View Full Version : Spot drill question???

07-16-2008, 01:23 AM
Hey guys! Are spotting drills supposed to be hard to get started? Or did I get a bad batch? I bought 4 of them awhile back. Everyone of them is very hard to get started.
Is this normal?

07-16-2008, 01:49 AM
Not the ones I use. They have almost no web at the point and start very easily.

doctor demo
07-16-2008, 02:21 AM
Hey guys! Are spotting drills supposed to be hard to get started? Or did I get a bad batch? I bought 4 of them awhile back. Everyone of them is very hard to get started.
Is this normal?
How hard are the spots you are trying to drill:D
I better quit befor you guys hire a hit man.
Seriously, the only time I have trouble is with a batch that was given to me and i did not notice they were tapered little suckers and went wierd in my jacobs chuck i snapped it off before i realized what i did.

07-16-2008, 03:40 AM
I just bought about 30 surplus drill bits from Surplus Herbys the other day for 25 cents a piece. Really nice high quality brand new bits up to 1/2 inch or so, mostly metric but some letter and fractional sizes too. I found about 6 screw machine bits in the pile. They have a three flatted shank and about 3/4" of flutes, real stubby. I have been using them in the lathe as spot drills and they work perfectly, no flex and they start dead center.

07-16-2008, 05:12 AM
Most Hardware stores - here anyway - sell quite cheap packs of a dozen or so 1/8" HSS drills. They are often "short/stubby" and some-times double-ended. They are used a lot by of people who drill and pop-rivet sheet-metal etc. on-site using portable electric or battery-operated drills.

If I need to "web-thin" them I use my "Proxxon" die grinder. It really is a great tool.

I have found them to be very handy for "spotting". If I break one I have plenty of spares on hand.

I find they work even better- as will most drills - if I centre-punch where I want the drill to go. I get no "wander" at all that way.

I often drill right through with the 1/8" drill and use it as a "pilot" for a follow-up (usually 1/4") drill and just "sneak" the drill up to the size I want. Its usually a better faster job than just using a "spotter" followed by the 1/2" drill.

If I want a hole dead-centre in the lathe, I start it, usually with a centre drill, then bore the 60 degree angle out with a small boring bar. The drills just follow it dead centre as nice as you like.

I do not like drills spinning in my tail-stock or in a chuck. Heavier drilling where a tang on a MT shank is required is done on the pedestal drill or the HF-45 Mill-drill.

07-16-2008, 08:06 AM
These are pretty expensive(about $10 each) 3/8" dia spot drills. I'm only using them in mild steel.
I'm using all three drill presses in my hole drilling "station". I have a jig the plates pop into then spot them....then on to a pilot hole etc.
The idea here is maximum speed. I don't have time to fool with measuring and punching hundreds of holes.
It doesn't matter what I've tried these in...lathe, mill, drillpress...they are still hard to start. The points look sharp, the cutting egdes are sharp...there's just something wrong. I thought they'd be like going into butter....they aren't.
LOL... I may have paid a lot for these but that doesn't always mean they are good...
I may have to fire up my Franken sharpener and see what I can come up with.

Bill Pace
07-16-2008, 08:10 AM
Same here, Russ --- I also got 4 of em recently and they wont start a hole worth a crap, -- the web appears to be much to large. On starting a hole, in the center is this gnawed up area that is obviously not being cut ... I'm sure not impressed with em.

07-16-2008, 08:21 AM
What deg angle are they? I use both 90 and 118 deg spot drills and the 90's definitely have a harder time starting in the harder materials so they are use for mostly aluminum. The 118 have no problem with steels or stainless. Can you get away with just using a shorter screw machine drill first? eliminates one op and you have your pilot hole.

Thinning the web like tif said will help also although for ten bucks a pop I would be a little pissed at having to do this, its not like you are drilling some odd material, they should be fine out of the box.

