# Stuck Knee On Jhead!!



## Neiko (Mar 18, 2016)

Good afternoon form Kansas City Ks!
  I got a Jhead Bridgeport with a broken Gib and a knee stuck, all way down and wedged tighter then a Tick on a hound dog!! I removed the table ,saddle and the head. I have up some major upward pressure on the Gib  and knee with no success at all. i layed it on the backside and also removed the jack screw and stand. So there is nothing holding the knee but the Gib wedged in place. Any thoughts on how to remove the gib at this point? Im getting to the point of drilling a hole or tourching a hole under the Gib so I can get a bar to it and smack it with a 3lb hammer and progress up to a 10lb hammer if need be! Any help would be great!


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## Metal (Mar 18, 2016)

wow thats a tough one, how much clearance do you have underneath the knee, or is it right against the base of the column?  Is it rusted up or just jammed?

If it is just jammed, the gentle way of doing it might be to put an engine hoist on the knee with a good amount of force, but not enough to lift the whole column (or maybe a mm or so if it is on a pallet still) and then gently warm and cool it with a torch a few times.  which sounds like what you've done.

your hammer idea is probably the least dicey thing I can think of, later you'll have to tap and pop a bolt in that hole to keep oil in, you could also try drilling and tapping the gib itself.

How's the Z axis screw? you unbolted that and aren't fighting that too right?  whatever you do make sure you keep the hoist on the Z because once it comes lose it's going to move.


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## chips&more (Mar 18, 2016)

If my memory is correct? The wedge is such that pushing up on the knee will just make things tighter. The knee needs to go down OR just the wedge needs to go up. Can you put a threaded hole in the end of the wedge and attach a slide hammer to it?


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## Neiko (Mar 18, 2016)

That sucker is down. bout 4 inches from the foot and the gib is sticking 2 inches below the knee. I removed the knee jack screw and its post already. So the only thing that is holding the knee is the gib....wedged in. I will be back working on it Monday and ill take pics of the mess! 
 I put a spud bar on a block levering upward against the Gib with all 240lbs of me on it.. then put the pallet that has the table,saddle and head stored on the spud bar and that was not enough to get it to move. So Monday will be interesting to say the least


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## Neiko (Mar 18, 2016)

chips&more said:


> If my memory is correct? The wedge is such that pushing up on the knee will just make things tighter. The knee needs to go down OR just the wedge needs to go up. Can you put a threaded hole in the end of the wedge and attach a slide hammer to it?


I don't belive that I can get a drill and tap down to the gib to put threads in it... it did cross my mind. and maybe a option im going to look into monday


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## John Hasler (Mar 18, 2016)

Neiko said:


> That sucker is down. bout 4 inches from the foot and the gib is sticking 2 inches below the knee.


A drill extension (or extra-long drill) and a pulley tap?


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## kd4gij (Mar 19, 2016)

Neiko said:


> That sucker is down. bout 4 inches from the foot and the gib is sticking 2 inches below the knee. I removed the knee jack screw and its post already. So the only thing that is holding the knee is the gib....wedged in. I will be back working on it Monday and ill take pics of the mess!
> I put a spud bar on a block levering upward against the Gib with all 240lbs of me on it.. then put the pallet that has the table,saddle and head stored on the spud bar and that was not enough to get it to move. So Monday will be interesting to say the least


 
 Try beating on the bar with a big hammer. The impact is better than steady force.


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## cathead (Mar 19, 2016)

I don't really know if this would help but maybe a hydraulic jack pushing  up would do it???


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## Metal (Mar 19, 2016)

If you have the part that broke off so you can meausure the depth of the gib I can measure mine and give you exactly where to drill that hole since my knee will be off until next weekend


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## Silverbullet (Mar 19, 2016)

Is there a way to plug the gib hole with a grease fitting? if you can get it in the hole you can pressure rise oil to try to loosen the way pressure . Just thinking outside the box? worth a try pressured kroil or even try carb carb cleaner to loosen any hardened lube which may not be the right kind ?


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## chips&more (Mar 19, 2016)

Make a drill bushing/guide kinda thing that will go into that 2” space and guide your extra long drill bit. Then thread it. Then connect the gib to the slide hammer with a good grade set screw.


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## jmanatee (Mar 20, 2016)

Pull the turret,  head,  table and saddle, turn the column upside down,  apply upward force (ratchet strap) on the knee as you tap smartly on the side where the gib is.


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## Neiko (Mar 20, 2016)

jmanatee said:


> Pull the turret,  head,  table and saddle, turn the column upside down,  apply upward force (ratchet strap) on the knee as you tap smartly on the side where the gib is.


tried very similar action already. using a lift truck. no dice.


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## Neiko (Mar 20, 2016)

here is the little bugger sticking out of the bottom of the knee. will be messing with it tomorrow and will have success!


