Hi Everyone,

  I hope this is the right forum for this.  I have an old Craftsman drill press. I was taking the belt off so I could replace it and the motor mounts on two rails that you can adjust the distance from the pulley on the drill shaft.  Well, when I was tightening the bolts,(one on each rail), I sheered the head off of one.  Now I can't get the bolt out.  It is kinda rusted and I have tried a stripped screw head extracter bit but I think it is too small.  All it has done is carve out an bowl in the bolt.  Does anyone have any suggestions on how I can get this bolt out ?

                                                                                                   Kerry

Get an "EZ out" (trade name). Drill out the center of the bolt and use the EZ out to remove it. They come in a variety of sizes, and sets, and can be found at most hardware stores for a few bucks. Spray the bolt with penetrating oil to help removing it.

If you remove the remaining bolts will it give you access to the broken one -- so you could get some vise grips on it?

It's common practice to use the method "Racer" gave you with the easy out. Use a EZ-out and drill bit size, slightly smaller then the size of the broken bolt. You could try heating it up some with a propane torch, insert the EZ-out and it should remove the broken bolt. Applying a good penetrating oil a few times and allow it to work will help break the frozen bolt free also to help in the removal.

Thanks Guys for your help ! I will go get an EZ-out and use that. Bill, removing the other bolt does not expose the sheered off bolt. Each bolt goes directly to the round rail that the motor is attached to. But thanks for the suggestion. Thanks again everyone !! I will let you know how it goes.

Kerry

What size is the bolt.

If large enough you can use a center punch and back it out.

Replace with a grade 8 bolt.

The bolt is about 1/4 " in diameter.  It sheered off flush with the surface and after I tried a stripped screw head extracter, it is now bowled into the surface.

                                               Kerry

Kerry,

Can you post the exact model of Craftsman drill press?  It will be on the nameplate which may be difficult to find/see.  (mine is)  It will be three numerical digits followed by a period and then 5 to 8 numerical digits possibly with a letter near the end.

You apparently used a left-twist screw extractor that was probably undersized for the application.  (I've generally found them less than satisfactory.)  The good thing is that it probably made a nice starting point for drilling a proper hole for an EZ-Out type bolt remover.  For drilling that hole, if you can find a left-twist drill bit of the correct size, the left turning might just back the bolt out while you are drilling.

Some other thoughts:

A good rust-busting penetrating oil has to be used and allowed to soak for a day.  Kroil is my favorite but others like products like PB Blaster and others.  WD-40 is almost useless for this application.

A little physical shock is a help once the penetrating oil is well applied.  Don't be shy about center-punching down in the bottom of that "V" shaped bowl you've already cut.  It tends to loosen things up.

Needless to say, remove everything around it, including motor and mounts.  If you can, remove the 'rails' so you can take them where it is easier to work on.

When everything is removed, is either end of bolt sticking out where you can get a Vice-Grip on it?

 

This is the Kroil Penetrating Oil Bob is refering to. Quite some time back on the OLD FORUMS we had good testimonial from members who use this product.
At the bottom of their home page there is a discount sale using a Google sale code. Two King size cans for under $15. I suggest and recommend you check out this product. It may be to late for this problem but I'm sure you will find a use in the future.

Based on Kano's scientific discoveries, Kroil
creeps into millionth of an inch spaces, dissolves rust,
lubricates and quickly loosens frozen metal parts,
frees rusted bolts, frees frozen shafts ...
Serving the Fortune 500 companies since 1939.

http://www.amazon.com/Kano-Aerokroi...dpp_img_ex

http://www.kanolabs.com/google/ 
use this site for the discount special order 2 for 1 at a cost of only $12 plus transportation.

To add to Oldman's post about heat, and penetrating oil.......
Apply heat with a propane torch (it doesn't take much), THEN add the penetrating oil.......The heat will help "draw" the oil deep into the threads as it cools off....sort of like the capilary action of soldering.
GOOD LUCK

eeyore

Did you get the bolt out yet? I have much experience removing broken bolts, and agree with the advice given so far. There are still more options available.

The simplest way to remove a bolt/screw that is not under too much tension is to use a very narrow rotary cutoff tool (mine is about 1/32” thick and 1” diameter, and fits into a Dremmel tool) to cut a straight slot into the stud/ stripped head, then remove the screw with a straight-slot screwdriver. If cosmetics are not important then you might consider if it is alright to cut into the surrounding metal to cut the slot deep enough.

Sometimes, a welder might be able to weld onto the stud and remove it. This doesn’t sound like this is an option in this situation, and it would be difficult after penetrating oil has been applied.

