Help on model engine tooling

[D&J Fitzgerald]

Hello out there. Regarding the Panther pup engine. Is a Vertical Mill absolutely required ,or can I get away with just a Lathe?

I saw photo's of the castings for the pup engine, which included two parts I could not recognize in there unmilled state, the two a flywheel and a timing chain cover, I do not under stand because I could just simply mill a flywheel and timing cover. As for the other larger part which I assume is part of the crankcase that can be milled to can't it?

In place of a vertical mill can I get away with a face plate for awkward weird milling requirements? Please let me know thanks.

I read members asked questions about cooling the panther pup , I am very experienced in the marine model field. Air cooling first, yes you can, miniture computer fans work best six or twelve battery required. I would mount four computer fans the 2inch square model would work well, one on the side of each cylinder facing the exhaust pipes as well four because each cylinder must have the same cooling temp. Or else you will have one running hotter then the other . this could destort eventually your aluminum cylinder or brass cylinder.

Water cooling yes it can be done look at the drawings for the depth of each set of cooling fins then chech the distances between each cylinder, now take that measurement that measurement - a say 1/62 is the size of each water jacket. You can silver solder thin pliable brass into round jacketes or you can anneal brass tubing and wrap each around a cylinder head, here is the problem the Pushrods on the vertical may present a issue. I do not have the plans as yet so I cannot say.

I must learn how to read engine construction plans these are much different then model ship plans are there any books on how to read and understand engine plan symbols. Does anyone know how well the details are in plans for the panther pup engine?
Could someone please tell me, what tooling I require for my lathe to build the pup engine, what kinds. Face plate, boring tools, reamers measuring tools etc. Please help.me out thanks kindly Daniel. Also does anyone know the most economical store to buy good quality mini lathe tooling. Thanks

 

[ShopShoe]

Daniel,

I have not built the Panther Pup, so I have no input regarding your first question.

On your purchasing question, the answer partly depends where in the world you are located. Here in the USA, LittleMachineShop specializes in supporting the 7x and other mini lathes, and they also sell the Panther Pup kit. As to economical, the cheapest is not always the best and poor support from a dealer or supplier is sometimes more expensive than paying a little bit more (How much is your judgement). Usual disclaimer: I have no connection to LMS, but have been a satisfied customer of theirs.

Regarding understanding plans, some study of some of the plans available for free will help you come to grips with building from them. Once again, some conventions differ according to where in the world you are, but in most cases you can figure it out.

One more thought: You don't say whether you have made any other engines before. I would suggest if you have not, then try building a simple air-powered single-cylinder engine first and made from bar stock. There are many free plans available and many posts on this forum about getting started.

--ShopShoe

 

[D&J Fitzgerald]

Hello, thank you, we live in Canada. I thank you for your email. No I have not built a model engine ever. But am more then able to. I just need to familiarize my self with the tooling for my 7 by 14 lathe and the appropriate cutting tools and various measuring instruments
And the pup.plans. castings, I can make the castings based upon wood plugs if the plans detail the dimensions of the parts that require moulds. I prefer to mill the parts that requiring castings. However I do not have a milling machine .

I had asked if I absolutely require a mill-vertical mill, to build a engine . I have noted the some builders use a face plate to cut work that would require a mill, there are mill attachments, the little machine shop sells a milling attachment for a lathe.

I checked Stuart Steam Engine castings which are expensive and most require a lathe and mill, so I opted out of that idea.

Building the pup should be no problem for me once I understand my lathe and the tools required. I have read some frightening stories one fellow in england built a single cylinder model engine he did a great job, but he um forgot to taper the bore in the cylinder, he had no compression, so he got mad, and bought a CNC you know, star trek punch the coordinate s and wamo a block with no errors, I cannot like the rest afford a vertical mill or fancy CNC stuff, needless to CNC required great skill with a keyboard. I have checked out some free plans one is all castings, he does not explain ,there was actually little to go on regarding the taking measurements for the castings so desided no i'l pass. I can read the drawings no problem and I can determine based upon the drawings if one can really build the engine, some plans I have seen do not as I see have enough information to build one others do. When it comes to reading model ship blueprints these no problem, engines well its some of the symbols on the plans that I am not sure what they mean, but I will learn.

