harrycatcat1 Posted January 8, 2023 Report Share Posted January 8, 2023 (edited) I have been drilling and tapping stainless Steel posts for my daughters balustrade. I've drilled and tapped 12 holes but on the last hole part of the drill tip snapped off. I have been cooling the drill whilst drilling. I have about 20 or so more holes to drill. Question, do I need to buy two drills whilst I'm at it? Or is it me not cooling it. Also where is the best place to get a HSS Co 5% 4.2mm drill? Edited to say Toolstation have 2x 4.5mm titanium drills in. Will the threads be ok or not thread, tbh the tap seems tight with 4.2mm? 🤔 Edited January 8, 2023 by harrycatcat1 Quote Link to comment Share on other sites More sharing options...
old'un Posted January 8, 2023 Report Share Posted January 8, 2023 Stainless steel is a bit of a pig to drill, gets hot quickly and takes the edge of the drill, tungsten carbide is good for stainless but its like glass and snaps easily so no good for hand drills, if you have a bench grinder you could re-sharpen the drills you have, if not you will have to buy some more. These will do the job...https://www.rennietool.co.uk/products/copy-of-10-x-cobalt-jobber-drill-bit?currency=GBP&variant=17139381633097&utm_medium=cpc&utm_source=google&utm_campaign=Google Shopping&utm_campaign=gs-2019-04-16&utm_source=google&utm_medium=smart_campaign&gclid=CjwKCAiA8OmdBhAgEiwAShr402fqaPIMxX2EVSwZjjCdMim-A6Sf35n9dbTREoeB8S8EEgu9RwIJCBoCfJkQAvD_BwE Quote Link to comment Share on other sites More sharing options...
ditchman Posted January 8, 2023 Report Share Posted January 8, 2023 use lamb fat and colbalt drills....and use slow speed on your drill Quote Link to comment Share on other sites More sharing options...
Mice! Posted January 8, 2023 Report Share Posted January 8, 2023 18 minutes ago, harrycatcat1 said: Edited to say Toolstation have 2x 4.5mm titanium drills in. Will the threads be ok or not thread, tbh the tap seems tight with 4.2mm? 🤔 I take it your drilling for 5mm? For what your doing I wouldn't worry about the 0.3, it'll just make it easier to tap. Quote Link to comment Share on other sites More sharing options...
old'un Posted January 8, 2023 Report Share Posted January 8, 2023 35 minutes ago, harrycatcat1 said: I have been drilling and tapping stainless Steel posts for my daughters balustrade. I've drilled and tapped 12 holes but on the last hole part of the drill tip snapped off. I have been cooling the drill whilst drilling. I have about 20 or so more holes to drill. Question, do I need to buy two drills whilst I'm at it? Or is it me not cooling it. Also where is the best place to get a HSS Co 5% 4.2mm drill? Edited to say Toolstation have 2x 4.5mm titanium drills in. Will the threads be ok or not thread, tbh the tap seems tight with 4.2mm? 🤔 are you using a full set of taps or just one?, as Mice said 4.5mm will be ok. Quote Link to comment Share on other sites More sharing options...
amateur Posted January 8, 2023 Report Share Posted January 8, 2023 I use tallow as a lubricant for stainless (thanks Old Farrier for the tip a few years ago) and a lathe centre drill in a slow speed power drill to start the hole off, having centre punched the starting point, then finish off with the correct size tapping drill, again lubricating the tap with tallow. Quote Link to comment Share on other sites More sharing options...
derbyduck Posted January 8, 2023 Report Share Posted January 8, 2023 (edited) Harry you need cutting paste for the drill and for tapping , what sort of screws are going to be using ? its no good using galvanized or zinc plated they will rust you will need stainless screws ! Edited January 8, 2023 by derbyduck Quote Link to comment Share on other sites More sharing options...
amateur Posted January 8, 2023 Report Share Posted January 8, 2023 I used to use relatively expensive cutting paste, but I have found tallow to be better on stainless. You certainly need a good lubricant on the tap and don't force it. Retrieving a broken tap is another level of botheration. Quote Link to comment Share on other sites More sharing options...
harrycatcat1 Posted January 8, 2023 Author Report Share Posted January 8, 2023 1 hour ago, old'un said: Stainless steel is a bit of a pig to drill, gets hot quickly and takes the edge of the drill, tungsten carbide is good for stainless but its like glass and snaps easily so no good for hand drills, if you have a bench grinder you could re-sharpen the drills you have, if not you will have to buy some more. These will do the job...https://www.rennietool.co.uk/products/copy-of-10-x-cobalt-jobber-drill-bit?currency=GBP&variant=17139381633097&utm_medium=cpc&utm_source=google&utm_campaign=Google Shopping&utm_campaign=gs-2019-04-16&utm_source=google&utm_medium=smart_campaign&gclid=CjwKCAiA8OmdBhAgEiwAShr402fqaPIMxX2EVSwZjjCdMim-A6Sf35n9dbTREoeB8S8EEgu9RwIJCBoCfJkQAvD_BwE I've just fetched these to try 1 hour ago, ditchman said: use lamb fat and colbalt drills....and use slow speed on your drill Where do you get lamb fat? 1 hour ago, Mice! said: I take it your drilling for 5mm? For what your doing I wouldn't worry about the 0.3, it'll just make it easier to tap. I thought so thanks 👍 1 hour ago, old'un said: are you using a full set of taps or just one?, as Mice said 4.5mm will be ok. Thanks 👍 51 minutes ago, amateur said: I use tallow as a lubricant for stainless (thanks Old Farrier for the tip a few years ago) and a lathe centre drill in a slow speed power drill to start the hole off, having centre punched the starting point, then finish off with the correct size tapping drill, again lubricating the tap with tallow. Where do you get tallow from? Won't greese do? That's what I've been using. Quote Link to comment Share on other sites More sharing options...
