# Center-Punches



## The_Apprentice (Feb 27, 2018)

I am wanting to be able to center-punch some steel, including some stainless steel as well down the road. Mostly for just getting a drill started into the metal.

I am curious, is something like this perfectly feasible for this?

https://www.princessauto.com/en/detail/5-pc-centre-punch-set/A-p8548075e

If so, I'll grab a pack.


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## benmychree (Feb 27, 2018)

Probably, but you should also have a prick punch; they have a 60 degree point instead of the 90 degree point of the center punch. You use them to make a small impression on the intersection of layout lines before enlarging it with the center punch; when the prick punch when sharp can feel the intersection of the lines as you drag it along one of the lines at an angle, you then upright it and tap it lightly with a small hammer, then look closely and if it is squarely on the intersection, tap it a bit harder, followed by the center punch.  It is possible to locate a hole within a few thousandths with an accurate layout by this method.


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## whitmore (Feb 27, 2018)

The_Apprentice said:


> I am wanting to be able to center-punch some steel, including some stainless steel as well down the road. Mostly for just getting a drill started into the metal.



The most convenient approach is the springloaded autopunch (after making a prick mark, locate the point in that small dent,
and a simple hand push causes a small internal hammerblow under spring pressure).   It's pocketable
and doesn't take a hammer.
This one is nice


https://www.amazon.com/Starrett-18C-Automatic-Heavy-Duty-Adjustable/dp/B000VDVR6W 
but the Harbor Freight version  isn't too bad either
	

		
			
		

		
	




https://www.harborfreight.com/automatic-center-punch-with-brass-handle-62141.html


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## ttabbal (Feb 27, 2018)

Just out of curiosity, I have a hell of a time with my HF version deciding not to hammer. I'll likely buy a better one anyway, but I am curious to know if anyone has a thought about fixing it to work better. I found it's more reliable if I unscrew it a little, but it's still not great.


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## The_Apprentice (Feb 27, 2018)

I had already orderd this on Amazon:
https://www.amazon.ca/gp/product/B0037UUO60/ref=ya_st_dp_summary?ie=UTF8&psc=1

Will get here by Thursday as I'm an Amazon Prime customer.

But to be honest, something that is just spring-loaded, surely can't make as good a dent as something to be hit with a hammer? So I thought on getting both types.


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## benmychree (Feb 27, 2018)

I have had an automatic center punch for many years, but prefer the old standby, I think it is easier to pick up the center lines, as I posted earlier.


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## mmcmdl (Feb 27, 2018)

An old standby is the tip on a spiral flute tap ! I don't understand the value or added usage of 5 center punches with different body diameters , it's the point that does the work .  Buy 1 good punch and hammer away . I have many auto center punches but they are always out of reach when I need them , so I use anything hardened with a point . I guarantee your workpiece won't know the difference !


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## rwm (Feb 27, 2018)

Also look at buying or building an optical center punch. I love mine.
Robert


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## woodchucker (Feb 27, 2018)

I like the Square General, it doesn't roll. I agree only one is really necessary.  I have 2 plus an auto. The auto is not as nice on round stock, I like a regular punch.
I have 2 because I use one for fine work, the point is perfect. The other is perfect too, but it is bigger and I really pound on that and am ok if it dulls. I can always sharpen it. But the small one means its always sharp and ready, while the big one means it takes a licking ...


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## benmychree (Feb 27, 2018)

mmcmdl said:


> An old standby is the tip on a spiral flute tap ! I don't understand the value or added usage of 5 center punches with different body diameters , it's the point that does the work .  Buy 1 good punch and hammer away . I have many auto center punches but they are always out of reach when I need them , so I use anything hardened with a point . I guarantee your workpiece won't know the difference !


Taps are hard all the way back and could chip when hammered( might put somone,s eye out)


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## The_Apprentice (Feb 27, 2018)

> I don't understand the value or added usage of 5 center punches with different body diameters ,



I was wondering about that myself. Thought it was just me...


