Troddenmasses Posted March 7, 2007 Share Posted March 7, 2007 Help. I need a 12.8mm drill bit, and an M14*1.25 tap (Metric Fine). This is to drill and tap one piece of steel plate to accept a spark plug. Unfortunately, it is too big to fit on the lathe, so I can't cut it that way. I would buy one, but it is looking like £17.70 for the drill and £15 for the tap, plus p+p. That is somewhat steep for one damn hole. Does anybody know where I could borrow one from, buy one cheaper than that, or alternatively, get hold of an M14*1.25 nut. I could turn a nut thin enough to be able to screw onto the spark plug on the other side of the plate. Any suggestions gratefully accepted. TM. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 7, 2007 Share Posted March 7, 2007 Tap & Die Co should be able to sell you everything you need. Or you can buy a weld-in lambda sensor boss (same thread) in normal or stainless from the local exhaust supplies. Quote Link to comment Share on other sites More sharing options...
Mark90 Posted March 7, 2007 Share Posted March 7, 2007 GR Fasteners in Stroud should be able to sort you with the nut, and probably get you the tap and drill if needed. Quote Link to comment Share on other sites More sharing options...
MogLite Posted March 7, 2007 Share Posted March 7, 2007 12.8mm is very close to 1/2" I think I've got a morse-taper 1/2" drill. Wind an old spark-plug in - let it tap its own thread Quote Link to comment Share on other sites More sharing options...
glen anderson Posted March 7, 2007 Share Posted March 7, 2007 A 1/2" drill is 12.7mm - more than close enough for the job. You should be able to get a good HSS one pretty much anywhere for under a tenner. As to the tap, well I'm afraid £15 is about right. Could you could drill a clearance hole and weld a nut to the outside of the plate? Regards, Glen. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted March 7, 2007 Share Posted March 7, 2007 Or for what you want, hacksaw a piece of old exhaust out and weld the lambda sensor holder to your pipe? Quote Link to comment Share on other sites More sharing options...
SiWhite Posted March 7, 2007 Share Posted March 7, 2007 Dare we ask what you are making? It's not going to be an exhaust flame thrower is it? Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted March 7, 2007 Share Posted March 7, 2007 12.8 is the preferred size, however, ½ inch is 12.7mm and this will be more than adequate when using a standard fluted tap. In fact a lot of reference material shows 12.5mm as the tapping drill size Last night I tapped 14mm x 1.5 thread for an air temp sensor collar. The material was hard as it used to be a rocker shaft. Drilling at 12.5mm and then tapping using Trefolex cutting compound produced an easy, first class thread. Ian Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted March 7, 2007 Share Posted March 7, 2007 In fact, if you're working in a soft material like aluminium for a disposable/consumable part, you could use the spark plug to cut the thread. Bung the scrap man £5 for as many old plugs as you can carry in a bag and put a hacksaw cut at an angle on each side of the thread (a "farmer's tap"), then screw it in. Quote Link to comment Share on other sites More sharing options...
dollythelw Posted March 7, 2007 Share Posted March 7, 2007 bash 'im in wiv an 'ammer an weld 'im Quote Link to comment Share on other sites More sharing options...
minivin Posted March 7, 2007 Share Posted March 7, 2007 M14? is that for a handbrake cable? I had to buy an M14x..... to do my hand brake conversion, think I also have the 12.8mm drill lying around somewhere..... Quote Link to comment Share on other sites More sharing options...
Troddenmasses Posted March 7, 2007 Author Share Posted March 7, 2007 Thanks for all of the replies. I'm making a jet engine... I have a new lathe/milling machine and really want to learn how to turn things properly on there, so I decided to get a project going, and i'm producing all of the fittings, plus most of the other parts on there - unfortunately, this part is a little too large for it. I've learnt quite a lot of 'what not to do' already. The first part is a combuster - basically you have a lined tube, with holes in the inside tube. Blow in lots of air and propane, and huge amounts of heat should come out of the end. This links up to an old turbocharger, which in turn creates loads of air. Route this back to the beginning, and it should be self sustaining. I can't believe how long fabrication takes.... Turbocharger's father has found me an old turbocharger that spins. I have made flanges for all of the connections to it, and am in the process of making pipes that link the burner to the turbocharger - 120mm at one end, 60mm at the other - with a nice smooth transition. It takes bloomin ages to get all of the cuts right - heat up the pipe, bash it into shape, weld it up, grind it back, weld the end flanges on etc etc etc. All I'm left with 9 hours later is a piece of pointy pipe, which looks as though it wouldn't take 5 minutes to make. Still, I'm enjoying every minute of it. Quote Link to comment Share on other sites More sharing options...
