Milling machinist wannabee is the proud new owner of a 25 year old
Bridgeport Series I vertical mill, being delivered this week. I will
be using the machine to fabricate firearm parts, mostly small parts.
10 pounds would be an unusually heavy piece. Being a newbie I need
some real basic advice.

1) My concrete floor is out-of-level by 1/4" side-side across the 2'
width of the machine base, and 3/8" front-back along the 3' length of
the base. Would leveling pads be advisable?...or would steel shims
under the base bolt holes be just as good? Or is anything at all even
necessary?

2) I have single phase power. The mill is a 3 phase 2HP. No CNC
equipment in the foreseeable future. I will add a DRO, and probably
traverse power feed (I have longitudinal). I believe the power feeds
are 110VAC plug ins and if so would be a separate circuit. I have
gotten the full range of recommendations. Some say a static electronic
converter at $150 is plenty sufficient; others say I should go with a
$500+ rotary converter with a 5HP capacity (I don't plan to add any
other 3 phase equipment); and one fellow suggested making a "pony
motor" from a used 2-5 HP 3 phase motor, wired with the 2 legs of
single phase input power to 2 of the 3 motor terminals, and then the 3
terminals to the machine, equipping the pony motor with a hand start
pull cord, ever hear of that? I'd like to hear the thoughts of you
experienced folks.

3) Suggestions as to a good 2 axis (with the 3rd on the spindle if
affordable) DRO system a capable mechanic inexperienced with DROs
could retro-fit?

In article , FLowen says...

gotten the full range of recommendations. Some say a static electronic
converter at $150 is plenty sufficient; others say I should go with a
$500+ rotary converter with a 5HP capacity (I don't plan to add any
other 3 phase equipment); and one fellow suggested making a "pony
motor" from a used 2-5 HP 3 phase motor, wired with the 2 legs of
single phase input power to 2 of the 3 motor terminals, and then the 3
terminals to the machine, equipping the pony motor with a hand start
pull cord, ever hear of that? I'd like to hear the thoughts of you
experienced folks.

The pony motor is a single phase motor that takes the place
of a (dangerous IMO) rope pull.

The larger three phase motor that is being started this way
is called the 'coverter' motor or more commonly the 'idler'
motor.

You can see my setup with a 5hp idler motor and a 1/8 hp
pony motor to spin it up before I turn on the power to
excite the idler:

http://www.metalworking.com/DropBox/_2000_retired_files/Conv.jpg

The entire thing was built for free, and runs all my machines, none
of which are more than 1 hp apeice. Because the motor is large
in comparison to the load motors there is no fancy tuning required.

The pony motor spins the idler up to speed, I turn on a fused
knife switch to excite two of the three wires in the idler motor,
and then it locks in to the line frequency and runs on its own.

I lift up the hinged platform that the pony motor sits on and
the belt flies off. The thing is so quiet when running I've
been known to nearly forget and leave it running. It consumes
about 200 watts when it is not powering the load motor.

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================

you can also just use a start capacitor and a momentary push button to
start a 3 phase 'idler' motor. This to me is a cleaner setup.

But I would consider a VFD

I leveled a machine with wood blocks

On 2 May 2004 14:27:19 -0700, (FLowen) wrote:
Milling machinist wannabee is the proud new owner of a 25 year old
Bridgeport Series I vertical mill, being delivered this week. I will
be using the machine to fabricate firearm parts, mostly small parts.
10 pounds would be an unusually heavy piece. Being a newbie I need
some real basic advice.

1) My concrete floor is out-of-level by 1/4" side-side across the 2'
width of the machine base, and 3/8" front-back along the 3' length of
the base. Would leveling pads be advisable?...or would steel shims
under the base bolt holes be just as good? Or is anything at all even
necessary?

