You have probably seen the bench top drill press conversions. The
results of these conversion seem to be questionable at best. So I decided
to try something a little different. I have been a long time wood worker
and found the Shopsmith
multi-purpose tool to have some nice features. I have found several Model
E / ER machines made in the late 40s early 50s. These machines I
have set up as single purpose tools such as a drill press and lathe.
Although no longer supported by Shopsmith, they are pretty easy to come by, in-expensive to purchase and restore. In the fall of 2003 I set one up in
drill press mode and added a cross slide drill vice from Harborfreight
to test the idea. I set up a fly cutter and put some of the Gingery
lathe castings in the vice. I was very surprised at how well the
operation went considering there was no modification to the machine and only a
basic attempt made to square the table to the cutter. With this test
proving positive I felt comfortable converting one to full time "mill"
mode and the search was on to find another machine.
Shortly after my experiment I found that I was not alone in this idea.
Bill Cleary has documented his conversion of this machine. You can see his
work in this
document. There is also an article in The Home Shop Machinist by
Robert Bailey titled Lathe Ball Making Accessory. This article starts in
the 2003 Nov/Dec issue where he specifically mentions using his "modified
Shopsmith" for milling the parts for this project. Could be I am not
so crazy :)
So stay tuned for the up dates to this adventure.
|The basic machine is a mostly stock
model ER. Made from about 1947 to 1950. They are cheap and use
off the shelf replacement parts (belts, bearings). The main castings
are cast iron a nice weight advantage over the newer Shopsmith
models. They use two 1.75" round ways to support the carriage
and headstock as well as the pivot support. On the older models
these tubes are about 1/4" thick making them plenty strong and
resistant to bending.
|The base is a recycled table saw frame and cast
iron saw top. Drilled the frame to mount the top using the existing
saw carriage holes. The Shopsmith is bolted to the top. No
modifications to the Shopsmith were made. After some use I have
found that some vibration and movement is a result of this stand. A
replacement wooden stand with a heavier base and storage is in the
works. stay tuned.
|2 - 3 - 08 After using the machine for a while now I have
decided the base is not stable and adds considerable vibration. I
think I will be replacing the base as well as the Shopsmith mounting
castings. Got a short warm spell end of January. Couple pieces
of 2' x 2' x 3/4 MDF makes a nice square box. It is much stiffer than
the original base. The Tubes go through the top and rest on the shelf.
There is a hidden piece that looks like the tie bar inside the case.
It keeps the tubes aligned. It has made a HUGE difference in
vibration. This would be an ideal base for those who just want to use
the SS as a dedicated drill press. I have removed the SS cast iron
base. So far the tubes have not moved.
|The DC motor is a Pacific Scientific.
These were popular at the time I purchased it. Offered on the surplus
market as new at around $30. This one is a 120v DC 1.5hp 11 amp
4800rpm continuous duty. Two 5/8 keyed shafts. There was no mount so
I made a simple pattern and cast one in aluminum. So far it
has proved to be plenty of motor for my needs. I kept the stock
pulleys to give me variable speed within 3 speed ranges. This allows
me to have plenty of torque at low speed. It is great when using a
1" bit and have the spindle at the proper speed for drilling.
|Look under the pulley on the far right.
There is an index wheel for a digital tachometer I purchased from Littlemachineshop.
More on this later...
|DC motor control. Original
plan was to use a Cycletrol 150. They are made by
Danfoss and now available from Grahm. I had one hooked up for about
a year. Then I decided to do the DC conversion on my 9x20
lathe. While doing the research I ran across a new KB electronics
Penta Power KBPC-240D. This is an amazing piece of hardware. I
just had to play with it and hooked it to the mill. WOW I am
impressed. I seem to get much better motor response and better
torque. I added the reverse switch as well as an AC line switch and
Run/Jog switch. All stock parts from KB. All come pre wired
with terminals on the board. The reverse switch is not just a
standard DPDT switch. It forces you to stop before switching from
forward to reverse. This prevents feedback from the motor causing
damage to the controller. A feature I will need on the lathe while
threading but not a big concern on the mill. I doubt there will be
much need to reverse the motor in a hurry on the mill. Now that I
have used this controller I want one for on the mill. :) At
the moment there is no mounting scheme for a controller till I decide what
I want to do. These things are not exactly cheap. I have about
$190 in this one with all new parts off of Ebay.
