I recently purchased a vertical milling machine.

My problem is that I am having trouble with

1.setting the origin

I set the vice parallel to the mill table using a dial gauge, then I
attach an angle bracket to the table at one end of the vice to act as
a stop. This enables me to put the small plastic enclosures that I
need to mill into the vice in the same position each time.
I try to line the mill bit up with the stop for X origin but cannot
get it accurate (the cut ends up 1-2mm out). For the Y setting, I move
the mill up to the edge of the job but end up marking the job by accident.

How can I set the origin (my x=0,y=0 point) accurately.

2.calculation to make allowance for slot drill diameter.

I am using a 6mm End slot mill bit. When I make a test cut by moving
the table 10mm and then measure the cut length, I find that the amount
of cut taken up by the drill is only 4.75mm and not 6mm. (I drill down
to start the cut (this should have put a 6mm hole in the job), then move
10mm to the right and I should have the 10mm moved + 6mm drill diameter?)

I know about the backlash and ensure when I change direction that I
re-zero the dial reading to take out the backlash.

Currently I measuring cuts with the dials on the handles manually (which
is very tedious and easy for mistakes), but have ordered some digital
scales that should make life easier.

Thanks for any help to get me started.

PS. Is there a web site someone knows of that would show the various
allowances that need to be made when making cuts etc. I have purchased a
book but it does not mention those details.

David wrote:
I recently purchased a vertical milling machine.

Congratulations!

My problem is that I am having trouble with

1.setting the origin

I set the vice parallel to the mill table using a dial gauge, then I
attach an angle bracket to the table at one end of the vice to act as
a stop. This enables me to put the small plastic enclosures that I
need to mill into the vice in the same position each time.
I try to line the mill bit up with the stop for X origin but cannot
get it accurate (the cut ends up 1-2mm out). For the Y setting, I move
the mill up to the edge of the job but end up marking the job by accident.

How can I set the origin (my x=0,y=0 point) accurately.

There are things called edge finders that work well for this. They have
a shank that you chuck into your mill instead of a cutting tool and an
end that can be displaced from center. You set the mill up to run slowly
and sneak up on the edge of your part with the tip of the edge finder
slightly displaced from center. As you approach the part, the flat on
the tip of the edge finder will touch the part once per revolution, and
more importantly, move a little bit closer to centered. As you approach
the correct stopping point, the tip of the edge finder will be almost
perfectly centered, so it transitions from touching once per revolution
to continuous contact. At this point, the center of the quill on your
mill is offset from the edge of your part in this axis by the radius of
your edge finder. Zero the dial on that axis of your mill, taking the
radius into account. Now move the mill table so that you can approach
your zero line on the other axis and repeat the above process. Approach
your work in the same direction that you plan to make your cuts so that
the backlash in the leadscrews is closed. With the locating arrangement
that you have described, you should only have to zero the dials once.



2.calculation to make allowance for slot drill diameter.

I am using a 6mm End slot mill bit. When I make a test cut by moving
the table 10mm and then measure the cut length, I find that the amount
of cut taken up by the drill is only 4.75mm and not 6mm. (I drill down
to start the cut (this should have put a 6mm hole in the job), then move
10mm to the right and I should have the 10mm moved + 6mm drill diameter?)

This is probably a backlash problem mostly. Back your table up one full
turn of the handle on the axis away from where you want to start your
cut. Now return to where you want to start your cut, moving in the same
direction that you want to cut in. Stop at the point you want the cut to
begin and lower the tool into the work. Complete the cut by moving the
table the cut length - tool diameter. Raise the cutter.

I know about the backlash and ensure when I change direction that I
re-zero the dial reading to take out the backlash.

Don't re-zero your dial! Make all your dimensioned cuts in the same
direction that you zeroed the dial from originally. Otherwise, you will
spend a huge amount of time rezeroing and probably still get
disappointing results.


Currently I measuring cuts with the dials on the handles manually (which
is very tedious and easy for mistakes), but have ordered some digital
scales that should make life easier.

Thanks for any help to get me started.

PS. Is there a web site someone knows of that would show the various
allowances that need to be made when making cuts etc. I have purchased a
book but it does not mention those details.

I know about the backlash and ensure when I change direction that I
re-zero the dial reading to take out the backlash.

Explain in more detail how you do this.

A good investment would be an edge finder for $10 or so. It will get you
within a half thou.


Currently I measuring cuts with the dials on the handles manually (which
is very tedious and easy for mistakes), but have ordered some digital
scales that should make life easier.

You're not allowed to use digitals untill you master the dials.

"Tom Gardner" wrote in message
. com...


(snippage)

You're not allowed to use digitals untill you master the dials.



Well, dammit, Tom. That's a cross for this amateur to bear with an old
Burke/Millrite vertical, backlash, and high-mileage eyes. You guys are
tough on the novices here.

Garrett Fulton

" Well, dammit, Tom. That's a cross for this amateur to bear with an old
Burke/Millrite vertical, backlash, and high-mileage eyes. You guys are
tough on the novices here.

Garrett Fulton

It's like my little nephew explaining that he didn't have to learn math,
that's what calculators are for. You have "Special Dispensation" but,
didn't you believe your mother when she said: "Stop doing that or you'll go
blind!"

"Tom Gardner" wrote in message
et...

" Well, dammit, Tom. That's a cross for this amateur to bear with an old
Burke/Millrite vertical, backlash, and high-mileage eyes. You guys are
tough on the novices here.

Garrett Fulton

It's like my little nephew explaining that he didn't have to learn math,
that's what calculators are for. You have "Special Dispensation" but,
didn't you believe your mother when she said: "Stop doing that or you'll
go blind!"


I quit when I needed glasses.

Garrett

I quit when I needed glasses.

Garrett

I've seen those "Coke Bottle Bottoms" of yours.

"Tom Gardner" wrote in message
et...
I quit when I needed glasses.

Garrett

I've seen those "Coke Bottle Bottoms" of yours.


Well, shoot. Coffee all over the keyboard.

Garrett