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Drill Bits


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I'm after some decent drill bits, but should i be looking at Cobalt/HSS bits, or TiN (Titanium Nitride) coated bits, or just standard HSS bits.

Can anyone reccomend some decent ones that will cut throught anything time and time again?

EDIT: Oops, i ment to post this in tools & fabrication :blink:

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AH its here now....explains why I couldn't post a reply just now.......................

I can't really comment on different grades and brands of bit but in my humble opinion the bit is only as good as the drill its in. HSS bits will last forever in a pillar drill at correct speed with a bit of oil. The most expensive titanium double molybdenum alloy bit will probably break first time you use them in the cheap rechargeable hand-drill with the ever so slightly wonky chunk! I bought a reasonably good set of all sizes to 13mm in HSS and whenever I break one I buy a box of 10 from Screwfix in that size...

That reminds me- I just broke my 13mm bit in my slightly wonky rechargeable!

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That makes sence, however i cant fit the d-lander in the garage, let alone the pillar drill!!!

I tried to drill some holes for a fairlead last night and it took ages and they were brand new standard HSS bits, so i'm thinking somthing er, better would benefit me as i've got a lot of holes to drill!

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That makes sence, however i cant fit the d-lander in the garage, let alone the pillar drill!!!

Show off :)

I tried to drill some holes for a fairlead last night and it took ages and they were brand new standard HSS bits, so i'm thinking somthing er, better would benefit me as i've got a lot of holes to drill!

You need to concider chuck speed and feed speed whatever drill you are actually using.

All this should be in the Zeus table, sticky post at the top of this section :) .....or pop into an engineering tools supplier and ask for one :)

If you want to get real nerdy about this look for the Machinery's Handbook on Amazon, this is like a real hard core Zeus table and some :D

HTH

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I have a Zeus pocket handbook here being an engineer it comes in handy from time to time (altho not much call with sewage work design!)

Feed speed is a tricky one, as its all drilled by hand its dependant on position, time of day, time since i ate, tiredness and how fed up i am with drilling holes :lol:

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Feed speed is a tricky one, as its all drilled by hand

(shaking head) You should be making swarf not little chips.........have you pilot drilled first?

As with many things in life lubrication is the key;...........WD40 and 3in1 are just not going to 'cut it' :ph34r:

No intention to teach egg sucking here, just stuff that is often overlooked in the heat of the moment :)

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I have found that the screwfix ones are almost disposable - ie use once and chuck, however, touching them on the bench grinder does liven them up a bit. I think there is a post from a while ao by simonr about a good method of sharpening drills...

When I want the hole to come out round, and the correct size I generally use Dormer TiN coated drill bits though. They are reasonably priced (I think I got a set of 1-10mm in 0.5mm increments for about £25) and are just so much nicer to use than the cheap chocolate drill bits.

At the other end of the scale though, I bought for my dad a set of cobalt drill bits (again 1-10mm x 0.5) recently as they are supposed to be indestructible. He had tried a couple, and was really pleased with them, hence he wanted the set, but at £100 for the set they aint cheap, and I shall stick to Dormer!

As has been already said though, the right speed, some lubrication, and not applying too much pressure when drilling will really help prolong the life of your drills though....

hth

Mark

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Yup, pilot drilled and enlarged a few sizes at a time, its fairly thick plate as its a rear crossmember for a winch and could well have suffered local case hardening from the plasma cutting of the "letterbox".

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I'm after some decent drill bits, but should i be looking at Cobalt/HSS bits, or TiN (Titanium Nitride) coated bits, or just standard HSS bits.

I used to Use Cobalt but I found they would Chip Very easily and hence become unusable - I went back to "Standard" HSS and have not had any problems even when drilling Large holes in very thick-Hard steel (as long as you keep the drill bit cooled-lubricated). I haven't tried any TiN drill so I canoot comment on these.

Lyndon C

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Plain HSS - and learn to sharpen them.

Use the money you save over buying Unobtanium bits to buy a grinding wheel from Screwfix

Here is an illustrated post by someone showing how.

I think I bought my current set of drill bits (from Wurth) in 1999. A couple are getting a bit short and a couple are lost/broken and It's getting time for a new grinding wheel - but I must have saved an absolute fortune over the years.

Si

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Another issue is pilot holes. Technically the pilot should not be significantly larger than the size of the web (the 'horizontal' tip) of the drill to follow. More often than not people complain about blunt drills but it's because they're allowed to 'rub' on the job which heats then blunts them very quickly rather than applying the correct pressure to get them to cut cleanly. I bought a set of screwfix HSS drills ages ago and have been ok - certainly not significantly worse than a set of Dormers.

Oh, and according to my irate-engineer-type-house-mate a drilling machine drives a drill which when it breaks becomes a bit of a drill ... bleedin' woodworkers use bits, engineers use drills. Unfortunately I'm really a chippy so I get told off a lot! :)

AndyG

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Note also that if you work up through the drill sizes trying to drill a hole, that only a small portion of the cutting edge is used and so blunts quickly.

I use a Black and Decker bullet drill, which drills it's own pilot as it goes. Reasonably priced, they cut nicely and last well in my experience.

These

HTH

Mo

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I use a Black and Decker bullet drill, which drills it's own pilot as it goes. Reasonably priced, they cut nicely and last well in my experience.

These

Never tried them though have been tempted. I read somewhere that B&D were the biggest producer of drills in the world ... so they must be getting something right!

AndyG

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I read somewhere that B&D were the biggest producer of drills in the world ... so they must be getting something right!

or getting it wrong :rolleyes:

Otherwise we'd ever need to buy one drill in any size. (but it wouldn't be good business to make an indestructible drill :blink:).

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excellent posts, over the years done a fair bit of drilling, in the end plain HSS bits seem to work the best, with the right drill corrctlty sharpened

I've a copy of one of those pre war (2nd) engineering books, well 3 volumes. there is 3 chapters on drilling alone in pillar drills and a couple more on the lathe, and a whole chapter about how to sharpen one, plus how to make "flat" ones, would like to say the bit about sharping is correct.

I use one of those Jigs up against a grineing wheel, plus a water wheel to keep some cool, get them sharp and the correct angle and almost any drill will do including some of the bench mounted hand ones. For accurate work or plastic they are about the best, but take time.

I've made a few flats, mainly to remove spot welds, they are great but takes time and some skill to make them

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