That is a bargain over purchasing one from a KB supplier.
|OK we are building a mill so will need some
form of cross slide table. I thought about building one but decided
that would only delay the project and add to any frustration. This
is a standard import offered from many Ebay
sellers as well as Enco.
The top is 6" x 18" with 11" x 7.5" travel. The
base is 8"x 10.5"and stands about 5" tall. There are
two T slots that take a standard 1/2" bolt and clamp sets. I
paid about $100 shipped to me from an Ebay
seller for the table. I also have a standard import 1/2" clamp
set for about $35 from Enco.
While it is not a high precision table it is amazingly smooth. Even
the screws are pretty clean. I will work on modifying the screw/dial
mounts and look into modifying it for better backlash control. I
doubt I could have done a better job without having a mill to get it done.
|Now we have a table we need to mount it.
Original plan was to use the stock Shopsmith table saw support and
table. This would allow tilting the mill table. Problem!
It just was not sturdy enough. I thought I would add a second
carriage and modify the Shopsmith table. Same result.
NEXT :). Lets keep the 2 carriages and use an angle
plate. Great till I find out a plate big enough weighs about 100lb
and will cost near as much as a mini mill. Off to the scrap
box to find some 1/2" plate and bed rail. Now practice my
welding skills. The piece sitting against the carriages is the
1/2" plate. Its bolted on through the 2 holes originally used
for the table raising cranks. The upper supports are 1.5" x
2" x 3/16 angle. The lower supports are 1" x 1/8"
angle. Its not a perfect 90deg but darn close. I still need to
tram the table to the support. I did not modify the carriage
locks. So far it has not been a problem. With the two
carriages there is very little play when you move the whole assembly up
|Here is the first shot of a basic DRO (digital
read out) This is a standard 6" scale mounted to a piece of aluminum
which is mounted to the headstock. I had to drill 2 small holes
through the head stock into the quill hole. Fortunately there is a
recessed area in that hole for the screw heads to hide. The bottom
is bolted to the quill stop through the stock set screw hole. The
head remains stationary and the scale moves up and down with the
quill. Future plans are to have scales on the table (X,Y) and
eventually hook them up to a Shumatech
|Fine down feed. Plan is
to make a worm and gear to mount on the left side of the headstock. This set up will
sit in a casting that replaces the return spring housing you can see in
the picture above. I will use the existing spring. Click
HERE for info on making the worm and
gear. More to come on the housing to hold everything.
|Spindle. I used this machine because of
the difference in how a drill chuck mounts. The Shopsmith uses a
5/8" straight shaft for a spindle. Accessories mount using a
set screw. This should prevent the typical loosening problem
associated with the standard drill press mill. So far it has worked
well. I use a standard 5/8" saw arbor to mount slitting saws
and a 1/2" router chuck to mount fly cutters and end
|I am considering making a new spindle to handle
mill tooling such as R8. After considerable thought I decided that
an R8 would simply be to big for this machine. I will go with ER32
collets. These are pretty cheap and I can use the same set on
my 9x20 lathe. This will
require making a Quill extension to hold a larger bearing to support the
collet chuck. I should be able to keep the upper bearing as well as
the drive pulleys in place. Here are the 2 ER32 straight shank
chucks I picked up as a pair cheap from Ebay. Far right is the ER 32
MT3 chuck and collets I got from this
Ebay seller. Initial testing with the MT3 Chuck and collets in the
lathe indicates very good results. Much better than the 3 jaw chuck.
December 9 2007
Spindle replacement has begun ----- I had some problems with the
half nuts on my lathe. They were stripped. :( So much
for zinc castings. The new ones are bronze with smoother
performance. This led to another setback. My
tumbler reverse ran rough. It was
built without bearings i the gears. Its being fixed at the moment.
|Stay tuned for more updates.......