How To Fix A Threaded Hole

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I drilled and tapped 4 holes in order to mount a plate. I used the holes in the plate as my template for marking the new holes. I got 3 out 4 properly aligned. One is slightly off and now I am unable to bolt the plate because of this one hole. I drilled into an aluminum plate and used a 6-1 mm thread. Is there a solution other than restarting from scratch?
thanks
tony
 
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My guess this is an "all depends question" whats it do, hold, etc. Anything from a step stud, plug welding machine a step plug (from the back side) then drill and tap,
a larger alum screw which again is drilled and tapped. And the list goes on. The quickest is to weld, the class act is a step plug then pressed in.
I see you are a neighbor !
sam
 
Maybe a little sloppy, but can you file or drill the hole bigger in the piece to be mounted? Or maybe inlage all of them? I seem to have the same problem pretty consistently using transfer punches. I get the best results with setting up in the mill and using DRO to lay out holes and drill. (Too late for that now)

Tim
 
timvercoe said:
Maybe a little sloppy, but can you file or drill the hole bigger in the piece to be mounted? Or maybe inlage all of them? I seem to have the same problem pretty consistently using transfer punches. I get the best results with setting up in the mill and using DRO to lay out holes and drill. (Too late for that now)

Tim
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I agree. Also sometimes just flipping the plate around a certain way will give you just enough wiggle to get all 4 screws started. The holes in the plate might not have been exactly square and parralel from the start, so if the plate is not oriented the way they were marked, that can screw things up. If that doesnt work just drill the 4 holes in the plate a little bigger.
 
I cannot flip the plate, since it's one of two plates that go on a cnc machine. I like the idea of putting an aluminum screw, use locktite, and then redrill. I'll into a step stud. First time I hear of it....
thank
tony
 
Use a course thread and be sure the plug and hole are clean of cutting fluids so the permanent Loctite® will bond. A miss align happens to the best of us. If the base is thin transfer punches can slip sometimes. Good luck
 
Tony, a step stud; Years ago, more than I can count = they were not made sold & nobody heard of such a thing (around here) this was a repair for truck rear axle hubs
where as some crow mag ruined axle studs. I use to re-drill larger and tap the hub then thread that to 'say' 1/2" then tread the other end of stud to '3/8'', so I thought
I invented the "step stud" ??? Most likely not so , they must have been invented, but it was a time with phone booths and no internet, just mom & pop hardware
stores.... We had to machine things back then. sam


"put the shop classes back in high schools"
 
plug the threaded hole and drill & tap again, using the cap as the reference for the new hole.

a tip i learned from a mentor was to do 1 hole at a time and put a bolt/screw in the hole you just drilled and tapped before moving to the next.
it's a lot slower- but it's really hard to mess up and you won't have to do it twice.
 
I did one hole at a time, but the 1/2" template had a pretty deep counterbore and a thin wall , so the long transfer punch must have gone crooked. In fact, the last hole I decided to do it differently. I found a drill that was the exact diameter of the counterbore, reversed it into the chuck, and used it to center my mill chuck relative to the hole. I then was able to drill the hole perfectly. On a different note, in order to thread a small rod, I needed a metric die. I have a 1 1/2 die holder, but knew that most dies sold at the local hardware store are 1". This gave me an opportunity to make an adapter for a small 1" die. After a couple of hours and feeling good about the results, I went to the hardware store and , to my horror, the dies were all octagonal, which , of course, wont fit into my round adapter.
Also, what is a good cleaner for wd-40? This what I used as a lubricant for tapping.
thanks for all the good information.
tony
 
If you add some set screws to the adapter you made, you can use the set screws to tighten up against the die for holding! 3 set screws would most likely suffice

Carb Cleaner, Lacquer Thinner, Brake Cleaner are all on my shelf for degreasing
 
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