# Replace or repair the gibbs on milling machine.



## CMS (Nov 17, 2009)

The gibbs are as far in as they will go. Pumping the table full of grease and snugging the the table stops down to get the slop out is getting old. Do I get new gibbs or do I try to reposition the gibb by cutting the back side of the gibb slot and adding a spacer to the adjuster screw?


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## rake60 (Nov 17, 2009)

I have seen and used repaired gibs in a work environment a few times.
They would braze a strip of banding along the back side of the
gib then machine it flat. It does get the machine back into service
very quickly. If I owned the machine I would buy new gibs over repairing
the worn ones. They *WILL* works as long as you don't mind readjusting 
with every move you make.

I expect this opinion to be challenged, but in my experience 
a gib is one part of a machine that is best left to the manufacturer.
You can make a better tool post, hand wheel or compound clamp.
You can't make a better gib...

Rick


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## hammers-n-nails (Nov 17, 2009)

rick is alot more experianced than i am but i will "challenge" what he says, simply putting a continuous piece of shim stock behind the way seems to work fine in my own limited and i stress limited experiance. its worth trying, it will be alot cheaper.

zach


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## Davo J (Nov 17, 2009)

hammers-n-nails  said:
			
		

> rick is alot more experianced than i am but i will "challenge" what he says, simply putting a continuous piece of shim stock behind the way seems to work fine in my own limited and i stress limited experiance. its worth trying, it will be alot cheaper.
> 
> zach



I agree,I have heard of a lot of people doing it that way. I don't think there is any reason to attach the strip as it gets jammed in between the gib and the dovtail. Also if it wears more in the future you can add a thicker one easily.
Dave


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## rake60 (Nov 17, 2009)

Any shim attempt should be to the back flat side of the gib.
Attempting to shim between the front side and the angle is not an option.

Rick


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## rake60 (Nov 17, 2009)

I just re-read my last post and it does read as being a little course.
Please allow me to tell you why. It is a safety concern.

Unless the gib is completely trashed there is very little chance of it working
loose. A shim behind that gib has the pressure of several adjusting screws
against it to keep it in place. A shim in front of the gib has nothing but
pressure to hold it. It can work and wear to a point where it could slip.
If you are drilling or milling that head is going to be sucked into the work
piece. Least damage would be the destruction of a cutting tool.
I don't see a need to go into a worst case description.

I apologize for leaving this out of my last post.

Rick


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## Blogwitch (Nov 18, 2009)

I would wholeheartedly agree with Rick on this one.

Gibs are what stands between a machine working accurately or not, and with over 40 years experience of working with such things, it was always considered foolhardy to play about with shims or bits added. They need to be a very rigid one piece structure. Bodging, which is what you are talking about, is OK to get a machine working while new gibs are ordered or made, but not for continual use.

With very little work, new gibs can easily be made. Maybe even less work than trying to bodge them up to get a few more months of innacurate use out of them.


Maybe not relevent, but I made a couple of gibs not long ago, and if care is taken, they are very easy to make.

http://madmodder.net/index.php?topic=2083.0

Making one for a standard gib would be much easier.


Blogs


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## Twmaster (Nov 18, 2009)

Blogs...

Thanks for the link to that project. Gave me some ides for a couple of gibs I need to make. Also, that big radius on your fly cutter bit... That seems to do a magnificent job. And lastly... I need to get one of those digital angle gauges.


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## CMS (Nov 19, 2009)

I came up with an even easier solution. After some measuring, I wound up taking .500" off the threaded end of the gibb adjusting screw as it was bottoming out. I then took .450" off the tail end of the gibb so it wouldn't patrude out the rear of the table. This allowed the gibb to go deeper and reduce the side to side slop from almost .050" to a modest +/- .0015". Talking about one happy dude!!! Here's some pictures of the project, maybe they'll help someone with a similar problem.


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## d.bick (Nov 21, 2009)

Well done. That repair will last many years as long as plenty of slideway oil is used. I bet there are many Bridgeport owners who would like to know you could cut a bit off the gibb and screw.

I repaired our Bridgeport by adding a bit on the end of the gibb. The only thing you have to take care off, is the joint of the bit added, must not fail. I T.I.G. welded it using Nickel wire.
I have a Bridgeport in my home workshop. At the moment in bits. I have had the slides and bed reground a very expensive job,The gibbs alone cost £200, but I would not have been able to reset the gibb as much of the wear was in the middle of the travel. 
 The problem with many machines in a working environment is the lack off lubrication. The one-shot lube system is great if you can get the operator to use it. Thats why many new machines have automatic lube systems electrically interlocked with the on/off button. We in our home machine shops can be generous with the oil
          All the best Dave B


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