terence Posted January 16, 2018 Report Share Posted January 16, 2018 Hi need to drill 2 holes into granite used 2 masonery bits got about 2mm deep any ideas what bits to use thanks Quote Link to comment Share on other sites More sharing options...
Saltings Posted January 16, 2018 Report Share Posted January 16, 2018 (edited) sds drill and bits if using an ordinary drill you will just burn the tips off the bits or porcelain cutters or spear drills for tiles in screwfix if a granite worktop do not use sds setup too vicious porcelain cutters / drills ordinary drill slow speed no hammer action and lubricate Edited January 16, 2018 by Saltings Quote Link to comment Share on other sites More sharing options...
terence Posted January 16, 2018 Author Report Share Posted January 16, 2018 thanks will look at screwfix for spear drills Quote Link to comment Share on other sites More sharing options...
jonny long shanks Posted January 16, 2018 Report Share Posted January 16, 2018 (edited) For something like a granite worktop, in my experience, a spear bit would not work. Take a look at the diamond tipped drill bits. They can be used at high speed but need to be cooled with water. I fill a spray bottle with water to constantly clear the cut and cool the bit. Edited January 16, 2018 by jonny long shanks Spelling Quote Link to comment Share on other sites More sharing options...
Konnie Posted January 16, 2018 Report Share Posted January 16, 2018 I cut marble and granite for a living what size holes are you talking about, we use diamond tipped core bits down to a certain size tap holes the like, on a pillar drill that has a water feed, keeping the drill bit cool is the secret its the heat that damages the tip, steady speed. If you want any more help just ask, I will try my best to help. Quote Link to comment Share on other sites More sharing options...
terence Posted January 16, 2018 Author Report Share Posted January 16, 2018 1 hour ago, Konnie said: I cut marble and granite for a living what size holes are you talking about, we use diamond tipped core bits down to a certain size tap holes the like, on a pillar drill that has a water feed, keeping the drill bit cool is the secret its the heat that damages the tip, steady speed. If you want any more help just ask, I will try my best to help. the holes need to be 7 mm its for fire hearth thanks Quote Link to comment Share on other sites More sharing options...
Konnie Posted January 17, 2018 Report Share Posted January 17, 2018 If you message me your mobile I can text you pictures of the bits we use, We also manufacture fireplaces, what are you trying to achieve, might be able to help, or advise. using the best diamond drill bits you can find, put a ring of plasterscene (spelling) about 2" round where you want the hole put drill in place fill with water and off you go, drilling granite with everyday tools will be a slow job. Quote Link to comment Share on other sites More sharing options...
terence Posted January 17, 2018 Author Report Share Posted January 17, 2018 6 hours ago, Konnie said: If you message me your mobile I can text you pictures of the bits we use, We also manufacture fireplaces, what are you trying to achieve, might be able to help, or advise. using the best diamond drill bits you can find, put a ring of plasterscene (spelling) about 2" round where you want the hole put drill in place fill with water and off you go, drilling granite with everyday tools will be a slow job. Fitted new fire and the front legs should be screwed down will send pm Quote Link to comment Share on other sites More sharing options...
getthegat Posted February 18, 2018 Report Share Posted February 18, 2018 (edited) Anybody got any recommendations for steel bits? I can't seem to find any quality ones that don't snap( 2 - 4mm size) and they seem to be quite soft, meaning the edge is lost quickly. Cheers. Edited February 18, 2018 by getthegat Incorrect spelling Quote Link to comment Share on other sites More sharing options...
Stonepark Posted February 18, 2018 Report Share Posted February 18, 2018 (edited) 1 hour ago, getthegat said: Anybody got any recommendations for steel bits? I can't seem to find any quality ones that don't snap( 2 - 4mm size) and they seem to be quite soft, meaning the edge is lost quickly. Cheers. It comes down to heat, small drills heat up very quickly and don't have a large capacity to absorb heat without altering temper. Liquid (water) lubrication is the key. Edited February 18, 2018 by Stonepark Quote Link to comment Share on other sites More sharing options...
getthegat Posted February 18, 2018 Report Share Posted February 18, 2018 Water! Not heard that before. I buy a lube spray or sometimes the old WD. It's when using them free hand, not in pillar that I break so many. Quote Link to comment Share on other sites More sharing options...
silver pigeon69 Posted February 18, 2018 Report Share Posted February 18, 2018 26 minutes ago, getthegat said: Water! Not heard that before. I buy a lube spray or sometimes the old WD. It's when using them free hand, not in pillar that I break so many. If your breaking a lot more "free hand" than in a pillar drill, if using the same bits and drilling the same material, it sounds as though you are not holding the drill straight/square which would cause them to break. Quote Link to comment Share on other sites More sharing options...
