Screw extrator hints... Stubborn bolt.. (1 Viewer)

Can anybody give me pointers in how to use a screw extractor:



I bought a set from Black and Decker for various diameter screws and was wondering what is the general idea. No instructions on the box and I did find one site where i got the picture above but it says you have to drill out the bolt and then use the "screw extractor" above. That means I don't use the screw extractor to drill the hole, but a slightly skinnier drill bit and then use the S-extractor in reverse to back out the stuck bolt.

The bolt is a 6mm hex bolt that fixes the rotor to the hub on a '97 BMW 328i. I did the passenger one fine, but I think I rounded out the 6mm bolt. I even tried a electric impact wrench which just rounded it out even more! D'oh

Jay

If it is the extractor I'm thinking of, you should just be able to stick the bit in the existing hole and go from there. You will probably need a variable speed drill and work slowy until it grabs and comes free. You'll also need to lean into it a bit to get it to grab. Controlling the speed is the key, as too fast and all you are doing is drilling!
Also, if you can get at it, whack the screw with a hammer to hopefully loosen the threads a bit, or use WD40 on it first.

If you stripped it from torque, I'd bet the extractor will not do any good. What I'd do as the first attempt is to get a dremel, a diamond straight bit, and with a little patience enlarge what is left of the hex pattern into a 7 or 8mm size.

what mike suggested is what I do

I guess the first image's URL changed...

I did eventually find instructions for it, but I need to borrow a drill from a friend. My father has the drill down in Delaware. The procedure according to what I've found is to drill a hole into the bolt then bang the extractor in and use a T-handled tap wrench to back it out. They say even a Left-handed drill bit is the best as you would be drilling in the direction of loosening and the bolt might come out just by drilling. So I'm going up to my sister's to borrow her husband's drill and seeing if he has a tap wrench. Then I shall go to a Home Depot and see if I can get one and perhaps a LH drill bit of the right size...

I have a dremel tool but my last ditch effort of using an (electric) impact wrench has simply completely rounded out the hex.

Jay

Okay, that's not what I thought you had. Craftsman makes a set of bits that are specifically designed for taking out stripped screws with no drilling required. They were the hot ticket item last Christmas.

Well, got the bolt out, except there's a small part in the back that's stuck cause the head of the bolt was so hollow the whole head sheared off. I got the old rotor off but unfortunately, the new one wont go on until I can drill out the rest of the bolt. I can even see about 1mm of bolt out the back side but its so small and rusty I cannot get any kind of grip on it with pliers. It's too skinny to use regular wide pliers and needle nose pliers do not get enough of a grip.

So I'm trying to drill out the rest of the bolt and it's not working, I bought a Ti drill bit and was using that for a bit but it's at a point where it's simply spinning and not getting grip. I've tried 2 smaller drill bits and broke 'em

I might try a dremel tool and the guide next. But afterwards I think I should be able to use a tap and drill and rethread the remains and still use a new fixing bolt of the same size... I didn't drill out the actual outer thread diameter.


[ edit] Whoohoo, I got the bastard off... I managed to use a drill bit that didn't break and got a hole through the back, after that it was simple to simply use larger drill bits to ream out the hole. Now, after talking to some BMW folks, I'm told that bolt is really just fixs the rotor to the hub so the 5 lug bolt holes line up. It's not there for any structural necessity!!! Didn't think so, looking at how small that bolt is. The 17mm lug bolts go through the wheel, through the rotor and then to the hub so that keeps the rotor from spinning when the brakes are applied...

Oh well, I am going to try to tap and drill out the hole I just created and see if I can use a bolt that I got but at least now I know I don't have to shell out money for a new hub!!!...

All weekend, I'm trying to wonder why I am going through this, but then always go back to the dealer wanting $960 to change rotors and pads... GASP!!!!! when new rotors and pads can be gotten for less than a third of that price.

Jay

too late now, but sometimes machinists use left hand threaded screws, don't know why. But you might have been able to drill a small hole like you did, then screw that in, works about like the extractor you bought only it's not tapered.
Like I said, I'm backwoods and gring a slot in em with the dremel, then use a large flat bladed screwdriver to pop them loose

I think left threaded screws are used simply because if you do use a drill, you can use the forward speeds when drilling which for left handed screws means you're loosening them. The way I was drilling the bolt out, I was using a standard right threaded drill bit which is in the tightening rotation. I tried to use the reverse speed on the drill to see if I could get the remains out, but that didn't work and I didn't want to ream out the hole too much for fear of not being able to use the bolt I bought...

I looked at Home Depot for a diamond tipped dremel bit but they told me to go to Sears The one I go to doesn't carry them and like the big box stores, nobody else is in business anymore :frowning:

Jay

Does anybody know where I can find a METRIC 8mm threder, I think they call it a tap, but it puts threads on a drilled out hole... The bolt I got out is an M8x14 which means it's 8mm O.D. and 14mm long (I didn't measure the pitch yet but it looks fairly standard at that size. I have checked a HD and all they have are SAE sized taps...

Besides online, do you know of any hardware chain that carries metric stuff... ALL my bikes and cars are all metric sized and everytime I go to a hardware store, 90% is SAE.. what gives?

Jay