The most important question I have is this, do you think I MUST have a vertical mill to build the pup? I say no based on seeing pup which I have studied in videos on YouTube, unless there are angled holes to be drilled I should not have a problem, the cam and crank shaft milling on my lathe will be a challenge if I blow a few that's fine I will just try again, I am going to start by building model ship parts and order a vernier caliber mostly spinning and cutting, also make a mini table saw, some reduction pulleys some SST model ship shafts, and a model brass mini cannon for practice, for me its reading the plans and setup for the cutting. I would like a cylinder micrometer to measure my bores and for proper taper, but I don't think they make them that small.

Tell please were in the world are you, and what have you built.

Better stop its tea time , look forward to here from you.
Best Regards
Daniel.

 

[deverett]

To answer the last part of your question:

Until the comparatively recent addition of vertical milling machines in the home workshop, many fine models were made using just the lathe with a vertical slide. Later on, some lathes had milling attachments available as bolt-on extras but were not very popular.

The downsides to using a vertical slide, or other milling contrivance on the lathe is the necessity of breaking down a set-up between turning and milling operations; this can entail good forward planning of the work sequence. Also, the milling slide is inherently much less rigid than a 'proper' milling machine and that means much finer cuts to avoid chatter and therefore the extra time taken for any task. Some work can be held on a faceplate and a milling spindle held in the toolpost.

Another disadvantage which may not be a problem for small parts, is the range of movement of the cross slide and the lathe spindle height above it + the small area available for mounting (and securing) the workpiece.

OK, so we are not in a production scenario but when the tools to make a job easier are available then it makes sense to avail oneself of them when possible.

A milling slide is a lot cheaper than a milling machine, so go ahead and try that way initially. You may enjoy the challenge of working with it, or if not enjoy the challenge of saving up for a milling machine and enjoy the productive fruits of your endeavours.

Dave
The Emerald Isle

 

[Hopper]

I've built model steam engines, stirling engines and a precision dividing head entirely on the lathe, with a vertical milling slide attachment. The main limitation is you can't mill large or long objects because the cross-slide travel is limited when compared with the table travel on a mill. But it's plenty enough to do small model engine work. The only other drawback is that you are sort of working sideways all the time with the job bolted to a vertical slide, so can get a crick in your neck after a long session!

 

[MikeG]

Daniel
You can purchase the Panther Pup book with drawings and narrative from LMS. I suggest you do that first. I've built two "Pups" one air cooled (original) and one water cooled both with modifications. I strongly suggest you purchase a vert mill. As hopper said the travel in the lathe cross slide will not have enough travel on your 7X14 lathe. And as ShopShoe mentioned, start on a single cyl engine first, get to know the fits, finishes, tolerances and so forth. I made wood patterns for the Pup (according to the book) and the castings were a disappointment so I finally bought the castings and used them as patterns. As you can see on the photo I modified View attachment 102016 the manifolds (intake and exhaust) and the dist assembly etc. They're both good runners.

Regards

MikeG

 

[goldstar31]

' Forgot to taper bore a cylinder?'. Perhaps you could elucidate for us mere mortals.

Please explain

Cheers

N

 

[D&J Fitzgerald]

Well thank you all for your information. I spoke with the little machine shop about the pup engine. a mill is required, i am looking into that right now.

regarding education on a tapered bore i will explain. ALL car engines, diesel engines have a tapered bore in the cylinder as the piston moves up the cylinder on the compression stroke the rings tighten at BDC the cylinder is slightly wider the rings loosen quite simple basic stuff.

i read about a 4 cylinder vertical gas engine smaller then the pup and saw it running on youtube the man that built it did a great job. He offers the plans for 40$ A pdf down load i prefer rolled up mail me plans. i am thinking on that. Steam engines are a wonderfull item as well, but for me a boiler is the issue, building a boiler is a difficult task, i could build one there are plans for a horz. or vertical. maybe i will go with a 20cc single gas engine as a start. there are small engine too in the 10 to 15 cc which i am open to anything smaller is of no use. my model ships are giant scale, the reason for interest in the pup engine is that i am going to build a 7 ft model of the jaws orca. currently i am working on a 7 ft tugboat the Hermes the hull almost complete. and some smaller craft to sell as mantle models .

a nice sized twin gas engine that can be mostly built on my lathe would be nice but i cannot find any plans for such a engine.