There is one option which is generally used as a last resort, which takes patience and skill, and is best performed on a milling machine, but can be done at home. I have “saved the day” many times this way: First, use a rotary (dremmel) tool or center punch to get the center of the stud hollowed out in the middle. Then select the bit long enough for the job; it may take progressively longer bits. For a ¼” bolt, I would probably go with a 3/32” carbide ball mill, or HSS drill. (You have to be careful not to run the tool too fast if using HSS in a rotary tool, but a hand drill won’t normally spin too fast for a small bit). Then drill to the bottom of the bolt, taking your time and keeping the hole as close to the center as possible. The root diameter of a 1/4- 20 bolt is about .201, so if the hole is centered real good then go ahead and open the hole up with progressively larger drills until the root of the female threads begin to be exposed. A 3/16” drill works great if all you have is fractional sizes. The goal is to remove the core of the bolt, and then the remaining threads can be plucked out with a sharp-pointed pick. You might have to go back and carefully remove bits of metal with the rotary tool, being careful not to remove too much female thread.

Having already tried an extractor set that failed, you just start this technique where appropriate. It usually works, but not always. Keep in mind that the deeper the threads, then the total amount of thread which is needed to hold the new bolt is less important. If all this fails, then consider just drilling the whole thing out and adding a larger bolt, but that’s too simple, right? Yes, of course you need to be able to put a larger bolt in that place, and you need a tap.

Then there's the "helicoil" method, but that takes expensive tools, and might be cheaper to have a machine shop do it for a one-time case.

Another option to consider, if the top threads are damaged too much, and if there is enough room for a longer bolt, is to simply drill the hole deeper and tap the hole for a longer bolt. Sometimes, if the core of the bolt is removed, the tap can carefully be used to loosen the deepest threads left in the hole from the bolt. A poor man’s tap can sometimes be made from a hardened bolt, which has a “V” ground perpendicular to the threads at the tip of the bolt, IF the base metal of the female threads is soft enough, and lubrication is used. This is also a great way to restore damaged threads before putting a good bolt in place. Identify a hardened ASE bolt by the 5 or more radial lines on the head. Metrics are different. Hope this helps.

Andyman,

Great post! Obviously the voice of experience. Are you available for hire when a really tough one comes up??? LOL

Wow !!! Thanks again everyone for the good advise !! I heard that this forum was a good place to get advise, but this is above and beyond what I expected !!
As an update, I have been so busy with work and of course, my daily "Honey do" list, (those of you who are married know what I mean), I have only had time to spray it with some WD-40. Bob, I will look at it today after work to see if I can find a model number and post it. I know it is pretty old. It used to be my father's. The casing on it is like a cast iron, maybe aluminum. The bolt is not sticking out on either end. It tightens right onto the rail that the motor is attached to.Oldman, thanks for the info on Kroil Penetrating Oil. I will definately look into that. Andyman, WOW !! What alot of good info !! I think I will start with the EZ out first. That sounds like it would be the easiest. Then if that doesn't work, I will look into the other options you said.

Kerry

I have a set of left hand drills that are a little smaller than the original tap drill size. They have saved the day quite often.

Randy

 

I'm a bit concerned that you tightened the bolt enough to shear the head, unless the bolt was defective. You shouldn't have to apply that much torque. If I were you, once you get the bolt extracted, I'd replace it with at least a grade 5 bolt which will take more torque than a standard grade 1 or 2.

Ok guys,

 The model # is 101.03581.  Here is some pictures of it.  I tried drilling it and using a stripped screw head extractor to get it out.  The only problem now is the cheap screw head extractor broke off in the now hole.stripped screw head extractor broke in hole.As you can see I took off the motor so there wasn't the added weight pressing down on the rods that it rides on.
So, now what ?

                                                       Kerry

Wow! When you said it was an "older model" you weren't kidding. I think, judging by the age, a good long soaking in penetrating oil would be the very first step. If you can get it onto it's side would allow the penetrant to stay in place where it can do it's job most effectively. Also looks like you will be needing to use a flame wrench on that bad boy as those bolts have had plenty of time to grow roots Good luck. If all else fails, take it to a local machine shop and have them arc weld a bolt onto the old one, then heat around the threaded hole before trying to extract it.

Dewy,

I can get it on it's side. I just have to unbolt it from the table it is on.  What is a flame wrench ? It is only the one bolt that is sheered off.  You can see the hole in the photo.  But that thing in the middle is not the bolt.  That is the stripped screw extractor that I snapped off in it.

                                                          Kerry

Posted By khubert on 09-12-2010 07:53 PM
Dewy,

I can get it on it's side. I just have to unbolt it from the table it is on.  What is a flame wrench ? It is only the one bolt that is sheered off.  You can see the hole in the photo.  But that thing in the middle is not the bolt.  That is the stripped screw extractor that I snapped off in it.

                                                          Kerry

Sorry, may be a mechanics term, lol, flame wrench = oxy / acetylene torch

Try a very small cold chisel (sometimes called a 'coal chisel') on that stuck extractor. They are quite brittle and should shatter.

EDIT  --  It will be a lot easier to work on laying flat on its side.  Kroil will work better there too.

(Now I think I understand what you mean by 'rails'.)