Stonepark Posted February 18, 2018 Report Share Posted February 18, 2018 30 minutes ago, getthegat said: Water! Not heard that before. I buy a lube spray or sometimes the old WD. It's when using them free hand, not in pillar that I break so many. Oil is a good lubricant but allows the drill to heat up too much, as most people just give a spray but such a small amount heats up quickly as well , using water and the plasticine method above works well with horizontally drilled surfaces, some industrial drills have a water attachment to allow a constant flow of fresh cold water in both horizontal and vertical configurations. Quote Link to comment Share on other sites More sharing options...
panoma1 Posted February 18, 2018 Report Share Posted February 18, 2018 Years ago I worked in light engineering and remember a water soluble oil that was used in constant flow, for drilling, it was an oil mixed with water which then turned a white/cream colour......was it called suds oil?....that may be worth investigating? Quote Link to comment Share on other sites More sharing options...
getthegat Posted February 18, 2018 Report Share Posted February 18, 2018 I have seen this for lathes, mills etc, just never thought about it for free hand drilling, will now though. So basically is one HSS drill bit much like another? Quote Link to comment Share on other sites More sharing options...
Bazooka Joe Posted February 18, 2018 Report Share Posted February 18, 2018 Quote I can't seem to find any quality ones that don't snap Having the right cutting speed is important, plenty info on the web. Smaller the drill the higher the speed, bigger the drill the lower the speed. Cutting low speed with a small drill has only one out come, High speed with a large drill will temper the cutting edge & render the drill useless. Cutting speeds are very important, + cutting fliuds, + cutting feed. Quote Link to comment Share on other sites More sharing options...
vampire Posted February 18, 2018 Report Share Posted February 18, 2018 i use a diamond tip with wax core on hard tiles (cant spell porcalene ) and bosch tct blue fluted on every thing else. Quote Link to comment Share on other sites More sharing options...
Mice! Posted February 18, 2018 Report Share Posted February 18, 2018 2 hours ago, getthegat said: I have seen this for lathes, mills etc, just never thought about it for free hand drilling, will now though. So basically is one HSS drill bit much like another? Your lathes etc are using water with a diluted oil coolant, only about 5-8% oil but it makes a difference. plus what bazooka Joe says above, then drilling free hand you have to think about pressure, you need to let the drill cut as opposed to forcing it through. you can buy better than hss but on small drill bits your always risking spending out on something which can easily break. what are you trying to drill? Quote Link to comment Share on other sites More sharing options...
Mice! Posted February 18, 2018 Report Share Posted February 18, 2018 the other thing i do is use centre drills from work, we have loads of different sizes metric and English you just need be careful if your only drilling sheet stuff as you will easily wind up with a 6mm hole when you wanted a 2mm Quote Link to comment Share on other sites More sharing options...
getthegat Posted February 20, 2018 Report Share Posted February 20, 2018 We drill various materials. Sometimes drilling out broken studs. Sometimes just mild steel or ally. Sometimes stainless. Anything other than exact angles and they seem to break easier than I would have thought. I guess not all drills are created equal, but if there is something a bit more robust out there..... Quote Link to comment Share on other sites More sharing options...
Mice! Posted February 21, 2018 Report Share Posted February 21, 2018 we do use a lot of carbide and through coolant drills, it would help a lot if you used a pilot drill or centre, that way your drilling into a good hole especially on things like bolts, we do some nasty hard stainless alloys always spot drilled then drilled but generally just 90 degree on cnc. I thought you were just drilling at home, if someone else is paying use carbide instead of HSS. Quote Link to comment Share on other sites More sharing options...
old'un Posted February 21, 2018 Report Share Posted February 21, 2018 On 2/18/2018 at 07:01, getthegat said: Anybody got any recommendations for steel bits? I can't seem to find any quality ones that don't snap( 2 - 4mm size) and they seem to be quite soft, meaning the edge is lost quickly. Cheers. Drilling a 2mm hole with a hand drill, use a center punch to make a start for you drill, have about 8mm-10mm sticking out of the chuck, run drill fairly fast, try to brace your body/arm/hand against something solid, when braking through ease pressure off drill otherwise it will snatch and brake the drill, if you do not have any machining suds you can use cooking oil mixed with water, use HSS drills not carbon drills. And just one other thing…make sure the drill is running the right way. Quote Link to comment Share on other sites More sharing options...
getthegat Posted February 21, 2018 Report Share Posted February 21, 2018 Cool. Great advice. Many thanks. Drills do go anti clockwise don't they??? Quote Link to comment Share on other sites More sharing options...
old'un Posted February 21, 2018 Report Share Posted February 21, 2018 Actually you can get left hand drills, left handed hammers are a bit harder to find though... Quote Link to comment Share on other sites More sharing options...
la bala Posted February 21, 2018 Report Share Posted February 21, 2018 20 minutes ago, old'un said: Actually you can get left hand drills, left handed hammers are a bit harder to find though... And if you do find one, dont use it with a left handed chisel. Quote Link to comment Share on other sites More sharing options...
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