[nlh]

Does anyone know what the spindle nose is for an early LB-15 lathe? I have my manuals, but can find nothing in there that tells me exactly what the spindle is. There are some drawings but I can't find anything on the net for dimensions to compare to.

Thanks

[Thawk53]

If it's a big bore machine, it's probabaly an A2-8.

[underthetire]

Most are A2-6. Some VERY early ones were a flat nose. You need to take the chuck off and measure it up. As other post says, a big bore could be A2-8 if it's a later one.

[nlh]

Thanks guys,

Appreciate the info. How big is a big bore machine, mine has 1.75" bar capacity.

It's a green screen 5000L control if that is any help. In the end the only way to know for sure will be to take it off. However last time I tried, nothing would budge. Is there some way to lock the spindle so it doesn't turn?

Thanks again

[CNCZILLA]

No you can't lock the spindle. Lathes do not come with spindle orient unless special ordered with it. Put the right size allen wrench in the chuck bolts, place a good size cheater pipe on it, then start turning the chuck away from you and jerk back in the loostening direction this may break them free. If this doesn't work then get creative. Try freezing the bolts and chuck with some fire extinguishers and then try to break them free. If you still cant get the chuck bolts loosened then something may have to be sacrificed in order to get it off.

[Bulldog101]

In MDI mode you can "half-ass" lock the spindle with an input of S0 M03, just to keep it from rotating a bit. You get the same result after the machine reads an M30; after it does put it in Manual mode and push the spindle cw or ccw button. With no S value it defaults to 0 rpm

[DIFF OVER]

look for Data managment Card in back cabinet. If not there call your dist and give then serial number. they can access build sheet on okuma intranet.

[underthetire]

If you really need to lock the spindle, put one jaw on the chuck so it does not protrude in to the bore. Place a BFW over the jaw and rest it on the front casting. If its the drawtube thats stuck, sometimes you will have to remove the actuator from the back side so you can pull the chuck with the drawtube out, may end up cutting the drawtube in half to get it out, then buy a new darwtube with a chuck. ITS A REAL PIA to do it this way.

Data sheets are fine, but Okuma never seemed to keep records of the the older machines. Any time you purchase a chuck or collet through ATS they will send you a sheet to fill out with dim. on it. Thats the only way to confirm you are getting what you need.

[nlh]

Thanks again guys,

Upon further inspection I found the data card previously mentioned. There was a lot of information there, but nothing on spindle nose. I can verify that it is an `84 machine, or at least that's when it was delivered.

Biggest issue I found when trying to remove the chuck the first time was the draw tube nut (it was stuck HARD). I should spray some Aero-Kroil in there and let it set for awhile.

What I am trying to do is face off cast iron slugs and hold .001 on thickness. Right now I can do it with the 10" chuck and alu pie jaws that are currently on, but I don't feel there is enough consistency. Realistically I think I am only capable of holding .002 on a large number of pieces, with my current setup. I'm thinking a new 8" chuck will help out on this. What do you guys think?

[Algirdas]

What do you guys think?
look at Your personal messages. I have sent You one advice.
You didn't forgot to make chuck clamp/ unclamp all the time, I guess? You know, draw tube is free of hydraulic pressure in the way of traveling between clamp / unclamp positions only. It is clamped by hydraulic pressure at the ends and impossible to unscrew.

[nlh]

Algirdas,

When I attempted to unscrew the draw tube nut, there was nothing in the chuck, it was unclamped, but the chuck was at it's max travel in the open direction. Basically what your saying is to open and close the chuck repeatedly while trying to unscrew the nut? Am I correct on what your saying?

Thanks for the PM.

[Algirdas]

there was nothing in the chuck, it was unclamped
at the end of the travel the draw bar is pushed (or pulled) to the nut with full hydraulic force. That's how it works.
to open and close the chuck repeatedly while trying to unscrew the nut?
exactly.
You'll see: the nut goes easy while in travel and stucks at the end

[nlh]

Thanks Algirdas!

Something so simple too....

Soon as I can, I will attempt it again.

Concerning the accuracy question, am I asking too much?

[underthetire]

The other thing to watch out for, is the ring in the chuck seizes up. Remove the cap bolts holding the chuck on to the nose, and unclamp the chuck. The chuck should come away from the spindle enough to turn the whole chuck assembly. Once it starts moving, place a 1 1/2" bar in a boring bar holder and stick it through the center of the chuck. That way when you get to the end it has somewhere to fall other than your hand.