[mikemill]

Reading through the many interesting exchanges on making camshafts, and wanting to get my new CNC mill to justify it's cost, I was convinced a CNC machine could generate a decent cam

Undoutably the best way to make a camshaft is with a cam grinder, but there is an old saying ' what's the point in owning a dog and barking yourself ' , so I set about writing some G code to generate a camshaft.

The princible as follows, useing a slot drill ( two fluted end mill) centre over shaft centre, that will give you a square profile, zero Z axis on OD of shaft, jog X to centre of cam and zero, also zero A axis (rotary table set verticle).

This process uses only two axis Z & A, start cutting by lowering Z onto shaft by 15 thou, and rotate A to desired degrees say 120 then -120, go back and forth to the depth that give you the base circle dia required.

Now with cutter running, A at 120 raise cutter by 10 thou and rotate A to 125
then A at 5 degree and Z at 10thou increments cut to 140 degrees, then go to 10 degee increments around to 180 degrees, and Z at 0, now rapid around to -120 and repeat.

This process gives you a series of very small flats , but all is requied is a wipe with some emery cloth and you have a very exeptible cam with slight curved flanks and nice rounded lobe. By altering Z and A increments you can get a wider or narrower lobe to give longer or shorter valve opening.

If you make the last line of code A90 and then zero A when you move along to next cam to cut, your cams will be perfectly indexed.

Try it out, now where's that dog!

Thanks

Mike

[stevehuckss396]

#1 I bevieve you have violated some rule of posting by not posting photos.

#2 That is how i made my cams only I cut everything by hand. Instead of Gcode I made a spreadsheet of the lift of lobe at what degree. Please post some photo's if possible.

[HuFlungDung]

Tighten your seatbelt for the appearance of NCcams in this thread!

You would not want to use a flat (square end) cutter, because the possibility of the cutter gouging the part where you are not paying attention, is almost a certainty. But, a ball nose tool should have adequate clearance to allow this. Depending on what cadcam you might use, it is possible to break the contour into very small fractions of a degree and take many many increments to end up with something that is decently smoothed. Its still not likely to be smooth enough to race with, I would not say that, but it might be a good exercise for you.

[mikemill]

Hi Steve
That was my point, to make full use of these wonderfull machines, will post pics soon

Your cylinder head looks interesting, also large, could you post more info on it, looks like an Offy.

Thanks

Mike

[John S.]

Mike,
You also need to make a move in X at each cut otherwise you will not get a flat cam due to the radius of the cutter unless you are using something very large diameter on a narrow cam.

Other than that it will work OK and clean up easily.

John S.

[NC Cams]

The advent of home affordable CNC's has made it a LOT easier to craft up previously "secretly" made parts - camshafts fall into that category.

Although 2, 3 and 4 axis machines have made the process easier, it has not eliminated nor prelaced the need for true expertise when it comes to creating and/or duplicatng profiles.

Yes, it is possible to create a cam "shape" but to literally create a cam tha will both move the valves or system and NOT wear and/or violate the laws of dynamics and physiscs is not easily done nor readily shared or conveyed.

Can a DIY cam be crafted? Yes, we did it but did so after spending a lot of time first learning how to design cams and then how to make them as iit would be done day in and day out "for real". We then essentially duplicated high volume production methods in low volume prototype tooling. We have since learned how to use unsophisticated "you can't do that" machines" to make high RPM professional quality race cams. And we do it on a onesy twosy bais LITERALLY on a custom basis for pro and /or DIY budgets - not via the "cookie cutter" off the shllf cam profiles that the name cam companies make but literally all new, custom, one off designs. This is not cheap but tailor made suits never are

This is tno to say that the cookine cutter profile is wrong or bugus - we just CUSTOM tailor easch cam profile to the specific blend of parts that the client wants/needs to use - not every guy needs or wants this but if you do, we offer the service. To do this, you can't simply "cut a cam" - you literally have to ENGINEER the whole system (cam/springs/parts/etc) from the get go. The fact that we helped a client win 12 of 16 "restrictor plate" race wins with the technique goes to show that there is a value to the process when you get to "That level" of competition.