JKD Posted January 8, 2023 Report Share Posted January 8, 2023 Just now, harrycatcat1 said: I've just fetched these to try Where do you get lamb fat? DOH !!! 🐑 🙈 😂 Quote Link to comment Share on other sites More sharing options...
harrycatcat1 Posted January 8, 2023 Author Report Share Posted January 8, 2023 50 minutes ago, derbyduck said: Harry you need cutting paste for the drill and for tapping , what sort of screws are going to be using ? its no good using galvanized or zinc plated they will rust you will need stainless screws ! I've been using grease 👍 they are stainless screws 👍👍 46 minutes ago, amateur said: I used to use relatively expensive cutting paste, but I have found tallow to be better on stainless. You certainly need a good lubricant on the tap and don't force it. Retrieving a broken tap is another level of botheration. Oh I've broken taps in the past so gently gently, quarter turn and return. Quote Link to comment Share on other sites More sharing options...
amateur Posted January 8, 2023 Report Share Posted January 8, 2023 I bought tallow from eBay item 134127485225 Quote Link to comment Share on other sites More sharing options...
old'un Posted January 8, 2023 Report Share Posted January 8, 2023 21 minutes ago, harrycatcat1 said: I've been using grease 👍 they are stainless screws 👍👍 Oh I've broken taps in the past so gently gently, quarter turn and return. don't use grease, if you cant get any cutting suds use some washing up liquid, mix it with water until it feels smooth between your fingers, not to runny and not to thick. Quote Link to comment Share on other sites More sharing options...
TIGHTCHOKE Posted January 8, 2023 Report Share Posted January 8, 2023 Cobalt drills and lubrication are the only way to go! Quote Link to comment Share on other sites More sharing options...
harrycatcat1 Posted January 8, 2023 Author Report Share Posted January 8, 2023 21 minutes ago, amateur said: I bought tallow from eBay item 134127485225 Thanks, I'm unlikely to use too much ever again is there an alternative? 16 minutes ago, old'un said: don't use grease, if you cant get any cutting suds use some washing up liquid, mix it with water until it feels smooth between your fingers, not to runny and not to thick. I will try it thanks 👍 Quote Link to comment Share on other sites More sharing options...
old'un Posted January 8, 2023 Report Share Posted January 8, 2023 14 minutes ago, harrycatcat1 said: Thanks, I'm unlikely to use too much ever again is there an alternative? I will try it thanks 👍 even better mix is some widow cleaner containing ammonia just put a drop of washing-up liquid in it and you have the perfect cutting mix. Quote Link to comment Share on other sites More sharing options...
harrycatcat1 Posted January 8, 2023 Author Report Share Posted January 8, 2023 24 minutes ago, old'un said: even better mix is some widow cleaner containing ammonia just put a drop of washing-up liquid in it and you have the perfect cutting mix. Thanks I will try it tomorrow 👍 Thanks everyone for your advice 👍👍👍 Quote Link to comment Share on other sites More sharing options...
Newbie to this Posted January 8, 2023 Report Share Posted January 8, 2023 You cannot beat tallow for drilling or cutting threads. Quote Link to comment Share on other sites More sharing options...
amateur Posted January 8, 2023 Report Share Posted January 8, 2023 1 hour ago, harrycatcat1 said: Thanks, I'm unlikely to use too much ever again is there an alternative? There are plenty of alternatives, it's just that I've found tallow to be more effective than the others, and it's relatively cheap. Quote Link to comment Share on other sites More sharing options...
old'un Posted January 8, 2023 Report Share Posted January 8, 2023 8 minutes ago, Newbie to this said: You cannot beat tallow for drilling or cutting threads. I think metal cutting lubricants have moved on a bit since beef dripping, having said that I did use it when I was doing my apprenticeship in 1965 and it did the job. Quote Link to comment Share on other sites More sharing options...
harrycatcat1 Posted January 8, 2023 Author Report Share Posted January 8, 2023 3 minutes ago, amateur said: There are plenty of alternatives, it's just that I've found tallow to be more effective than the others, and it's relatively cheap. Yes I appreciate your advice 👍 I'm hoping to get more holes drilled tomorrow and looking for alternatives, I wasn't dismissing your advice . Quote Link to comment Share on other sites More sharing options...
amateur Posted January 8, 2023 Report Share Posted January 8, 2023 24 minutes ago, harrycatcat1 said: Yes I appreciate your advice 👍 I'm hoping to get more holes drilled tomorrow and looking for alternatives, I wasn't dismissing your advice . No problem. Quote Link to comment Share on other sites More sharing options...
Newbie to this Posted January 8, 2023 Report Share Posted January 8, 2023 (edited) 1 hour ago, old'un said: I think metal cutting lubricants have moved on a bit since beef dripping, having said that I did use it when I was doing my apprenticeship in 1965 and it did the job. I still find tallow the best, I've used the likes of CT 90 etc. and find tallow better. Also tallow does not require a COSHH store, where as the likes of CT 90 does (Obviously not for personal). Edited January 8, 2023 by Newbie to this Quote Link to comment Share on other sites More sharing options...
derbyduck Posted January 8, 2023 Report Share Posted January 8, 2023 2 hours ago, old'un said: I think metal cutting lubricants have moved on a bit since beef dripping, having said that I did use it when I was doing my apprenticeship in 1965 and it did the job. yep they have indeed !👍 Quote Link to comment Share on other sites More sharing options...
harrycatcat1 Posted January 9, 2023 Author Report Share Posted January 9, 2023 Was going to drill some posts this morning but it's lashing it down. Map on met office says chesterfield is clear, who do you believe 🤔 😉 😀 Quote Link to comment Share on other sites More sharing options...
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