Another pivot bearing broke.

[MCSS]

One and a half year old GSX machines. This will be the 5th pivot bearing that has broke. This one decided to take out a few things with it. Snapped the stroke limiter shock stud in half, the rest is fine. Broke one pin gripper on the #4 pinholder. The T-stop did not suffer any damage which was kind of surprising.

So I got all the parts replaced and ran it in diagnostics for 15 minutes everything seemed good. Well I just found out that it's knocking pins over. Not sure if it's spot or respot. I did notice when I was replacing the parts that the chain the runs from the bottom and top of the 10 pin side tube had slack where it mounts to the top of the tube. It's slacking enough that the link that mounts to the tube sits at a 45 degree angle the rest of the links are straight. It's easy to move so there is no tension on it. But there is tension on the bottom of the tube chain link. when the table is down the chain is pretty tight except for the top link. when the table is up the entire chain is sloppy. Much like the rest of the house. The chain I'm referring to is part number 47-075486-004. So I'm not sure what could have happened to the chain to make it sloppy like this.

I can understand the stoke limiter shock breaking, but I'm having a hard time figuring out what broke the pin gripper. In a downward movement the gripper should have been pushed upward.

I guess it crashed pretty hard as it made a lot of noise.

Does anyone know of a stronger version of the pivot bearing. If not I'm thinking of taking a spare pivot bearing to a fabricator to see what they can do. This thing just scares me, it just isn't designed to hold the weight of the table. I tried lifting the table to put 2x4s under it and could not lift it at all. Had to use a pry bar.


Any help would be appriciated.
Mike

[Trifecta]

Re: Another pivot bearing broke.

If the table free fell onto the pins after losing a pivot bearing, it probably didn't fall completely straight, a standing pin could have hit the bottom of the gripper, instead of in between the two.

You should measure the distance from the pin deck to the bottom of each of the table tubes, make sure they are even. You may want to pull them out, make sure one of them didn't bend. Or maybe the alignment is off, which could be why you have several break. I have GS-10s which use guide gears and tooth racks on the table tubes instead of chains, but we count how many teeth down from the top of the tube until we find the tooth that is meshed with the gear, do the same on the other tube and sometimes we find that it is one or two teeth off. The set up for GS-X is a fuzzy for me, but is there any way you can count the chain links in a similar fashion to compare?

[MCSS]

Re: Another pivot bearing broke.

The table is 1/2 higher on the 10 pin side. The chain on the 10 pin side is very loose. So I'm at a lose as to what happened here. I can't find anything in the manual that would involve these chains. I know I can level it out at the table to tube mounting point but nothing has changed there. So it's somewhere else.

Any help is appreciated.
Mike

[MCSS]

Re: Another pivot bearing broke.

I counted the links of chain and it's the same. But the chain tension is different from side to side. 10 pins side the bottom part of the chain where it connects to the tube is has a lot of slack. 7 pin the top part of the chain has a lot of slack. So I'm assuming one of the sides is off a tooth. I'm guessing it's the 10 pin side since it got pulled up 1/2 inch.

Mike

[sbrooks]

Re: Another pivot bearing broke.

Loosen the 2 bolts that hold the bearing housing part # 47-085348-003 then loosen the jam nut on the adjustment bolt under it and raise the housing up. This will tighten the chain(s)by raising the shaft and sprocket. Tighten everything up and you should be good.

[MCSS]

Re: Another pivot bearing broke.

Yes I was thinking about doing that. But will it fix the table level? For now I just leveled the table out where that table mounts to the post. No school and were packed so I just had to let it go with that. As much as the chains jerk and stuff I'm sure its not good.

Keep in mind this machine had no issues before the pivot bearing broke. Its almost like a chain jumped a tooth.

I guess I'm asking does anyone know the best procedure to getting those chains back in time with each other. I tried setting the table on pins so I could disconnect the chains from the tubes but it wouldn't allow me to do much. I can't find anything in the book about them.

Thanks
Mike

[sbrooks]

Re: Another pivot bearing broke.