The aftore mentioned techniques of hogging out metal will affect cam shapes. However, there is a bit more to the process and that could invllve weeks of time to develop the processs and untold experience and expertise associated with metallurgy and/or heat treating. I will not bad mouth well intended efforts spent to learn new processes or techniques. However, as this is my livelihood, you'll surely understand why we don't share EVERYTHING when it comes to 'splaining how do you do that????"

Why? Not? because we offer that servcie for a fair and reasonable price and stand behind the work we do perform. References and pricing provided via PM to serious inquiries ONLY. Training on the "how to's" offered only at a much higher price....

[John S.]

Nr NC Cams,

Wow, Sorry I didn't realise you spent that much time effort and expense on a $40 model IC engine which is what Mike and company was talking about.

[Mcgyver]

Mike, good stuff, I made cams before on a manual mill by raising and lowering the table while indexing the cam....did the math and made up a table. while technically a 'faceted' cam, the increments are so small you just about blow on it and it knocks the corners off.

NC, I wished you'd put as much effort into teaching us some the hows and whys instead of how tough it is to do and how well you can do it. us amateurs would love to get some help, insight, ideas, knowledge etc into this specialized area of which you have so much expertise, doesn't help much though just hearing about how inadequate it is what we're or how you have 1.5m cam grinder.

[mikemill]

As a relitive newcomer to the CNC world I find these forums very usefull for the exchange of ideas and help when you get stuck. But please guys lets keep it in context.

Pro engineers are one group and model engineers are another, whilst the latter can learn a lot from the the former, there is no need for the former to look down on the latter, and with a bit of inlightenment we can all learn from one another. I have been model engineering for 30+ years and have had a lot of enjoyment solveing the challenges varios projects thro up, hence attempts to make camshafts.

I have some pics of cams but can't seem to load ,when I press insert images, promp asks for a URL rather than browse. anyone know how?

Thanks

Mike

[NC Cams]

"Teaching" how to make cams is not something I do - afterall, I MAKE them for a living and rely on the proceeds to survive.

GUys like MACHINETEK (a tech by trade) frequent the board to HELP guys with this hobby - yet yet the guys who run EMI (bridgeport techn's and engineers) do NOT frequent the Zone because they actaully design and engineer the stuff as OEM's. Hence, EMI does NOT "give" away their secrets in trade EVER. I offer no more nor less with regard to my camshaft expertise..

If folks REALLY want to learn how to make cams, there are books written on the subject. Ditto that for desinging. How did I learN? Bought ALL the manuals and ALL the books and then set about LEARNING how to make cams - sometiems by hooh and sometimes by crook. And not the least of all by making some and making them WRONG and still having to make good on the parts that I was on the hook to provide in the first place.

M/S doesn't "give away" their O/S. THe guys at Mach don't do so either. Are we, as profewssional cam makers supposed to "give away" our trade secrets??? If so, tell me where as I've spent WAY too much hard work and money learning when I could have got it for free on the internet. Get real guys - doing it for a hobby is one thing, for a livelihood is a whole different level of involvement. Better yet, call Harvey Crane (creator of Crane Cams) and ask him to "show you how" to design a cam. IT simply won't happen.....

Want to learn how to make cams? Look for a manual written by Don Hubbard. It is THE BEST primer on how to make cams. Probably athe best $100 or so you'll ever spend to get started. Then go looking for some articles from the early 1950's in Machine Design that deal with "polydyne cam designs'. The article was written by Stoddard or Stoddart - can't recall. Regardless, pretty much ALL the computer based cam design programs are/were developed from this seimnal article. Once you find that areticle, start doing bibliography searches thru SAE and other references. Over time, you'll find enough to get by on and you'll have enough foundation to know what NOT to do - the rest wil come with time and effort.

ONce you understand the math concepts conveyed in the articles, cam design and manufacturing become easy. Lacking that knowledge and background, yes, it is NOT easy nor simple to convey until/unless you do know the math - at least the way we and other pros do it.

Essentially, what guys seem to want is an "easy" way to craft up a camshaft. Frankly, the OEM's have tried to do just that and haven't been able to do so. They've tried fine blankkng, casting, billeets and P?m and god knows what else. to this dday, there are still only so many ways to grind/make cams that WORK and work reliably. Even today, the Berco and other "rocking table" cam grinders (condieved in the 1950's) are "stare of the art" when it comes to grinding cams. Yes, even Norton and Landis grinders of the 56's and 6o's still make cams today. Some technologies simply DON"t change.