A mill doesn't *have* to be level, but it is nice if the coolant drains
off in the correct direction, and if parts don't roll off the table on their
own. Either leveling pads or shims would be fine to compensate for
the tilt of your floor. It doesn't have to be perfectly level, but getting
it closer sure won't hurt.

2) I have single phase power. The mill is a 3 phase 2HP. No CNC
equipment in the foreseeable future. I will add a DRO, and probably
traverse power feed (I have longitudinal). I believe the power feeds
are 110VAC plug ins and if so would be a separate circuit. I have
gotten the full range of recommendations. Some say a static electronic
converter at $150 is plenty sufficient; others say I should go with a
$500+ rotary converter with a 5HP capacity (I don't plan to add any
other 3 phase equipment); and one fellow suggested making a "pony
motor" from a used 2-5 HP 3 phase motor, wired with the 2 legs of
single phase input power to 2 of the 3 motor terminals, and then the 3
terminals to the machine, equipping the pony motor with a hand start
pull cord, ever hear of that? I'd like to hear the thoughts of you
experienced folks.

I'd use a VFD or a rotary converter. A rotary converter is dead cheap
to build, I wouldn't buy a commercial one. You can make it self-starting,
start it with a pony (small 1 ph motor), or even rope start it. For the size
converter you need, self-starting design is very practical.

My rotary is bigger (20 hp), so I start it with a 0.5 hp 1ph pony motor
to reduce the starting surge currents down to something my electrical
service can handle. I use it to run several machines, including a 7.5 hp
lathe. I'd guess I have $50 total in it.

The other alternative is a VFD. A 2 hp rated TECO VFD from Dealer's
Electric www.dealerselectric.com will handle your mill spindle. It also
gives you the ability to fine tune the spindle speed by varying the drive
frequency. I use one on my mill for that very reason. It cost right at
$200 for a brand new in the box unit.

3) Suggestions as to a good 2 axis (with the 3rd on the spindle if
affordable) DRO system a capable mechanic inexperienced with DROs
could retro-fit?

I like this one http://www.star-techno.com/index3.htm

Gary

FLowen writes:

I have single phase power.

Another option is DC drive:

http://www.truetex.com/dcdrv.htm

In article ,
FLowen wrote:
Milling machinist wannabee is the proud new owner of a 25 year old
Bridgeport Series I vertical mill, being delivered this week. I will
be using the machine to fabricate firearm parts, mostly small parts.
10 pounds would be an unusually heavy piece. Being a newbie I need
some real basic advice.

1) My concrete floor is out-of-level by 1/4" side-side across the 2'
width of the machine base, and 3/8" front-back along the 3' length of
the base. Would leveling pads be advisable?...or would steel shims
under the base bolt holes be just as good? Or is anything at all even
necessary?

2) I have single phase power. The mill is a 3 phase 2HP. No CNC
equipment in the foreseeable future. I will add a DRO, and probably
traverse power feed (I have longitudinal). I believe the power feeds
are 110VAC plug ins and if so would be a separate circuit. I have
gotten the full range of recommendations. Some say a static electronic
converter at $150 is plenty sufficient;

It is not electronic -- purely electrical components --
voltage-sensitive relay, heavier relay, and starting capacitor. It is
*useless* for plug-reversing -- e.g. when tapping in the mill and you
need to stop and reverse the spindle quickly to avoid bottoming the tap
and breaking it off in your workpiece. Also -- you only get about 66%
of the motor's full power rating using one of these.

others say I should go with a
$500+ rotary converter with a 5HP capacity (I don't plan to add any
other 3 phase equipment);

Spending $500.00 for a rotary converter which you can make for
less than $100.00 does not make sense -- except for a company, which is
likely to be able to get the three phase from the power company.

and one fellow suggested making a "pony
motor" from a used 2-5 HP 3 phase motor, wired with the 2 legs of
single phase input power to 2 of the 3 motor terminals, and then the 3
terminals to the machine, equipping the pony motor with a hand start
pull cord, ever hear of that? I'd like to hear the thoughts of you
experienced folks.

