Drill bits for metal

[Lons]

I do find however hard I clamp a bit, with gloves and grunting, that it can still spin when drilling deep into hard wood - that's one for another thread though !

Either your chuck is worn, drill bits blunt (do they smoke / overheat while drilling?) or most likely you're not withdrawing the bit to clear the chips. Some woods are very hard and will clog the bit, especially if not bone dry and that will lead to overheating, blunting and wearing out the chuck.

That said, if it's drilling ok, I usually drill through in one go so don't follow my own advice. :lol: (hammer)

 

[MikeJhn]

The only round file I have is slightly too big, only about 1cm goes in, I tried to get a rythm going but hard to keep the pressure on/the file in and I need it to line up exactly with the slot below so I gave up doing it that way, it didn't strike me to buy a smaller file but I can see myself doing a bit of metal drilling here and there so want to get a few bits to keep for just that.

It sounds like the perfect file, don't try and use it conventionally, but screw the file into the hole, one way and then the other to loosen it, each part revolution will take off a little bit of metal, eventually you will open the hole up to what you want.

Phil

I know what you mean about the amount of drills in the box, sometimes it takes two or three goes to get them organised and the lid closed, but I have found that even after market bits are still the same length as the originals, I don't know if that is coincidence or there is a standard length for each diameter?

Mike

 

[Phil Pascoe]

I expect there is a norm if not a universal standard, although I've had loads that were different.

 

[MikeJhn]

I wonder if its a multiple of the diameter, I am sure someone on here will know?

Mike

Found this on Wiki:

Screw-machine-length drill[edit]
The shortest standard-length drills (that is, lowest length-to-diameter ratio) are screw-machine-length drills (sometimes abbreviated S/M). They get their name from their most common application: use in screw machines. Given the industrial nature of most demand for screw-machine-length drills, they are generally sold only by metalworking supply businesses (not in hardware stores or home centers).

Jobber-length drill[edit]
Jobber-length drills are the most commonly found type of drill. The length of the flutes is between 9 and 14 times the diameter of the drill, depending on the drill size. So a 1⁄2 in (12.7 mm) diameter drill will be able to drill a hole 4 1⁄2 in (114.3 mm) deep, since it is 9 times the diameter in length. A 1⁄8 in (3.2 mm) diameter drill can drill a hole 1 5⁄8 in (41.3 mm) deep, since it is 13 times the diameter in flute length.[2]

Aircraft-length drill[edit]
Extended-reach or long-series drills are commonly called aircraft-length from their original use in manufacturing riveted aluminum aircraft. For bits thicker than a minimum size such as 1/8 inch, they are available in fixed lengths such as 6, 8, 12, or 18 inches rather than the progressive lengths of jobber drills.

#-o (hammer)

Mike

 

[sickasapike]

In a stirring demonstration of the indomitable human spirit... I have drilled an 8mm hole in metal, hoorah !

Cue marching bands, bunting etc - splendid, the riving knife that the hole is in bolts in nicely now, thanks all.

The DeWalt extreme bits are very sexy, I only needed the 8mm in the end but nice to have 9 & 10 too. They do have a pilot nipple thing at the end, but I was expanding a 6mm hole so didn't touch that, but was concerned there wasn't a cap, and that it'd skitter but went really smoothly with a drop of oil.

 

[MusicMan]

Lots of useful replies.

Here's a useful table plus information on drilling speeds. http://www.vikingdrill.com/viking-Drill ... dSpeed.php
Worth printing out and keeping handy. Small sizes need surprisingly high speeds, and harder metals surprisingly low speeds. And almost all require lubrication (except 60/40 brass).

Concerning organisation of drills, the usual one-hole-per-drill-size is really inadequate for smaller sizes, since you need several backups, and also holes for sizes in between the mm or half-mm increments. I commend the following type of holder, which has saved me more time in the workshop than any other storage device:

The main mm holes take the stated sizes of course, and the ones in between take the sizes in between the main holes. There's five holes in the smaller sizes and three in the larger ones. It's made of hardwood (teak floorboard) and is a useful drill gauge too, for sizing screw holes. Not my idea, nicked from someone on YouTube.

Keith

 

[Racers]

I have a set of 1 to 6mm in 0.1mm increments which are very handy for all sorts of jobs.

Pete

 

[MikeJhn]

That's 54 different size's, I have enough trouble with 0.5 size's between let alone 0.1 that's insane IMO.

Mike

 

[Honest John]

Just for completeness! I have had many good results with uk drills, but as you were looking at Screwfix, I must also mention their “ Erbauer” drill bits. I know that brand of tools/machines has few followers, but I have found their drill bits brilliant in cast iron and mild steel, and as cheap as chips. No experience with the brand beyond their drill bits.

 

[sickasapike]

Either your chuck is worn, drill bits blunt (do they smoke / overheat while drilling?) or most likely you're not withdrawing the bit to clear the chips. Some woods are very hard and will clog the bit,

It's actually a brand new chuck, the drill is a pratically new Record one (300 quid job), the pre-installed chuck kept falling out so I had that replaced, lots of cleaning of the slghtly conical sleeve thing and the second one went in with one meaty tap and has stayed there so far, it's probably had under an hour of actual run time.

Some of my bits are rubbish, or were, I still had some that I brought back from Indonesia... not the finest quality (comically bad in some cases, somewhere I have a photo of a new steel hammer I bought at ACE hardware there, on it's maiden day whacking nails into beams the head half broke off so was facing 45 degrees upwards !!) but shipping is by volume not weight so I brought a lot of stuff I could have ditched but I bought a new DeWalt set recently and chucked out a load of the rubbish ones, some of the problem was probably down to that.

I try to make sure it clears enough and use the right speed (I wrote out the material/bit size/speed matrix and sellotaped it to the machine) but yep, it's probably my old drills and beginner technique and is a lot better when I use grippy gloves to cinch it nice and tight - thanks for the advice.

 

[ApplebyWT]

Reisser are advancing their metal drill range currently, and are coming out very competitive in terms of price and let's be honest, if it has the Reisser name on it its got quality.