Want to really "learn' now to grind and make cams? take some money, buy a grinder and LEARN. That's how I did it. I literally bought a company too and LEARNED. Paid DEARLy for the learning process. Am I supposed to share all my hard learned/earned experiences on a message board??? Good opportunitity if you can find it. 10 plus years and nearly 1/4 million dollars later and I "know how".want to learn how? care to venture a gues what the coast would be???

We offer custom cam services to pro's and DIY'ers alike and offer the services in the form of finished cams. We do not offer OJT on how to cmmpete in an already competitive market. And to an earlier comment, yes we do NOT spend that much time and money crafting cams for $40 model engines - we do so for REAL engines and it costs a LOT more than the cost of the model.

[NC Cams]

Another good book is "Cams, Design, Dynamics and Accuracy" by Harold Rothbart. This book and the bibliography containted therein, should provide ANY camshaft devotee with enough seminal infomration on "how to" make and design cams.

After buying and studying these and other books, I thought I knew enough to take the plunge into camshaft making. So I bought into a company. Piece of cake. Yeah, right. Hundreds of hours later and thousands of dollars later, I know enough to get by on. We can make cams that work and live. We do so with pride and verve.

Clients want miracles. Racers want the stfuff for free. The employees think that money grows on trees. IC engine enthusiasts hope that we'll explain how to make these not so easty to make jewels "for free". If the business were more altruistic in nature, perhaps but not in this life time....Besides, if it were easy to do, there would be far more people than there are making cams and people are NOT really llning up to carry on what some consider to be a diminisihing need for the process.

[stevehuckss396]

Hi Steve
That was my point, to make full use of these wonderfull machines, will post pics soon

Your cylinder head looks interesting, also large, could you post more info on it, looks like an Offy.

Thanks

Mike

Close, It's a Bugatti. 1933 vintage. It's 90% done with only 25% to go!

It is 1/4 scale so that makes the head 8.25 inches long. Came out to 5 cubic inch. The cam lobes were scaled down from a 330 Oldsmobile cam. .075 lift.

[NC Cams]

Note to MCGYVER re 1.5cm cam grinder:

I don't have one but there are plans published and readily available for one - there is/was a feature article in Home Shop Machinist not long ago wherein a guy MADE a bench top cam grinder for grinding model cam engines. Essentially, it is a scaled down version of a "real" rocking table cam grinder. Depending on the integrity of the profile that is concieved/designed, it would/should grind a pretty good cam - it is doing pretty much EXACTLY what our "real" grinder does albeit on a much smaller scale.

The real "secret" to grinding cams is found in how well and how accurately one generates the valve inducing motion shape. Yes, a "faceted" cam is readily makeable - we did that. When you figure out how to remove the facets so the thing does not sound like a machine gun while its running, you've LEARNED part of the secret to making a cam. As in "generate a SMOOTH, continuous shape WITHOUT steps and or faets - after all, "all you have to do is remove the facets". Really???.

Anyone who's developed a stepper based drive and who can make a smooth continuous curve should be able to do it - as in remove the facets. How we do it is/was based on the machines we used and developed our processess to work with (all servos). It was NOT easy. It took custom G and M code writing and we literatlly pay a royalty for each and every profile we cut with the software - and gladly we do so. IT was a piece of "you can't do that software" that a guy did "for grins". He grinned as much as we did when the damn program did what "experts" said could not be done.

Our cam business is essentially a boutique business that pays the bills - we have fun and we make parts. We do it for the fun of it as much as for the profit but, mostly, I do it because I wanted to learn how and I set about to do it. And did it under some prettty stressful circumstances at times and literally paid for it with my "real career" - I used to work in the auto industry until my side business became my prime goal rather than a 9 to 5 paycheck.

There are days when we'd all like to do something else. There are days when you can do NOTHING finer. When you send a cam to a client and you KNOW it is/was YOUR cam that helped them do what they did with their car, there is a sense of pride and accomplishement that is literally priceless. That sort of process hard to instill in an employee but those in whom the trust is placed and takes hold, have a similar sense of pride and accomplishment. They are and become as much of the process as any part of the operation - in fact, without them, the whole deal would fold.

