开云体育

In a message dated 05/10/2000 10:28:17 PM Hawaiian Standard Time,
fom@... writes:

<< I have tried different feed rates (slow to ultra slow) faster speeds,
light cuts, different mills, drowning it in lube--in short everything I can
think of and still get mill marks in the cuts >>

Many will tumble the part or process with a vibratory mill after machining.
This will remove sharp edges, machine marks and surface imperfections in the
original rolled surface wherever it remains. You can use ceramics, metal
shot, plastic, and many other media's to get different results.

Peter
THRD, Inc.

IF you are seeing this more then once--I'm sorry-- But I'm new and
will lear my way around

I currently have both a Sherline 5400 mill and Sherline 4400 lathe.
These have been converted to CNC by Backtrack CNC. I an trying to do
milling on Alum paintball gun bodies. this is basicly "engraving"
using a ball mill. I have tried different feed rates (slow to ultra
slow) faster speeds, light cuts, different mills, drowning it in
lube--in short everything I can think of and still get mill marks in
the cuts (whick will later be anodized and look like shit)

I've decided that the Sherline is just not ridgid enought to get good
results on this type of work (I can SEE the head delflecting at the
start of a cut)

At any rate- I'm thinking real hard of getting a Smithy. I've seen
the machies in person and they loog good to me--of course they weigh
about 10X as much as the Sherline too. I'm thinking of the Midus
with
the CNC conversion. Does anyone have any expericence or coments on
this? Thanks in advance

Craig

Walt & Craig Smith wrote:

IF you are seeing this more then once--I'm sorry-- But I'm new and
will lear my way around

I currently have both a Sherline 5400 mill and Sherline 4400 lathe.
These have been converted to CNC by Backtrack CNC. I an trying to do
milling on Alum paintball gun bodies. this is basicly "engraving"
using a ball mill. I have tried different feed rates (slow to ultra
slow) faster speeds, light cuts, different mills, drowning it in
lube--in short everything I can think of and still get mill marks in
the cuts (whick will later be anodized and look like shit)

I've decided that the Sherline is just not ridgid enought to get good
results on this type of work (I can SEE the head delflecting at the
start of a cut)

At any rate- I'm thinking real hard of getting a Smithy. I've seen
the machies in person and they loog good to me--of course they weigh
about 10X as much as the Sherline too. I'm thinking of the Midus
with
the CNC conversion. Does anyone have any expericence or coments on
this? Thanks in advance

Craig

------------------------------------------------------------------------
Double your manufacturer's warranty on all computers,
home appliances, and electronics AND win up to $500
towards your purchase!

------------------------------------------------------------------------

Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the discussion of shop built systems, for CAD, CAM, EDM, and DRO.

Addresses:
Post message: CAD_CAM_EDM_DRO@...
Subscribe: CAD_CAM_EDM_DRO-subscribe@...
Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@...
List owner: CAD_CAM_EDM_DRO-owner@..., wanliker@...
Moderator: jmelson@... [Moderator]
URL to this page:
FAQ:
bill,
List Manager

You will always get cutter marks. You have to hand pollish them out, just like in injection molds
Larry

Gentlemen,

I would have to disagree...I use a CNC'd Sherline mill to cut 400 series stainless regularly, and as long as you understand that a
mirror finish is a second operation, and that you must limit your cuts with a 3/8" end mill to ~0.035...The Sherline works
wonderfully...

Joe at Sherline told me, after I admonished him because the mill cut 400 series so well when his ads and other info implied
otherwise (with the understanding that small cuts have to be taken), he said, and I am summarizing...That as soon as he says
stainless, people treat these small machines as if they were Bridgeports or whatever, and are then unhappy with the results...so he
will talk with those who understand that a little machine means little cuts in tough materials.

Slow and easy...and if you don't have the coupla books offered at the Sherline site, you should have them. It may be that the
Sherline isn't enough machine for what you are doing. I know, from talking with Joe, that he always undersells his machines
abilities. Then people are not disappointed.

You have a fine miniature mill and lathe...the question is, was it the right choice for what you are doing...if not, let people know
what you have on eBay, and much of the money you have spent...sorry about that...will fade into the background:

Ciao,

Craign

At 08:27 AM 5/11/00 -0000, you wrote:

At any rate- I'm thinking real hard of getting a Smithy. I've seen
the machies in person and they loog good to me--of course they weigh
about 10X as much as the Sherline too. I'm thinking of the Midus
with
the CNC conversion. Does anyone have any expericence or coments on
this? Thanks in advance

Craig

I purchased the base Midas about 6 months ago with the intentions
of maintaining manual operation with the addition of hanging some
surplus steppers on it and writing my own software for CNC.

