Finally Got Some Spotting Drills

[keeena]

I've read the same thing and typically use a center drill or a 120-deg. spotting drill. The tip of a typical center drill is ground to 118-120, then at the base of the shank a 60 deg angle. A center drill is fine as long as you just hit the tip.

I would bet a beer that this is why folks have used center drills as spotting drills. You are 100% correct that if you just use initial narrow part of the center: it should be ok as a spotter for typical 118* drills. A center drill is pretty short with a relatively thick middle portion, which should mean it won't flex much (a good attribute of any spotting drill).

The main 60* portion of a center drill isn't ideal as a spotter, and the tip wouldn't be ideal for drills w/ a 135* point angle (if you believe the hype...but does seems logical to me). Drill away!

 

[projectnut]

I guess I have no convictions either way. I use them on occasion, but treat them as any other tool in the inventory. In my opinion just one more option.

 

[BGHansen]

I personally appreciate the level of sarcasm but I'm genuinely unclear as to whether you're a fan of spotting drills or not.

Sorry for the "evasive" answer, but I use spotting drills. These are my "go to's"; 120 deg. tip as I 99.9% of the time am using 118-deg. tipped drill bits.



It makes sense to have the drill bit hit the point of a spotted hole for the drill bit to stay on center. My question is still "if we use a spotting drill with an angle greater than the angle of the drill bit to ensure the tip of the drill hits the center of the hole", why aren't center punches at 120 degrees? In that case we make a 90 deg. dimple that's hit with a 118 or 135 degree drill bit.

Sorry, I lived in a "trust, but verify" world when I was working; just because someone says something doesn't make it true. The line we used was, "In God we trust, all others bring data". I would imagine someone did a study at some point with some actual hard data instead of anecdotal?

No big deal and not worth getting worked up over for heaven's sake! I swallowed the Kool-Aide and use spotting drills as it's just as easy to stick one of those in the collet than a center drill. I'd still be curious if there was a study done or if it's all theory/marketing.

Bruce

p.s. Has anyone seen the ads for the "Watt Saver" devices like this?




They claim to be able to do this to your electric bill:



Another case of "show me your data"; I highly suspect it's a scam. I suspect (me being cynical me . . .) the only way it'd cut your electric bill by 90% is if it shorted out your box for 27 days of a 30 day month.

 

[BGHansen]

Obviously you haven’t come to the conclusion yet that you too may be a Neanderthal.

Common wisdom of the day is that it wasn’t invented or learned in my lifetime it doesn’t apply to the world today.

It’s sort of a regressive learning curve. Not too far from the old adage. “If you don’t learn from history you’ve destined to repeat it”.

Rant over.

No problem and no offense taken! Actually, I am part Neanderthal; in fact, we all are!

Bruce

 

[keeena]

I think a center punch is just a quick 'n dirty way to keep the chisel tip from walking, especially when hand-drilling. Better than nothing, but not the same as establishing a full diameter cone for the drill (full diameter being an important aspect of a spotting drill).

 

[projectnut]

No problem and no offense taken! Actually, I am part Neanderthal; in fact, we all are!

Bruce

View attachment 485557

No offense intended. I was a bit shocked when they used that picture as part of the study. I thought the better one was my profile from the other side. At least they didn't use the one with my knuckles dragging.

 

[BGHansen]

No offense intended. I was a bit shocked when they used that picture as part of the study. I thought the better one was my profile from the other side. At least they didn't use the one with my knuckles dragging.

Right back at you "cousin"!

 

[SouthernChap]

Sorry for the "evasive" answer, but I use spotting drills. These are my "go to's"; 120 deg. tip as I 99.9% of the time am using 118-deg. tipped drill bits.

View attachment 485546

It makes sense to have the drill bit hit the point of a spotted hole for the drill bit to stay on center. My question is still "if we use a spotting drill with an angle greater than the angle of the drill bit to ensure the tip of the drill hits the center of the hole", why aren't center punches at 120 degrees? In that case we make a 90 deg. dimple that's hit with a 118 or 135 degree drill bit.

Sorry, I lived in a "trust, but verify" world when I was working; just because someone says something doesn't make it true. The line we used was, "In God we trust, all others bring data". I would imagine someone did a study at some point with some actual hard data instead of anecdotal?

No big deal and not worth getting worked up over for heaven's sake! I swallowed the Kool-Aide and use spotting drills as it's just as easy to stick one of those in the collet than a center drill. I'd still be curious if there was a study done or if it's all theory/marketing.

Bruce

p.s. Has anyone seen the ads for the "Watt Saver" devices like this?

View attachment 485554


They claim to be able to do this to your electric bill:

View attachment 485555

Another case of "show me your data"; I highly suspect it's a scam. I suspect (me being cynical me . . .) the only way it'd cut your electric bill by 90% is if I shorted out your box for 27 days of a 30 day month.

I was replying to @projectnut not you!

But thank you for an interesting post anyway.

 

[Larry$]

I have two carbide spotting drills. I use them when I use jobber length bits. If I'm going to do a lot of holes I'll set the depth stop so I end up with a chamfer hole. Much of the time I use screw machine bits that are stiff enough not to wander so no spotting.

 

[RaisedByWolves]

We ( old timers ) were not taught wrong . Spotting drills were made for CNC production machines . Z depths were cut 75% and tool setting was simple to achieve the required chamfer angle and diameter . Just another tool to cut production costs .

I’ll add these are referred to as start/chamfer as if you use the correct size for your tap hole you spot and chamfer in one operation.