I have seen many many engines
the builders are brillient. i am not one to build out of aluminum, i prefer either lead steel or perhaps brass. Iam not a machinist yet and never claimed to be, but will be soon. i have been a model ship builder for just over 30 years.

i am going to buy as the little machine shop suggested a start up kit for my lathe.

end note. I am not pleased with sellers on ebay regarding metal lathes and mills, the cost is way to high. i am looking into china to find a mill that is affortable for all home machinists. it saddens me that some friends out there are resorting to trying to manipulate a drill press into a mill. if i can find good mini chinese mill that is reasonable outside of those little toy ones i will pass the cost to other people who can then buy one. i have contacted several chinese manfactures looking for that solution. no one should pay more then 400.00US for a mini bench milling machine. i will find one then give the details here on how to get one.

again thank so kindly all for your suggestions.
D.

 

[Cogsy]

regarding education on a tapered bore i will explain. ALL car engines, diesel engines have a tapered bore in the cylinder as the piston moves up the cylinder on the compression stroke the rings tighten at BDC the cylinder is slightly wider the rings loosen quite simple basic stuff.

Not sure where you got this information from but it is simply not true for almost all engines. Some (generally ringless and generally model aero or RC car engines) utilise a tapered bore but these are only one specialised application. The great majority of full-sized and model engines have straight bores and much time, effort and money is expended to get the bores as straight as possible. In full size you would be introducing the potential for increased ring land wear and piston slap, neither of which are things you want. In model sizes your engine would likely run, and with the limited amount of running model engines get it wouldn't likely be a problem, but it is still not a desirable feature. I would say that most model engine builders, if they accidentally make a tapered bore, will either redo/repair it so it's straight, or simply pretend it's straight and never mention it to anyone.

 

[D&J Fitzgerald]

Thank you kindly for the information, i was aware, that many model engines have a straight bore. steam engines do, but the idea is to build enough compression to explode the vaperizing fuel. i have a few articals on those building diesel engine models, they have problems with injectors working, perhaps the mini injectors worked just fine, but a diesel engine does require a tapered bore due to great compression required to fire the fuel. if machinists are finding that there mini injectors are working but the engine will not fire, and milled straight bores with no taper then its possible the engine is not reaching high compression on the fuel stroke to fire. I am aware that many model engines don't have a tapered bore, in diesel engines and car engines they taper the bores larger at BDC and smaller at TDC.

i have received a email from a chinese manufacture on a small mill cost per unit 475.00$ usd i do not have the size and details yet, does not include shipping by seafrieght. i will present the details and size of the unit here if anyone is interested please let me know.

On the Subject of metal mills and lathes for those whom use the term Cheap china lathe, let me tell you something, 90% of all the milling tools and machines you have in your shop are manufactured in china. big and small, some home machinists have mills built decades ago in the west and the EU. many companies in china build a exellent machinery there are like in america and other western nations companies that build garbage this is a problem in all nations. China has come along long ways in manufacturing. What is a chinese cheep metal mill, answer, one you pay 1200.00$/for on ebay plus another 600.00$ for shipping.

i want a good quality metal lathe and milling machine that we as home machinists can afford with out risking a devorce from our spouses. I cannot build the pup with out a milling machine, my new lathe is 7 by 14. if i order four vertical milling machines then the above cost i indicated as 475.00$ usd per unit FOB or cost of frieght on board will be lower. i will get all the details on the model and enter them here.
i am not profiting at all on this. i will let you all know.as i get the specs, i think its a 550 watt model i would like one that tilts at various angles.

I have a suggestion for those that may not know, most probably do, i always use a small level when drilling to level my work so that i get a straight hole. another item i have not seen in the model engine forums is a mini cylinder cross hatching stone honor, its a very important tool after the bore is cut to hone the cylinder as doing so, will help the piston to seat properly.

finally some diesel engine modelers indicate that there mini injectors are failing to atomize the fuel, and this has been they claim the cause of engine failier, i would check the compression in the cylinder because with model diesel engines a tapered bore is a must.
my chinese baby diesel i had atomized at 2000 psi no problem
and still did at 1500 psi. if there is not enough heat build up in the bore then the fuel will not explode. when we look at the success of the Taplin diesel engines of the past, the key to success was that T-handle on the head not the fuel transfer.

must go ,to long here. Thanks again for the advice. today i clean and test my lathe.
Daniel.

