how to remove a broken off screw

[atr]

Hi guys,
a friend brought over a very nice Zastava model 70 in .308Winchester but it had a broken screw in one of the holes on the receiver for securing scope bases. The top of the broken screw is flush with the top of the receiver. I would appreciate any suggestions on how best to remove this screw. If the screw can't be removed then I suppose the other option would be to have the a new set of holes drilled and tapped.
you thoughts would be appreciated.
best
atr

[akajun]

Take it to a good gunsmith or machine shop along with the scope base
Thread should be 6-48
They’ll put it in the mill and drill it out undersized and clean out the threads

[pworley1]

I have removed them by using a left handed bit smaller than the hole.

[LAGS]

I often have drilled like 1/16" hole in the broken screw.
Then I pounded an Allen wrench that fits snug into the hole.
Then just unscrew the broken screw.
You might want to warm up the receiver a little in case the screw is rusted in place or is bottomed out in the hole.
Be sure you drill the hole in the center of the broken screw.
Also.
Putting a drop of Crazy Glue on the tip of the Allen wrench helps it attach better when you drive it into the broken screw.

[country gent]

You can use a small prick punch to walk t out by tapping it in the right direction. If its been locktited this will be a lot harder. I have removed a lot of screws like this. You can drill it out with a solid setup, a left hand drill works best. I would start with a clay dam and soaking in kroil for a couple days

A solid drill press min better a mill, center drill and then drill keep the bits as short as possible for rigidity.

[Recycled bullet]

If it was my gun I would heat up the broken screw with the soldering gun and then try to walk it out with the smallest drift or an awl if it is possible to do so without skipping and damaging the bluing or scratching the receiver.

[contender1]

One tip I use is to put the gun under a magnification lamp, and CAREFULLY flatten the broken area of the screw PRIOR to trying to drill it or tap it out etc. I use a dental burr in a Foredom tool to do this. Go slow, flatten the piece,, the start the removal process. And as noted,, heat or soaking in Kroil is also very desirable.

[truckjohn]

If you don't want the gun all dinged up - take it to a machine shop. An automotive machine shop will work fine. Removing broken screws is bread and butter for them. Just be aware that you may be required to wait at the shop while they work on it if they are not a licensed FFL.

[dtknowles]

There is a tool called and EZ-out (SP)

https://www.harborfreight.com/screw-...a28801593589fe

You can get a cheap set from Harbor Freight or maybe better ones elsewhere.

You still have to center drill the stuck screw. Heat, pen oil, etc. help but it not locktited should come right out. Like most machining operations getting set up right is very important. Need a good vice, drill press or mill. Need to center punch and be close to level. Since you are using an undersized drill you don't have to be perfectly level (perpendicular). Like others have said, a shorty drill bit or just chokeup on it so it doesn't wobble, you are not drilling a deep hole and you don't want to hit the bottom of the hole.

Tim

[GregLaROCHE]

This thread has convinced me to buy a set of left hand drill bits, to have around just in case. Are left hand drill bits used for anything else?

[Jimmynostars]

Build the broken screw up with a Tig until proud, weld a scrap of flat to this and unwind once cool.

If scrap breaks reattach. The heat will cook any locktite, the expansion and cooling also helps to break free rust etc

[Rapier]

You can use a LH bit the same as a RH bit to drill a smooth hole. Most folks use the LH bit with a centr drill bit, to remove broken RH bolts or screws. It is quite normal process in shops. They tighten stuff, real well and some bolts or screws are defective and just snap off. But the public has no clue hen it comes to thread locker, if a little is good, a lot is better, so pour it all over everything, making a huge mess.

While on the subject, clean the screw hole and screw shank threads with acetone on a q tip. Put a toothpick's tip size drop on the screw thread only, just one little drop on one side of the shank. Screw the scope base screws in tight. No more thread locker than that.

[Soundguy]

I have removed them by using a left handed bit smaller than the hole.

ditto this. a fine tipped diamond abrasive or center punch to start it straight.. then drill out left. unless a red loctite was used.. usually the bit pulls the screw out before you get thru it anyway.

[Electrod47]

[QUOTE=country gent;5580122]You can use a small prick punch to walk t out by tapping it in the right direction. If its been locktited this will be a lot harder. I have removed a lot of screws like this. You can drill it out with a solid setup, a left hand drill works best. I would start with a clay dam and soaking in kroil for a couple days

This method has always worked for me also. Use patience and a steady hand, even take more than one attempt. I fussed with one for 3 days and it finally started to move.

[dtknowles]

Can't use a left hand drill bit on my drill press or lathe, they don't reverse.

[Soundguy]

Small lefty and a hand drill. Just get it centered..pin punch or a diamond bur. Slow is often better.. You pretty much WANT the bit to grab and extract the screw.

[LAGS]

The left hand drills work great.
But finding them and spending that money for something that you probably only use once in a great moon isn't that good for the average guys.
But if you are a full time gunsmith they are well worth the cost.
And you brought up a good point.
Lots of drills or presses do not have a reverseable option.
Hand drills do.
But drilling in the center of the small screw is a little more difficult than with a drill press.
I try to provide options that the average guy can do if needed.

[atr]

thanks guys.....the only suggestion that confused me was the one about applying the hot tip of a soldering iron to the stuck screw. Wouldn't the heat EXPAND the screw making it tighter in the hole?
I can understand if the screw was place with blue lock-tight, the heat would help break that.

I am off to my cabin for the next week or so, If you want to see cabin pictures go to Outdoorsman/hiking and my "I did it" post
best and have a good safe Memorial Day.....Memorial Day means something to me.
atr

[MostlyLeverGuns]

I have used a a fine pointed diamond tip in a Dremel to cut a groove in the scres for a very small screwdriver. Must be held solidly in a vise with two hands on the Dremel. Not easy, great care required.

[LAGS]

Heating the broken screw will not expand it far enough to prevent removal.
But it will soften any rust or Locktite.
If you use that Allen wrench method.
You have to be sure you don't use a Allen Wrench that mushrooms out the hole and expands the broken screw too much.
When I use that method.
I found that it sometimes helps if you taper the tip of the Allen Wrench just a tiny bit so it starts into the hole easier.
But the corners on the Allen Wrench still dig into the broken screw for a better bite.