western Posted March 7, 2007 Share Posted March 7, 2007 Sounds like a fun project, are you going to fit it in the LR, fuel use might go up a bit, can we have some pictures please Mr. Quote Link to comment Share on other sites More sharing options...
reedx Posted March 7, 2007 Share Posted March 7, 2007 M14? is that for a handbrake cable?.. Thought the end of the handbrake cables were M16 x 1.5 ? Quote Link to comment Share on other sites More sharing options...
Pyrover Posted March 7, 2007 Share Posted March 7, 2007 Sounds like a fun project, are you going to fit it in the LR, fuel use might go up a bit, can we have some pictures please Mr. Yes, Yes... Pictures would be nice. Quote Link to comment Share on other sites More sharing options...
minivin Posted March 7, 2007 Share Posted March 7, 2007 Thought the end of the handbrake cables were M16 x 1.5 ? dunno, will check what I have in the machining kitbox tonight Quote Link to comment Share on other sites More sharing options...
minivin Posted March 7, 2007 Share Posted March 7, 2007 yup, M16x1.5, that's that blown then Quote Link to comment Share on other sites More sharing options...
SteveG Posted March 7, 2007 Share Posted March 7, 2007 Turbocharger's father has found me an old turbocharger that spins. for some reason I found this so funny that it took me ages before I could read the rest. I need a rest now Steve Quote Link to comment Share on other sites More sharing options...
Paul Woodward Posted March 7, 2007 Share Posted March 7, 2007 You can get cheap taps, dies, reamers etc from http://www.tracytools.com The cheap ones will be carbon steel rather than hss but if you're only going to use it once it will do. M14x1.25 is £6.00. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted March 7, 2007 Share Posted March 7, 2007 Why do you think I'm called Turbocharger? There's a pile of ten of the things at home, and they interest me because there's as much engineering in one as the rest of the engine... Quote Link to comment Share on other sites More sharing options...
scrumps Posted March 9, 2007 Share Posted March 9, 2007 Why do you think I'm called Turbocharger? There's a pile of ten of the things at home, and they interest me because there's as much engineering in one as the rest of the engine... Hi , If you're still after a 14 x 1.25 tap...I've just found a couple in the garage/workshop whilst having a clear out. I've checked it against a spark pl;ufg from my MG ZS 180 and it looks correct (thread form that is). I'm dropping sandbags Disco into Wooton-under edge on Thursday for a service . I'll leave the tap with my mate in Parts if you can collect it. Just post it back when you've done. Let me know if this is OK!! Regards Scrumps Quote Link to comment Share on other sites More sharing options...
Troddenmasses Posted March 12, 2007 Author Share Posted March 12, 2007 Thank you very very much for the offer, but I found the correct sized nut in a machine shop in Gloucester. I turned it down so that it was about 1/2 as thick as it had been, and have used that. You are very kind to offer, though. Will post some pics up when I get it running. At the moment, i seem to be buying loads of stuff from e-bay, like oil pumps, pressure gauges etc. Hopefully, it will all be worth it. Quote Link to comment Share on other sites More sharing options...
simonr Posted March 16, 2007 Share Posted March 16, 2007 I'm impressed Keir! It's one of those must do projects I'll probably never have time to do! If you get it going, I saw a nice one on the web made out of a ring of 6 truck turbos feeding the same exhaust and generating a very respectable amount of thrust! If you need any help or anything - just ask & I'll do my best! If you need a test pilot for the jet tea trolley - there was a chap I met once named Bickerton (I think?) who had the ideal build and emboldened with half a can of shandy seemed to be up for that kind of thing. Si Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted March 17, 2007 Share Posted March 17, 2007 Shandy? I need vodka now, after discovering the resonant speed for your bar stool's steering. Quote Link to comment Share on other sites More sharing options...
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