Rupert Posted October 25, 2013 Report Share Posted October 25, 2013 I am about to restore a pillar box for my garden.As I stripped the brass off some of the set screws sheared off,i know from when I did my last one the thread is old obscure and unavailable so I can get some brass replacements in metric but neet to retap the holes.I know you have special size drill for the relevant tap and this info was in a handbook but as I don't know whwt its called google is not my friend.Does anybody know the name of this book have one for sale or know where I can buy one? Quote Link to comment Share on other sites More sharing options...
bruno22rf Posted October 25, 2013 Report Share Posted October 25, 2013 You should find it in a ZUES book-if not just google it-most smaller metric are drilled about .8 under the thread size from memory. Quote Link to comment Share on other sites More sharing options...
Gordon R Posted October 25, 2013 Report Share Posted October 25, 2013 http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=1&ved=0CCwQFjAA&url=http%3A%2F%2Flittlemachineshop.com%2FReference%2FTapDrillSizes.pdf&ei=lb1qUvPiILSn0wXZpYD4Cw&usg=AFQjCNE_vIxWZB-dtyjAoHkRiGWCnt6iCQ&sig2=HDX5HpebEolnQhZU7OOoiw&bvm=bv.55123115,d.d2k Quote Link to comment Share on other sites More sharing options...
Jega Posted October 25, 2013 Report Share Posted October 25, 2013 Here you go buddy, http://store.curiousinventor.com/guides/tap_drill/ Quote Link to comment Share on other sites More sharing options...
philm Posted October 25, 2013 Report Share Posted October 25, 2013 Does this help? http://littlemachineshop.com/Reference/TapDrillSizes.pdf Quote Link to comment Share on other sites More sharing options...
webber Posted October 25, 2013 Report Share Posted October 25, 2013 Tapping size for metric threads. Diameter of thread , say M10 - pitch of thread, 1.5mm. Tapping size = 8.5mm webber Quote Link to comment Share on other sites More sharing options...
Rupert Posted October 25, 2013 Author Report Share Posted October 25, 2013 (edited) Thanks Folks PW comes good again. And ordered. Edited October 25, 2013 by Rupert Quote Link to comment Share on other sites More sharing options...
spandit Posted October 25, 2013 Report Share Posted October 25, 2013 Be careful with taps - they can break very easily and drilling them out is unpleasant. Hopefully you've ordered a set of three (taper, second & plug) - don't just try winding them straight in, try about one full turn, then half back. Good luck! Quote Link to comment Share on other sites More sharing options...
Rupert Posted October 25, 2013 Author Report Share Posted October 25, 2013 Be careful with taps - they can break very easily and drilling them out is unpleasant. Hopefully you've ordered a set of three (taper, second & plug) - don't just try winding them straight in, try about one full turn, then half back. Good luck! No I just got an assortment box from the machine mart. Quote Link to comment Share on other sites More sharing options...
Peely Posted October 25, 2013 Report Share Posted October 25, 2013 Be careful with taps - they can break very easily and drilling them out is unpleasant. Hopefully you've ordered a set of three (taper, second & plug) - don't just try winding them straight in, try about one full turn, then half back. Good luck! 2/3 of a turn clockwise, 1 turn back to clear it. Use plenty of cutting compound and take you time!! Quote Link to comment Share on other sites More sharing options...
JohnFreeman1310 Posted October 25, 2013 Report Share Posted October 25, 2013 It's always good to try a left hand drill bit first it u have some. Quote Link to comment Share on other sites More sharing options...
figgy Posted October 26, 2013 Report Share Posted October 26, 2013 (edited) I always use a slightly bigger drill than thread depth as webber said 1.5 mm for a 10 mm thread is 8.5 drill,I use a 8.6mm drill bit that way the shaft of the tap won't become bound so easily. A point one or two bigger drill makes it so much easier. Figgy Edited October 26, 2013 by figgy Quote Link to comment Share on other sites More sharing options...
goodo123 Posted October 26, 2013 Report Share Posted October 26, 2013 What ever you do don't put the tap in a drill and use it. You may see many Muppets doing this but it is wrong on so many levels. Check it's level/square earlier before you start cutting to many threads, use plenty of lube, never force a tap, let it do the worthe enk, don't put taps down on hard surfaces (this will damage the tap) keep them clean and oiled, if it's a blind hole don't be afraid to remove the tap and clean the hole, just make sure you pick back up on the threads you've cut, the more times you run the tap down the looser the thread will get, wear eye protection as they can shatter, also gloves due to dwarf etc, use the taps in the stages their supposed to be used eventually finishing with a plug tap, you can identify them by the end of them, the one you start with will be more pointed and will have less threads to the end whereas the plug tap will more or less resemble a bolt with cutting edges and will have a flat end. Use propper cutting fluidpaste, don't use silicone compounds or penetrating spray unless that's all you have. Don't use a tap dry unless in realy soft materials plastic etc. If you have no cutting compound you need to fling a really green grogger and keep it topped up. The amount of turns ratio forward/backwards will depend on many things, cutting compound, strength of material, hole depth, size of tap, how sharp the tap is, etc try using your sense of touch rather than counting turns. Make sure you prep the hole before you tap. Ensure it is smooth with no burrs etc. Especially on the opening as this is where the tap will allign itself. If it all goes wrong and the tap does snap you can get removal tools, or you can (realy carefully) sometimes use punches to remove them. Don't try drilling a tap out with standard drill bits as this will end in tears and/or injury and a mess of the workpiece. Never laugh if someone snaps a tap as you probably will at somepoint. Drill sizes can be slightly out from what they are marked up as, use a vernier caliper/micrometer/hole gauge to pick one nearest to the recommended size, the drill size can be found in the tap manufacturing manual or their are engineers thread cutting books with reference charts. When drilling your hole make sure you do this properly as it can work harden your material and cause issues. That's about it really. Thread closure time? Quote Link to comment Share on other sites More sharing options...