A bit of mix-up of terms there.

The rotary converter uses an "idler" motor -- a *used* (and
therefore hopefully dirt-cheap) three-phase motor with perhaps
50% more horsepower than your milling machine's motor. This is
started by one of several ways:

1) A pull rope to manually spin it up just before applying
power-- simplest construction, but an exposed pulley while
it is running.

2) A "pony motor" -- a smaller single-phase motor to spin the
idler up just prior to applying power. I've seen these designed
with the pony motor hinged to the plate holding the idler motor,
and as it starts, the operator lifts the pony motor, and the
belt is thrown off of the pulleys.

3) A voltage-sensitive relay, and a heavier relay, and starting
capacitors (just like you would find in the so-called "static"
converters.) This is the so-called "self-starting" rotary
converter, and is probably the best bet for long-term service.

Any of these can be improved by adding tuning capacitors to
improve the balance of the generated third leg, and this can
reduce the current drawn from your circuit breakers. (You would
not be charged for that extra current, as it is reactive, not
resistive, but it still wastes power heating wires, and
sometimes tripping circuit brakers.

There is a lot of information on this to be found in the
archives of this newsgroup -- in particular, look for the
articles by "Fitch" covering this subject. He took a good
analytical approach to the design of one, which can save others
from having to repeat the work.

However -- there is yet a third approach, which *does* involve
electronics. This is commonly called a VFD (Variable Frequency Drive).
I *think* that your 2HP Bridgeport will have the variable-speed pulleys,
so you probably don't *need* a VFD -- but one is more efficient than a
rotary converter, and can allow you to fine-tune the speed if you have a
step-pulley head on your Bridgeport. (It can also allow you to get a
wider total speed range than the vari-speed pulleys alone.

3) Suggestions as to a good 2 axis (with the 3rd on the spindle if
affordable) DRO system a capable mechanic inexperienced with DROs
could retro-fit?


Shooting Star would be a nice one. I'm sure that others
will have their own suggestions.

Good Luck,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

I have a textile machine shop and use the cheap under $100.00 ststic
converter from McMasterr Carr on my Bridge-port...
No problem for 10 years so far.... Works great...

The 3-phase problem is best solved with a VFD rated for single-phase input.
They are commonly available for about $200. The VFD provides soft start,
variable speed, dynamic braking, reversible on the fly. Another advantage
is you will not have to use the BP variable speed pulley system which is a
known maintenance item. www.automationdirect.com is a good source for
VFD's.

If you can spend a little more for a DRO, I recommend the Newall 2-axis. It
is very easy to install, with hermetically sealed scales and reader heads.
Plus it comes with an assortment of mounting brackets that will fit damn
near anywhere on the mill.
www.candomachinery.com is a good source for DRO's and sells several
different brands. For the quill DRO(3rd axis), the little dedicated
Mitutoyo unit is easy to mount, battery powered, easy to see. Most any
place that sells Mitutoyo handles them.

Randy

"FLowen" wrote in message
om...
Milling machinist wannabee is the proud new owner of a 25 year old
Bridgeport Series I vertical mill, being delivered this week. I will
be using the machine to fabricate firearm parts, mostly small parts.
10 pounds would be an unusually heavy piece. Being a newbie I need
some real basic advice.

1) My concrete floor is out-of-level by 1/4" side-side across the 2'
width of the machine base, and 3/8" front-back along the 3' length of
the base. Would leveling pads be advisable?...or would steel shims
under the base bolt holes be just as good? Or is anything at all even
necessary?