Learning how to cut/make cams is just like any other technical effort. There is a well documented science behind it that has been highly published - specific references cited previously and in other postings I've made on the Zone. The question is not one of "will this guy tell us what to do" but rather how much research is a person willing to do to learn from the REAL experts exactly how to do it???

The only reason I know what I know is becasue I took the time to learn from the REAL experts who were brilliant and kind enough to write their papers and publish them so many years ago. The laws of physics and dynamics don't change - hence, the "ancient" papers are as relevant today as they ever were.

You'd be amazed at where the words "polydyne" and "Stoddard" when simultaneously Googled will take you.....

for example: http://www.audietech.com/Newsletter/CAMBiblio.htm

When you take the time to study the above bibliography, you too can take on the mantle of self proclaimed expert - every cam designer I know has or at least claims that as a level of expertise at some point in their career - and if they have made or designed a cam that works, they deserve the title....

[mikemill]

Hi Steve
Your Bugatti is a fine piece of work, did you scale and draw the parts yourself? I am interested as I am attempting to design a scale DOHC V8, hence the cam tests.

The Royal Collage of Art in London had a Bugatti exhibition about 1978, on one weekend 40 Bugatti's from a Royall to type 57 and many other examples were on display, most with engines on show, deffining good engineering as art.

Re the pics could you let me know how to load them as in my last post.

A word to NC Cams, if those with little knowledge did not attempt to learn how, without the arrogance and destain of the knowledgable it would be poor world. All your ranting and complaing ads nothing to the enlightenment and pleasure to those who paticipate in this forum,

Thanks

Mike

[stevehuckss396]

Hi Steve

1 - Did you scale and draw the parts yourself? I am interested as I am attempting to design a scale DOHC V8, hence the cam tests.


2 - Re the pics could you let me know how to load them as in my last post.

3 - A word to NC Cams, if those with little knowledge did not attempt to learn how, without the arrogance and destain of the knowledgable it would be poor world. All your ranting and complaing ads nothing to the enlightenment and pleasure to those who paticipate in this forum,

Thanks

Mike

1 - Yes I drew up the plans myself based on some photos and a 1/8 scale Pocher model.

2 - If you don't mind giving me your E-mail address, I will send some mail's with an explaination and some screen shots. This is not the place but i will help you elsewhere.

3 - Sometimes it's hard to ignore those who like to tell you they can and you cant. Try to ignore those who wont help and focus on those who want to help. That is after all why we are here.

[mikemill]

Steve
email : michaelpalmer[at]tiscali.co.uk

Thanks

Mike

[Mcgyver]

Note to MCGYVER re 1.5cm cam grinder:

...

I meant the $1.5 million dollar cam grinder reference as per the other recent diy cam making thread

http://www.cnczone.com/forums/showthread.php?t=30633

[mikemill]

Further to origional post here are pics of first test cuts

Thanks

Mike

[NC Cams]

O,K. So you want to learn how to design and grind cams??? Here's how.

First it helps to understand HOW the profiles are developed. Being of an engineering background and discipline, I was able to take advantage of the math as put forth in the Machine Design articles written by Stoddard and Engemann back in 1953. The articles outlined the "polydyne" concept wherein by polynomials and dynamanics were combined to create a profile. The basic math needed to do tool paths, figure out forces and pretty much EVERTYTHING else was developed in the Stoddard articles. The articles are the foundation for most if not ALL of the computer programs EVER written for doing cams.

Too much math for you???. Spend your own money and buy canned design programs from Andrews Products.

ONce you spend you hard earned $$$ (the Andrews stuff ain't free) and get your fill of that process, get hold of the Don Hubbard manual (see prior bibilography). Don is now retired and lives in Florida. The manual is/was about $125 and worth 1000 times that in "how to" as far aa camshaft making goes. Too cheap to buy the manual??? Figure it out yourself for a lot more.

Profile creation is somewhat intutive and or hack and slash unless you have a math/dynamics background. If you have one, it can be relatively easy to "figure out" as in "engineer" valve motion. Otherwise, you can simply throw stuff around which is pretty much what the pioneers did and some guys still do today as they hunt and peck their way into camshaft history/oblivion.

