Bridgeport Basic Q's - quickish help needed!

[ASTRO_AL]

Hi, I have been offered a couple of Bridgeport mills.

The first is an Interact 1 series 1, the second is an Interact 2 series 2. Roughly the same price.

I'm searching for info on the differences, but just can't find ANYTHING. Can anyone point me in the right direction please - a general guide or something???

Also, the Int 2 is fine but the table has been heavily marked/cut into by a cutter. For what I need it for, it looks like it's not too much of a problem (and helps bring the price down), but what would my options be for fixing it up (if I think I need to) - best to get a replacement table? How about filing it with something & regrinding? I would guess the channels cut into it are about 3-4 mm deep by about 5mm wide(!).

Should I just pass on it?

Is there a guide for what to check when looking at buying an Interact or similar?

Thanks for any input. Great site by the way.

Al.

[NC Cams]

If the prior user was careless enough to bury a tool into the table, you can bet that he/she could care less about some of the other fine points of machine maintenance and/or care. From what I was taught, burying a tool into a table was categoric grounds for dismissal and/or dismemberment.

Then again, the previous owner may have bought the machine used and then simply turned it into a dedicated tool with special grooves for special setups. Older machines are often used in such a fashion.

It the grooves look intentional, you might use this a a negotiating ploy to get a better price. If they are/were an "OOPS", I'd be inclined to pass on it for reasons already stated. Besides, repairing old machines can really cut into the cost savings associated with the purchase of a seasoned part.

Start looking for other signs of abuse or neglect. Dirty/old grease is not a good sign. Noisey motors are also indicators that service is needed. Loose/sloppy unevenly worn ways/tables are also indicators of wear or abuse. Look under the machine and in areas that would be hard to clean. These can give a true indication of care or lack of same.

[machintek]

Both machines have the same head. The Series 2 can supprt a LOT more weight and has more travel (18 by 12 VS 30 by 14.5). More important would be what series TNC control they have.
Many machines placed a "stevens plate" on top of a table. This is a aluminum plate with evenly spaced threaded holes for fixturing, etc. Why not cover the offending table with a similar plate to cover it and mount your vise to this.
The series 1 has dovetail ways. The series 2 has box ways.
Listen to the head run. vibration/noise equals money. Motors that do not feed smoothly at low speed need service and that also equals money.
BOOKS! MANUALS! Parameter back up?

George

[Adobe Machine]

Now wait a minute NC...Are you saying you have never had a tool touch your Bridgie table ?Wish I could say that ...Even some of my best machinests had accidents, including me..I can explain, teach and feel the difference between 0.05 and 0.5, but just a few times I have directed the cutter to see if it could find the ballscrew..Used Machine Tools..Look at the oiling system, look at the scraping , ways, gibbs and listen, listen..If it sounds bad, its most likley expensive to fix. Take a dial guage with you to check the machine out..Believe NO ONE who is selling the machine.Repaints are ok, but did they include the ways, dials etc..stay away from those deals..Records and the manuals are a must, no manual ? Might wanna ask some questions. Shop wisely and carefully, boat anchors in the garage or shop are not fun..


Adobe (old as dirt)

[NC Cams]

First thing Iwas taught to look for is "OOPS's" on the table. By Bridgeport Extrak was bought on price but it has a nice table that is pretty much OOPS free even though it came out of a production shop.

The Bridgeprot V2XT I just took posession of has NO damage whatsoever and it was used in a production shop to cut name plates for stamping dies - it is a 1998 machine.

The first think I tell a user of my machines is that if they drill into the table, IT BECOMES THEIR TABLE AND THEY BUY ME A NEW ONE. THey also have Kurt vices fitted to them and NOBODY drills onto an unprotected table.

The house rules are that you leave the machine in as good if not better condition than you found it - or you lose machine access privileges. Hence, the stuff stays VERY clean and well maintained as a result. THis may be why MY tables and machines are essentially pristine and remain that way.

My neighbor drilled into the table of my home drill press twice - first and last time. I thought he knew better so I didn't give him the warning noted above - that was my oops. That "oops" is the only major one I have in any of my current machines.

My spare Excello mill (which has rebuilt motor and is for sale with the DRO) has a couple of small table rash marks - it came out of the same shop as the Extrak. For a machine that old and with that much vintage, it is fairly OOPS free.

Mistakes from a broken/flying tool are one thing. Drilling into a table is a preventable occurance that is preventable via proper training and a bit of discipline.

Granted, my operation is a bit laid back but the "rules" are explained at the outset of one's experience here and refortified by scheduled "clean up/policing" sessions.

Interstingly, guys who let machines get sloppy dirty tend to make sloppy parts and/or have sloppy work habits. Guys who drill into tables also seem to be less concerned about craftsmanship in their work - one seems to beget the other.

My formerly "lazy good for nothing" grinder operator has evolved into a grinding artisan - he just needed some discipline and training and the conveyance of high performance expectations.

[ASTRO_AL]

Thanks for all your inputs.

The controls on both are TNC145, which I think is fairly primitive? Are there any documents online with the specs of each machine and different TNC systems?

I'm now less concerned about the table and more concerned about the general health of the machine. Unfortunately, I live in Paris, France and the machine (and my workshop) are in England so it's not easy to check it out for myself. Where can I find the correct way to check runout on the spindle?

Cheers, Al.

[NC Cams]

Spindle runout check:

It all depends what kind of spindle nose you're dealing with.

If it is an R8, take a known good collet and mound a known ROUND gage pin in it of a decent diameter (I'd go for 0.750" dia) into the spindle. Rotate spindle by hand and check runout with a dial indicator having 0.0001" resolution.

A decent ball bearing fitted spindle should show less than a few tenths TIR. If you have runout that approaches 0.0005" or more, it could be in the bearings (not likely if they are quiet) or in an improperly rebuilt spindle wherein standard bearings were fitted and the spindle ID was not ground in place afterwards.

If it has a MT or some other taper, you need to do the same thing with a known GOOD tool holder that is runout free. THen do the same sort of test.

A spindle rebuild can be costly, especially to do it right so as to regrind the spindle taper properly to re-establish the tool axis to be concentric with the axis established by the bearing rotation axis.

Some guys think that a bearin R&R is sufficient to "rebuild" a BPT spindle. Sorry, NOT. Due to the selective fit process that was used by the OEM to build spindles via the selective fitting of bearings to spindles, a bearing R&R will only fix noisey bearings at best. It will NOT guaranted a properly cutting spindle that is free from runout.

That pretty much covers it....

[gus]

both are solid machines, but heidenhain no longer support the 145

monitors die, and can be expensive

they are 2 1/2 axis machines with a 1000 line programming limit

I have 3 similar machines, but I would tend to try and fine a slightly newer one, as the 145s must be 20 years old now