Bridgeport Knee Mill CNC ?

[madman]

I been thinking of cnc ING my old bridgeport mill. I would be happy with (for now at least x and y axis) Are these machines rigid enough for a cnc application>? I been looking at Industrial hobbies (now out of business the Tormacn and so on) I for one being a firm believer in American Iron would loathe to have asian imports in my shop. Thats just my opinion though. I would probably make motorcycle comp[onents and other stuff primarily 1.5 inch to two inch thick aluminumn billet chunks. Im wondering which is the best way to go with the cnc a complete kit or buy bit here and there. Im confused though as to which pieces will work with which other parts successfully. My electrical electronic skills really suck. Manner of speaking. Tips guys? Thanx Mike

[rsr911]

Buy a BP Boss series machine. I've got a Boss 5, CNC right out of the box and much more rigid than the manual machine. There are lots of options for upgrades to modern CNC, right now I run code in through the serial port to the machines computer.

[Wirecutter]

I've also thought of converting my Bridgeport Series 1 (J head) to CNC. As an intermediate step, I added on a nice Newall 3-axis DRO. I've looked around at CNC retrofit packages and the prices of CNC mills. A nice Centroid CNC upgrade package, with software, would run me $10-15K, depending on options. I believe Centroid is a bit on the high side, you may be able to go with a more economical system using steppers for $3-4K.

It seemed to me that the better way for me to go when I go that route is going to be to sell my existing mill and buy a used CNC machine. The usual cautions apply about careful shopping, etc. I may wind up with a CNC machine that gets some upgrades after I get it. Unless I really wanted the satisfaction of doing the upgrade myself, it just seems better to buy a good second-hand CNC.

Of course, first I have to A) recover from my recent back surgery, and B) scare up a few thousand spare bucks for any CNC anything.

-Mark

[DR]

Madman,

A CNC mill conversion as a money maker????

How many machine shops have you seen with "homemade" CNC's? Does the answer to that question tell you anything?

[madman]

Money maker possible. I make fishing reels race car parts. Lots of these items would be a lot easier and quicker to make up with a cnc. Would work for me. i dont wanna work like a real shop just have some fun in my shop and if i can squeeze out a living im happy. Sick of rat race and working for others.

[DR]

Okay, but this is strictly my opinion from being in the business a number of years....

Buy a factory built CNC machine and make parts (and money) tomorrow. This option requires some up front money and good credit. This machine has re-sale value.

Do a conversion and you'll be without your B'port for 3 to 6 months and when you're all done with the conversion you'll have a half-assed computer controlled machine that's almost a "real" CNC. This option requires about the same or more up front money. This machine has less re-sale value than the unconverted mill.

[John Stevenson]

I think DR has summed it up quite well in that he points out that converting a machine not designed for CNC will de value it.

It would be far better to sell the manual Bridgy and buy a CNC mill with dead / obselete controller.

The manual bridgeport never had a head fitted suitable for conversion to quill drive. To drive these heads the ball screw has to be that far forward it wants to tip before to powers down.
Lack of ballscrews, pressure oiling and did I mention the glass head ? don't help.

OTOH a dead BOSS CNC will furnish a far more rigid machine, usually chrome slides, ball screws, pressure oiling and a big far rigid quill drive.
Add to this the electrical boxes will furnish a load of future bits.

.

[rsr911]

OTOH a dead BOSS CNC will furnish a far more rigid machine, usually chrome slides, ball screws, pressure oiling and a big far rigid quill drive.
Add to this the electrical boxes will furnish a load of future bits.

.

This is what I was getting at. I bought a running Boss 5 in great shape 2 years ago for $1200. I've done nothing to it except buy tooling and vises. I have had the occassional hiccup like blown transistors that these machines where known for. I've bought a breakout board that uses the original Boss stepper drives and will eventually move to a full upgrade. For now the machine makes me plenty of money with the original factory setup. It's FAR more rigid than a manual BP, has ballscrews, chrome ways, and a rigid ram head. I put two 10" import vises on it with soft jaws and make all sorts of parts.

[rsr911]

BTW,

My only compliants on this machine are not a large enough envelop for my future needs (12x18") and speeds/feeds. About 4200 RPM max and 32 IPM. It's fine for HSS tooling but doesn't take full advantage of carbide in smaller sizes. For your needs it would likely be a great machine. You could stick four small vises on the table and make parts in sets of 4, or build fixtures. I make special disks, 4 sets of 8 at a time. Very simple, turn on machine, load code, start, come back in an hour and it's done!

[Michael Moore]

Mike, I'm another one who decided to not convert my manual mill, and instead sold it and bought a used CNC knee mill. I probably should have stuck with the working OEM control to start instead of immediately doing a control retrofit, but I wanted lots of bells and whistles. Plus, the tiny monochrome monitor was pretty hard for me to see versus the 17" LCD I've got on the Tree with the Centroid control.

There's a lot of detail differences between a manual machine and a "designed for CNC" machine. My Tree has a 10x42 table, but weighs about 3X a 9x42 manual Bridgeport. Beefy is a good description. The quill is bigger, it comes with big ball screws, big servo motors, power lube everywhere, box ways, Turcite, CAT40 spindle, etc etc.

cheers,
Michael