07-16-2008, 08:28 AM
Mo, I tried using a stubby lil' drill...some i got from Boeing. This new chinese steel has a ton of ugly (lumpy) millscale on it. the smallish drills just skate around on it and wander.
The spot drills... you can really lean on them and they don't skate. however.. you shouldn't have to lean on them for that kind of money.
i'll see if i can get a closeup of one later so you real guys can maybe see what's up.
I'd send them back but I'm in the middle of a big job right now and need them.
Bill... That sounds just like the ones I have.

07-16-2008, 08:39 AM
I've been using 1/4" diam ones from KEO for a while now. Extremely pleased with the results.

The web is very small and there appears to be no deflection on starting the hole. I figure they were made well.


07-16-2008, 08:39 AM
Russ, not that you don't know what one looks like, but i picked this 1/4" KEO up at KBC, figured a pic would let you compare points.

small web, cuts very well


07-16-2008, 08:47 AM
McGyver... Thanks for that! I think I see the problem.
Mine are waaay pointier than that. Now I'm thinking they are the ones Mo said he only used in alu.
These ones come down to an almost needle point... there is no web on them.
Nope.. I don't really know what they are supposed to look like.
I've always used center drills for spotting.... until i read i was doing it all wrong.

07-16-2008, 09:25 AM
imo, the whole reason they are the right tool for the job is that the angle is the same (supposed to be at least) as a drill's so it doesn't start with chatter like they can with a centre drilled hole. now i'm wondering what you are use.....glad the pic was useful

07-16-2008, 09:31 AM
McGyver.. i just asked the salesman to send me some good spot drills.
I will say.. the sharp lil points make it very easy to pick up a mark...but it's the drilling part i don't care for.

d kirby
07-16-2008, 09:48 AM
Russ, I have had the same problem with ctr. drills sometimes and I found that I was not spinning them up fast enough. Maybe trying different rpms may help in your situation. Just a thought.

07-16-2008, 10:44 AM
imo, the whole reason they are the right tool for the job is that the angle is the same (supposed to be at least) as a drill's so it doesn't start with chatter like they can with a centre drilled hole. now i'm wondering what you are use.....glad the pic was usefulI wont argue with that but I'll add that it is the right tool for starting holes because thats what they are made for:D. I do a lot of aluminum parts in the cnc and the 90deg spots are easy to program depth wise so that I end up with a small chamfer on my hole without a third op, never really noticed them causing any chatter with the different angle drill. A center drill can/has and is still used for this op a lot and it isn't necessarily wrong but a broken center drill point in your part can be pretty frustrating, so why bother with it and just use them when you need a center hole for your live or dead center. For the home shop guys, you could probably use a center drill for years and never have a problem, just take it easy and use some lube, torker is making money now though and needs to move his a55;), messing with a broken center drill tip is just money going out the door.

07-16-2008, 12:12 PM
Mine are a full range of Keo 118* just like Mcgyver's picture. I use them in both steel and aluminum with no effort.

07-16-2008, 08:50 PM
I know this is going to be a bit of extra work, but it might just make it a bit easier and faster. Doesn't take much to think out and make, but may reduce the number of errors as well as reducing the total job time.

Why not make a plate/jig/guide - call it what you like - that fits over your base-plates (clamped is better) with say 1/4" (please yourself) holes in the position of the holes you require. This will guide/restrain the drill/s to go where you want them and will at least get the holes "spotted" or started. Remove the guide and away you go.

If I were "spotting" those holes (in the "jig") I'd use and old say 1/4" drill with minimum flutes and "web-thin" it so as to get the use of the "full 1/4" on the shank.

You have hit on one of the weakness of CNC-ing the drilling of holes as the drill will tend to "wander off" no matter what common machines are used unless it is constrained (jig/guide), centre-punched or "spotted".

07-16-2008, 09:15 PM
I've been doing the same as Evan for 15 years or better.Using a good quality split point screw machine drill.Cheaper than spotting drills or center drills and you go right to pilot.

07-16-2008, 10:05 PM
If you have a drill sharpener just re grind them from 90 to 118 that easy I sharpened about 200 last week at work 1/4 - 3/4 both angles They do work good but you need the right one for the right job.

07-16-2008, 10:07 PM
I hand sharpened one today to look more like McGyvers spot drill...works mucho better...