been busy during lockdown mini cam grinder in process

[the engineer]

hi there trying to keep busy during our lockdown had this in mind for a couple of years
 had it built in my  mind  but never had the courage to put it down on paper or cut metal to make a start so i have progress to show
 still have to key slot or flat the length of the master cam shaft
and also make the mastercam and stylus for  grinder unit
dc motor drive so i can easily do reverse rotation if required still a long way to go ie degree wheel etc  but in the mean time 4 cyl cam  can be made just by two cross drillings in the drive spiggot and use a mastercam with two lobes with the desired degree split
grinder is a chainsaw sharpener  taken off its pedestal and will be fitted with a wider profile wheel
non drive side is left so as to be adjustable  if need be for a longer cam

[awake]

 

I look forward to seeing how this develops!

[Don1966]

I am interested I will following along also!



Don

[the engineer]

sorry if this is in the wrong area moderators please feel free to put into the correct category
regards john

[nj111]

Interesting and very worthwhile project. I made one some years ago and initially went down the route of a sliding table for the motion - that gave a bump on the top of the cam as it changed direction even though it was made well and with IGUS ptfe linear slides, I couldn't get rid of the bump.  So I changed it to a hinged action like I think you have there and that totally solved the issue. The other mistake I made was to use an air motor to rotate the cam being ground, (with massive epicyclic reduction) - just because I had one to hand, the thought being I'd have smooth and infinite speed control through a regulator, without buying a DC motor. Well that appeared to give a very smooth rotation by eye but having ground a cam profile it was clear that it was a very pulsed rotation, so I changed it to DC motor - running around 30 rpm and that is perfect. Works best removing a thou (0.001") per rev. Enjoy the project and keep us updated!

[the engineer]

thanks for the thoughts  and encouragement  certainly helps dc motor is geared to 9 rpm  or ma be 14  not sure now had it for too long to remember  this is the reason for the build

[nj111]

They look like exceptionally nice castings - where are they from?

[the engineer]

 i bought them off ebay from a guy in the uk  but originally they came from profi in the ucraine i tried them to get the specs for machining several times  but to no avail
 so eventually  sat down with the full size specs and scaled down to fit what i had i have made the crank and rods and cylinder  liners
also made a cam with individual cams but were not happy with the result but yes they are beautiful castings
 i am tempted once its up and running to try and make an ardun or similer  overhead valve conversion head for it

[the engineer]

fruits of my labor  made all the extra bits and made the machine more rigid as i felt it was too lightly built
made my first cam lobe then experimented with different master cam profiles to achieve the profile i wanted
i ended up using a plastic cam lobe from a late briggs and stratton engine to re profile a smaller  cast iron pair from an early series 3 hp engine
busy machining my first full camshaft doing number three  exhaust lobe and i realised i had not used the firing order needed 1243 ( ford ) 1234 wont work rectified my mistake and carried on i may be able to weld and re grind just that one lobe as all shafts have a register for re visiting  any operation
no  need for a degree wheel as the master shaft has 4 flats  for 4 cyl  or six for six cyl just slide in to what you want and lock the grub screw do two lobes inlet and exhaust per that cylinder then rotate to the next flat  and do the next set of lobes  and so on until finished
overall very happy with what is achieved

[Roger B]

Those are some very nice castings 

Looks like youve got the cam grinder sorted    That's something I must make one day 

[nj111]

That's all looking great. What a useful little cam grinder you have devised!

[the engineer]

thanks  folks  yep i should have put my fears aside and built it when i had the idea long ago  i had been looking at them on model sites and google but they were all so complex
and on talking with my like minded workmates  we all said think like the old folks and how they did things with minimal  machinery but with desired outcome
one of my workmates favorite saying is  success rarely comes  without failure first
 my first attempt at individual cams on the lathe now when you see the  finished product was dismal failure
so thanks for the kind words and encouragement
 and now i can replicate a sealion cam that was ruined in corrosive liquifaction in our earthquake 9 years ago