small camshaft

[awake]

Best forget CNC shops. As paid jobs, I don't know what shop rates are nowadays, but expect to pay 75- £80 setting time before they pick up another spanner. I dropped off a job once as a "favour" job. I picked the piece up again two years later, still with the busted 10 BA tap in it. Companies seem fascinated by miniature engineering, but making a living always comes first!

Road to hell, etc.

Yep. I'd say the shops CAN make it, but just don't WANT to - not for the price that a one-off hobby user would need. Easier for them just to say "No."

 

[sarel]

http://www.floridaame.org/Plans/HHM1/HHM1-Complete Engine Model.pdf
on page 11 of the drawings it explains a way of machining a cam.

 

[timo_gross]

@Jasonb: I "grabbed" (I am a hoarder) a copy of the xls file, (it seems to work fine with Libre Office too).

Thank you.

I had one more look at drawing and I think a quick and dirty approach would be ....

p.s. can a standard CNC lathe do this kind of work?

cut few contours stacked on top of each other with a T-slot cutter.

But of course that does not allow for a complete cam shaft, but only the 15 mm high cam parts. But I saw the drawing does not "insist" of a one piece part.
80/127 inch stock would be sufficient.

What happens to a reamed hole during hardening?
How are the cam lobes fixed to the 7mm shaft?

Greetings Timo

 

[timo_gross]

http://www.floridaame.org/Plans/HHM1/HHM1-Complete Engine Model.pdf
on page 11 of the drawings it explains a way of machining a cam.

Another free download for the hoarder? Do I understand correct that this is a "free gift", means can be used to make an engine?

Greetings Timo

 

[sarel]

Hit and Miss model engine
it is stated in the link at you can use for free, not sell, copyright maintained, etc.

 

[Jasonb]

Timo, yes you could do it like that on a CNC or manual mill using the tee slot or woodruff cutter to clear the upper lobe. Much like this method using a boring head where the protruding toolbit gives clearance.

Could probably be done on a cnc lathe moving the tool in an dout as the work rotates but could not rotate that fast as tool could not keep up., better if you have live tooling or easy on a CNC mill with 4th axis.

 

[sarel]

It is also possible to do with an end mill if the camshaft is set horizontally in dividing head or rotary table.

 

[timo_gross]

It is also possible to do with an end mill if the camshaft is set horizontally in dividing head or rotary table.

The horizontal setup has the advantage that this is a "standard set up" and getting the G-code out of the software for this contour is very beginner level, so even I can do it.
Putting a manual dividing head into the CNC defeats the purpose a litte . (just a little, not totally, there are occasions were it makes sense).

Greetings Timo

 

[anday1]

thanks jason
the cam draw is just what i needed... i will show my progress. the cam case has been more challenging than i thought it looked simple on the drawing...but 3rd attempt and i'm there
many thanks

 

[kf2qd]

A grinding setup, with a master cam - only needs to be one lobe, with the necesary hardware to time it. The cam munted horizontally in a vertical fixture that pivots at the base, so it acts like a pantograph witht he master cam having a larger movement than the camshaft. The master cam and the camshaft driven together by a timing belt/chain. as the master cam rotates it rests against an adjustable stop so as it rotates the upright frame holding the camshaft and master cam move toward and away from the grinding wheel.

 

[Jasonb]

But you still have to make the master which would need doing in one of the ways suggested and you would really want to at least rough out the cam blanks to a thou or two over before grinding, again needs doing with the mill.

The main advantage of grinding or the CNC is there is no hand finishing to blend the facets left my milling at intervals of a few degrees.

Milling the profile with the cam laid flat only works for one or two lobes before you get too muck sticking up and flexing so not what you want for say 8 lobes as a single camshaft. Since I got the CNC the last two engines that needed this type of cam were done that way with the individual lobes Loctited to a shaft

 

[Vietti]

I copied what others have done and adapted a Van Norman piston grinding machine into a cam grinder. It takes some effort and probably there are better, easier options but it works and these machines are pretty common and cheap as the old auto machine shops disappear. They also make a good cylindrical grinder and can be used to make model crank shafts.

 

[D and D]

I grind mine the master is made by hand.

 

[anday1]

Cam shaft made with help from jason and appreciate all your help and comments