The tube guide is connected to chains when you raise the shaft you raise the chain and the table will raise, the sprocket on the bottom is free wheeling. I try to keep all mine so they are tight but still have a little deflection.

One other thing to check is are the shaft sprockets or the sprocket key way worn on the table shaft, this will allow one side of the table to drop lower than the other due to the worn sprockets twisting on table shaft, usually the 10 side is lower. If sprockets are worn Brunswick has a replacement sprocket with set screws.

[MCSS]

IMG_20110221_142144.png IMG_20110221_142106.png Re: Another pivot bearing broke.

Here are some pics and video to show you what I'm seeing. The video will show how tight the chain can be then how very loose it can be just by the different positions of the table. I checked the keyways and sprockets all are great.

[MCSS]

Re: Another pivot bearing broke.

sbrooks I see what you are saying. The 10 pin side is the side the table is raised, and also the side where the chain has all the slack. The other side has slack but nothing like the 10 pins side.

What I think I'm going to do is set the table on pins in a false out of range at the 1, 7, and 10 spots so the table is somewhat level with the pin deck and disconnect both chains and set them both the same and see where that gets me.

I haven't been able to really spend time with the machine yet today. We are jam packed.

Mike

[jday]

Re: Another pivot bearing broke.

Just put a couple of milk crates under the table, then lower by hand. When the weight is off the table, try counting links to the top gear, you may have jumped one. Do your pivot bearings not have the metal band around them. The older pivot bearings were crap until they put the metal band around them. Since I installed the new style I have never had another problem in 8 years.

[MCSS]

Re: Another pivot bearing broke.

So I got to spend time with that machine today. Sorry for the wrong info in my past posts. The tubes are level with each other. Its the pindeck that is tilted. I measured from the frame of the machine rather then the pindeck and the tubes were dead on with each other. So my problem is with the chain tension. so depending on the direction the table is traveling or if the table is on the stroke limiter changes the chain tension. Do I want both sides of the chain to have equal amount of tension or just one side? As you can see in the pic I have a chain link laying over? But the other side of the chain is nice and tight. I don't want to ruin parts from making the chain to tight. This was not covered at the school and is not in the manual. Do I adjust the tension with the weight of the table on the chains or should the table be on something?

[Trifecta]

Re: Another pivot bearing broke.

Were those pictures taken with the table at the same height? It does look like the 10 pin side tube is one chain link closer to the sprocket (higher) than the 7 pin side....is this normal for GS-X? I can't imagine why it would be..

Also I do not ever recommend adjusting the table chains without the weight of the table being supported, by the stroke limiter at least.

[MCSS]

Re: Another pivot bearing broke.

Were those pictures taken with the table at the same height? It does look like the 10 pin side tube is one chain link closer to the sprocket (higher) than the 7 pin side....is this normal for GS-X? I can't imagine why it would be..

Also I do not ever recommend adjusting the table chains without the weight of the table being supported, by the stroke limiter at least.

Yes the pictures were taken with the table at home position. The video links work if you copy and paste, not sure why they didn't show up. But the one video shows how the chains become very loose when the table is on the stoke limiter, and tight any other time.

I was looking at other machines and it appears to be happening to other machines as well. I have no clue if it's normal or not, I've only been working with them for 1 and a half years. My experiance is with AMF machines, so I'm still learning these. This area was not covered at the school.

I suggest watching the video. I feel if I tighten the chains with the table one the stroke limiter the chains will be way to tight when it leaves the stoke limiter. I may be wrong. I don't have spare chains so I can't afford to break things right now. LOL.

[Trifecta]

Re: Another pivot bearing broke.

From the pictures and video, it looks like the chain on that side jumped. I would put the weight of the table on something (i.e. stroke limiter, milk crates, even an out of range pin) and advance the chain. This would essentially lower that guide tube by one link, and I believe it will keep the chain from forming that "kink" when the table is at home and keep the strain off of it.

However, if you are sure the bottom of the tubes are level with each other...this would screw that up...I'm not sure. I am an AMF guy myself and my experience is with GS-10s which don't even have that chain. I wish I could offer more help.