2) I have single phase power. The mill is a 3 phase 2HP. No CNC
equipment in the foreseeable future. I will add a DRO, and probably
traverse power feed (I have longitudinal). I believe the power feeds
are 110VAC plug ins and if so would be a separate circuit. I have
gotten the full range of recommendations. Some say a static electronic
converter at $150 is plenty sufficient; others say I should go with a
$500+ rotary converter with a 5HP capacity (I don't plan to add any
other 3 phase equipment); and one fellow suggested making a "pony
motor" from a used 2-5 HP 3 phase motor, wired with the 2 legs of
single phase input power to 2 of the 3 motor terminals, and then the 3
terminals to the machine, equipping the pony motor with a hand start
pull cord, ever hear of that? I'd like to hear the thoughts of you
experienced folks.

3) Suggestions as to a good 2 axis (with the 3rd on the spindle if
affordable) DRO system a capable mechanic inexperienced with DROs
could retro-fit?

I used a "static converter" for many years on a 2HP Bridgeport clone. The
static converter is not really a converter, it just gives the 3rd phase in
the motor a temporary kick of juice when you hit the motor power switch.
This allows the motor to start turning, but then the motor drops back to
running on 2 power phases.

The only drawback on this is that you only get about 2/3 of full motor
power. However, on a Bridgeport type mill, that's usually plenty of power
uniless you are planning on pushing the machine to the max. For the
prototyping and small run work we do, I never had a time where the machine
didn't have enough power with the static converter.

However, I recently switched to a VFD to get the variable speed, instant
reversing and automatic braking. I bought a 2HP Teco unit from Dealers
Electric. It works great, and I really like it and I put one on my lathe
also. If you go this route, buy the optional braking resistor, the allows
you to set the spindle braking and reversing time to about 1 second. The
documentation for this unit is a little cryptic, but they have an 800 number
with pretty helpful tech guys that really know the units.

If you're tight on dollars, I'll sell you my retired static converter for
1/2 of new cost, its the common Phase-o-matic unit, give me a call at

415-467-7886 x122

Good luck-

Paul T.

What I did in your exact situation: level the machine adequately with
wedges, I used wood, but you can now make aluminium , and use a static
phase converter. Worked passably well for me, I have stalled the motor a
few times under heavyish cuts but I have a 1.5hp motor, so I am realizing
only 1 hp. Upgrade later, unless you luck into a VFD at a great deal.

Brian
"FLowen" wrote in message
om...
Milling machinist wannabee is the proud new owner of a 25 year old
Bridgeport Series I vertical mill, being delivered this week. I will
be using the machine to fabricate firearm parts, mostly small parts.
10 pounds would be an unusually heavy piece. Being a newbie I need
some real basic advice.

1) My concrete floor is out-of-level by 1/4" side-side across the 2'
width of the machine base, and 3/8" front-back along the 3' length of
the base. Would leveling pads be advisable?...or would steel shims
under the base bolt holes be just as good? Or is anything at all even
necessary?

2) I have single phase power. The mill is a 3 phase 2HP. No CNC
equipment in the foreseeable future. I will add a DRO, and probably
traverse power feed (I have longitudinal). I believe the power feeds
are 110VAC plug ins and if so would be a separate circuit. I have
gotten the full range of recommendations. Some say a static electronic
converter at $150 is plenty sufficient; others say I should go with a
$500+ rotary converter with a 5HP capacity (I don't plan to add any
other 3 phase equipment); and one fellow suggested making a "pony
motor" from a used 2-5 HP 3 phase motor, wired with the 2 legs of
single phase input power to 2 of the 3 motor terminals, and then the 3
terminals to the machine, equipping the pony motor with a hand start
pull cord, ever hear of that? I'd like to hear the thoughts of you
experienced folks.

3) Suggestions as to a good 2 axis (with the 3rd on the spindle if
affordable) DRO system a capable mechanic inexperienced with DROs
could retro-fit?

I just wanted to thank each and all for your input! This excellent
kind of info xchange makes all the frustrations with computors
tolerable. Type to you all later.
Thanks again to all.

Fred

I have done some woodwork and found that the Jaguar drives work well with my needs with my 15hp lathe. Hope this helps.