My US Burke Millrite model MVI vertical mill (resembles a Bridgeport,
but 2/3 the size) came with a X-Axis power feed, an Asong AS-250. This
unit never really worked correctly, and kept on blowing speed control
pots out, as discussed in the thread "Repair of an Asong AS-250 X-axis
power feed" in January 2010. This is a general problem with Asong.

I eventually replaced the original tenth-watt carbon-film pots with a
five-watt wirewound pot, which worked for a while, and then it too blew
out. At which point I gave up: if a wirewound pot won't work, what
will?

The circuit diagram that comes with the unit is an artists impression,
and is neither a correct circuit diagram nor matches what I have in the
slightest, so fixing the circuitry was likely to be a chore.

So, after some research, I bought a Servo "Dymano" model D-1000X-0200
unit. Servo is the traditional US maker of power feeds, and Dymano is
their Taiwan-made answer to Asong et al.

The bolt patterns didn't quite match, so I made a new adapter plate to
go between the cast-iron right-hand end bracket on the mill and the
power drive unit.

The leadscrew is too short, and so I reused the extension shaft from the
original Asong installation, and machined the brass hub (with helical
gear track that engages the drive pinion) to accept the large end of the
extension. The large end is a sleeve, and is pinned to the original
leadscrew with a bit of 0.125" brass rod that is trapped by the hub.

The hub also had to be machined to fit properly into the engraved drum
scale, so the scale graduations would be close to the indicator line.

All machining of the hub was carried out on a lathe, and a lathe is
essential. (If there is a Dymano kit that's better for mounting on a
MVI, I didn't find it, but this was all sight unseen.)

Anyway, it all works, although some spacer shims will be added to set
gear clearances et al.

What is not mounted is the switch that stops motion if the table moves
too far in either direction. The switch is designed to fit on a
Bridgeport, and is far too large for the MVI, and wrongly-shaped to
boot. The Asong switch had the same problem, and was never mounted
either. The theory is that the 0.125" brass pin will shear and save the
day. I will eventually make a custom switch for the MVI.

Joe Gwinn

On Jun 19, 9:20*am, Joseph Gwinn wrote:
My US Burke Millrite model MVI vertical mill (resembles a Bridgeport,
but 2/3 the size) came with a X-Axis power feed, an Asong AS-250. *This
unit never really worked correctly, and kept on blowing speed control
pots out, as discussed in the thread "Repair of an Asong AS-250 X-axis
power feed" in January 2010. *This is a general problem with Asong.

I eventually replaced the original tenth-watt carbon-film pots with a
five-watt wirewound pot, which worked for a while, and then it too blew
out. *At which point I gave up: if a wirewound pot won't work, what
will?

The circuit diagram that comes with the unit is an artists impression,
and is neither a correct circuit diagram nor matches what I have in the
slightest, so fixing the circuitry was likely to be a chore.

So, after some research, I bought a Servo "Dymano" model D-1000X-0200
unit. *Servo is the traditional US maker of power feeds, and Dymano is
their Taiwan-made answer to Asong et al.

The bolt patterns didn't quite match, so I made a new adapter plate to
go between the cast-iron right-hand end bracket on the mill and the
power drive unit.

The leadscrew is too short, and so I reused the extension shaft from the
original Asong installation, and machined the brass hub (with helical
gear track that engages the drive pinion) to accept the large end of the
extension. *The large end is a sleeve, and is pinned to the original
leadscrew with a bit of 0.125" brass rod that is trapped by the hub.

The hub also had to be machined to fit properly into the engraved drum
scale, so the scale graduations would be close to the indicator line.

All machining of the hub was carried out on a lathe, and a lathe is
essential. *(If there is a Dymano kit that's better for mounting on a
MVI, I didn't find it, but this was all sight unseen.)

Anyway, it all works, although some spacer shims will be added to set
gear clearances et al.

What is not mounted is the switch that stops motion if the table moves
too far in either direction. *The switch is designed to fit on a
Bridgeport, and is far too large for the MVI, and wrongly-shaped to
boot. *The Asong switch had the same problem, and was never mounted
either. *The theory is that the 0.125" brass pin will shear and save the
day. *I will eventually make a custom switch for the MVI.

Joe Gwinn

Good post Joe.

The MIllrite is a very nice HSM machine.

TMT

In article ,
Gunner Asch wrote:

On Tue, 19 Jun 2012 10:20:05 -0400, Joseph Gwinn
wrote:

My US Burke Millrite model MVI vertical mill (resembles a Bridgeport,
but 2/3 the size) came with a X-Axis power feed, an Asong AS-250. This
unit never really worked correctly, and kept on blowing speed control
pots out, as discussed in the thread "Repair of an Asong AS-250 X-axis
power feed" in January 2010. This is a general problem with Asong.

[snip]

What is not mounted is the switch that stops motion if the table moves
too far in either direction. The switch is designed to fit on a
Bridgeport, and is far too large for the MVI, and wrongly-shaped to
boot. The Asong switch had the same problem, and was never mounted
either. The theory is that the 0.125" brass pin will shear and save the
day. I will eventually make a custom switch for the MVI.

Joe Gwinn

Most of those switches are simply mounted in the middle of the slide and
a stop on the table is used to control end of travel.

