as a gauge to get the spigot a firm push fit into the hole. Once done clean up both parts and loctite them together.



Once the Loctite has had a good time to set the crank can go back into the lathe to have the web faced down to the final 3mm thickness. Doing it this way will ensure the face of teh web is at right angles to teh shaft even if it went on a bit crooked when loctited.



The crank pin is fairly straight forward turning, put a small undercut at the base of the thread to ensure it screws right into the web and the shoulder makes contact. Saw or part off then clean up to leave the lip 1.0mm thick and add a small chamfer.

J

[crueby]

Another great installment, nice sequence


 

[Jasonb]

Thanks Chris


Cam Disc

Drawing #7

I machined this on the other end of the bit of 40mm dia steel that the crank came out of.

Start by facing the end and then turn the 12mm dia x 6mm long spigot followed by drilling and reaming 6.0mm



The cam can be formed in a number of ways: milling, turning in the 4-jaw or even filing to the template included on the drawing. I opted to mill it using the rotary table as follows

- centre the rotary table under the spindle and zero the dials or DRO, lock y axis
- hold work in chuck , put a 6mm rod in the collet chuck and bring down into the hole
- move table 11mm in the x plane allowing the chuck to slide along the rotary table
- Bolt chuck to R/T
- Fit a cutter into the collet chuck and work your way in from the edge rotating the work on the table until the x axis is 25mm plus half your cutter dia.



Saw off from the rest of the bar and then hold by the spigot in the 3-jaw, face back to 3.5mm thick and then take a further 0.5mm cut but stop to leave the 8mm raised area in the middle which will make sure the cam only contacts the bearing inner race.



You could mill the two 10mm radius corners that blend the arc into the main diameter but I just opted to file it to shape.

Final job is to drill and tap for a M3 grub screw.



J

[Gas_mantle]

Looking great Jason :-)

Could you show what that parting tool is in your posting 17/6/16 (when you cut the cylinder grooves), I still struggle sometimes with parting off and wonder if a tipped tool might be worth buying.

At the moment I've only ever used HSS and find I get mixed results :-(

[pgp001]

I reckon it will be one of this type. Best thing I ever did was start using these.



I have a spare blade if you want to have a go with it. You will have to make or buy a holder for it.

Phil

[Gas_mantle]

Thanks Phil,

I may well take you up on that, now that I've upgraded my lathe I'm looking at buying more tooling.

[Jasonb]

Mine is the Glanze version and I have got mine the right way up It takes the 2mm nominal width tips which does not put too much load onto the lathe.

https://www.chronos.ltd.uk/cgi-bin/sh000001.pl?WD=parting&PN=New_Glanze_Clamp_Type_Indexable_Parting_Tool_Starter_acks%2ehtml#a776130

Without getting into the parting off debate you should be able to do it with HSS as well.

[Gas_mantle]

Thanks Jason, I'd like to try something similar.

Great work on the engine 

[Jasonb]

Bearing Block

Drawing #8

Start by milling up a block of aluminium to the overall 16x22x17mm. Then hold in the mill vice with the top facing upwards and locate it centrally below the spindle followed by drilling the two M2.5 clearance holes.



Change to a 6mm dia cutter, touch off on the top of the block and then lower so you are taking a 3mm high cut, cut in 4.29mm from each side and while at that height bring the cutter in from each side to form the counterbore centrally over the stud holes.



Now holding the block on it side drill and then bore for the bearings aiming for a light press fit, if you over do it then a high temperature Loctite such as 648 can be used to retain the bearings. I opted to use number 686 unshielded bearings which are 6x13x3.5 from ARCEurotrade but 12mm OD ones would work just as well. As the flame can lick around the bearings avoid ones with rubber seals though if you have some to hand the seal can be flicked out with a pin or small jewlers screwdriver.



The last job is to round over the top, I did it by holding the work on a mandrel and then taking cuts at 5degree intervals on the spin indexer and then finished with a file. Could also be done on a rotary table or just by filing.



You can now fit the bearings, slip in the crankshaft and check all turns over nice and smoothly.