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## Andre (Mar 20, 2016)

Depending on how much wear that gib has, you're lucky the gib didn't shear the side of the dovetail clean off from sideways force, scrapping the knee or creating a huge repair job.

Get a U shaped crowbar and use it as a lever to pry the gib up? Use a wood block inside the oil tray of the base to pry against.

One like this: http://vignette3.wikia.nocookie.net...wbar-1-.jpg/revision/latest?cb=20140707191338


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## JimDawson (Mar 20, 2016)

Neiko said:


> will be messing with it tomorrow and will have success!



That sound like something I would say!


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## Neiko (Mar 20, 2016)

Andre said:


> Depending on how much wear that gib has, you're lucky the gib didn't shear the side of the dovetail clean off from sideways force, scrapping the knee or creating a huge repair job.
> 
> Get a U shaped crowbar and use it as a lever to pry the gib up? Use a wood block inside the oil tray of the base to pry against.
> 
> One like this: http://vignette3.wikia.nocookie.net...wbar-1-.jpg/revision/latest?cb=20140707191338


Yea i tried a 2" square spud bar on a block with a lot of weight on it. 
I thinkin of drilling a 1" dia hole under the gib and pound it up tomorrow. Im praying that the dove tail is not trashed!! I know i will have to scrape all the ways on the knee and the base once its off. just hopping im not going to have to braze a bunch of it back together.


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## Neiko (Mar 20, 2016)

cathead said:


> I don't really know if this would help but maybe a hydraulic jack pushing  up would do it???


Also tried a 3 ton handi man jack under the knee while prying up on the gib at the same time. and it didnt move!


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## T Bredehoft (Mar 20, 2016)

Is there a way to put a pair of wedges under it and drive them together?  develop a lot of pressure that way.


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## Neiko (Mar 20, 2016)

T Bredehoft said:


> Is there a way to put a pair of wedges under it and drive them together?  develop a lot of pressure that way.


Thought of that... problem is the column is not square under the gib its radiused angle from vertical to horizontal right there.


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## Andre (Mar 20, 2016)

Why do you plan to re-scrape your knee way? That's a big job. Were you taking it apart to scrape anyway, or are you going to scrape it because of this mishap?


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## jmanatee (Mar 21, 2016)

do you use your column for coolant?  If not lay it on its back and drill a hole through the base inline with the gib,  use a long punch to tap the gib.


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## T Bredehoft (Mar 21, 2016)

Neiko said:


> its radiused angle from vertical to horizontal right there.



And the material probably wouldn't support (strengthwise) the effort anyway. 

Drill a hole and punch the gib upward.


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## John Hasler (Mar 21, 2016)

Neiko said:


> Also tried a 3 ton handi man jack under the knee while prying up on the gib at the same time. and it didnt move!


I don't think you want to try to move both at once.  I think you need to get the gib to move upward with respect to the knee.  Prying on the knee is just going to wedge the gib tighter.

Would it be feasible to cut off the protruding bit of gib and then drill all the way through the remainder lengthwise?


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## tertiaryjim (Mar 22, 2016)

Gibs are soft and will deform. The end my already be mushroomed and will need to be dressed as best as possible.
If there is any down travel left for the knee then the gib should be blocked and the knee forced down.
Just put the jack screw back in or build a cradle so it cant drop to disaster.
Use a good penatrant oil on both dovetails. Kroil is the best if you can find it. Keep it wet for a couple o days.
Then with a bloody big rubber dead blow or the best you can come up with " a soft block of wood" hit  the knee down.
Use light blows as a start. Hopefully you can rotate the head out of the way and have solid metal at the center of the knee close to the column.
If you must hit above the knee dovetails then "tap" one side n then the other.
Tap it good and walk away for a bit. The penatrent might work in deeper.
Don't get in a hurry.


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## Neiko (Mar 22, 2016)

Welp,I got that sucker out today!! IT took a Blue Flame wrench, a 14"long air hammer driver and some True Grit!!  I cut the smallest hole i could cut so it would be easy to fill with brazing rod. Knocking the gib loose at first with a 18" punch and 5 lb hammer and it snapped off... I was at wits end. I grabbed the long driver and air hammer and drove it up as far as i could. put a strap on the knee and lifted it up off the column like it was never stuck!!! good news is the ways are in good shape and not wore slick... almost all the Biax markings are still visible and no gulling!! So now its clean, paint, and get a Gib coming so I can get this back together! Thanks for the advice and words of encouragement!!!


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## Neiko (Mar 22, 2016)

As in scraping the knee... it looks good, ill bring the straight edges home tomorrow to check it out. now the table and the knee ways will need to be scraped. so that will be the second step after the knee is back together. I'm looking into haveing the table blancher ground since it has 70 years of being beat on by everyone who could!


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