Small milling machine cnc conversions

[John PParticipant @johnp77052]

 

Hi Murray

I thought it best to start a new thread to show some
photo's of the Dore Westbury mill as a cnc machine.
Some of these photo's have been seen in a short
Mew article in 2011 (MEW 179).

Hopefully some others may wish also to post some
small cnc machine conversions as i am sure these will
be of interest to many.

Photo's in album "Dore westbury cnc".

Photo 1. a general view of the machine ,the lower part
is still the Dore Westbury the Y axis slideway has been
reinforced and has a little extra travel now.The main
modifications are the head and column. The column is
made from 5 inch square tube welded to a large steel
block for the base, a cast iron slideway is bolted to the
column.A counterbalance weight fits inside the column
to hold the weight of the head assembly.
The machine uses Compucut one of the earliest
hobby cnc systems, as a unipolar system does not
have the speed of more modern cnc systems .The
machine uses pumped neat cutting oil ,side and front
screens contain any oil spray,as can be seen a deep
oil tray covers the full movement of both axis.

Photo 2. A view of the rotary table ,the machine and
rotary table has a Myford nose along with many other
machine parts that i have. Chucks are fixed to the table
with a faceplate, to prevent unscrewing
the split collar clamps the faceplate to the table spindle .
The rotary table is a fabricated unit made from a steel
block,it uses preloaded bearings on the output shaft
and the worm and is sealed and filled with oil.As far as
i can remember it is a 72 tooth gear inside driven by
a toothed belt brings the total ratio to 90 to 1.

Photo's 3 and 4 some of the castings that i made for
the conversion,in 3 the stepper motor mountings and
bearing housings ,three of these made one can be
seen on the end of the table, the Y axis motor is at the
back of the column out of the way and the Z at the top
of the column.The machine has been operational for
11 years now the conversion of the machine started 5
years before that some problems with the castings
(failures) meant some delays during the build as i do the
casting outside winter is not a good time for this.
The castings for the head the pattern here in photo 4 i
had similar problems with but eventually ended up with
a pair of good castings.

Photo 5. Some of the head parts the two castings
,the spindle is supported in 3 bearings 2 angular
contacts at the nose and 1 plain ballrace at the top.
An ER 16 collet fixing is direct in the spindle and
fixes the maximum shank size at 10 mm.

Photo 6. The head part at a more complete stage ,the
motor is 1450 rpm 550 watt 3 phase driven from an
inverter in conjunction with the belt drive which gives
3 ratios the speed range is from 100 rpm to 10,000 rpm.

Photo 7. Another view of the rotary table ,this underside
view gives a clue on how it is constructed ,it is probably a
little over engineered but is very solid.The part rotary
table on the right is for another project.

Photo 8. When a machine is converted in this way you
have to accept the loss of a machine as a result ,something
that many do not consider when doing this .
Something that you learn along the way all of the other
cnc conversions i have done have left machines as part
cnc and manual usage .

I eventually resurrected My Dore Westbury,
well part of it with this Axminster table and a few parts
and has been a very useful little machine over the years.

Some brief specification of my Cnc Dore westbury
X traverse 9.900 inches
y traverse 7.400 inches
Spindle nose to table max 18 inches min 1 .000 inch
Throat 7 inches
Resolution 0.0005 inch.
4th axis rotary table 18000 steps per rev.

Hope that you find the photo's of interest.

John

 

Edited By John Pace on 21/02/2016 14:34:16

[John PParticipant @johnp77052]

[Michael GilliganParticipant @michaelgilligan61133]

That's all rather impressive, John

Thanks for sharing the photos and details.

MichaelG.

[MWParticipant @mw27036]

Those patterns look great,you must be very pleased, what are they made of?

Michael W

[John PParticipant @johnp77052]

Hi Michael

The patterns for both of the castings are made
from hardwood and plywood,in the photo 4
the ends are just turned circular sections joined
by two flat sides .Any gaps are just filled with car
body filler ,sanding sealer is used to fill the grain
then just wax polish.

John

[MuzzerParticipant @muzzer]

John – that's fascinating. Thanks for posting those and sharing the background. I hope others will post details of their conversions if they haven't already.

I'm part way through a larger conversion myself but it's been parked excruciatingly for the last 15 months while we complete our move back to Blighty from Canada. Finally we are in a new house but there is the slight matter of building a garage before I can resume. The experience is similar to how I imagine it being like as an inmate in an open prison.

Murray

[John PParticipant @johnp77052]

Hi Murray

I know how you feel i had the same sort of thing from
a house move and was without a shop for about four
years,it seemed at the time that i would be at work all
week when the sun was shining and as soon as i had
a day off it was raining .Its hard going laying bricks while
holding an umbrella.
It is now hard to believe that it is eighteen years ago
that the new workshop was finally completed .
A positive attitude will see you through .
Hope you are up and running soon.

John

[MWParticipant @mw27036]

Posted by John Pace on 21/02/2016 18:22:45:

Hi Michael

The patterns for both of the castings are made
from hardwood and plywood,in the photo 4
the ends are just turned circular sections joined
by two flat sides .Any gaps are just filled with car
body filler ,sanding sealer is used to fill the grain
then just wax polish.

John

 

Wow, Does it cost much to get them cast, or do you do it yourself dare i ask?

Michael W

 

 

Edited By Michael Walters on 21/02/2016 20:44:04

[John PParticipant @johnp77052]

Hi Michael

The castings are done at home and like all
of these activities requires making the equipment
to be able to do this. I started doing my own castings
back in the early eighties ,i would think that now it
would fairly easy to make up the equipment needed
as there are many more suppliers around now.

Myfordboy has very good and instructional videos
on the castings that he does and are well worth watching.

J.W. Winter has all of the sundries required for
home casting.

John

[MWParticipant @mw27036]

Thanks for the info John, I am intrigued by casting yes, I wouldve thought it was quite hard to achieve the temperatures to melt the iron with only home equipment but i am obviously talking to one of the early casting masters

Michael W

[John PParticipant @johnp77052]

Hi Michael

There are a couple of photo's in album"Furnace".
This furnace was based on a book by David Gingery,
" Gas fired crucible furnace" in which it claimed to be
able to melt 20 lbs of cast iron in 45 minutes.
I have never melted iron only aluminium and brass
but have no doubt that it would easily melt iron.
The furnace was constructed around 1990 using MPK
bricks which cut easily and have some insulating properties.
Aluminium melts easily at 1/4 throttle ,i have never run it at
full throttle at just over 1/2 throttle a jet of flame is coming
out from the exhaust.The internal dimensions are 8 inch
diameter and 12 inches deep.Runs on propane on the left
of the photo is the centrifugal blower ,the gas enters the
flame tube and mixes and ignites just in the entrance
to the chamber .
See a recent post by Pat Jorgensen "Green Twin
Oscillator" there are some rather nicely done iron
castings.

John

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