Cam Grinding

[bruce]

[color=#000000]A little brain storming here . . . I purchased a machine a few years ago (old Van Norman piston grinding machine) that I have been planning on turning into a camshaft grinding machine for my small engines. This project has sat for WAY to many years with nothing going on with it. I would like to get this project up and running or at least work on it as I have time.

I want to be able to take my masters and use them for various lobe centerlines so one master would be able to grind various combinations of lobe separations. I'm trying to come up with a way to index my cam blanks to the pattern. Pattern is on one end of the arbor and the blank is on the grinding end. I'm thinking a simple index plate with holes so I can move my blank in relation to the pattern either +/- degrees from 0 (0 being vertical). I think I have a good idea but wanted to see if anyone else might have some input or ideas. Would I need 1/2

[106-1194218389]

[color=#000000]If it was me I would love to see the ability to move it just 1/2

[Tony]

Bruce, I have seen small rotary tables advertised on e-bay. Some of these are quite small, probably intended for model making applications. These should be readily settable to some fraction of a degree and then lockable.

If the whole rotary table could be bolted solidly to your arbor, and your cam blank attached to a fixture bolted to the top of the rotary table, you could then index the full 360 degrees.

These small rotary tables could be junk, I do not know, never seen one this small. But a well constructed one may be up to the job. This particular example is 36:1 and three inches in diameter, and it appears to have 0.1 degree graduations.

[bruce]

Let me post a few pics of my machine:

This one shows the head and grinding wheel end. I machined a new head spindle with a 5C taper so I can use this machine as a cylindrical grinder also. So any tooling I machine up to fit the grinder needs to be 5C taper.

[bruce]

Next picture shows the pattern end of the spindle

[bruce]

Over all grinding area, tailstock spindle is removed right now. Trying to find a live center to fit the taper.

[bruce]

This would be a basic camshaft, most of my cams will have the gear removed and a flat surface in it's place. The gear is indexable on those cam blanks. Note this cam was my old camshaft but the exhaust lobe got "wiped out" as can be seen in the picture.

The hole on the top above the lobes is the lobe reference hole. It sits in the center of the lobe profiles.

[bruce]

Backside of the cam for reference

[bruce]

I'd also like to add this project is a "not for profit" venture and will be used for mostly my own and maybe a friend or two's cams. But really more for a "gee I can actually do it" project and be able to say . . . I do run my own cams!



Edited By bruce on 1205620058

[Tony]

Not a lot of room in there to work with Bruce !

Only other idea I can think of right now would be a pair of round flanges drilled with different numbers of holes. Say one with sixty holes and the other with sixty one holes. The two flanges could be locked together in rotation with an easily moved dowel pin. This would give phasing increments of 360 / 60 x 61 = 0.098 degrees (roughly 0.1 degree theoretical steps).

Something a bit more crude with say a sixty, and a sixty one tooth sprocket and an external screw down locking bar to lock these sprockets together directly across the roots of two adjacent teeth maybe ? Sounds a bit primitive, but properly constructed it should be entirely practical.

[bruce]

Yep room is a problem, I was thinking a sector of about 180 degrees, drilling sets of holes every 1/2 degree over that sector even degrees at one distance from center say 3" odd degrees at 2.75" and 1/2 degrees at 2.5" mark off a scale for quick reference and use a pin to lock in the holes. The cam fixture would be fixed to a plate that rotates on the indexing plate with the locking pin. This would allow me to have different cam fixtures for different blanks and still use the same indexing fixture.

Typing this out in brainstorm fashion for input gave me some ideas . . .

I'm not building NASCAR or F1 engines here so it's pretty much "redneck" engineering, I've known guys who have taken cams to a bench grinder and run them all season!!

[Tony]

The "swiss cheese" solution would certainly work.

Provided you have reasonably easy to read degree wheels at each end on this machine, knowing where you are within half a degree should not be a problem. Adjusting the phasing, then only requires something to move the master blank around. That could just be some threaded stops you can adjust and then lock.

[49-1183904562]

Bruce;

I think Tony is dead on with the Phasing (patern to blank), it should not be hard to set your patern location but doing it twice the same way against a blank could be tough.

Rick

[bruce]

[color=#000000]I think with my setup that holding 1/2

[106-1194218389]

I don't know how your flathead is setup, but most cams also have some taper on the lobes and the bottom of the lifters convex so the lifters will spin when running. That is so the cam and lifters don't get wiped out. I used to have an automotive machine shop and the guy in the shop next to me had a cam grinding shop. Very interesting operation.

John