Harbor Freight Micro Mill 47158

Has anyone tried retrofitting this amchine to CNC. I am in process
of upgrading it to ball screws for small repetitive CNC model hobby
related tasks.

I am trying to find the size of the lead screws the machine comes
with, if anyone knows this, I would also appreciate any sugestions as
to motors and a good controller, I am thinking 160oz/in motors will
be a good start, if anyone has already gone this route. Eventually I
will do it if no ones has done it yet, but I am sure someone out
there has done this already. The machine has been on the market for a
little while now, but I have not had luck finding any info on
retrofits for it so far, I just bought the machine and just starting
looking.

The 47158's base and colum are SOLID!

Initially I was considering designing my own dedicated CNC micro
machine for another of my neverending micro manufacturing tasks, or
retrofiting one of my Sherlines and machining a new xy table for it
with enough heigh top allow the intallation of 1/2" of less
expensive 5/8" ball screws.

A call to Sherline and a talk with Joe Martin convince me that it
would have been more trouble to do it with the Sherline, so this
steered me into looking for other cost effective alternatives. I
still think the Sherline has great potential to be retrofitted
inexpensively, as compared to some very expensive models out there,
even with ball screws. Something I will eventually do when I have
some free time to rethink all the redesign through carefully. Just
for the joy of it.

The price for the 47158 is perfect.Of course I am looking at how this
applies to my needs and this may not necessarily apply to everyone.
Some people may want to look into this machine if you do fun model
work, the price in my view is unbeatable and even if the machines
turns out to be a dud after use, I can still use it for simple
machining taks. The thing with me is that I always find a good use
for all types of machines. I rarely get rid of ones that fall into my
posession.

I almost bought a used DynaMyte 2400 on Ebay, so GLAD! I din't get
suckered into purchasing one of those, I was ready to pay $3000 but
figured I purchase a nice small solid base and column machine and
upgrade it the way I want to, to do exactly what I want it to do.

Besides I already have a Bridport mill too bulky for most of the
stuff I do and even the DynaMyte weight was a concern. If I can not
move it alone it becomes a mayor taks for me and something I try to
avoid. The bridgeport is an exception it can not be moved once
located and I had planned for this when I got it.

I understand that DynaMyte 2400 has similar quality lead screws to
the 47158, something I would have had to retrofit anyway on the
DynaMyte at a higer expense not counting the freight for shipping the
DynaMyte to my place and the cost of a lift to move it around my
shop.

I have several Sherlines and MaxNC converted to CNC that I use for
dedicated micro manufacturing tasks, and surprisingly these machines
when set up correctly can do some amzing stuff, some people will
disagree with me, but perhaps they don't do the type of work I do.
These machines have good rigidity but the 47158 has more mass and is
small enough (in the Sherline micro size range) with a larger solid
steel table bed perfect for miniature model work.

The 47158 xy table looks very easy to retrofit since there aren't
many set screw settings and adjustments as in the MINI Mills (next
size up) sold by the same company Harbor Freight or similar ones like
the Micro Mark mini mill, Grizzly, etc, etc.

The 47158 size is something I was lookign for but price for similar
size CNC retrofitted micro milling machines was prohibitting. I think
the 47158 has tremendous potential for CNC precision model work at a
fraction of the cost of machines that run in the thousands $$$ range.
Concider we are not talking Hass or Fadal precision but a good amount
to do model work, not NASA space shuttle parts. After all, some
higher priced micro machines are nothing more than similar mechanical
machines manufactured in China that use very similar quality
components upgraded with better lead screws or balls screws and
retrofitted for CNC.

The 47158 comes with steel backlash compensating split nuts which
appear to have good tension and antibacklash compensation, as is, and
I think will work just fine if set up properly, but for precision
micro cnc work,I think ball screws is the way to go.

I've figured by the time this machine is retrofitted to fit my
application, I will have spend a fraction of what I was willing to
spend on similar retrofitted machines. The only thing is my time for
retrofitting the machine, but I really enjoy doing retrofits and
working qwith simple machines,so long it doesn't turn out to be a
major task like retrofitting a much arger and heavier machine.

I disassembled most of the 47157 machine upon receipt, cleaned up the
protective shipping grease that the machine comes coated with and put
it back together using machine oil for lubrication. I love the ease
which the lead screws are attached to the Z column and xy table. Very
soimple. I have not removed the handwheels yet so I don't know what
type of couplers I would need but it loos like they could be 1/4"
diameter very easy to couple to ball screws I think. The XY screws
look like they are 1/2" diameter 16TPI but I am not sure, if someone
can double check this for me, I'd appreciate it.

The XY screws appear to be metric not sure on the Z axis. I have
called the distributor and they can not tell me much beyond what the
instruction booklet specs say, not much. This is the
only drawback, but I can live with that, since nowadays one can get
almost any type of information through the internet and forum like
this one.

The 47158 uses a drawbar which I think is also metric perhaps
M10x1.5? Harbor Freight sells some tool holders threaded to fit this
size drawbar and Morse Taper #2 wich is what the 47158 spindle calls
for, I saw similar ones from Enco but the they are MT2 with 3/8-16TPI
trheaded tapped ends. The tool holders Harbor Freigth sells only go
down to 3/16 tool shanks, I have to look closer at other tool
distributors like MacMaster Car, MSC, etc. to find suitable tool
holders and adapters if people don't beat me to this information.

Worst case, I will need to make adapters or find an adapter to use
with the Sherline tool holder. I have a considerarble number of tool
holders for the Sherline but not sure exactly what the threading is
on them looks to be 1" diameter, an adapter to use these Sherline
Tool holders is something I am looking for also, this way I can cross
use tool holders between the Sherline and the 47158. If anyone
knows of any retofits or adaprter with a MT2 for tool holders, please
let me know ASAP.

Overall I believe the 47158 has a solid base, it does have a drill
press lever, independent from the Z axix, but I have decided to lock
the drill press lever in place, remove its handle and use it stricly
as a CNC milling machine, the spindle is pretty solid, no sideplay
noticeable after applying considerable side forces by hand, something
I found surprisingly interesting since most inepensive similar
machines that have drill press type spindles tend to have a bit of
side to side play.

For the price I paid for this 47158, new close to $300, I knew I
would only use the base platform and retrofit it with balls screws is
my ultimate goal.

I am sure there will be pros and cons with the use of the machine as
with all things, my goal is to tackle the cons and if more people
find this machine useful the better!.

I get so upset when I see the rip off in some of these Ebay autions
for machines that one could build/retrofit with minimal expense and
a little elbow grease at a fraction of the cost. Some people may
disagree with me but I have seen enough to know that one need not go
the expensive route if one looks carefully at the alternatives.

I hope to get feedback and will post more as I (we) expand on this
topic.

Thanks
Mario