What is a twist drill used for?
The twist drill is possibly the most common used drill as in its basic form will drill holes in most materials: steel, wood and plastics.
In a specialised form will drill into concrete and brick.
The twist drill has a vast range of sizes, but over 1/2” they are beyond the scope of the average hand/electric had drill unless specially adapted.
The standard twist drill bit is two fluted and can be constructed in various materials which have benefit advantages, depending on the material being drilled.
There are various combinations of material that twist drill bits are constructed from and the three that are considered the best are:
Combat, Titanium and High Speed Steel (HSS).
When drilling the spiral will aid the clearance of the swarf but if drilling a deep hole it is beneficial to withdraw the drill to allow the swarf to de cleared.
Twist drills are manufactured in two main sizes: decimal and fractional.
They can be purchased in sets and depending on requirements the fraction set can start as small as 1/64” and go up in increments of 1/64” up to 1/2”.
Decimal range from 1mm to 10mm going up in 1/2 mm increments.
The normal length of a drill is classified as a jobber, should a drill be required longer it is possible to purchase, but then they are normally sold singularly.
Sharpening a twist drill requires some skill if attempting this by hand, there are several jigs indicated tools for grinding the correct profile.
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Following our consideration of the 5 best sets of twist drills:
- The drill bits are supplied with a useful storage bar which keeps them all in one place and marked with the size of each bit.
- Sizes range from 1/16” up to 1/4” which are the popular sizes for the DIY operator.
- They are able to drill plastic, unhardened metal and wood.
The reviews generally good and are appreciative of the low price of the 10 piece set of drills.
There are however some critical reviews stating that drills broke relatively easy this could be due to being an imported product and quality control was not 100%
- The shank has a Hexagon end to be used in high torque drills and gives a non slip grip in standard chuck drills.
- For effective swarf removal the twist drill bits have long flutes.
- The drill bits are Titanium coated to minimise friction.
- The twist drill bits are sized from 1/16” – !/4” in steps of !/32” and then there is a 5/16” and a 3/8”.
- The tip is designed to non skate and accurate start.
- Manufactured to cope with high-carbon and heavy gauged steel.
The reviews are good finding the use of an impact drive useful for an easy change of the drill bits.
Some considered the small diameter twist drill bits too short in length.
- The drill set is house in a convenient plastic case.
- The twist drill range is a comprehensive range from 1/16” up to 3/8” that covers all the needs of the DIYer.
- Is capable of drilling all metals and this includes hard metals.
- To eliminate the drill bits from walking on first contact they are produced with a spilt point.
- Drill presses are a very good exponent using these drill bits.
- These twist drill bits are impressed with ‘HSS Co’ this means High Speed Cobalt, giving an indication that the composition of them is of a high grade steel.
The reviews of these drill bits endorse this by having very high reviews and a very low critical review.
- The 15 piece twist drill bits are supplied in a rubber over molded case which is size indexed for identifying and simple access.
- This gives good protection for onsite working.
- The Drill bits are Titanium Nitride coated to reduce friction and heat and this gives the cutting edge life up to 6 times that of other HSS drill bits.
- To increase durability the drill bits are manufactured from premium high speed steel.
- The drill bits have a 135degree split-point designed to minimise ‘walking’ and to start drilling on immediate contact.
The reviews are excellent and there are no critical reviews at all.
Drill America DWD29J-CO-PC Qualtech 29 Piece Cobalt Steel Jobber Length Drill Bit Set in Plastic Case, Gold Oxide Finish, Round Shank, Spiral Flute, 135 Degrees Split Point, 1/16″ to 1/2″ Size
- This twist drill bit set is supplied in a plastic case that is waterproof.
- The 29 piece set sizes from 1/16” to 1/2” in 1/64” increment steps.
- This makes the set a very comprehensive and suitable to cover any eventuality that a workshop requires.
- The drill bits are manufactured from Cobalt steel with a gold oxide finish to act as a lubricant to give wear resistance.
- The Cobalt Steel is used to provide extended life and maintain the drill bits toughness.
- The 135 degree split point is designed to be self centering and to produce smaller swarf chipping and so to minimise clogging.
The reviews are very good and there are very little criticisms and of those I consider they were asking too much from the drill bits.
This is an American made product and so deserves the American National Standards Institute conformation.
Recommendation What is a twist drill used for
There are many twist drill uses and in keeping there are many manufacturers of twist drill bits.
In the review we have compiled a cross section of choice.
The one that was considered the best is the Drill America DWD29J-CO-PC Qualtech 29 Piece Cobalt Steel Jobber Length Drill Bit Set in Plastic Case, Gold Oxide Finish, Round Shank, Spiral Flute, 135 Degrees Split Point, 1/16″ to 1/2″ Size.
It was however the most expensive so for those with not so deep pockets we also recommend the Irwin Tools 4935607 Titanium Coated High-Speed Steel Drill Bit Set, Pro Case, 15-Piece.
Both are of equal merit but the Drill American does offer that little bit more.