Re: [CAD_CAM_EDM_DRO] Bridgeport CNC Mill???

If you decide not to buy it please let me know.


Steve



________________________________
From: ""hanermo" - CNC 6-axis Designs" <gcode.fi@...>
To: CAD_CAM_EDM_DRO@yahoogroups.com
Sent: Thursday, September 29, 2011 6:43 AM
Subject: Re: [CAD_CAM_EDM_DRO] Bridgeport CNC Mill???


At 700 $, its a steal.
The ballscrews and nuts alone are worth 2000$ (if they are ok).

The questions are;
1. Is the spindle ok ?
Can it be run, at all speeds, does it make noise.

2. Are the ways ok ?
Most Bp CNCs were little used, by all reports.
If so, this is a great deal.

If 1 and 2 are good, you have a great machine.
If not, the cost is high.
Reconditioning the whole thing is about 2500$.

Is it worth it ?
Absolutely, if you need an indusrtial CNC mill.
If not, well then it depends. What a hobby worth ?

New bearings cost about the 700$ mentioned, installed.
NOS may be available, but hard to find, at around 150-200$.

The old steppers are junk, so their condition is immaterial.
Bin them, use new steppers, new drivers. Cheap.

It is relatively easy to anything on a CNC Bp, and costs for pieces are
in the 200-500$ range, per piece.

A perfect running condition CNC Bp (I assume this is a BOSS, not a
series 2) can do excellent work to current commercial quality stuff,
somewhat slower (1/2 - 1/5) than a new commercial VMC at 35.000$.

Desired upgrades cannot be quantified with this info.
It depends on how much you can afford, how fast you want to go, and how
big you want it.
For 1800$ or so in bits, assuming 1 and 2 are good, you get treadmill
servos, a hw controller, micron resolution, industrial quality hw. Add
1000$ for brushless industrial servos (needed only/mostly if running
production).
Centipede 600$, 1 kW treadmill servos with 1 micron encoders, 70-130V
DC, granite devices servos (or HP UHU), 1:3 HTD belts and pulleys, 400
inches rapids.
That would be about 4x more accurate than factory new, 3x more powerful,
3x faster.

For 800$ new steppers, gecko 251s, belts, psu, bits n pieces. Add
200-300$ for cables, connectors, energy chain, estops, bobs etc.,

Add 800$ and put linear guides knee. Huge enevelope, very accurate, rock
solid, very rigid.
Add 200-1800$ for ballscrew on knee (C5, quality rolled) to C1,
precision ground.

Pick any set you like.
Any nr of guys can make you a kit, mounts, cables, etc etc if you want.

I have a combo on everything above, and these are the numbers as I found
them.
Note that the steppers, nema 23 3Nm ones, are only 50$ or less, each.
Total non.issue.
Note that industrial quality mounts, if you cannot make your own, for a
ballscew, are about 700$.
You can make almost as good for 50$ in parts per end (make them heavy!
in good steel) with 32006 AC bearings and a good lathe, if you know how.
Note you need 6 ends (one is cheap).
A better  solution is a screw in tension, and rotating nut. not hard,
just different.

So the end result is, there are lots of good options and lots of right
answers.
My mill has steppers, and works well.

If I start to produce parts for $, I will put in industrial brushless
servos, at 1000$/axis.
Some options, for you to have an idea of the ballpark, for now.

>
> I'm just a Home hobby guy. I do want to make some Billet
> snowmobile/ultralight heads with it.
>
> What I'm wondering is, has anyone here upgraded one of these to run off
> Mach3, with a PC?
>

Many have, it´s quite easy to do so.

>
>
> I think it has stepper motors, not servos.
>
> Does this have Ball Screws already since it's CNC already?
>

Yes.

>
> I was short on time when I got there, and I'm not sure if it has an RS232
> port. Can you send G-Code to it from a PC?
>
> What upgrades would you recommend for it, and approximate cost?
>
> .001 is good enough for anything I will ever make. So I don't have to get
> to high tech.
>

> I know it's 3 phase. Last time I checked I couldn't get that at my house,
> so I'm looking at using one of them VFD's.
>
> Thanks for any info.
>
> Rich Gillen
> Ames, IA
>

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