Milling (mill-drill) machine:
|Second hand HM-30
(similar to ZX-30 - drill=32mm, face mill=76mm, end mill=28mm), plus new
stand. It is a perfect unit for what I want to do.
It was a bargain too good to miss & I thank the person that found it for
What I saved on the purchase price has allowed me to
small set of Q24-16 MT3 collets (not as popular or quite
as large as ER-32, but they were half the price), plus a small set of HSS end mills
& slot drills.
Misalignment of the
traverse screw was corrected by milling slots in the support mounts (the
mounting holes were slightly out of alignment. This meant, at the
end of the table traverse the screw was under load & would not turn
freely). The motor was 'fixed' by replacing the run-capacitors & a new
power switch installed. A new swarf apron
was made from an old rubber car mat.
Replacements for missing hand dials
were made (temporary, but will
suffice until I'm able to cast aluminium ones). They were completely made
from old scrap, so cost nothing but time.
||Original cast aluminium hand dial (the only original that came with the
machine). The projecting handle was missing, so was replaced by a
bolt with it's head machined round, length of copper tube, lock washer
||This hand dial was made from the cam timing gear of a 560cc 'Suzuki
bushed to fit the shaft & locked in-place with a grub screw.
||The hand dial for the quill fine feed was made from an old cast iron
vee-belt pulley, machined down, bushed & grub screwed.
||The lock handle for the quill fine-feed is an old valve handle.
The hexagonal recess for the bolt head was milled out using an old broken
1/8" drill, re-sharpened to be a small 2-tooth fly-cutter.
Future tasks are:
|Morse taper Key (for removing tooling)|
|Milling clamping extras
|Auxiliary milling table|
|Adjustable angle plate
& so on.|
Drawbars (Metric & Imperial): - Cost = $3.95 total
I made two drawbars for the milling machine. One is imperial
(3/8"-Whit), the other metric (M12x1.75).
Each drawbar was made from half a 36" (915mm) piece of galvanised,
pre-threaded bar (3/8-Whit.) from the local hardware store.
|The bar was cut in half to give 2 pieces about 455mm long.|
|The ends were chamfered in the lathe. For the
Imperial bar this completes it.|
|The metric bar was reduced to 6mm diameter for a length of 25mm at one
end, ready for an M12x1.75 threaded metric sleeve.|
|The M12x1.75 end piece is from an old Toyota
engine bolt. It was drilled out to 6mm. 25mm of the threaded
section parted off, both ends faced off.|
|This piece was brazed onto the machined end of the second drawbar (as
shown in the photo) forming the metric drawbar.|
|Next an old 75mm length of 16mm round stock (scrap box) was turned down until 50mm of the 'nut'
was a few mm larger than the hole in the top
of the quill & can slide freely into the driving spline without contact.|
|The nut was step drilled to tapping size. 6mm into each end was
drilled to a clearance fit (as a guide into the thread) & tapped with
|The small diameter end of the nut is an easy sliding fit into the top of
the quill (for centring the nut) & chamfered to fit the taper inside its
entrance. A small amount of relief was cut each side of the knurled section & the centre of the nut knurled.|
|The nut was parted off, ends faced off & chamfered.|
These small T-nuts were made to tide me over on the mill-drill until I can
make some full-size ones. I chose to make them smaller than normal so the
mill can use the bits & pieces I made for my lathe. Normally a
mill-drill this size uses 1/2" UNC bolts, not the M8 x 1.25 used here.
|A flat bar was milled with recesses (1/2" wide)
& lands between them (5/8") to fit the T-slots. I chose to mill the recess
this way around to minimise hacksaw work later.
|The holes were step drilled to tapping size for the threaded rod/bolts, (M8 x 1.25)
|When tapped, they are sawn off & cleaned up a bit, ready for
use. Here, one of them is shown after machining, but before cleaning
up. With the sort of work they will be doing, they don't have to be
Homemade Power Feed
I can't afford the $550 (+ $99 for transformer) for the
manufactured power feed, so I cobbled this together. I used things I
already had on hand & it cost me nothing.
I converted a windscreen wiper
motor mechanism into a milling table power feed using the following method.
The casing of the (scrounged) windshield wiper
motor was been modified to fit on the table feed leadscrew, a collar with
drive pin made (swimming pool gate latch), motor mountings (scrap aluminium
boat fitting.) Control is with a PWM motor speed controller (kit
form), powered by an old CB radio power supply.
The motor draws 2.5A maximum continuous, 5A peak momentarily at start-up.
The PWM (pulse width modulated) motor speed controller can be found in kit form
in many electronic hobbyists stores. Any old simple DC power supply will
work if it is about 12 to 14VDC & can handle a surge of about 5A with 2.5A
I can get a range of table feeds
from 0.3"/min - 5.25"/min (7.5mm/min - 133mm/min).
I have made the controller's output dependant on 2 external switches
being in the closed position. If these switches become open circuit, the
travel will stop. This means I can use 2 micro-switches to control the
limit of movement of the table under power feed. When not required, these
switches can be bypassed on the back panel with a jumper.
||The wiper motor's original gear cover was removed & the closed side
machined off to leave the gearing mechanism exposed. It was then
mounted on a piece of 6mm aluminium plate with slots milled for adjustment
of its position. This was mounted on a 25mm aluminium spacer block,
which in turn is bolted to the end of the table. The gear drives the
shaft through a drive pin installed in the boss.
||The nylon (?) gear was bored out on the lathe & a steel bushing made
from scrap. It is a loose fit so the shaft can rotate within the
gear when the drive boss & pin is removed for manual operation. The drive
pin passes through one of the holes in the gear, to engage with a hole in
the original collar which is attached to the shaft.
||The drive boss with the drive pin visible. The grub screw isn't
really needed as I made it a close fit on the shaft, but I put it there
for peace of mind.
||The controller I put together. It is just a PWM 10 to 24 volt
motor speed controller.
Controls include: Main power switch. Rotary speed control.
Direction reversing switch (centre position is off). 2 momentary contact
switches; one which bypasses the controller for maximum speed (fast
return), the other is a 'jog' switch. See below.
The jog switch is used when 'end of run'/table movement limiting switches are
being used. When a limit has been reached, the switch is now open, the
'jog' switch bypasses these external switches to 'jog start' it off the switch
in the opposite direction for the table return. Pressing it simply
bypasses the external switches, allowing power to drive the motor for a brief
period (as long as you hold the switch down that is).