 

[D&J Fitzgerald]

hello all again. i have great admiration for those attempting to build a multi cylinder Diesel engine, as the tollerences are much higher then a gas or steam engine in some respects.

those machinists whom are having troubles with fuel atomization due to the fact that the diesel fuel for such a small injector perhaps is not thinned enough for vaperization must consider or learn about something called a glow plug, there are missconceptions on glowplugs they serve a few purposes other a cold winter start and its this exact thing that machinists must have clear crystal understanding in order to help solve there problems. in order to understand, you must gain knowledge on Diesel Fuel Viscosity. diesel fuel is oil based when the temp . is not correct like all oils it thickens making atomization difficult. in winter time in colder climates construction machines engines will have a glowplug, which believe it or not creates a high temp in the cylinder that is why when turned on, the cylinders will take upto five min. to warm up before a start attempt is initiated. why because, the diesel fuel has tbickened and will NOT atomize as it enters the cylinder upon start up, also diesel engines vary in compression anywhere from 15.1 to 22.1 the lower the compression the more a glowplug is required to heat the cylinder as this happenes, fuel injected into the the hot cylinder, once in the HOT cylinder the tiny amout of fuel is heated by the glowplug which immediately thins it, then on the compression stroke wham the heat from the plug in conjuction with the compression stroke is enought to atomize the fuel. and the engine will fire. so one of the machinist ideals upon building a model multi cylinder diesel engine should consider and must consider the temp. of the fuel prior to feeding the mini injector, answer try placing a heater under models fuel tank let it heat the fuel up moderatly for say five min. then pump it to the injector as the oil viscosity in the fuel should be much thinner, look, Oil is very thick a small mini injector must have the fuel tbinned as much as possible before it will inject it at the correct viscosity.
Thanks for help me out, so i repeat the same.
D

 

[D&J Fitzgerald]

another commentary.

Subject: Regarding Straight Cylindee Bores in Model Engines. I like Ringed engines, i also like or prefer cylinder liners as opposed to a straight bore, pressed cylinder liners are used for example by OS and K&B usually of brass nicol, did i spell that right? the nice thing about a liner is that you do not wear out your hard worked bore with the piston, and simply replace the liner. regarding a straight bore with no taper, if car truck manufactures thought that a straight vertical milled cylinder waa indeed the way to go, they would have done so. For low compression engines and those where heat does not expand the cylinder or the cylinder is cast iron for example great. This is why i would never mill a model engine with a straight aluminum bore a liner would be a must,as aluminum heats it expands. i think my pups cylinders will be lead steel with a brass crankcase no fins my cylinders will be round not oval and i will have two oil rings and one compression ring and i will taper the bores, no liners required. lead steel is soft for milling so after word i will harden each cylinder. each cylinder will encorperate a waterjacket for my Orca model, i will run a water jacket around my 4 into 1 dry exhaust as well.
i will build a mini water pump that will run off of the crankshaft balancer, on the say port side, on the starboard side a electric start motor for the engine which will disengage oncw the engine fires. Someone is indicating right now, that i must spend 700 on my mill, i will make sure its INSURED.

i will also build my own marine transmission with a one to one ratio with reverse and N.

i will not have a drysump engine no thanks, a wet sump is the best way to go. as soon as i can set up the second bedroom of my house and get rid of a free loader that has not paid me rental storage for MY SHED in 20 years nor the previous owner.

anyway thanks again
D.

 

[goldstar31]

I must agree wholeheartedly with Cogsyon this
In all my years I have never seen a tapered apart one badly machined

If an in-line boring bar is used between centres it must bore parallel regardless of the tailstock setting

Regards
N

 

[10K Pete]

I have been wrenching on engines for almost 65 years now, all types from large oil engines (think 18" cylinder bores) to .o49 glow engines and I can say without reservation that the ONLY tapered bore engines I've ever seen or heard of were compression ignition model aero engines. No one in their right mind would design or build an engine with a tapered bore!! The problems are many and manifest.

Reading your posts, you have never made a model engine or any other engine for that matter so how do you come off saying what you did in your posts? You're blowin' smoke buddy.

Pete

 

[abby]

Well said Pete !
Dan.

 

[D&J Fitzgerald]

i will respond to the above, no actually i am not blowing smoke as you call it, ans yes indeed i have built engines, but real ones as opposed to model engines, if you do not believe me, then ask mr Conley. I took a auto mechanics course the books used for the course are indepth and cover the boring of engine blocks and there is a very slight taper in the bores of car blocks this is why the rings compress as the piston moves up the cylinder. this is also why a cylinder micrometer is used to messure the bore and the taper, i think before you talk and be insulting you should call detroit u are in for lesson in table manners my friends. no i have not built a model engine and no i have never used a mill or lathe, nor did send any post reflecting the wrong use of a boring bar, so just why that comment i frankly lost. if you as machinists never heard of tapered cylinder bores then iam shocked, all engines real engines gas for cars and so are infact bored with a taper. later as milage adds up, a tired engine will show increased piston slap at the bottom of the stroke. as for model engines, i will judge according to the blue prints i purchase.