Too bad you can't buy Cam Doctor's anymore but you can buy Ezcams - only about $20,000 per copy- a mandatory option when it comes to measuring/inspecting cams. These devices are to camshaft makers as "flow benches" and milling machines are/were to head porters. I bought one of these too as I was figuring out how to make cams. Some of the best money I ever spent on the process. BTW we offer the inspection service if you want your cam precisely measured and don't have the cash to buy your own device.

The 'rules" behind cam design are pretty simple. Hit stuff as hard as you can and don't break it. Make cams big in lift and duration for high RPM power and short in duration and high in lift for low RPM torque. Use low lift to reduce stress and high lift to get high flow areas and high power. The fact the the goals are mutually exclusive tends to complicate things but that's the fun part you get to work out. If you can measure other folks cams (buy or make an Ezcam), it really helps the learning process as in "seeing" what other guys do/get away with on/with their cams.

Everything inbetween is a lot of PERSONAL work and study. It is also EXPENSIVE when/if you are NOT adept at writing your own software code and/or computer programs. Frankly, if you don't know or learn the math, why bother???? It is also a bit tougher if you do not have a good math or science background. Why? because the science of cam design is just that - a science that is math and dynamics based. Without a basic understanding of it, it is like expecting your dog to type. Sort of like playing with electronincs and not knowing Ohms law....

The guys who I learned cam stuff from told me NOTHING. I had to hunt, peck and look for it in archives and manuals BEFORE the internet existed. I also had to BUY a lot of EXPENSIVE stuff to get/learn it. THis included trips to libraries, universities and basements of some pretty seedy places. Why? To figure out/learn the "secrets" of cams.

Eventually, I stumbled across a 'holy grail'. I found a guy willing to SELL me programs that would do most of the math. I eventually got him to customize some of the programs for me. These programs are still in proprietary use today - these and others that we PAID to have written and PAY regular royalties to continue their use. Aftyer all, this is my business - it is NOT my hobby. What more do you want me to convey in the way of a "how to"???? Perhaps leave the front door open to the shop after I draw you a map to the front door???? Get real guys....

Today, you can go to the internet, google "polydyne cam design" and get nearly 5 years worth of the research that I slaved thru and get it while sitting at your PC in your underwear. Nice work if you can get it. What are you waiting for???

The rest of the work - as in how to mill and machine and heat treat - I literally BOUGHT a company and PAID to learn that part of the process. I don't see anybody from Bridgeport Machines or Haas GIVING away the sourcre code to their trade secrets, do you? Should I as a cam arttisan do likewise? Perhaps when Bill Gates makes his source codes public but don't hold your breadth.

I've published the Hubbard bibliography in an earlier post. The amount of source info in this bibliography dwarfs any, no ALL of the info that I ever located in the years of searching for cam design and mfg technology. If you go to/thru the trouble to secure the articles listed in the bibliography - exactly what I did to learn the process - you too can acquire the expertise and do so in a lot less time and with less toil than I spent.

With this posting, I've showed EVERYONE where to find the info and in EXACTLY the same places I looked/learned so many years ago.

YCDBBSOYA (you can't do better by sitting you your asses) so get going and start looking for the "expertise". I've showed you WHERE and HOW to learn, now it is up to YOU if you REALLY want to GOYA and Learn. If you want PERSONAL training, that too can be arranged but at a much higher price. PM me only if seriously interested.

It is hardly a "rant" when you show people where to find info on "how to" find the answer but a good rant does not necessitate that the ranter drag someone to the answer and then rub their noses into it although that may be easier to affect. I hope that the camshaft devoltee who take the time to READ and absorb this will read between the lines - there is a LOT of VALUABLE information contained in this rant.....

[NC Cams]

MIKEMILL's efforts as pictured clearly shows that he knows what's going on. Even the profile looks like a "real" cam lobe one as opposed to a kluged up shape...

From the shapes that he's made, it appears that he's got the basics well in hand. Clearly not the effort of an inept person, rather quite the contrary.

Goes to show that you don't have to be taken by the hand and escorted to/thru the process, not in todays world with internet access to the WORLD of information.