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## RJSakowski (Feb 27, 2018)

I make my own scribes, prick punches, and center punches.  Old chain saw files, broken in half and a point ground to suit.  If it is a struck tool, draw a deep blue temper on the struck end.  Old pulley taps also work well.  Cut the shank above the threads with an abrasive cutoff saw,and grind to the desired point. cut the square drive off the end and chamfer.  You will need to heat high speed steel to a red heat to soften the struck end.


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## cathead (Feb 28, 2018)

RJSakowski said:


> I make my own scribes, prick punches, and center punches.  Old chain saw files, broken in half and a point ground to suit.  If it is a struck tool, draw a deep blue temper on the struck end.  Old pulley taps also work well.  Cut the shank above the threads with an abrasive cutoff saw,and grind to the desired point. cut the square drive off the end and chamfer.  You will need to heat high speed steel to a red heat to soften the struck end.



I would be categorized as a pak-rat as I save all my broken taps, broken end mills, round and flat files.  All that is still good
metal just needing to be reshaped into something useful.  I like to silver solder old carbide inserts to fashion custom made
boring tools or lathe tools.  Old end mills can be ground down to make miniature boring bars or inside threading tools.  
Old carbide table saw blades are a good source of small pieces of carbide.


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## FanMan (Feb 28, 2018)

The_Apprentice said:


> I had already orderd this on Amazon:
> https://www.amazon.ca/gp/product/B0037UUO60/ref=ya_st_dp_summary?ie=UTF8&psc=1
> 
> Will get here by Thursday as I'm an Amazon Prime customer.
> ...



It's  not "just spring loaded".  When you push it the spring compresses up to a point, then it releases and a small "hammer" inside the punch strikes the tip.


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## RJSakowski (Feb 28, 2018)

benmychree said:


> Taps are hard all the way back and could chip when hammered( might put somone,s eye out)


Any struck tool should have the struck end softened to avoid chipping. 

I have also made mild steel"handles" by drilling a press fit socket to fit the tool.  Any shock created by being struck is safely distributed to the end of working tool.  I have used this method for making pin punches from drill rod and dowel pins.  For 1/4" pins, I use a 1/2" bar.


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## Tony Wells (Feb 28, 2018)

You should always pay attention to the hard/soft issue. It the struck object is hard, hit it with something soft; if the struck object is soft, you can hit it with something hard. Of course, soft on soft is fine, but may damage either or both objects. But *NEVER* strike a hard object with a hard object. That's a lesson I carry with me, literally. There is a small bit of a Cinci drawbar embedded in my right bicept. I just grabbed the nearest hammer from a guy at work (which really shouldn't have even been in the shop) and gave the drawbar a good whack.....it was a carpenter's claw hammer. A small piece of the hex broke off and hit me like a bullet. Thought it was never going to stop bleeding. It was too deep for me to dig out, and being young and probably stupid, I decided to skip the ER trip. It bruised about 3" wide, and was sore for 2 weeks, but eventually healed up. In reality, my body has probably dissolved it by now, but for a long time I could feel the lump it left behind. It never occurred to me that nails are soft, so a claw hammer should be hard. I also never would have thought the drawbar hex would have been hard, but apparently it had to be somewhat hard to prevent mushrooming. Probably not as hard as the hammer, or as hard as a file or tool steel, but hard enough to shatter. I learned.


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## RJSakowski (Feb 28, 2018)

One incident that I always remember is a case where a fellow was breaking up a concrete deck with a jack hammer.  He got the moil point stuck in the concrete and as it happens, he was able to get underneath the slab and he was hammering to pop it out.  A piece of the point flew off and took out his eye.


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## vocatexas (Feb 28, 2018)

I tried one of the Harbor Freight springloaded center punches. It's a FAIL. First time I used it, it didn't mark the metal, it just flattened the end of the punch....


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## ttabbal (Feb 28, 2018)

vocatexas said:


> I tried one of the Harbor Freight springloaded center punches. It's a FAIL. First time I used it, it didn't mark the metal, it just flattened the end of the punch....



That's really bad. Mine does punch, but half the time the hammer doesn't trip. I'll probably just wait and buy a Starrett.


