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Jun 26, 2010 17:32:34 GMT
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it can be a pain in the when your tryin to drill thru steel and the bits are blunt... so what drill bits do you use/ rate well? I'm bored of buying drill bits that seem to only last a few weeks before useless.
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purplevanman
Posted a lot
Way too orangey for crows
Posts: 3,830
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Jun 26, 2010 17:46:14 GMT
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I use mostly Dormer stuff but all will blunt very quick if used incorrectly Slower speed less pressure? Most B&D type drills always seem too fast I also learnt how to sharpen them, bench grinder and a bit of care, look at how it is ground from std and just copy If it goes blunt and you try and force it through it will just get hot and the drill is then scrap.
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Welder, fabricator, general resto work
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Jun 26, 2010 17:50:32 GMT
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i defo agree about the speed, spraying wd40 on seems to helped aswell to keep them cool and last longer.
just seems as soon as u reach the 3mm+ thick its death to the drill bit.
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drill bitsDeleted
@Deleted
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Jun 26, 2010 18:10:50 GMT
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don't bother with coated drill bits... its a con cause you cant sharpen them so they are effectiely single use drill..
rolled HSS drill bits are created by rolling a straight shaped profile into the drill shape and are prone to unrolling if they get hot and bind in a workpiece so are also not worth a toss...
I use the cobalt steel ground bits, they are about 25 quid for a set from 1-10mm with the .5 sizes inbetween so not very cheap, they are a ground drill and hard as anything, I never push hard with them and drive them as slow as I can without the drill stalling aiming to get a long continuous swarf, if its a bitty blue coloured swarf you are going too fast and this will kill them, wd40 isnt the best choice of lubricant as it can let a drill bit polish itself into a workpiece, proper cutting oil is the best, it can be bought in foam form and is a worthwhile investment if your doing a lot of drilling,
go for a decent brand, Dormer as said above are well respected...
for the record I drill up to 20mm thick plate at work and my current set of drills is about 6 months old and have done a lot of work.. yes ive had to sharpen them a few times but I'm getting better at that too, keep big tub of water by the grinder and as I'm sharpening I keep dunking them, grind till the water evaporates off through heat then dunk again straight away so they don't overheat...
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Jun 26, 2010 19:27:01 GMT
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will
Posted a lot
Posts: 4,023
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drill bitswill
@familybanger
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Jun 26, 2010 20:08:26 GMT
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don't bother with coated drill bits... its a con cause you cant sharpen them so they are effectiely single use drill.. rolled HSS drill bits are created by rolling a straight shaped profile into the drill shape and are prone to unrolling if they get hot and bind in a workpiece so are also not worth a toss... I use the cobalt steel ground bits, they are about 25 quid for a set from 1-10mm with the .5 sizes inbetween so not very cheap, they are a ground drill and hard as anything, I never push hard with them and drive them as slow as I can without the drill stalling aiming to get a long continuous swarf, if its a bitty blue coloured swarf you are going too fast and this will kill them, wd40 isnt the best choice of lubricant as it can let a drill bit polish itself into a workpiece, proper cutting oil is the best, it can be bought in foam form and is a worthwhile investment if your doing a lot of drilling, go for a decent brand, Dormer as said above are well respected... for the record I drill up to 20mm thick plate at work and my current set of drills is about 6 months old and have done a lot of work.. yes ive had to sharpen them a few times but I'm getting better at that too, keep big tub of water by the grinder and as I'm sharpening I keep dunking them, grind till the water evaporates off through heat then dunk again straight away so they don't overheat... Exellent post, everything you need to know in a single reply. We use Dormer at work too and they seem pretty good but it is more how you use it than what you got (as long as it's sharp)
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Jun 26, 2010 20:57:50 GMT
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Won't be much help but I like to try and get into the spirit ;D I have bought numerous drill bit kits from your high street DIY stores. After My dad died I was passed on his DAD's (my grandad's) tools. My granddad used to be a lecturer at the local technology college. Nothing from Grandad's Stash has ever let me down. Drill Bits incuded, but all the stamping has worn off. But goes to show newer isn't always better.
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Jun 26, 2010 21:10:41 GMT
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some great advice, I'm going to try and go much slower when i buy some new bits, cheers
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Jun 27, 2010 11:11:47 GMT
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aircraft grade cobalt drills steal them with every contract i get so i always have loads
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Jun 27, 2010 13:41:55 GMT
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It's the same as those packs of screwdriver tips. They seem to all be made out of cheese.
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drill bitsDeleted
@Deleted
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Jun 27, 2010 16:01:52 GMT
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basically as been added to my post.. piloting for the larger drills saves them the very hard job of dragging the middle material out into the flutes and drastically reduces their workload. you will find as you sharpen the bigger drill bits that the flutes tend to spread in the middle to the point you will need to pilot to get them to work, this is just down to the way drills are shaped, after all they don't want you to sharpen them they want you to replace them... I too keep a box of dormer 3mm drills just for pilot drilling, just listen to the drill, if you hear the motor slowing back the pressure off, if you hear a whistling noise from the drill back off a bit, if your swarf looks hot (blue hue to it) add more water or cutting oil, I use a cheapo garden sprayer which was about 99p at B+Q at work for when I'm drilling and keep it filled with the same suds we use on the lathe an chopsaw which is a combination of water soluble oil and water.. looks like milk, cheap as chips but cools really well, don't know if you can buy it I'm small quantities but know for a fact someone will post up an ebay link to something suitable as my work buys it in 5litre tins ready to mix (made by morris lubricants)..
ill get a picture of my drills when I'm at work monday and try to get some of some sharpening going on as might help you maintain your drills when you get some new ones..
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drill bitsDeleted
@Deleted
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Jun 27, 2010 16:30:55 GMT
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Only use Dormer, but would consider Henckel or whatever that other make is. The key to keeping them sharp is don't use them in battery drills and use lots of cutting compound or WD40
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