Need Help!- Stuck Hydraulic Chuck Draw Tube

[machinist360]

Does anyone have any good methods of removing a stuck draw tube?

[Geof]

In what way is it stuck?

Can you not unscrew the nut inside the chuck or is it the drawtube stuck inside the spindle?

[machinist360]

I can't get the nut to budge. I have the chuck off of the taper on the A26 spindle nose and can move it out about .125 but it stops. I detached the actuator and powered up, when I operate the pedal the actuator moves back and forth away from the headstock. It seems that in addition to the nut on the chuck end not coming loose that the draw tube is also stuck in the headstock. The machine has been setting for a couple of years.

[gridley51]

Try and get the actuator back on.Then you can work at getting the chuck off the drawtube.If you can get the chuck forward a little more it will be clear of the locating pin and you will be able to turn it independently off the spindle and hopefully unscrew it off the drawtube.If the drawtube is stuck in the spindle due to dried up muck,get some plus-gas or similar into it and leave it to free off.If it`s due to cast iron turnings it will be a bit more difficult,I use inhibited hydrochloric acid for these ones.

[Geof]

It could be 'big hammer' time.

On a very tight nut one time I held the wrench in with a large live center in the turret so the little dogs on it could not jump out of the nut. Then blocked the chuck from rotating with pieces of wood and just started being a gorilla with a long bar in the wrench. Fortunately it worked.

If you have the actuator loose before doing this maybe you could try squirting penetrating oil into that end, rebolting the actuator and working it a few times to see if the drawtube will start to move.

[machinist360]

Originally Posted by gridley51 Try and get the actuator back on.Then you can work at getting the chuck off the drawtube.If you can get the chuck forward a little more it will be clear of the locating pin and you will be able to turn it independently off the spindle and hopefully unscrew it off the drawtube.If the drawtube is stuck in the spindle due to dried up muck,get some plus-gas or similar into it and leave it to free off.If it`s due to cast iron turnings it will be a bit more difficult,I use inhibited hydrochloric acid for these ones.

I got the chuck a little forward and unscrewed it. Now of course the draw tube is still suck in the spindle. I can't tell what the offending material is. It is very rusty and may be decomposed cast iron. What is this inhibited hydrochloric acid you speak of?

[gridley51]

Inhibited acid is acid that will attack the scale and rust but will not touch the base metal.You guys have another name for it and I`m trying to remember what it is.
I`ve used it to clear a lathe spindle that was half closed up with years old cast iron turnings.

[machinist360]

It looks like I am going to have to bore it out!

[Geof]

Originally Posted by machinist360 It looks like I am going to have to bore it out!

What about trying to push it out.

Machine a plug to fit inside the chuck end of the drawtube with a head that is no larger than the spindle bore.

Make a flange with bolt holes to match the chuck mounting bolts.

Put the plug in and then bolt on the flange against the plug and push the plug and drawtube into the spindle. You need to unbolt the hydraulic cylinder of course.

You should be able to get a pretty good push with three bolts on the flange.

When it moves (be optimistic) just slacken the bolts and put something in as a spacer and retighten.

[machinist360]

I'll give it a shot. Thanks.