Is Starrett 18C the only reliable auto prick punch?

[Bob Korves]

Do you find 120 degree punches easy to use Bob? I would imagine it would be harder to see exactly where to make the indentation.

Ken, I actually use the standard prick punch lightly to initially locate the hole, and then use that hole to start the 120 degree punch in. The prick punch to mark the location most precisely, followed by the 120 degree punch for locating the following drill. Finish with a boring bar if the hole does not test to being in the correct location, well before the hole reaches full size. This is only for fussy work...

 

[darkzero]

I did enjoy spending you money Will, probably just as much as you did mine, $32 USD sounds about right, I paid $39.53 Canadian but I also had to pay ~ $15 for shipping. I agree ,the price in either currency is quite reasonable . for all we know, Amazon could jack up the price just before Christmas.

Did you get yours yet? Mine arrived today. I didn't want to say anything until you posted about it since this is your thread. So I'll just simply say that I like it. I guess I may start using automatic center punches more often again. Thanks again Ken & myself.

 

[Ken from ontario]

Did you get yours yet? Mine arrived today. I didn't want to say anything until you posted about it since this is your thread. So I'll just simy say that I like it. I guess I may start using automatic center punches more often again. Thanks again Ken & myself.

Mine is coming tomorrow by UPS.
So why don't you tell us what you think of it, does it strike with every push? looking at the photos I noticed the red knob on the end adjusts the amount of force that it delivers , is it actually sensitive enough to work ? can it punch thin Aluminum as well as 1/8" thick mild steel? that's what I'm hoping for. I want to be able to adjust it to mark 22Ga copper and also set it on max to punch let's say heavy gauge mild steel or even stainless steel.

 

[darkzero]

So far mine has struck evertime I tried. It's not a replace all IMO, it requires considerable force to strike. Not that it's hard, the fat handle knob makes it easy to use since it fits the palm with more surface area. I remember my hand getting sore when I needed to use an auto center punch so much in a short period of time. The knob is fixed with the rest of the handle, the entire handle turns when adjusting. For more delicate work/thinner materials I'd use a smaller one.

Here's the auto center punches I have in the garage. Left is a cheapie from Enco (not sure why I still have it), Starrett 18A & 2 Generals.


Same order, max tension on all, 16ga square tubing. The arrow is pointing to the Enco in case you can't see it. Not sure why I haven't tossed that thing out already. It's worthless, barely leaves a mark on steel maxed out & doesn't strike half the time. The Rennsteig is just slightly stronger than the larger General I have but it's a lot more comfortable to use



The adjustment for force doesn't seem to be a great range of change. Again on thinner materials I'd prefer to use something smaller. This is aluminum just under 60 thou thick. Top set of punches is the Rennsteig, set from low to high, no particular order. Bottom 3 is the Starrett 18A, set mediumish


Backside



I like it & I hope to use it more often than my I did with my others but still I prefer a punch & a hammer at home. Unfortuantely the thing is too fat to fit in the drawer that I keep my auto center punches in. Need to find a place for it where I don't forget & easily accessible otherwise It may never get used.

 

[Ken from ontario]

Thanks for the photos and detailed explanation, the size of the Rennsteig is substantial when compared to your other punches and seem to produce decent divots, I think for copper/thinner gauge metals the smallest 20-50 N model(or maybe 60-130 N) is more appropriate.
Thanks for the review, now I have an idea what to expect.

 

[darkzero]

the size of the Rennsteig is substantial when compared to your other punche

It sure is, that's exactly what put me on the fence about getting one. It's definitely not convenient in size & can be cumbersome but I can appreciate what Rennsteig had in mind with the design.... comfort & possibly less fatigue if used a lot. The black portion on the handle is cushioned & they even put flats on the knob to prevent rolling. Still much more convenient than a punch & hammer with 2 hands. Zee Germans always overthink things (which is good in this case).

I think maybe I'll just leave the thing on my bench. That way it'll always be easy to access.

 

[mikey]

I like it & I hope to use it more often than my I did with my others but still I prefer a punch & a hammer at home.

I only have a General automatic punch that still works well but it just sits. I, too, prefer a prick punch followed by a center punch because I am more accurate with it. Plus, I don't like big divots that the automatic punches make. I prefer as tiny a spot as I can make as long as it is accurate. This is usually enough to get a spotting drill located, which is the goal after all.

Not dissing your choice, Ken and Will. Maybe I'm just an old guy that prefers old school ways.

 

[darkzero]

I only have a General automatic punch that still works well but it just sits. I, too, prefer a prick punch followed by a center punch because I am more accurate with it. Plus, I don't like big divots that the automatic punches make. I prefer as tiny a spot as I can make as long as it is accurate. This is usually enough to get a spotting drill located, which is the goal after all.

Not dissing your choice, Ken and Will. Maybe I'm just an old guy that prefers old school ways.

Everyone has their own preferred methods, nothing wrong with that. Automatic center punches have their place, I used one a lot when I worked at my buddy's race shop, kept one in my shirt pocket. I prefer a punch & hammer cause it easier to control how deep of a divot I want rather than having to guess by setting the preload on the spring. But the automatic ones are convenient & quick if I'm not at home.

I actually prefer a deeper divot most of time. But really usually when I'm going to drill with a handheld or drill press & don't use a spotting drill. On the mill I don't bother center punching if there's a reference on the part that I can indicate off of & I'll just start off with a spotting drill.

 

[Ken from ontario]

I see all the logic behind everyone's method in marking the workpiece( prior to milling/machining)., in my case though, when I work with thin aluminum/copper sheets (for light fixtures, fixtures, stained glass frames ,etc.) I often need to rivet two (already formed/bent) pieces of i.e. copper, . so I would need a series of indentations on two layers of thin copper, since the workpiece is often not flat, I temporarily clamp the layers with one hand while punching/marking for rivets with my other hand, the ideal tool would be an auto center punch with a very narrow or sharp angle tip that can mark both layers easily but it looks like the search will continue.

 

[francist]

Could you just grind the tip to whatever profile you want? I ground my General years ago (still don't use it though).

-f