Eric Cox | 20/05/2017 10:55:49 |
![]() 557 forum posts 38 photos | I've tapped a hole M2 and inserted a threaded rod, no problem I've tapped a second hole M2, an M2 nut will go on the threaded rod but the threaded rod will not go into the threaded hole,it won't even start. Any ideas ? |
roy entwistle | 20/05/2017 11:01:57 |
1716 forum posts | Did you use the same tap? |
Eric Cox | 20/05/2017 11:43:05 |
![]() 557 forum posts 38 photos | Yes, same tap same length of threaded rod |
MW | 20/05/2017 11:51:11 |
![]() 2052 forum posts 56 photos | try running the tap down again? Michael W |
John Haine | 20/05/2017 12:06:48 |
5563 forum posts 322 photos | I've recently had a similar problem with some M6 brass studding. I cut 2 studs from it and made some knurled thumbnuts tapped M6. These go sweetly on to an M6 bolt; M6 hex nuts go on studding freely; brass nuts bind on to studding as if the thread is wrong. Turned out that one end of the studding (1 metre length) was slightly oversize - the thumbnuts went fine on to the other end. So, try the other end of your threaded rod in the hole. |
not done it yet | 20/05/2017 13:00:24 |
7517 forum posts 20 photos |
One or more of the three items is the wrong size.
Either your tap, the nut or the threaded rod.
You need to find out which and then buy the correct sized item(s). All will be fitting properly, then.
I suspect you are buying uncertificated items as far as dimensions are concerned - probably cheap stuff made in China. |
Neil Wyatt | 20/05/2017 13:15:58 |
![]() 19226 forum posts 749 photos 86 articles | Posted by not done it yet on 20/05/2017 13:00:24:
I suspect you are buying uncertificated items as far as dimensions are concerned - probably cheap stuff made in China. Really? How many certificated taps have you got? Neil |
Robbo | 20/05/2017 13:43:53 |
1504 forum posts 142 photos | Run an M2 die down the threaded rod. Off-the-shelf nuts are often a very loose fit, so not a good guide. Does threaded rod no 2 fit in the hole where threaded rod no 1 fits? If so then threaded rod no 2 is probably oversize. |
Eric Cox | 20/05/2017 15:00:16 |
![]() 557 forum posts 38 photos | I can't try no2 in no 1 hole as no 1 is thread locked in. I'll try an M 2 die and see what happens. |
not done it yet | 20/05/2017 17:09:00 |
7517 forum posts 20 photos |
How many certificated taps have you got?
Hopefully none from China. But I do buy my threaded items (and materials) from a reputable source, where they do have a record of the supply chain, for anything where it is important quality-wise. I pay more but am confident the parts are what was ordered, not a close-ish approximation.
Obviously easier to check the nuts and bolts (or threaded rod) for size, if there is a problem - and if the rod checks out under size at one point and different at another, it is not too dificult to conclude that the rod is not the best quality. Somehow I doubt if it was the same rod (that threaded in OK) which would not thread into the second hole. If it was, the tapping must have been at fault? Perhaps the tap was worn out after that first use?
|
SillyOldDuffer | 20/05/2017 18:10:11 |
10668 forum posts 2415 photos | I suggest taking a magnifying glass to the threads in the hole and the rod. If the start on either is damaged expect trouble. Even if the hole was tapped OK, it's quite easy to damage small threads on assembly by cross-threading. You didn't say if you are cutting lengths off the threaded rod and fitting them into the M2 hole. If you are, it's very likely that the thread on the rod will need tidying up with a file before it will fit. I did a fair few M2 holes and studs on the first model engine I built. After various setbacks, the following worked well for me:
Dave |
duncan webster | 20/05/2017 21:10:38 |
5307 forum posts 83 photos | I bought some M3 stainless studding off ebay. It was total rubbish, you could push a nut along it without turning it, and looking at it through a loupe it was obvious the thread was hardly there. Got my money back, and made the studs by cutting the heads off long screws. I used M2 brass to hold my side tanks together for soft soldering. An ancient battery drill made short work of tapping the holes. I got it for nowt as the battery was kaput, so now has a flying lead to a lead acid battery, and can be rigged up with an external reversing switch so you're not using the switch on the drill with the tap screwed in Anyone got a good supplier for small studding? My local engineer's merchant starts at M6 Edited By duncan webster on 20/05/2017 21:15:30 Edited By duncan webster on 20/05/2017 21:16:32 |
Ian S C | 21/05/2017 11:15:37 |
![]() 7468 forum posts 230 photos | Before cutting threaded rod, put a nut on it so that after cutting the nut may be unscrewed straightening any bent threads. Ian S C |
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