Gunsmithing Broken rail screw won't back out...

I

Indypendent

Just a dude
Full Member
Minuteman
Nov 8, 2009
160
1
49
Yuma, Arizona, USA
#1
I broke the head off the forward most of the 4 screws on the top of this R700. I tried backing it out with a small flathead...didn't work, there was no positive surface to tap against. I tried drilling/prepping it for an easy-out but I can't a bit to start a hole on that screw.

Any suggestions?
 
#4
Re: Broken rail screw won't back out...

I take it the base is off the rifle.....

Is there any of the screw shank above the receiver?

If so, use a pair of needle nose vise grips and grab the exposed shank. Add a little bit of heat and it should back out.

Or......using a cratex wheel on a dremel, polish the shank down flat, center punch, drill and then use the easy out.
 
#6
Re: Broken rail screw won't back out...

You may have to use a center drill if the shank is broke even with the receiver. Try a sharp center punch prior to drilling.

If it were me, I'd dimple it with a center drill. Afterwards, drill with appropriate size bit and retap it.
 
#8
Re: Broken rail screw won't back out...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AJ Goddard</div><div class="ubbcode-body">Take it to your gunsmith and have him upgrade it to 8-40 screws. </div></div>

+1
 
#10
Re: Broken rail screw won't back out...

Smack it hard, with a round/flat punch, then center punch. Might try drilling with a left hand drill, you might get lucky.

....and quit using loctite. If the fastener is not doing the retention job with lubricated threads/torqued in place, then you need a larger fastener.
 
#11
Re: Broken rail screw won't back out...

Use 135 degree double ended jobber bits in an air drill. Electrics have too much
torque on fire up. Next , you are going to have to use heat after drilling it to remove the screw because of the locktite. I keep a set of left hand drills and a lot
of them unscrew while I am drilling as the drill creates the heat. In the job I was in
I literally have removed 1000's of broken screws.
 
#12
Re: Broken rail screw won't back out...

Use a stubby carbide drill bit. HSS steel is likely not going to cut the screw without risking a broken bit anyway. The carbide will blow through it like butter.

AJ's advice is the the cleanest, best route IMO. Have a 'smith blow it out with a 9/64 EM and have the holes trued up while they're opened to an 8-40.
 
#13
Re: Broken rail screw won't back out...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bigwheeler</div><div class="ubbcode-body">Use 135 degree double ended jobber bits in an air drill. Electrics have too much
torque on fire up. Next , you are going to have to use heat after drilling it to remove the screw because of the locktite. I keep a<span style="color: #006600"> set of left hand drills</span> and a lot
of them unscrew while I am drilling as the drill creates the heat. In the job I was in
I literally have removed 1000's of broken screws. </div></div>
If you are not familar with what they are, do some research and get some, it is what I used when I had to get my broken front screw out. The front screw broke because the screw was too long and it came up against the barrel threads before the rail got tight.
As a test, I now put the front screw in first to see if it going to tighten the rail down before it bottoms out.
Good luck,
SScott
 
#14
Re: Broken rail screw won't back out...

A #1 carbide center drill will put the required hole in the grade 5 screw to allow the use of an easy out and wont walk on you and damage the threads.

Just had to do this.

For larger tactical scopes and full lenght picatinny bases you should get your rifle upgraded to the 8-40 base screws.
 
#15
Re: Broken rail screw won't back out...

Carbide tools are not near as strong as HSS. The chance of breaking one off in
an uncontrolled environment is high. All clamped down in a good mill or press
they are fine. That is a lot of trouble to go through for a broken screw. Usually
a 10 minute job with a hand held air drill. One small hole and one the finish size.
And a 135 degree split point will eat those screws like butter unless it's some
cheap chinese crap with a piece of unmelted file still in it.
 
#17
Re: Broken rail screw won't back out...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bigwheeler</div><div class="ubbcode-body">Carbide tools are not near as strong as HSS. The chance of breaking one off in
an uncontrolled environment is high. All clamped down in a good mill or press
they are fine. That is a lot of trouble to go through for a broken screw. Usually
a 10 minute job with a hand held air drill. One small hole and one the finish size.
And a 135 degree split point will eat those screws like butter unless it's some
cheap chinese crap with a piece of unmelted file still in it. </div></div>+1 carbide is very hard but also very brittle. Chances of chipping or breaking the bit using a hand drill are very high.
 
You must log in or register to reply here.

Similar threads

L
Gunsmithing Stuck scope base screw
Replies
12
Views
806
Easy_E
E
B
Help removing broken Allen key
Replies
24
Views
826
Yakface
Y
Q
Gunsmithing Stuck B&L scope ring
Replies
4
Views
206
Mike Casselton
Mike Casselton
M
Officially a lifelong supporter of Seekins Precision
Replies
3
Views
425
Texascbr
T
hafejd30
SOLD FS/FT- ATX Gen 3 Elite Sand/Folding
Replies
2
Views
380
hafejd30
hafejd30
Top Bottom
Back
Home
Forums
Merch
Alerts