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METAL LATHE SMOKE, RPM LOSS, NEW LATHE MOTOR?

Hi MM, Guys,

I don't know if "Lidl" have shops in your part of the world, but they have 1000 grit flat carborundum stones here. Actually they are dual sided one side is 1000 grit and the other is 800 grit, they also have 600 / 400 grit stones as well. Both stones have a very neat knife sharpening tool inside the box as well. At about $12 Canadian, I think that they are quite good value.
 
MooseMeat said:
it was .0005/ish out on the lathe as with the mill, figured the lathe validated the mill, 😉 should I be happy, I'm thinking so, what should I be aiming for for accuracy.
Click to expand...

You are a hard guy to follow sometimes. Just when I think you are lost, you jump out of the bushes in front of me.

The question is: have you measured both sides of the disk simultaneously to determine if the runout is common to both sides?

Basically, what I'm getting at is that everything is rubber. How do you know that your lathe mounting system isn't warping the disk. Tenths is tiny and almost totally predictable. But I think your measurement is still more than I expected for a new disc. A brake disk is one of those rare automotive parts that reach well into the realm of precision parts.

The required precision is also why nobody recuts rotors anymore. Instead you pitch them and buy new ones. The new ones are not cut, they are ground. Typically to a few tenths.

Having said that, my experience is with domestic stuff. Who knows, maybe a few of the offshore folks have figured out how to make brake disks with more runout that don't shake, throb, or vibrate.

MooseMeat said:
I'd invite you over for beers and some shop talk, maybe good Scotch is your thing, I'm easy as stated by my wife......
Click to expand...

I'm a cheap date. Ice water, juice, pop, and morning coffee with cream is my thing.

So let's get practical. What you are getting is a totally reasonable number. Don't forget that it's over 8 or 9 inches (or whatever your sweep is). Unless you are squaring up big parts, you won't even notice the impact. Even so, your machine is gunna move as you apply forces to the cutter. Experience will teach you what your machine's practical performance limits are.

Whatever they are, will be what they are. You will need a decent surface grinder to do much better.

It might also be time to mention that you might get better finishes going in one direction or another. The cutter rotates in a circle. If the trailing edge is cutting too, it will often leave a mess behind. This especially true for large face mills and fly cutters.
 
Susquatch said:
You are a hard guy to follow sometimes. Just when I think you are lost, you jump out of the bushes in front of me.

The question is: have you measured both sides of the disk simultaneously to determine if the runout is common to both sides?

Basically, what I'm getting at is that everything is rubber. How do you know that your lathe mounting system isn't warping the disk. Tenths is tiny and almost totally predictable. But I think your measurement is still more than I expected for a new disc. A brake disk is one of those rare automotive parts that reach well into the realm of precision parts.

The required precision is also why nobody recuts rotors anymore. Instead you pitch them and buy new ones. The new ones are not cut, they are ground. Typically to a few tenths.

Having said that, my experience is with domestic stuff. Who knows, maybe a few of the offshore folks have figured out how to make brake disks with more runout that don't shake, throb, or vibrate.



I'm a cheap date. Ice water, juice, pop, and morning coffee with cream is my thing.

So let's get practical. What you are getting is a totally reasonable number. Don't forget that it's over 8 or 9 inches (or whatever your sweep is). Unless you are squaring up big parts, you won't even notice the impact. Even so, your machine is gunna move as you apply forces to the cutter. Experience will teach you what your machine's practical performance limits are.

Whatever they are, will be what they are. You will need a decent surface grinder to do much better.

It might also be time to mention that you might get better finishes going in one direction or another. The cutter rotates in a circle. If the trailing edge is cutting too, it will often leave a mess behind. This especially true for large face mills and fly cutters.
Click to expand...

Sasquatch, "You are a hard guy to follow sometimes. Just when I think you are lost, you jump out of the bushes in front of me".
😉

I am trying to process all the information here at once, so a persons thought procedure has to jump all over the place. So now the mill is somewhat accurate I'm gonna weld everything in place........
 
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