Included on the drawing are the 4 simple turned "washers" that fit into the counterbored holes in the sub base, once bonded in with JBWeld or similar they will look like cast.  bosses. Turn and drill sufficient material for the 4 parts and an allowance for parting cuts and then part them off and deburr.



J

[Jasonb]

Chimney

Drawing #9

The main chimney is a simple job from 10mm OD aluminium tube, thread one end M10x1.0 for a length of 22mm. Face to length and form the 9mm dia spigot on the other end. I used slightly larger OD tube so had to machine it down to overall diameter.



The base is just some 12mm stock drilled to 9.0mm and tapped M10x1.0 with the upper edge rounded off.

The top ring can be turned on the end of some bar and if you put a parting cut part way through so the bead can be easily shaped the drill will part off the work as it brakes through.



The parts can be assembled with a drop of Loctite 648 to hold the ring in place, make sure you have no more than 2mm of thread sticking out the bottom otherwise the exhaust passage in teh base will be restricted.



And a quick test fit to round off this installment.



J

[crueby]

Looking great!

 

[Jasonb]

Conrod

Drawing #10

This could be turned from a length of 10mm aluminium 6082 but I had a lot of 1/2" (12.7mm) so used that.

Cut off a piece about 20mm longer than needed, face each end and put in a small size 0 ctr drill hole, reduce one end to 8mm dia and the other to 10mm if using larger stock.



Now holding the rod in a mill vice the two holes can be drilled and reamed and the ends flattened off.



Back to the lathe hold the 10mm end in a collet or 3-jaw and offset the tailstock to form the taper, I used a small live ctr in a boring head to get the offset rather than disturb the setting. You could also set the topslide to an angle if prefered. Do the final cut swith either a small HSS tool with a rounded end or an insert tool like I used in the photo to give the fillet where the round rod joins the flat ends. Do take it easy as the rod is getting quite thin at this stage but will be nice and light.



The two bearings are simple turning jobs from a bit of bronze bar with reamed holes. I find the mill vice is quite good for pressing them in, use a spacer on the big end so the bearing can protrude evenly both sides. If your fit is a bit loose then high temp Loctite such as 648 should hold the bearings in place.



This is the finished rod together with the Gudgeon pin block and piston described earlier



That's another bit off the list, hopefully you won't have to wait so long for the next installment

J

[yogi]

Looking good Jason! 
I'm glad to see an update on this engine. Looking forward to the next installment. 

[Gas_mantle]

Great to see an update Jason 

I'm interested in the set up you have to cut the taper using a boring head as the offset as I want to do something similar for the Muncaster columns, is it a homemade live centre to fit the head ? I was planning on just making a temporary dead centre out of steel to fit 

[Jasonb]

Thanks Guys

Peter I know you have the photos for the Muncaster which show me doing the same thing but not easy to follow without my build description. I used the ctr from my old Unimat3 but a solid one would do and there are reasonably priced far eastern versions of the Emco one about.

[Gas_mantle]

Thanks, I didn't realise it was possible to buy small live centres with a parallel shank but it looks like this is the kind of thing I need 

https://www.rdgtools.co.uk/acatalog/Revolving--Center-for-Taper-Turning-Long-Tapers-1272.html

[Jasonb]

Shutter parts

Drawing #11

Shutter Rod Guide

I did not have any 5mm thick brass so thinned down the end of a piece of 1/4" material and then drilled the 2.0mm hole at least 31mm deep.



With the work now on it's side the recess was milled out with a 6.0mm cutter to give the required 3.0mm radius to the internal corners.



After cutting off from the parent bar the back face is milled to finished size and then the 1.0mm step cut from the lower end.



Turning the part the other way up the larger recess can be milled out, the two 2.0mm holes drilled and then countersunk then finish off by filing the 2.5mm radius around the upper screw hole.




Shutter

This starts life as a Stanley knife blade or "utility" knife as I think our American members call them. It is best to shape the knife blade after the steel block has been soldered on just in case it moves about during silver soldering. Also worth leaving te block a bit long to start with so just make teh 5x8 dims to finished size then solder.