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## Ironside (Feb 28, 2018)

I have a Harbor Freight one. It's currently decomposing out in the woods about 40 yards outside the back door to my shop.


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## The_Apprentice (Feb 28, 2018)

Ok, so I learned a lesson from reading this. Always wear eye-protection even when working with a center-punch...

I picked up a few punches today, but have so much other work to do, I will probably get around to trying them this weekend when I have time.


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## RJSakowski (Feb 28, 2018)

Ironside said:


> I have a Harbor Freight one. It's currently decomposing out in the woods about 40 yards outside the back door to my shop.


Some of the cheap tools aren't made from bad steel; they have just haven't been heat treated properly.  

You cna check for carbon content with a spark test.  Touch the steel to a grinder.  If you have highlt branched sparks, there is most likely sufficient carbon to harden.  To harden, heat the business end of the tool with a torch until a magnet will no longer attract it; usually a bright red to oarnge.  Let it soak in the heat for a minute or so and quench immedately in cold water or oil.  When the tool has cooled down swufficiently, test the business end of the tool with a fike.  It shield skate over the tool surface rather than biting in. polish the business end of the tool to remove the oxidization leaving bright steel.  Again with a torch start heating the opposite end of the tool while observing the polished surface.  You will see colors start to run the length of the tool, progressing from a faint yellow to a light straw to a brown to a purple.  You will want the point of the tool a dark straw color.  If the color bands are to close together, you shouldslow down the heating.  When you reach the desired color, quench the tool to stop the process.


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## The_Apprentice (Feb 28, 2018)

So, what I bought, and what arrived today. Also picked up some aluminum pipe to test some more lathe-work on...


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## The_Apprentice (Feb 28, 2018)

I have to say, I also watched Mr. Pete's video on the automatic. It was rather interesting...


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## benmychree (Feb 28, 2018)

Ironside said:


> I have a Harbor Freight one. It's currently decomposing out in the woods about 40 yards outside the back door to my shop.


"Returning to the soil" would be a (possibly) better similie.


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## benmychree (Feb 28, 2018)

My best would be to buy a Starrett set of a combination of prick and center punches; think of the bragging rights!


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## Moper361 (Feb 28, 2018)

Do you have a lathe here is my center punch i made not so long ago and it could be made a little different to mine and make it with a hss tip insert .very easy to make up if you have a  it of spare material laying around .I have used it quite a bit now just with hardened tip i made myself .but if you want to use on stainless and harder material make it with tip insert out of hss


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## Kiwi Canuck (Mar 1, 2018)

I have the Starrett shown above as well as the Lisle which i like a lot.

The Starrett is OK but not very smooth considering the price, sometimes it's feels a bit inconsistant in how it clicks.

Here's the Lisle one which has a nice light action.

https://www.amazon.com/dp/B000HTAH70/ref=psdc_2225055011_t3_B000VDVR6W


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## cathead (Mar 1, 2018)

RJSakowski said:


> Any struck tool should have the struck end softened to avoid chipping.
> 
> I have also made mild steel"handles" by drilling a press fit socket to fit the tool.  Any shock created by being struck is safely distributed to the end of working tool.  I have used this method for making pin punches from drill rod and dowel pins.  For 1/4" pins, I use a 1/2" bar.



Interesting RJ, my tool box has a bunch of those in it too including carbide tips.


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## cg285 (Mar 1, 2018)

RJSakowski said:


> One incident that I always remember is a case where a fellow was breaking up a concrete deck with a jack hammer.  He got the moil point stuck in the concrete and as it happens, he was able to get underneath the slab and he was hammering to pop it out.  A piece of the point flew off and took out his eye.



i had a similar experience. my neighbor was busting up concrete with a hatchet. my hand got in the way. carried my finger home with me.
 i was 5 at the time.


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## RJSakowski (Mar 1, 2018)

cg285 said:


> i had a similar experience. my neighbor was busting up concrete with a hatchet. my hand got in the way. carried my finger home with me.
> i was 5 at the time.


Ouch! I hope they were able to reattach it.


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## cg285 (Mar 2, 2018)

RJSakowski said:


> Ouch! I hope they were able to reattach it.


yep


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