Great to see this progress, and much respect to you sir. I remember referring to your book back in the 80's when I was studying city and guilds motorcycle mechanics at college. I remember the term for static friction was stiction, a problem you are currently dealing with.
Stiction (STatic frICTION) would be much more of a problem with the original and is one of the prime motivations for the conversion. This has been almost eliminated with the linear rails and ball screw.
Very interesting, I might go through you channel to have a look at how hard it would be to start putting some simple power drives to my lathe. Not to grind cams but at least get some accuracy and repeatability. Probably starting with VFD for the motor to get a better range in speeds.
Here is the playlist of my lathe mods. th-cam.com/play/PLyn2snGjYlHw_e4LomNphh8KleeqPiqpz.html It includes motor upgrade, adding a ball screw and a load more. Thanks for your interest
That is a good point and I am often telling others the same thing. However, that is not a concern in this application. A global temperature change will affect the global dimensions, but even an extreme error of say 0.1 mm on diameter would not be much of a problem. My concern is a step in the surface that backlash would cause twice per cam revolution.
I'm not sure that 7 microns backlash is going to be a killer even on a cam Tony. In old money that's less than 3/10,000", which just about any machinest would chop your arm off for. It'll be interesting to see how much you can reduce that by.
For normal turning that is true and I do mention that, but for cam grinding there are two cross slide direction changes for each rotation of the cam, each in the worst areas for valve train dynamics. A 7 um step is a big deal for a performance cam. You can improve things with some careful work with abrasive strip and to be fair that error is probably less than cams from not many decades back. I still want to be as close to perfect as possible, before any enhancing work.
I know some of the cnc prgrams have a backlash adjustment in the software. I think you can eliminate some backlash using 2 ball nuts if there is room. I don't have enough experience to say how good either one work. Nice job Tony.@@MotoChassisByTonyFoale
Just stumbled upon your channel. I'm impressed by your innovations and experiments!
Thanks.
Great to see this progress, and much respect to you sir. I remember referring to your book back in the 80's when I was studying city and guilds motorcycle mechanics at college. I remember the term for static friction was stiction, a problem you are currently dealing with.
Stiction (STatic frICTION) would be much more of a problem with the original and is one of the prime motivations for the conversion. This has been almost eliminated with the linear rails and ball screw.
Very interesting, I might go through you channel to have a look at how hard it would be to start putting some simple power drives to my lathe. Not to grind cams but at least get some accuracy and repeatability. Probably starting with VFD for the motor to get a better range in speeds.
Here is the playlist of my lathe mods. th-cam.com/play/PLyn2snGjYlHw_e4LomNphh8KleeqPiqpz.html
It includes motor upgrade, adding a ball screw and a load more. Thanks for your interest
Coming along nicely Tony! Is there any way to program your CNC control to compensate for the backlash?
I could do something in software but I want to get the mechanical solutions fully explored before that.
the temp increase or decrease in the room will change the volume of your steel machine more than that!
That is a good point and I am often telling others the same thing. However, that is not a concern in this application. A global temperature change will affect the global dimensions, but even an extreme error of say 0.1 mm on diameter would not be much of a problem. My concern is a step in the surface that backlash would cause twice per cam revolution.
Still fettling Aermacchis I see. Tony,when was the last time you raced on the Isle of Man?
in the 70s.
I'm not sure that 7 microns backlash is going to be a killer even on a cam Tony. In old money that's less than 3/10,000", which just about any machinest would chop your arm off for. It'll be interesting to see how much you can reduce that by.
For normal turning that is true and I do mention that, but for cam grinding there are two cross slide direction changes for each rotation of the cam, each in the worst areas for valve train dynamics. A 7 um step is a big deal for a performance cam. You can improve things with some careful work with abrasive strip and to be fair that error is probably less than cams from not many decades back. I still want to be as close to perfect as possible, before any enhancing work.
I know some of the cnc prgrams have a backlash adjustment in the software. I think you can eliminate some backlash
using 2 ball nuts if there is room. I don't have enough experience to say how good either one work.
Nice job Tony.@@MotoChassisByTonyFoale
@@MotoChassisByTonyFoale Can't knock going for perfection, I'm looking forward to the results.
@@toddk.5873 Software adjustment in software is a possibility as well as mechanical solutions. I will wait until I see if there is a problem to solve.