Small HSS Center Punch

[Paul Alciatore]

Well, the nays have me convinced. Or do they?

I ask, what about just not hardening the HSS? Get a drill blank in the annealed condition and make a punch from that. Good idea? Or just as bad? And would it stay sharp any longer than common punches? In other words, would there be any advantage for that?

Lets hear about that.

[Mcgyver]

I wouldn't stress over center punch shattering.

yeah I can hardly get out bed I'm so stressed over it. Making impact tools from brittle materials is a poor practice, esp when there is no real need: O1 abounds although they are cheap to buy that its hardly worth it. Its your shop, follow it or not.

If you're not giving a centre punch a decent wack, you may not be doing it properly, although it will vary with the work and intended hole size. Its function is to raise a divot so the drill can start. If you're just trying to make a mark for a location, use a prick punch (which should precede the use of a centre punch). It should get a light hit, it locates and its tip, being much more acute, isn't as robust. (however I still don't mess around with used HSS tools because punches are impact tools).

Paul, heat treating HSS needs some pretty exact temperature controls so isn't readily done in the home shop. If that's the route, starting from a blank, why not start with a tool steel you can properly let down?

[Noitoen]

I've used a worn out 6mm SDS concrete drill that I cut short leaving the SDS adapter part to hit with the hammer. This was designed to be struck by the hammer drill so there is no problem with a regular hammer

[eKretz]

I've been using center punches made from taps for nearly 30 years. Alongside quite a lot of other guys who have used them. I have never - not once - seen one shatter in use, nor otherwise. It takes a tremendous amount of force to break HSS. A punch generally gets a pretty light tap when used as a prick punch, and with a point suitable for a center punch (118°-140°), is obtuse enough to be ridiculously strong. Just a point of data.

[wdtom]

Square ones or ones with at least a flat on a side or two don't roll onto the floor.

[Willy]

I like those and as mentioned being square they don't roll. If this were a piece of 1/2 inch or larger HSS and it was being used as a drift with a largish hammer it would be bad practice. However it's only a tiny piece of 3/16 or 1/8 that will only see a light tap with an small hammer so it should never be an issue.

Even though I have lots of center punches including the automatic ones they always seem to be in a tool drawer away from where I need them.
So for the last couple of decades I've been using worn out chainsaw files either as as a scribe or as a center punch, depending on the length I break them off at or the profile I grind on the business end.The only issue has been rolling off of the counter.
Maybe I should level the counter.

However I can see a new purpose for some of those cheap old import HSS tool bits.
Gentleman, I have a new project today!

[J Tiers]

A blue temper punch will look like a blunt nail in no time. Dark straw is as far as I can draw it and not get a flattened end. Takes longer to be really bad if "tapping" it, but it happens just the same.

The real deal is where it is hard. You don't want it hard where you hit it, but you do need it hard at the point. Otherwise, "what's the point"?

With HSS you get no choice of hardness, but it's surprisingly tough. You are not trying to nail it through the part, just making a mark. I have very pointy (and hard) punches for finding the scribed line and marking, and much less sharply pointed punches to make the mark that a drill can find.

And, any time you are hitting a piece of steel (or anything, really) with a hammer, you need to be wearing eye protection. Just good sense.

[BCRider]

I've used a worn out 6mm SDS concrete drill that I cut short leaving the SDS adapter part to hit with the hammer. This was designed to be struck by the hammer drill so there is no problem with a regular hammer

I've got a few of those two from my shop renos where I wore out a half dozen 3/16 drills installing foam insulation and wall strapping over the foundations in the new digs. Oddly enough I found that the anvils on the "shank" were harder than the spiral portion. The points on the ground down spiral area don't stand up well as well as some other options. It's like the spiral was deliberately tempered back to be more springy than hard... Which makes total sense when we consider it.

I've had far better luck for cheap and impromptu center and prick punches with using old worn phillips hex bits. The cost is low so not all of them are really well done in the heat treating. But get a couple of good ones and they hold the points really well. And being hex shanked they don't roll.

I've got some 1/8 and 3/16 square HSS but they are being kept for making small boring bars and the like for the lathe.

[Tundra Twin Track]

I like those and as mentioned being square they don't roll. However it's only a tiny piece of 3/16 or 1/8 that will only see a light tap with an small hammer so it should never be an issue.

D

That was my thoughts also,the hammer I use only weighs 100grams,maybe your familiar with Surplus Herbies the hammer is $2.99 cdn.,that would be just about free in US dollars🤓

[Doozer]

Hit ANY punch with a brass or copper hammer, never with a steel hammer!

Thanks for that.

-D

[Dan Dubeau]

I'd use those blanks, but I'd use a brass/bronze hammer with them. I don't like using steel on hardened steel punches. I always poo poo'd the safety warnings about hitting hardened stuff with a hammer, until I got a piece of a tap lodged into my finger tip trying to back out a broken tap. Ya, it's still a pretty remote possibility, but I have a few nice small brass hammers so it's not an issue. I don't even hit letter/number punches with steel hammers.

I always make my center punches and such out of discarded 01 fixture/gauge pins from work. Not the best material, but I've got a ton of them, and they are usually knurled and the tips hardened already. Refurb/revise enough fixtures over the years and you end up with a lifetime supply of "nice little round things that I can make into something else". Everybody in here has a box full lol

[Doozer]

I honest to God have a piece that came off a pin pinch
in the palm of my hand. I did not know it was in there
and it healed over. Now a strong magnet will stick to it.
No shlt.

-Doozer

[J Tiers]

Hit ANY punch with a brass or copper hammer, never with a steel hammer!

A darn good way to ruin a copper hammer.

Instead, leave the POINT hard Not glass hard, straw temper or dark straw is fine). Draw back the striking end of the punch or chisel to at least a blue.

Then grind off any mushrooming when it occurs. You do not get just one punch that you must make last your whole life.... they are consumables, essentially

[nickel-city-fab]

I do like the idea of using a brass hammer instead.
I've always re-tempered my punches and chisels, even brand-new store-bought ones.
Dead soft on the shank and let the heat run down till its straw on the tip.

[BCRider]

While I see where the idea for non ferrous hammers on punches comes from I can't say that I've ever felt the need to do that. Perhaps with good older craft built hammers this was a thing? But given that I've dressed my asian import hammer faces over the years with an older file and found that it cut well enough to do the job I'd suggest that this qualifies as a "soft enough" face to get by.

Mind you the stuff that I really wail on are all proper soft ended punches and chisels as shown by how they mushroom over time. The harder stuff like the impromptu prick and center punches are used with somewhat more restraint.