The blade can then be roughly trimmed to size making sure the edges are true to the edges of the block. With the rod guide screwed into place machine a point onto some 2.0mm rod and pass that through the guide and use the rod as a scriber to mark the position of the M2 hole.





The hole can now be drilled and then tapped M2 and the block rounded over. I would suggest leaving the final shaping of the shutter until it is mounted on it's rod.

Shutter Rod

This is quite a simple job so no photos, face the rod to length and cut the M2 thread on each end to the lengths required.

This shot shows the finished part , the fork and cam follower roller will be covered next time.



J

[Jasonb]

Cam Follower and Valve

Drawing #12

Cam Follower

A simple turning job from brass, face off, drill 2.0mm and part off to 2.0mm thick

Cam Follower Fork

I did not have any 5mm square stock so milled down the end of a round bar and while in the indexer drilled and countersunk the 2.0mm hole then rotated it 90degrees and used a slitting saw to form the slot. Then into the lathe to drill 1.6mm and tap M2 before parting off to length.

Cam Follower pin

Another simple turning job, make sure the head is small enough to fit just below the surface of the Follower Fork.

You will also need a small dia spring to slip over the valve rod, about 20mm free length, 0.5mm wire. Does not need to be too strong as that will increase the load on the engine - just enough to keep the follower in contact with the cam


Valve

Face off the end of a piece of cast iron , turn OD down to 28.0mm and then part off a 0.5mm thick slice, if your parting tool leaves a pip in the middle don't remove it.



The eight sides that form the octagon can just be filed but make sure you leave a small part of the 28.0mm dia edge between each as it will help keep the valve centred within the base. The valve can then be lapped on some 1200g wet & dry using a disc of metal to keep it flat, this is where the pip helps.



Parting off will leave the valve slightly concave so you only need to lap the edge as can be seen by the polished area



J

[crueby]

Nice progress, watching along learning about this kind of engine, hope to make one someday!

 

[Alyn Foundry]

Hi Jason.

I like the relief valve !!   

I always used the metal base from those well known tubes of flavoured potato products.... " once you pop "   

The lapping was laborious but paid dividends if done right.

In fact it's the large size of the relief that makes them run so well !!

Cheers Graham.

[Jasonb]

Burner Support

Drawing#13

Base

A simple turning job, face off the end of a piece of 10mm dia brass, use a small round nosed tool to add the decorative moulding, drill 3.0mm and part off to 2.0mm thick

Burner Clamp

Face off the same bit of 10mm brass and then over to teh mill to cross drill the 5.0mm and 3.125mm (1/8") holes at right angles to each other. Back into the lateh and drill and tap the M3 hole before parting off.

Burner post

Form a decorative end on a piece of 5.0mm dia brass which can be done with a form tool of freehand and then refined with a file. Part off to length, reverse in chuck and drill and tap the bottom M3

Burner Thumb Screw

reduce the end of an 8mm piece of brass down to 3.0mm and therad M3. Then form an oval end again with a form tool or freehand. Over to the mill and cut 2.5mm off each side.

J

[crueby]

Hi Jason - the file link for drawing 13 gives a file-not-found error on dropbox.   

[Jasonb]

Burner Tube and Flywheel

Drawing #14

Burner Tube

This is silver soldered together from the three parts shown. The main tube has five holes drilled 0.5mm dia at a spacing of 4.0mm starting 5.0mm in from one end. This end has a small plug soldered into it which can be turned or a brass rivit can be used. The other end will depend on the gas hose that you have. Mine needed a hole to take a 6mm O ring seal and threading M7 x 0.75 for the union.



Flywheel

Flywheel I chose to use a casting but you could also machine one from solid. There are several suitable sized flywheels about this one came from Reeves and is their Perseus one, RDG do a part machined one and there are a couple of e-bay sellers that have flywheels too. Final dia and width of rim are not critical so just machine off enough to clean up the surfaces as any extra weight will help with smooth running

If you have a small enough boring bar then use that to take the bore to final size from say a 5.5mm drilled hole if not drill and ream. Add a M3 cross hole for a grub screw to retain the flywheel.