spandit Posted October 26, 2013 Report Share Posted October 26, 2013 also gloves due to dwarf etc, Are these related to the tool hiding pixies or drill bit blunting fairies? Quote Link to comment Share on other sites More sharing options...
goodo123 Posted October 26, 2013 Report Share Posted October 26, 2013 Are these related to the tool hiding pixies or drill bit blunting fairies? Yes, although the burrs tend to hang around with the 6" ******** and get picked on by the reamers. As a general ferrule of thumb tho they don't cause much slag. Quote Link to comment Share on other sites More sharing options...
Gordon R Posted October 26, 2013 Report Share Posted October 26, 2013 goodo123 - thanks for your post. I honestly picked up some decent tips. Bit sad considering I have built cars / motorbikes for nearly 40 years. Never too old to learn. :good: Quote Link to comment Share on other sites More sharing options...
Rupert Posted October 26, 2013 Author Report Share Posted October 26, 2013 I appreciate everybody's input so far.Handbook is ordered and a new battery for my vernier.Next week I should get chance to start my project.Step one is to strip it prior to taking it for blasting/priming. Quote Link to comment Share on other sites More sharing options...
goodo123 Posted October 26, 2013 Report Share Posted October 26, 2013 goodo123 - thanks for your post. I honestly picked up some decent tips. Bit sad considering I have built cars / motorbikes for nearly 40 years. Never too old to learn. :good: I'm sure you was taught it at somepoint, I've done a old school fitting using hand tools course Nvq level 3, was a lot of fileing, scraping, etc once you look into the correct methods you realize how much you don't actually know. Give someone a shifter and it's 50/50 if they use it properly. Their are propper methods for just about any tool but I think nowadays a lot of training is lost through cheaper equipment, time constraints and automation. Regarding the vernier caliper it's not super important on high tolerance stuff but it is good engineering practice, also they are useful for depth gauges after you have tapped the hole. Quote Link to comment Share on other sites More sharing options...
Gordon R Posted October 26, 2013 Report Share Posted October 26, 2013 Don't use a tap dry unless in realy soft materials plastic etc. That is my biggest failing. Quote Link to comment Share on other sites More sharing options...
kent Posted October 27, 2013 Report Share Posted October 27, 2013 I'm sure you was taught it at somepoint, I've done a old school fitting using hand tools course Nvq level 3, was a lot of fileing, scraping, etc once you look into the correct methods you realize how much you don't actually know. Give someone a shifter and it's 50/50 if they use it properly. Their are propper methods for just about any tool but I think nowadays a lot of training is lost through cheaper equipment, time constraints and automation. Regarding the vernier caliper it's not super important on high tolerance stuff but it is good engineering practice, also they are useful for depth gauges after you have tapped the hole. How can NVQ and old school go in the same paragraph? Perhaps I am older school than I feel Quote Link to comment Share on other sites More sharing options...
goodo123 Posted October 27, 2013 Report Share Posted October 27, 2013 How can NVQ and old school go in the same paragraph? Perhaps I am older school than I feel What I mean is it consisted of fabricating parts from scratch, using dti's engineering blue, scribes etc rather than putting a program in a cam machine. Quote Link to comment Share on other sites More sharing options...
NickS Posted October 27, 2013 Report Share Posted October 27, 2013 Just done "Cutting and Tapping Threads" with my Year 10 classes and found some good videos on YouTube. A tip here is not to search anything with "screwing" in the title without turning off the whiteboard projector... Nick Quote Link to comment Share on other sites More sharing options...
kev56 Posted October 27, 2013 Report Share Posted October 27, 2013 I am about to restore a pillar box for my garden.As I stripped the brass off some of the set screws sheared off,i know from when I did my last one the thread is old obscure and unavailable so I can get some brass replacements in metric but neet to retap the holes.I know you have special size drill for the relevant tap and this info was in a handbook but as I don't know whwt its called google is not my friend.Does anybody know the name of this book have one for sale or know where I can buy one? Where a bouts are you, down south ? got a shed load of taps & dies, metric and old thread forms and tapping drills, wrenches etc. You are welcome to use them. Quote Link to comment Share on other sites More sharing options...
Rupert Posted October 27, 2013 Author Report Share Posted October 27, 2013 Where a bouts are you, down south ? got a shed load of taps & dies, metric and old thread forms and tapping drills, wrenches etc. You are welcome to use them.thx for the offer but im in West Yorks. Quote Link to comment Share on other sites More sharing options...
fazzer Posted October 27, 2013 Report Share Posted October 27, 2013 do you know what size tap you need,the pitch is normally stamped on the tap. Quote Link to comment Share on other sites More sharing options...
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