Removing stripped set screw

Hey Folks,

Any suggestions on how to remove a firmly stuck set screw that is now stripped? Set screws are the four short screw/bolts that clamp the Rover halves to the boom. They're the ones that go into the corner of the frame tubes on Rovers of the last few years. I'm not talking about the older Rovers that had large bolts go straight through the frame.

In my case, I noticed sometime last year that 2 of the 4 were firmly stuck (presumably rusted in place), and in fact sheared off the bit on my 3-way allen wrench. Earlier this month I gave it another shot. This time did several passes of WD-40 over several days, getting both the exposed side of the bolts as well as squirting it into the frame to get the back end. 

I got one of them loose, but the other has now has it's hex hole stripped. Using the proper sized bit just results in the bit clicking around, and a larger bit won't fit in the hole.  Can the set screws safely be drilled out? How hard are they, are they hardened steel?  Any other ideas on how to get the last one out?

- PaulNM


  • A good diamond or carbide tipped drill bit run at low speed with cutting oil or other lubricant to cool it might enable you to drill far enough into or through the grub bolt to permit using an "EasyOut" to remove it.

    Another alternative that may or may not work is to heat cycle that area of the frame. The frame and the grub bolt will have different coefficients of expansion relative to temperature. Alternating between heating that part of the frame and grub bolt until too hot to handle and then icing it down may be enough to allow you to break the bolt loose. You will probably have to repeat this method several times... and even then it may not work.
  • You may find an easy-out that will work in the set screw without drilling. Just find one that needs to be tapped (struck lightly with a hammer) into the stripped hex key hole. Use a heat gun or hair dryer to heat the area around the screw. Then use a can of computer cleaner air (the cans of compressed air for blowing out keyboards and such). Turn the can upside-down and lightly spray the liquid into the hex key hole to cool the screw. Then insert the easy-out and give it a try.
    As jamesr said a t-handle tap wrench works very well for turning the easy-out.
    Even with cobalt or titanium drill bits it is near impossible to drill a set screw. They are extremely hard.
    Once you have succeeded in removing the old set screws, go to an auto parts store and get some anti-seize compound. Use this on the threads of the new screws instead of grease. It works much better and lasts longer.
  • I haven't had much luck with easy-out type products in the past. The screw/bolt I'm trying to remove always seems either too hard to actually tap into, or too soft and I'm just boring a small hole into the head.

    I'm thinking of sacrificing a hex bit and using something like j-b weld to bond it to the set screw. Then use a combination of heating the frame with a hair dryer and cooling the set screw with an upside-down air can.

    I just don't want to damage the frame itself, or the paint. 

    - PaulNM
  • I agree with jamesr. His idea of using an impact driver is spot on. You should be able to find hex bits locally too. If you go this route and not sure how to use the thing, just ask. I use to work on commercial aircraft and those drivers were GREAT for loosening stuck screws.
    Thanks jamesr for reminding me of them.
  • The $9 item on HF is is an air compressor accessory, not a self-contained impact screwdriver. 

    I do have access to a an easy-out set, though the bits are too big for the power driver I have.  I think I'll try them with Mjolnir and see if it loosens the rust or lets the easy-out set in enough to use. [ Mjolnir being a beautiful wood-handled club hammer I got from my father. :)

    I'm still open to other ideas, though my big priority right now is taking care of my brake handles, brakes, and setting up my idler. (Once the new parts I ordered arrive.)

    - PaulNM
  • Interesting, that doesn't come up when searching for impact driver. I'm resisting the temptation to put in a mini-rant about crappy text indexing, but I doubt anyone would be interested. :)

    Thanks for the link, but now I'm confused how that would be any better than just using a hammer on the bolt itself. What am I misunderstanding about how it works? 

    I thought the reason people were suggesting impact drivers is because they can hammer the bolt more quickly than possible by hand. (More vibration = better breakup of rust/friction)

    Still thankful for the suggestions,

    - PaulNM
  • You twist the impact driver as you hammer it. The twisting action converts to very strong torque in the same direction as your twisting with each hammer blow. The impact driver was one of my irreplaceable tools back in my days as a sewing machine mechanic.
  • Ah, that explains it. I was thinking of the hammer drill setting on most power drivers, where it just hammers back and forth. The manual impact driver you folks pointed to converts some of the energy from hammering into torque. (Kind of like a salad spinner or hand held food chopper does.)

    The problem in my particular case is that the the hex hole is stripped, so there's nothing for the twisting motion to bite into.

    I'll take another look at it this weekend, though. (When I borrow my father's easy-out set.) I'm pretty sure the hex walls are stripped all the way to the back of the hole, but it's possible I'm wrong. In that case, there may be enough in the back to bite into if enough force is used on the driver.

    - PaulNM

  • Sadly not. (Regarding larger bit) That was one of the first things I thought of. I have both imperial and metric hex bits, and the next size up in either set is too big to fit. :(

    It's supposed to be pretty cool this weekend. (I actually had to turn on the heat today!) So prior to the easy out I'll try gently heating the surrounding frame with a hairdryer for a bit. I'll also recheck how badly it's stripped. Unlike a flathead or phillips hole, stripping a hex hole usually results in a smooth circle. Maybe I'll get lucky and find just enough purchase left to wedge a flat head bit into?

    - PaulNM
  • Just a thought. If the hole is too smoothly rounded out perhaps a torx bit could be driven in. The edges might be able to bite in enough to provide some purchase.
  • too bad your not anywhere close to me id knock it out for you
  • Sooooo...... Update time:

    I did the hot/cold expansion trick, and bashed the set screw a bit with my club hammer and a bit to try and loosen things up.

    Then I went ahead and hammered an easy-out into the set screw. One nice surprise that I didn't anticipate was that the easy-out screw was wide enough to also bite into the walls of the stripped hex hole for extra grip.

    Used a wrench and started turning the thing, and it looked like it was working. Either that or it was just screwing further into the set screw.

    Next thing I know, the easy-out broke. :( So now I have a firmly stuck set screw, with a broken shard of metal firmly ensconced in the hex hole. The shard broke at such an angle that I can't really get a grip on it with anything to pull it out.

    So yeah........

    I'm taking a break from this particular project for a little while. I just got my new brake handles and idler setup, and plan to send time this week getting them installed. 

    - PaulNM  
  • Here's how to remove the broken easy out. The metal is extremely hard and therefore brittle. You can get dry ice from local grocery stores or Walmart.
    Using an old towel, or whatever you like, pack dry ice around the entire area where the screw is. A towel will allow you to wrap around the dry ice and hold it in place.
    WEAR GLOVES!!!!! WEAR GLOVES!!!! Dry ice against bare skin can get you near instant frost bite.
    Leave the area wrapped for at least 1/2 hour. It may take longer, so if you've got the time, use it. Just make sure the dry ice doesn't completely melt away.
    Wear safety glasses!!
    Once the screw is as cold as you can get it, use a punch and hammer to strike the easy out. The extra cold will make it shatter like glass and not harm the surrounding material.
    Don't try to drill the easy out. It is WAY too hard.
    I've been in your position many, many times and have used this method to remove the broken easy out.
    Have another easy out ready. As soon as you get the broken one out, try using the new one to remove the setscrew. It might just come out.
    Good Luck!
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