Here's my impressions so far...

All three axis have *lots* of backlash (on the order of ~.040)
making it IMHO, unsuitable for an open loop system using steppers
only. I've worked out some of the backlash but ball screws will be
required on the X and Y axis if I pursue my original intentions of
stepper motors. The Z axis is worm screw driven so of course the
ball-screw option is out. Most of the backlash here can be corrected
by removing the front "drill press" manual levers, removing the
useless dial cover and attacking the manual engaging device with
a MIG welder. You lose the manual drill press option and it's rather
crude, but it eliminates the majority of the backlash problem. I
also removed the Z axis takeup spring and extended the smaller side
hand crank to give me more leverage. This retains manual operation.

I removed the front facing X axis fast crank assembly, as again IMHO,
it's useless for actual work - way to much movement from hand crank
to table motion to suit me. As the lathe is configured "out of the
box", the addition of a motor to the X-axis disables the ability to
use the lathe manually. So, I modified the end of the X-axis to take
both the CNC gear and an extended handle. Hey, what can I say, I
like leverage.

Most of the Y axis backlash was found to be in the slop of the cheezy
nut the screw rides in. I split the nut with a bandsaw and squeezed
it together taking up most of the backlash.

Overall quality is ok for Chinese I guess, of course; 'ya gits what
ya pay fer'. Since I use the lathe for semi-production of aluminum and
plastic work, it's ok and I have no real regrets.

---------------------------------------------------------------------

Here's something the rest of the group might me interested in...

As it stands now, I'm currently using the lathe manually as I've
become disillusioned with adding steppers to this lathe. My biggest
complaint besides the backlash, is the nuisance of being able to feel
the stepper motor while using the lathe manually. My intentions are
now to remove the steppers and replace them with reversible DC
gearhead motors that are somewhere in the neighborhood of 100 rpm.
From there I plan to manually control all movement of the lathe
electrically via a pendant. With the future addition of a computer
readable DRO and an interface to the pendant I'll have a closed
loop system. Ultimately I'll be able to use the lathe manually for
most of the work but allow the computer to control such tasks as
radius turning, tapers and the like.

Later -

O-Tay (tm)
-----------------------------------------------------------------
Mark A. Taylor (U$UA 15484)

Walt & Craig Smith wrote:

this is basicly "engraving" using a ball mill. I have tried
different feed rates (slow to ultra slow) faster speeds, light cuts,
different mills, drowning it in lube--in short everything I can think
of and still get mill marks in the cuts (whick will later be anodized
and look like shit)

Ball end mills will not leave the best finish even in a Bridgeport if
the depth of cut is too great. Has a lot to do with the clearances and
the fact that the center of the cutter is at virtually zero surface
speed. Try recutting your engraving with a finish pass a couple thou
deeper and see if it doesn't improve. I've heard of some folks engraving
with a center drill, might give that a try also.

Jon

--- In CAD_CAM_EDM_DRO@..., "Walt & Craig Smith" <fom@m...>
wrote:

IF you are seeing this more then once--I'm sorry-- But I'm new and
will lear my way around

I currently have both a Sherline 5400 mill and Sherline 4400

lathe.

These have been converted to CNC by Backtrack CNC. I an trying to

do

milling on Alum paintball gun bodies. this is basicly "engraving"
using a ball mill. I have tried different feed rates (slow to

ultra

slow) faster speeds, light cuts, different mills, drowning it in
lube--in short everything I can think of and still get mill marks

in

the cuts (whick will later be anodized and look like shit)

I've decided that the Sherline is just not ridgid enought to get

good

results on this type of work (I can SEE the head delflecting at the
start of a cut)

At any rate- I'm thinking real hard of getting a Smithy. I've seen
the machies in person and they loog good to me--of course they

weigh

about 10X as much as the Sherline too. I'm thinking of the Midus
with
the CNC conversion. Does anyone have any expericence or coments on
this? Thanks in advance

Craig

machining aluminum parts on sherline cnc requires a finish pass of
about 0.010" deep.You will get mill marks no matter what kind of tool
you use.I'm working with a KIA industrial machine center(the size of
a compact car)we machine small 6061 aluminum parts 8 at the time,and
when they get out of the machine it looks like shit,burrs,and mill
marks,(but not steps) after this they send it to the deburring and
tumbler and still you can see the mill marks.
if you are doing 3d engreving than the z axis on sherline mill is
not very good for it(backlash).
backlash is a pain!
One possible solution is to have the parts being soaked in a acid
solution prior to be anodized,this way the acid would eat some of the
aluminum.