Its easy to mount that switch and then simply figure distances and
either install a stop bolt to hit the switch buttons or if you have a
dovetail on the front of your table..a pair of movable stops.

All true. The problem is the limited space, especially with the DRO
scale. And limited time.

There is a 1/4" T-slot in the front of the table, and the moveable stops
use this T-slot. The is a fixed stop in the center. I would replace
this fixed stop with the switch housing. Within the housing would be a
pair of microswitches. I just have not gotten around to designing and
fabricating it.

Joe Gwinn

On Jun 19, 9:20*am, Joseph Gwinn wrote:
My US Burke Millrite model MVI vertical mill (resembles a Bridgeport,
but 2/3 the size) came with a X-Axis power feed, an Asong AS-250. *This
unit never really worked correctly, and kept on blowing speed control
pots out, as discussed in the thread "Repair of an Asong AS-250 X-axis
power feed" in January 2010. *This is a general problem with Asong.

I eventually replaced the original tenth-watt carbon-film pots with a
five-watt wirewound pot, which worked for a while, and then it too blew
out. *At which point I gave up: if a wirewound pot won't work, what
will?

The circuit diagram that comes with the unit is an artists impression,
and is neither a correct circuit diagram nor matches what I have in the
slightest, so fixing the circuitry was likely to be a chore.

So, after some research, I bought a Servo "Dymano" model D-1000X-0200
unit. *Servo is the traditional US maker of power feeds, and Dymano is
their Taiwan-made answer to Asong et al.

The bolt patterns didn't quite match, so I made a new adapter plate to
go between the cast-iron right-hand end bracket on the mill and the
power drive unit.

The leadscrew is too short, and so I reused the extension shaft from the
original Asong installation, and machined the brass hub (with helical
gear track that engages the drive pinion) to accept the large end of the
extension. *The large end is a sleeve, and is pinned to the original
leadscrew with a bit of 0.125" brass rod that is trapped by the hub.

The hub also had to be machined to fit properly into the engraved drum
scale, so the scale graduations would be close to the indicator line.

All machining of the hub was carried out on a lathe, and a lathe is
essential. *(If there is a Dymano kit that's better for mounting on a
MVI, I didn't find it, but this was all sight unseen.)

Anyway, it all works, although some spacer shims will be added to set
gear clearances et al.

What is not mounted is the switch that stops motion if the table moves
too far in either direction. *The switch is designed to fit on a
Bridgeport, and is far too large for the MVI, and wrongly-shaped to
boot. *The Asong switch had the same problem, and was never mounted
either. *The theory is that the 0.125" brass pin will shear and save the
day. *I will eventually make a custom switch for the MVI.

Joe Gwinn

Good job Joe. I have a new import power feed waiting for me to
install it on my Powermatic Millrite. There was an article on this in
HSM a few years back. Seems like there was more fabrication and
modification involved that what you mentioned. I haven't found a copy
of that article, but I think I have the text and the photos the author
used.
Now I just need a Round Tuit.

In article
,
Rex wrote:

On Jun 19, 9:20*am, Joseph Gwinn wrote:
My US Burke Millrite model MVI vertical mill (resembles a Bridgeport,
but 2/3 the size) came with a X-Axis power feed, an Asong AS-250. *This
unit never really worked correctly, and kept on blowing speed control
pots out, as discussed in the thread "Repair of an Asong AS-250 X-axis
power feed" in January 2010. *This is a general problem with Asong.

[snip]

Joe Gwinn

Good job Joe.

Thanks.


I have a new import power feed waiting for me to
install it on my Powermatic Millrite. There was an article on this in
HSM a few years back. Seems like there was more fabrication and
modification involved that what you mentioned. I haven't found a copy
of that article, but I think I have the text and the photos the author
used.

I'd be interested in the HSM article as well.

The most time consuming part of the effort was precisely measuring the
locations of the four large flat-head hex-socket machine screws that
hold the adapter plate to the cast iron end bracket. I think the
original was done by clamping plate to bracket and drilling through
both, so the parts matched exactly, but were on no precise pattern.
Anyway, I did measure them well enough, and the new plate screws to the
bracket perfectly.

I reused a few parts from the Asong installation, but it would not have
been that hard to make those parts, if they didn't come in the kit.

Actually, while I didn't do this, I should have called Servo and asked
them which kits are best for mills not directly supported. I used their
standard kit for such mills, but for instance the Asong came with a
suitable extension shaft, while the Servo did not.

By the way, the MVI will work just fine with the right hand table
bracket missing and the end of the leadscrew flopping in the breeze, so
you would have no problem milling the key slots in the adapter using
some small endmills. (X-axis motion is controlled by the left hand
table bracket assembly.) The trick is black sulfur oil and blow the
chips out of the slot from time to time, so chip re-cutting doesn't
widen the slot.

Again, one can remove the entire X-axis leadscrew and use the same MVI
to drill the 0.125" diameter cross-hole leadscrew and extension shaft
together for the brass rod, using the Y-axis to position and center.

Joe Gwinn

Joe
Is your Millrite a beautiful RED machine? And if so I need some help.
Thank you Nelson Collar
nel2lar (AT) yahoo (DOT) com