Post by vinnyPost by vinnyPost by StarDustYou can't hold .0001" on a mill, no way! Mills not made for that.
Even on a grinder that close tolerance pushing it.
But I'm not going stop you, keep on dreaming!
Is this a troll or a lagit disagreement?
Id love to go into how to hold tenths on a mill, or any other machine.
Cnc mills are made to repeat within a tenth, thats all that is needed.
The heat, bearing heat, cutters, holders, and process are what needs
extremed out.
Of course im not talking about a bridgeport. However, ive bored holes in
weldments with positional accuracy of 2 tenths with an enco mill. Not
productive, but it can be pulled off.
On a 6x9 surface grinder in an air conditioned shop one tenth can be hit
all day long. 100% of the time.
grow or shrink per degree? You can hold the same with any Bridgeport
if you use a boring head. Better if you use a jig borer.
the temperature is one of the variables you need to manage.
its not the temp that matters, its maintaining that temp in the
spindle...its maintaining the ambient temp, as in dont point the ac vent
at your machine.
Manage the time between spindle stops so its constant as possible.
Stuff that seems common sence to me, except when doing the tenths thing
eveything matters right down to fat people walking up to your machine
while picking up.
Its extreme, but thats how a tenth is held.
Just like the bridgeport...I agree, using a boring head is extremely
accurate, but it needs taken to the next level.
If you have to bore 2 holes with location to each other, dont turn the
spindle off between holes, dont touch the locks, etc....
The machines repeat, and thats how tenths are held, using that repeating
to your benefit. The process needs to cater to the fact that
repeatability is the only thing the machine is doing for you, use
it...change your process to allow it to repeat, zero in on whats
important, is it size, location, spread location, etc...then do what
toolmakers do...make it happen.
If a machine doesnt repeat in a vacuum with no external forces applied,
its broke.
Nice post. I can agree with everything you had to offer. Now if you