and just because, i have not built an engine does not mean i am wrong. and if you want to be rood then please do not comment, you will find that if you buy a car that has a engine with a straight bore, you will black smoke exiting your pipe.

never speak until you speak with a engine builder, like i said call detroit you will find out your wrong. model engines some may have a straight bore but not real engines, conley knows ask him!? O and comparing a 049 to car engine is like comparing a Cat with jet engine.

on a positive note, if straight bores can be used successfully this would save some problems.
its all tollerences.



next question please?

i have a question can i build a single cylinder engine say 10 cc on a 7 by 14 with out a vertical mill?
thanks.
D

 

[10K Pete]

Well, D, I've never heard of Mr. Conley or of tapered bores in any engine save model aero engines. Neither has anyone I have known in the business. If this is something the auto companies are doing it's very new in the last couple of years and even then if it was a real thing it could be discovered. But nothing turns up.

The only place a tapered bore might exist is in a special engine built for a special purpose like a high performance racing engine. A custom work.

As for manners, when I detect BS I call BS.

Now show me some demonstrable evidence for these tapered bores. And not a taper of a couple of thou that's within bore tolerances..

Pete

 

[D&J Fitzgerald]

hello pete, now i havs a name, thats workable! I don't blame you for your disbelief. You mentioned you never heard of Conley, odd, you have never heard of the Conley V8/mini engine, he just v
brought out a blower kit for his 12000.00$ v8. You indicate you want some proof, i said call Chevy skunk works in Detroit ask for a guy named paul he is there chief designer if he is no longer there then ask for the design department.

A instructor of mine in Auto told us the class, and its in the book, i am shocked that you machinists of engines did not know this, perhaps the auto industry is keeping it a secret, piston slap occurs at BDC as the piston moves up the bore the slap stops, that is why when worn down the piston slaps the rings compress only slightly as they come up the cylunder, that is why you check for ring gap, when you replace the rings you will note once the piston is replaced into the cylinder, there is a slight gap , at the 180 intervals of the oil rings , when you place rings into a piston, you can press them into the grooves slightly if there was no taper then you would find that piston slap would occur at TDC but it does not, it occurs at BDC, cylinders that are out of round cause piston slap as well. they also check the cylinder for exessive taper at BDC, rings are designed to compress as the piston rises up the bore.
D.

 

[Cogsy]

On super high performance engines a few years ago (like 2000+hp drag motors), professional builders started bolting large, rigid chunks of steel to the top of the block to simulate cylinder head clamping distortion, while boring the cylinders perfectly straight, to ensure a straight bore during operation - exactly the opposite of what you're claiming.
Yes, I have built many full size engines myself as well, diesel and petrol, and am quite well versed in mechanical operation. I can also tell you yourself have not much experience, being that you indicate black exhaust smoke (unburnt fuel) is somehow related to poor compression in a pertrol engine. Finally, I have never seen a big diesel glow plug which operates for 5 minutes. Granted I don't live in arctic regions, but 'normal' diesel glow plugs engage in the range of 5-30 seconds in my experiences - from tractors to semi-trailers and heavy mining equipment.
I suggest you have a lot to learn and would be wise to consider the advice of people with many years of knowledge and experience instead of telling everyone how wrong they are on fairly fundamental principles. (A good case in point is using a level to drill a 'straight' hole - machinists use far more accurate indicators to ensure their mill/drill is in tram to get properly straight holes).

 

[Cogsy]

was no taper then you would find that piston slap would occur at TDC but it does not, it occurs at BDC, [snip] they also check the cylinder for exessive taper at BDC, rings are designed to compress as the piston rises up the bore.

I think I see what you're missing here. The pistons experience some variable side thrust from the con-rod over its entire travel, virtually zero at TDC and at its highest at BDC. This side thrust CAUSES uneven wear of the bores and CREATES taper. If you are rebuilding an engine you may want to measure this taper to see if a rebore is necessary or a simple hone will get you through. This taper is not designed in, nor is it beneficial in any way. Just think about it - if the 'tighter' bore at the tope of the stroke was required for proper ring compression and sealing, and was easily machinable to tolerance, why not run the same close tolerance over the entire bore for even better sealing? The answer, of course, is that is exactly what is done - precision, straight bores to close tolerances for best operation.