Well that's about it as far as construction goes. The cam should be adjusted so that the intake port is just starting to open as the crank pin reaches the 5 o'clock position when viewed from the shutter side and should be closed at about 11 o'clock. If all is right the engine will turn easily in the clockwise direction and make the farting noise as the piston descends but if turned over anti clockwise should be quite hard to turn as the piston comes up. Correct running rotation is clockwise when viewed from the shutter side.

Once the flame is lit the engine will need flicking over a few times to warm it up and will slowly start to run for a bit longer after each flick until it reaches a point where it will continue to run. You may have to play about with flame position to find the sweet spot and position can also be used to alter speed as can size of flame. The bearings and big & little ends can have a small amount of light oil but the piston can be run dry or if you feel the need apply a little WD40 (not while flame lit!)

I use a couple of colours of stove paint on the engine which does get hot so whatever you use should be heat resistant. A round wooden base can also be easily made on the lathe and gives somewhere to screw the burner support.













<a href="https://www.youtube.com/watch?v=YFk4ZhEA4kE" target="_blank">http://www.youtube.com/watch?v=YFk4ZhEA4kE</a>

J

[Jasonb]

Thanks for the heads up, link to drawing #13 should be OK now

[crueby]

Thanks for the heads up, link to drawing #13 should be OK now

Yes - thanks!  I've downloaded the whole set, its in my build queue. Getting to be a long queue!

Your engine runs very well!   

[cwelkie]

Nice tidy and fun project Jason - thanks for sharing it and the drawings.
Charlie

[Admiral_dk]

Another fine engine from you Jason  and a very easy starter + nice sound 

[Gas_mantle]

Great model Jason 

Does its performance change after its being running a while and the body gets hotter ?

I rather like these and Stirling engines but I understand they can be very tempermental and can need a lot of tinkering to get running well.

[Jasonb]

I've not run it over an extended period, maybe 5mins at a time and did not notice a drop off. Then again I tend to run my engines fairly slowly and would think that if run faster it would get hotter as you are sucking in more flame so that could affect running.

[Zephyrin]

Thanks Jason for the drawings and the detailed built along this thread with sharp and clear pictures and text.
the engine is stately when running.
Flame licker engines are always fascinating to watch, and I will certainly have a go at this one...

[Alyn Foundry]

Hello All.

Well done Jason, a lovely job.

They will and do run for hours at a time, in fact it’s usually the noise of them that you get irritated by!   

The “ Inverted “ CHUK engine was a lot quieter because the exhaust relief was under the engine and muffled by the base.

On my website there’s a photo in a gif format showing Martin’s high speed, fully balanced “ Desmo “ CHUK engine. With the right heat and position this engine could exceed 1000 RPM !!

Out of the three designs CHUK 2 or Jason’s CHUKY to me is the prettiest.

Cheers Graham.

[b.lindsey]

A beautiful engine Jason and a fine runner as well. Will definitely be adding it to the build queue here as well.

Bill

[Twizseven]

Jason,

That runs very nicely.  Am I correct in assuming there is no way to control the speed as it does not have a carburettor/throttle.

What stops the speed from just increasing.

Colin

[Jasonb]

The size and position off the flame will alter the speed.

[Zephyrin]

What stops the speed from just increasing.

Simply the mechanical drag rapidely equilibrates the tiny motive power...
a larger or hotter flame would increase the speed, but could be harmful for the engine !
the flame is just a source of very hot air, but not mandatory, one of my engine runs well with an hot air gun.

They will and do run for hours at a time, in fact it’s usually the noise of them that you get irritated by! 

flame lickers are surprisingly noisy, and this is certainly not related to their power, nothing to compare with a Stirling engine.
it is not easy to work out the source of the noise, the flow of air through the small passages and the valve movements at exhaust. maybe a sign that some power is lost with this noise !

[Roger B]

Just caught up on this one as well    Another excellent runner  Can you get any useable power from a flame licker, I know hot air engines as used to drive things (including cars) ?