Automatic center punch screw in tips snapping off.

[gellfex]

It's not like it happens all the time. But now I've got both a Starrett and General unusable with the threaded stub in there. I guess they must have unscrewed a little then fallen on the tip. They're a General #79 & a Starrett 18A. Any clever ideas on how to extract the piece? Since they don't seem to sell parts, I guess my only option is to make, tap and harden the pin and not think about how maybe I should just spend the $30 for a new one and not waste my time.

[Scottike]

If they are indeed loose just use a pair of compass points (bow compass) to grab and unscrew the stubs out to where you can get a grip on them.
If they're tight use a left hand drill bit (If you can get one small enough, 1/8" is the smallest I've found.)

[flutedchamber]

I had the same problem as you have written. I think you are right..the tip became unscrewed just a bit and a side load was placed on it and snap..it's broken.

I've had great luck with a 1/16 Allen wrench ground to a gentle angle to give you just short of a needle point. I used the point straight down to catch a rough piece of the tip and turn it out with downward and counterclockwise pressure. If there is no rough spot to catch then a small tap on the end of the pointed tool will give you a spot to catch the point on and turn the piece out.

I made replacements and hardened them then put a drop of low strength Loctite on it. These come out readily with a firm grip on pliers but don't come out by themselves.

[Duffy]

Starett sells replacement tips, but I think I paid about $8.00 for one, so they are NO bargain!

[RussZHC]

Your issue with the tips is perhaps the only thing with the General version I have had that has NOT gone "wrong".

Very, very disappointed with the function of the "automatic" part, works the first attempt maybe 20% of the time...

I am more or less done with automatic center punches, way to exasperating.

[gellfex]

I've tried persuading the stubs out with scribes and such to no avail. But Russ, I've had no problems with these punches as far as missed punches, and I have a 3rd Starrett functioning perfectly. Maybe you got a lemon. The little pencil General #87 version IS a piece of crap however.

Duffy, I assume you don't mean the screw in tip which costs $3-4. Where did you see them? I'd pay $8 to save a $30 tool I use everyday.

[Tony]

McMaster has the tips.

I went through the same thing just recently.. I had two scribes in the drawer
one small on "regular" both with broken tip threads I couldn't get out.

I even bought the replaceable tips before I tried to get the broken ones out.

So I was invested, know what I mean? :)

Anyway, tried everything, finally a wood dowel with the trip sharpened to
the largest size that would fit in the hole, in a drill, running backwards
(unscrewing) at high speed, with as much pressure as possible, got
them right out.

It was a shot in the dark but it worked.
Screw extractors did nothing.

In my case, I think the heat is what did it.

-Tony

[Lew Hartswick]

I can't imagine doing any sort of, even fairly accurate layout, with one
of those things. an 8 Oz. ball pein and a regular centre punch is the
answer. Preferably a "Prick" punch first so you can see the cross
scribed lines. :-)
...lew...

[JCHannum]

I keep two of the auto centerpunches on the bench for accurate layout work. A light one for the initial "prick punch" and a heavy one for the second punch mark. I find them as accurate as using a hammer and punch and less likely to go amiss due to shifting your attention when striking with the hammer.

It is all a matter of personal preference and what works best for you.

[Duffy]

Even if you dont think much of them as layout instruments, if you carry one in your car, they are the fastest way to break a SIDE OR REAR window to get out if you are ever trapped.

[gellfex]

I can't imagine doing any sort of, even fairly accurate layout, with one
of those things. an 8 Oz. ball pein and a regular centre punch is the
answer. Preferably a "Prick" punch first so you can see the cross
scribed lines. :-)
...lew...

I find it works for both, at least in the non-ferrous softer materials I typically use. A soft push for the prick, double check accuracy, then a harder push for the punch. BTW, the latest model of close up visor from Harbor Freight rocks for layout etc. They had an older version that was a POS.

Tony, even before I got to the end of your post I was thinking it was the heat. Worth a try!