Knee Jam

[Malzra]

I'm having a problem with my series II BP knee, It's jammed and it seems like the brakes are on but thier not engauged at all. Also I have the air on (I'm all ears on whats the correct pressure to use) but the screw going into the leadscrew seems to be free but the leadballscrew it turns is just froze up am I missing somthing simple or is this yet another problem.

It's a older machine and I've never seen it move up or down

I'm in my shop writeing this so I'll be messing around with it for another hour or so maybe I can unbind it

Thanks!

[tc429]

I had a manual bridgeport before I got the CNC- it had a severely stuck knee- the gib screws had been removed, and it was lifted by the knee to haul it out to the scrapheap...I managed to get a piece of steel under the gib and drive it out, but man was it tight...
just wondering if yours had sat unmoved a long time if the gib might be stuck too...
you could loosen the two bolts holding the nut support to the bottom of the casting first and try 'lifting' it by prying gently under the knee- just to see if the support/knee can be lifted the little bit till the bolts hit again - if so, the screw is locked up- maybe just dry/rusted to the brass nut, or a bad thrust bearing at the top of the screw...

if you can loosen the support bolts a few turns and lift the knee/support even 1/16 of a inch and block it up, you should be able to rattle the support/nut a little on the bolt clearance and try to shoot a little oil around the leadscrew, try to work it into the threads with no weight on it...
hopefully its not a stuck gib- you can knock them out, but cleaning is hard to do without removing the knee to clean not just the gib side, but the other half as well...any rust in there will work its way out with enough flushing, but will also likely take a little metal with it...

[Malzra]

Thanks for the info that post gave me enough to just go alittle harder today. This machine has been sitting up for years is my guess. It was just caked in old coolant so I cleaned the hell out of it (just luck it was near the top of when it stopped the last time)I was able to get it to move but there were a few tense moments where I thought i was going to strip the gear but it pulled right through. (LOTS OF WD-40 after cleaning) Problem is now I think that seal for the air assist pedistal is pretty much gone anyone know a good place to source the seal for a BP interact II series II?

Thanks!

[machintek]

Is this a S2 NC which had a stepping motor on the knee?
The correct pressure is 50 PSI plus 5 PSI for every 100 pounds on the table.
Too much pressure and the stepper cannot lower the table.

George