New drill bit sets?

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New drill bit sets?

Postby Louis » Sun Apr 06, 2014 4:48 pm

Does anybody know of quality new drill bit sets, I've tried buying a couple but they haven't been any good.

I've been collecting the odd ones from car boots, but they all need lots of work and I don't have a full suit.

Preferably imperial.

Many thanks!
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Re: New drill bit sets?

Postby SeanHellman » Sun Apr 06, 2014 10:00 pm

Very difficult to buy new in the UK these days. If anyone knows a supplier then I would like to know, hex shank, rather than for a brace.
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Re: New drill bit sets?

Postby Billman » Mon Apr 07, 2014 9:46 am

PRESTO and DORMER used to be the best UK makes - now most seem to be imported (and cost less than 10% of the prementioned makes) - I use cheap hex shanked ones up to 6mm - they are usually good, but the hex part is pressed on and often comes off after prolonged hard use...

Tracy Tools is always a good source of quality drills and other cutters... http://www.tracytools.com/ see: http://www.tracytools.com/hss-drill-sets

I have full sets of Dormer, Imperial, Metric, Letter and Number sizes - they only come out once or twice a year for special jobs - for general use I use the cheap (Taiwanese??) ones....
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Re: New drill bit sets?

Postby 81stBRAT » Wed Apr 23, 2014 8:42 pm

If I break a drill that has a hex end to it, it is easy to replace the drill bit.
Place broken bit in vice and knock off hex portion.
There is a fluid called bearing fix or some such name ,label unreadable I obtained mime from an agriculture merchant.
Drop of that on shank and tap drill shank back into hex portion leave overnight and it is ready for use.
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Re: New drill bit sets?

Postby Billman » Sat Apr 26, 2014 11:08 am

I do the same if the quality is good enough - some hex shanks are steel, others are a soft alloy - Loctite make bearing fit, threadloc etc - most are similar to super-glue in action, so a cheap tube of that would probably do nearly as well.... I have bought several packs of really cheap drill of thuis type - 12 drill from 1mm to 6mm for about £2.50 - they have lasted surprising well, so not had to use my 'proper drills'....
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Re: New drill bit sets?

Postby gavin » Sun Apr 27, 2014 8:42 pm

Gosh - are you saying a drill with broken shank can be glued back together??
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Re: New drill bit sets?

Postby jrccaim » Tue May 27, 2014 5:19 am

I have a lot of experience with drill bits. You would think this question is really very simple. It is not. First, there are some absolutely ironclad requirements for drill bits, new or old. (1) They must be absolutely round, all the way up the shank. If you own a micrometer or a pair of digital calipers, try it on your bits. You may be appalled to find your bits are elliptical. An acceptable tolerance is +/- 0.02 mm. (2) The diameter must match that specified on the bit itself. Most drill bits are about .01 mm (about a thou of an inch) oversize. A few are that much undersize. I find this quite acceptable for wood, for metal you may be a bit fussier. (3) The angle to which the bits are ground is the time-honored 59 deg (118 deg included angle). The edge must be ground. (4) the thing must be properly heat-treated. This is probably the single biggest failure point of cheap drill bits. (5) The bit must be straight. I assume, by the way, we are talking about twist drills and not auger bits, although exactly the same requirements apply to these.

Furthermore, cheap drill bits are sharpened erratically or not at all. You can rescue a lot of bits by learning to sharpen them on a dry grindtone. This is a knack. It is worth acquiring if you do a lot of drilling. You will find lots of helpful videos on YouTube. You could even re-heat treat them. More trouble than it is worth.

There are lots of places in the US that sell good drill bits. Lee Valley comes to mind, although their US catalog lists mostly Imperial sizes. In the UK, Axminster is your friend. In Europe, Germany, Switzerland, and Sweden do an excellent job; try the Dicke catalog (on line). In Asia, Taiwan and Japan do first-class work but I cannot reccomend a dealer; no experience. China (mainland) is one big game of roulette. I have had Chinese drill bits actually unwind when drilling metal! Others are still boring away, and I trust them on wood, but approach metal very gingerly with them. Like roulette, the odds are against you.
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Re: New drill bit sets?

Postby Billman » Tue Jun 03, 2014 5:27 pm

Gavin, no.... you can glue in replacment drill into 1/4" hex shanks if the old drill has come out/has broken and the end can be removed...

I have never found out why 118 degrees is the angle (engineering apprenticeship + 25 years teaching metalwork/design) - I find anything between 90 and 120 works OK (I used to sharpen to 90 when I didn't have a countersink to hand) - a steeper angle also work better on soft sheet material, such as aluminium....

If you sharpen a drill bit slightly off centre it will drill an oversize hole - this was an old trick for drilling say an 11mm hole with a 10mm drill.....

For cast iron zero rake works best, and for brass a negative rake is usual - this means grinding the back of the cutting edge, which seems counterproductive - in industry it was usual to get drills with a different helix angle, even left handed ones for use in multiple head drilling machines...

As the bodgers work mainly in wood, sharpening to a reverse point is also possible, i.e. a approximation to the 'winged' twist drills sold as wood drills...

However, many cheap wood drills are made from carbon steel, or an alloy, not high speed steel - they will not last long on steel (if at all)...

Final tip: carbide tipped drills, i.e. masonry drills can be reground to cut hardened steel, such as grub/allen screws - they will not have much of a rake, but will do the job if run at a lower speed than you would normally use*.

* Drill speed in rpm is dependent on a) diameter, b) materials being cut c) drill material -

increase in diameter, harder material, soft drill = lower speed

decrease in diameter, softer material, harder drill = higher speed

But also take into account cooling of drill bit, use of lubricant (when drilling metal) - a carbon bit, run at high speed in, say, oak could heat up enough to soften it if swarf (does this term apply to wood waste as well??) not removed frequently and drill not allowed to cool down between holes....
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Re: New drill bit sets?

Postby Juna » Fri Nov 30, 2018 8:20 am

I know it's an old thread, but maybe it will be a timely resurrection for someone.

I want to share my experience. Non-ferrous materials, such as aluminum, for instance, are softer than stainless steel. They don’t require much work. But if you are dealing with something more intense, you might need a sturdy instrument.

The primary factor is the material that is used in the manufacturing. And the fabrics determine the price accordingly. Take this into consideration when picking the most appropriate item.

As for me I have used DEWALT DW1354 14-Piece Titanium Drill Bit Set like this https://mechanicguides.com/best-drill-bit-for-metal/ for a very long time under very heavy use and they are still sharp. These destroy everything they drill through. I originally bought them to go with my cordless drill and have been endlessly impressed with them. The set features a good assortment and amazon offers a price lower than home improvement stores. One of my favorite features is the case. Having drill bits that last so long usually means the case will fall apart before they are done. I have owned craftsman drill bits in the past and the "hinge" of the case always breaks apart after opening and closing so many times. This case is extra heavy duty and hasn't failed me yet. I highly recommend the set as a whole.

For the end one usefull video https://www.youtube.com/watch?v=pmEeR5MTjrg
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