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MOUNTING INSTRUCTIONS FOR M247
AIR POWERED DRAWBAR
M247
Specications
Power Requirement 24V
Air Pressure Requlrement 90psi
Speed 3000 RPM
Torque 135 ft/Ibs
Drawbar Assembly
The goal of these procedures is to fabricate an entirely new
drawbar that will extend down through the spindle the same
length as your mill’s existing drawbar. Also, you must ensure
that the top shoulder of the new bolt head will be ush with the
mounting surface of the motor assembly
To assemble the drawbar:
1. Use a caliper to measure the diameter of your milling
machine drawbar bolt head (Fig.2)
Bolt Head
Drawbar Shaft
Figure 2. Bolt head and drawbar shaft.
NT40
Reduce the diameter
of the new bolt head to
matche thediameter of the
existing drawbar head
Fig.3
Existing New
If the diameter of your mill’s existing bolt head is 24mm, then proceed to Step 2.
If your existing drawbar is an NT40, use a lathe to turn the new bolt head to match the diameter of the your
mill’s existing bolt head (see A in Figure 3).
Note: The splines of the new bolt head are specically designed to match the socket of the drawbar motor.
DO NOT damage them.
Note: Before making any alterations to the new drawbar, read through the rest of the instructions to calcu-
late the correct lengths.
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M247
If your existing drawbar is a two piece drawbar then
you must build a drawbar motor mounting extension
ring that will allow only the full spline to be above the
mounting surface (see Figure 4)
.
2. Measure the length of your mill’s existing drawbar
from the bottom of the bolt head to the end of the drawbar shaft, then add 38mm (see Figure 5).
Note: The additional 38mm is the amount of the new
shaft that will be inserted into the new bolt head in a
later step.
Existing Drawbar
38mm
= Total length
of new shaft
New Bolt Head
with spline
Custom drawbar
motor extension
ring
0.7 - 1.5mm
Spindle
Figure 4. Example a custom drawbar
motor extension ring
3. Remove the necessary amount, if any, from the
top of the new drawbar shaft to make the total length
of the shaft equal to the total length calculated in
Step 2, then turn threads into the last 38mm
4. Insert the new bolt head into the top of the spindle, then measure the distance from the top shoulder
of the bolt head to the mounting surface of the motor
assembly (see Figure 6).
Figure 5. Calculating the length
of the new shaft.
Figure 6. Checking the measument
Top Shoulder
The amount
measured in
step 4 on the
head bolt
Measure
this
distance
5. Remove the amount measured in Step 4 from the
boffom of the new bolt head (see Figure 7).
Note: The top shoulder of the new bolt head below
the spline must be 0.7—1.5mm below the mounting surface on the mill to properly engage with the
drawbar motor.
6. Drill and tap 45mm into the bottom of the new
bolt head with threading to match the top of the new
drawbar shaft from Step 3.
7. Thread the new drawbar shaft into the bottom of
the new bolt head, as shown in Figure 8.
Note: We recommend the addition of four M5-.8 x 10
set screws applied through the bolt head to further
secure the drawbar shaft, as shown in Figure 8.
Set Screws
Threads
Remove
this amount
from here
Figure 7. Measuring the amount of the new
drawbar head bolt to remove.
Set Screws
Figure 8. Example of new drawbar.
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Installation
1. Prepare the top of your mill so that the mounting plate
of the power drawbar motor is center-aligned to the
spindle.
2. If the mounting holes in the motor mounting plate do
not align with threaded holes in the mill to accept the
three M6-1 x 20 cap screws and lock washers, drill new
holes in the motor mounting plate.
Notel The pneumatic motor must be mounted at with
and fully supported by the mill, and exactly centered
over the spindle opening.
3. Insert the new drawbar assembly, then mount and
secure the pneumatic motor to the mill.
4. Select a spot on your mill to mount the pneu-matic
control box and switch so that the air hoses can reach
the pneumatic motor and the switch can be connected
to a grounded 24V power source.
5. Connect the three air hoses to the pneumatic motor,
as shown in Figures 9-10.
Note: The two smaller air hoses are num-bered “1” and
‘2” and must be inserted into the corresponding connectors. To insert the air hoses, simply push them into the
self sealing gaskets. To remove an air hose, push the
black self-sealing gasket in while pulling the air hose
out.
M247
Torque Adjustment
Large Air Hose
Figure 10. Large air hose installed into the
pneumatic motor.
Set the motor torque adjustment shown in Figure 10
between “5” and “8”.
Note: A torque adjustment setting of “5” pro-vides the
least amount of operational torque to the drawbar, and
“8” provides the highest.
7. Mount the air regulator unit on your mill so that the
included air hose will connect this unit to the pneumatic
control box (see Figure 11).
Hose 1 Hose 2
Figure 9. Smaller air hoses installed into
the pneumatic motor.
8. Connect the power to the machines power supply (An authorized electrician should be used).
9. Fill the lubrication cup of the air regulator unit with standard pneumatic tool oil.
10. Connect the inlet valve to clean, dry com-pressed air of 90—120 PSI.
11. Pull the air pressure adjustment knob up, then turn it until the pressure gauge reads 90 PSI.
Pneumatic
Control Box
Figure 11. Example of the air regulator unit
connected to the pneumatic control box.
Included Air Hose
Air Regulator
Unit
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