Advice on Bridgeport BPJ to CNC

[ToMMY2ooo]

ok so my shopping list is nearly complete...I need to ring the bank

Femi: about those drives, I definately want them but I am short on capital at the minute. Could I send you a deposit and in 2 months send you the remaining payment?

I have more questions now than ever which Im sure for those time served machinists may seem obvious.

DeskCNC looks like a good package but for now I need to buy the mill, servos, controllers and get it all fabricated and wired up. Then Ill worry about the controller, software and GCode.

Cheers,
Tom

[femi]

Tom,

Ring the bank? I'm sure Prince Charles would be glad to loan you a pound or 2 (or should that be a Euro or 2)?

In your last post you said "drives", do you mean motors?
email me at femi@motovidia.com, let me know what you're thinking & we'll try to work something out

[ToMMY2ooo]

haha, its still pounds over here

IJ. Couple of questions...

Ballscrews:when you say blank, you mean the thread goes right to the ends?

In your thread (where I should have really posted this I suppose) you mention the hardening being close to where you had to machine.

If this is so, how did you clamp the ballscrews in the lathe?

Also how did you remove the thread on the Quill Z Axis? Grind it first then machine to perfection or...?

I guess what Im asking for is a explanation on each ball screw of what you did and how you did it.

Cheers,
Tom

[colin1544]

Hello There
I live in the UK and have a bridgeport series 1 CNC Machine with a boss 5 control the control went on the blink some time ago and I was not getting anywhere with the repair, so in the end I decided to shop around and in the end bought a Ajax CNC control. At the moment with the exchange rate as it is they work out quite reasonable, and the conversion dose'nt take long, and the result is it works straight away with very little messing about. although I have three phase power I now run it all on single phase, this is done by using a single to three phase inverter the rest of the system runs on single phase with a computer running the software provided. hope this might give you some encouragement. Cheers for now Colin

[ToMMY2ooo]

Well Im a little stuck here....

I want a bridgeport, but I know of two clones I can buy new...the Eagle:
http://eagle.en.alibaba.com/product/...g_Machine.html

or the SEMCO:
http://www.semcouk.com/

Now do I buy a used Bridgeport or a new SEMCO or Eagle?

I know that I could buy a new machine but the build quality might not be as good as the used Bridgeport which could alyways be re sprayed if I really wanted it all shiny.

I have a 5k budget for the machine so which way do I go...??

Advice would be appreciated.

Cheers,
Tom

[ToMMY2ooo]

PS

I have decided to get SAMSUNG CSM servos and the amps that go with them.

800w motors, 3000rpm @ 2.5n/m rated values, 7.0n/m peak torque....plenty of power

They take step and direction so I can easily hook my PC computer port up with the kit.

I am looking at getting OncCNC XR Advantage to take my Rhino models

Finally I know what I need

Cheers,
Tom

[ESjaavik]

Originally Posted by ToMMY2ooo Well Im a little stuck here.... I want a bridgeport, but I know of two clones I can buy new...the Eagle: http://eagle.en.alibaba.com/product/...g_Machine.html

Would you buy directly from China?
When he has some resellers around that told him that if he send them junk, they will stop buying from him, or that even may have their own people on site to do some quality control before shipping. What do you think he will do with those that did not come out very good?

Also AliBaba.com is not a good omen. Maybe you'll have to deal with one of his 40 ..... "merchants".

If you buy the same brand from a British company you pay a bit more, but you stand much stronger if what you get is not what you paid for. Of course German, French and so on is also close enough for you to have the same benefits.

[lerman]

Originally Posted by ToMMY2ooo PS I have decided to get SAMSUNG CSM servos and the amps that go with them. 800w motors, 3000rpm @ 2.5n/m rated values, 7.0n/m peak torque....plenty of power They take step and direction so I can easily hook my PC computer port up with the kit. I am looking at getting OncCNC XR Advantage to take my Rhino models Finally I know what I need Cheers, Tom

Tom,

I'm contemplating a CNC conversion of my Bridgeport clone (actually, a Unimac), so I'm following what you are doing with interest. If you could tell us the costs of the parts you are selecting, it would help me a lot. After all, if price were no object, this would be pretty easy.

I'm waiting to get some price info, but I'm looking at (the specs of) a Glentek, Inc GM4020-60 servo. It's 23 lb-in (2.6 Nm) cont. stall torque -- 5 times that peak -- .80 HP at max speed. The fact that it's max speed is 2200 rpm seems like an advantage in this application. A 5 pitch leadscrew would give 440 IPM. For my use, it would seem that 4:1 gearing would let it top out a 110 IPM (it seems faster when you say almost two inches per second). And the effective torque would be quadrupled. That brings it to about 8 pound feet. Or consider turning that six inch diameter wheel at the end of the axis. That's a 1/4 foot radius. So to equal the motor, you would have to apply 32 pounds of force to it. Oh yeah, and you would have to do it at many revolutions per second. That's the continuous spec for the motor. You would have to be able to apply a peak force of 160 pounds.

I guess I'm saying that there is such a thing as overkill. I suspect if you anchored a heavy vise to the table and accidently hit it with the quill, you might knock the ballscrews right out of the machine.

Good luck and, please, keep us informed.

Ken

[mactec54]

Hi
For ball screws you should try Hiwin they have kits for most manual mills
I use NSK myself as for motors AC servos are alot better than DC motors
They cost a little more but will run your machine a lot better I use Yaskawa
and I can give you all the spec if you want You can Email me at
fernmac49@att.net I have done 8 Bridgeport Boss 5 now and 28 other machines
some 3 4 and 5 axes I will post some photos of one that I have almost completed which is a Boss5

[titchener]

Regarding ballscrews, take a look at the ones from http://www.rockfordballscrew.com/

Some ballscrews have nuts that cannot have backlash adjusted out as they wear, while some have "double" nuts with adjustable backlash. I believe the Rockford kits are adjustable while the Hiwin ones are not.

Good luck-

Paul T.

[KSky]

Originally Posted by Al_The_Man The Nook preloaded ball screw part Nos are X axis table 36" 4976-36-01 ~ 42" 4976-42-01 ~ 48" 4976-48-01. Y axis 9" table 4976-09-02 ~ 12" 4976-12-02. Bracket (dogbone) 1541-00-01. .. 0.2"/rev precision rolled leadscrews. I am waiting for a new scanner or I would have scanned the page in. Most software packages allow you to calibrate the revs/unit of movement to what ever your system requires. Al

Do you have a price on these items?