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  #1  
Old 03-13-2020, 02:49 PM
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Default Off Center Hole Repair

What’s the best or easiest way to this mistake? Click image for larger version

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  #2  
Old 03-13-2020, 03:21 PM
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If It was me If I could I would pull the cover off and see what was there and possibly weld on a nut and try that.

Scott
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Old 03-13-2020, 04:05 PM
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Not sure what you need if just to get it centered and size does not matter I would machine a bushing with the hole centered put it into tne casting and re drill the hole. if the hole size is important then you need to weld or braze the hole shut and then drill through the bushing.
to make the bushing if you do not have a lathe or mill will take a little ingenuity chuck the bushing in a drill press and clamp the drill bit verticaly and rigidly to the table. it will find the center of the rotating bushing and drill a true hole in it.
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Old 03-13-2020, 04:32 PM
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In the case you will have to use "removable" drill bushings in order to go smaller.

one bushing to center with casting hole
a smaller bushing just to get a hole on center
then another bushing to size the hole.


see pictures. IN my case I had to center with a lower hole
the drill guide is centered with the pin to the existing hole deeper hole.
the drill guide is locked down with a nut from existing stud.



In your case I would use steel drill bushings.
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Last edited by GWIZ; 03-13-2020 at 04:41 PM.
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Old 03-13-2020, 08:38 PM
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Originally Posted by flametamer View Post
What’s the best or easiest way to this mistake? Attachment 155136Attachment 155137

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Are you looking for the best way to fix this mistake, or the best way to make this mistake. I have advice either way.
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Old 03-13-2020, 10:18 PM
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Originally Posted by flametamer View Post
What’s the best or easiest way to this mistake? Attachment 155136Attachment 155137

Dt


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Were you trying to to sink a hole for an easy -out?? Easy -out probably one of the most false terms in the English language. If you need one of the evil bastards nothing is easy from here. I really like some of the specialty welding rods for this although a little patience with a MIG and a nut plus a washer works well. I got sold on this https://www.youtube.com/watch?v=L4zohssWS7I
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Old 03-14-2020, 05:50 AM
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Depends on what tools you have available.

Can cover be removed to expose more of the broken stud? If so, then maybe can get vice grips on stud.

If tig welder is available, I have built up studs enough to get a grip with vice grips, or have welded a nut on them too. Or some people use stick rods, or mig also. One thing welding sometimes helps with it heats up the bolt, which expands it, and then when cooling down will shrink it breaking the rust bond in the threads.

If part is small enough, I have put them in the milling machine and machined them out. Usually the smaller the bolt, milling is the safest way.

I have used a die grinder with either a small stone or carbide burr too. If you can enlarge the hole just till you start seeing threads, you might be able to use a punch to loosen up the other side, especially if you have access to the top of the bolt, which you do not in this case.

Last one I did was on a cylinder base. 5/8-18 threaded rod. Drilled as close to center and then miller till seen thread edges, and picked out as much old bolt thread and retapped.

Previous one was an plastic extrusion die that I mounted a heavy plate too and used the mag drill. The drill bit walked off a little, and when I was using die grinder , I didn’t realize I was all ready into the main threads, so I ended up taking out 25% of the bore threads. The company decided to try it anyways, and I think it worked. My next step was to actually have to set up in other mill and move the head over to remill hole center and used a thread repair insert on it. But there was 5 other holes to hold the part together, and they thought it would be fine.

Heating up and melting beeswax or a candle may help loosen it, or let some other penetrating oil soak into it.


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  #8  
Old 03-14-2020, 08:52 AM
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There was a large crack in the water jacket on this engine that ran through where the oil cooler mounted. 2 of the bolt holes had to be ground out and filled. A bushing was my first suggestion (but the local machine shop is closed temporarily) The owner of the tractor decided to try and drill it by hand after the pilot hole was already off center. Bolting the cover back in place and using the square as guides he was able to get it close enough back centered to where it will work.

Thanks for the replies. I was just seeing if I was on the right track on how to save it.

Dt
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