'94 LNC-8 tail stock setting

Im trying to figure out the tail stock on my 94 LNC-8 with OSP5020...
Everything I can find in the manuals for this machine talk about a limit switches - where you set the depth range with a rod that is connected to the quill. Then you have an over travel, in position, and retracted limit switch. Thats all well and good, and I completely understand how that would operate... but my machine does not have that. There are no switches inside the tailstock, no rod connected to the quill, and no wires going to the tail stock at all. Only two hydraulic hoses and a lube line. I pulled the plate that is to house the switches and there is nothing there. And there is a cover plate where I would expect the rod would enter the housing.

I thought I would ask before I spent a bunch of time messing around. Anyone familiar with this set up? I was initially wondering if there was just a timer on the tail stock (like on the chuck on an old OSP3000L control I have) but with the tail stock turning enabled, I just get an error that the tail stock is not in position... so I figured thats not the case.

Im guessing Im just not seeing the obvious here...

Thanks
Wade

Wade,
We have a '95, with the same thing that you have. I'm not at the shop. I think it might use a pressure switch. Tomorrow, i can ask one of the lathe guys what they do if they get that alarm.

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The tailstock position confirmation is an option. Yours works based on a pressure switch and has a two position foot switch. Step lightly on it to jog it forward and step down fully to fully engage it. I think that yours will still have an over advance switch to make sure the quill did not reach the end if it's travel. If you contact the part and build pressure but do not over travel the machine should be satisfied.

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Originally Posted by OkumaWiz

Yours works based on a pressure switch and has a two position foot switch

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i heard that some mercedes car has a switch under acceleration pedal, so it blasts out pedal is down :)

The pressure switch would make sense... I have not tried it with it up against anything... was trying it with nothing in the chuck. I wondered that at one point but could never find a pressure switch in the tail stock lines so dismissed the idea. Kind of expected to find two or a double circuit one (one for extend and one for tract since there were no limit switches).

If its running off a pressure switch, they must be hiding it... as I looked around thinking that might be the case and never found a sensor. Where would they locate that critter anyway? And from there, Im guessing there is a range that it will operate in? What would the low side be? Or maybe it too is adjustable as is the hyd pressure?

I cant find a single wire leading to the tail stock, so dont think there is a switch there. Maybe the quill/piston of the tail stock has a bleed groove in it, so when the tail stock goes to fully extended - it allows pressure to bleed off and it wont trip the pressure sensor?

Ill give er a whirl with something in the chuck and "resistance" to the quill.

Thanks for the info.
Wade

Your pressure switch would be by the advance retract solenoid in the hydraulic circuit. It should be a black box about 3" by 4" and will have a translucent plastic plug on the front of it. Some machines have it located in the back ( I think that is where yours is) and others have it located in the front by the pressure adjusting valve. The plug can be removed and then the pressure setting can be adjusted, but you usually do not need to do this unless working with extremely fragile parts. The normal setting is at about 100PSI so if you turn your tailstock pressure below this setting you will get an alarm.

Best regards,

That's what in was expecting to find but haven't found anything yet that is in the tail stock hydraulic circuit that has any wires other than the two solenoids.

When I get back from harvest I'll play more and post a couple pictures.

Thanks!
Wade


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You need to have the tailstock up against some work, and then there is a minimum pressure setting on the hydraulic unit. There is a rotary knob to check tailstock pressure, chucking pressure and system pressure. If you don't have the chuck pressure set above the minimum you will get an error code....same with the tailstock.

I have not had a chance to test it yet (pressure on the tail stock) yet... but I did get a few pictures to go along with this... I opted for some pics because everything you guys are saying in terms of what should be there and how it would work, makes sense to me... I have an old 1980 LC10 that has the pressure switch box on it (though for that machine I believe it is for whole system pressure to trip an alarm if hyd pres is lost) - and I have seen LNC-8 hyd units that have them on the hyd unit. The rub is... Mine does not have them.

The pic labeled "backview" is the back of the LNC8. On the left, you can see the pressure regulator and solenoids for the tailstock. And of course the Hyd unit itself at the back of the machine. I traced the lines out of the hyd units distribution block, and they go directly to the tail stock solenoid/regulator block, and then the hoses go directly to that column the solenoid is mounted on, and then comes out up top and goes to the tail stock. There are three lines that go to the tail stock... two large ones (in and out) and a small one that looks like a lube line that feeds the dove tails?

You can see there is no other pressure switch mounted there, and no other lines that come out of that part of the hyd circuit. I have found the pressure switch for the chuck, but its on the end by the chuck actuator and the lines from the hyd unit head that way, and that all makes sense... so I feel like I have a good idea what I should be looking for... and just not finding it.

The "LC10" pic shows the back of the hyd unit on my LC10... and the pressure switch I was expecting to find somewhere. I retrofitted an LNC8 hyd unit to the LC10 because the LC10 unit was toast and it was cheaper to retrofit than repair. The hyd unit that came looked exactly like the one on my LNC8 - same dist block and everything... no switches or wires anywhere other than the power for the motor and the hose outlets. You can tell what was from the donor machine (cream) and originally from the LC10 (green).

Guess Im just a little confused at the moment. Seems like the pressure switch would have to be after the pressure reg for the tail stock otherwise it would just read full system pressure (450ish) all the time.

Ill post up when I get time to check the operation based on having a load on the tail stock.

Thanks again for the input and being a sounding board.
Wade

Confirmed the requirement of pressure on the tail stock to make it work... So you guys are exactly right on the operation there... which, at leasts gets me to where I needed to be for what Im doing.

But I would say Im still quite curious where the pressure switch for the tail stock actually is. So far the only pressure switch I have found is the one for the chuck that is mounted on the opposite end, with the pressure regulator for the chuck. Though that it is now merely curiosity rather than a need to know.

Thanks again for the info!
Wade

Posting an update to this so anyone that comes across it has a little closure...

According to an Okuma tech, there is no pressure switch on the tail stock. It is purely based on pressing the foot pedal completely to engage the tail stock. The engage pedal has two "steps" to it. Which I had read - and knew about - but apparently had not actually pressed hard enough to get there... I was also thinking I had tried it via MDI with M56 as well but apparently I was mistaken and only thought I had? So - in the end - there is no check for the tail stock position on this machine, its only check is that the foot pedal was depressed to the second stage (where it will extend all the way rather than the first stage where it will inch along until the pedal is released) or that M56 was called.

So in the end, apparently I am an idiot... and was chasing an issue I didnt have because I had not gone back over everything I thought I had checked, to verify things. I apologize for creating an issue I didnt have and having everyone deal with it.

And now you know... on both counts.
Wade

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Originally Posted by Wade C

So in the end, apparently I am an idiot... and was chasing an issue I didnt have because I had not gone back over everything

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take it easy man :) when something has not been done before, there is no clue where to start and where to end :)

allow me to joke : don't call yourself an idiot ... wait for others to say so :)

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Originally Posted by deadlykitten

...allow me to joke : don't call yourself an idiot ... wait for others to say so :)

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Heheheh, yeah, its just easier to take when I say it first :P
Wade