I need some threads fixed for some old plates and bolts of a suspension. I tried tapping/cleaning the threads on an old nut for practice before I tackle the plate that is threaded but it seems very loose fit now. Its a 5/16-24 unf. Its a critical part so I need it right. Is their different size taps to leave it tighter or looser.
- Thread starter Joe 90
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Seadog
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If they need to be cleaned out then try a tap in one. If there's a lot of corrosion it may just be that too much of the thread has been lost.
If you're in any doubt I'd Helicoil them, assuming that the plate is thick enough.
If you're in any doubt I'd Helicoil them, assuming that the plate is thick enough.
I tried the tap to rethread a nut which ended up very loose which is why I was afraid to do it to the plate as only the last thread is damaged. Is their a rethreading tool for this job that doesn't cut as much away?
Is this one.
Is this one.
Imperial UNF 5/16" x 24 tpi SAE re-threading thread repair cleaning tap inc VAT | eBay
5/16" x 24 tpi (SAE fine pitch). Imperial re-threading / thread cleaning repair tap.
www.ebay.co.uk
Kram
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Yes, grind a bolt into a crude tap, it will clean the thread without cutting any excess as its slightly smaller than a tap would be - taps cut a slight clearance.
There are different classes of thread.. for imperials the standard thread is a 2A/2B. Does your tap have 2B etched on the side?
Your tap, I think is the problem, looks low quality - its not a proper tap.
These are used but good, got one last week.
There are different classes of thread.. for imperials the standard thread is a 2A/2B. Does your tap have 2B etched on the side?
Your tap, I think is the problem, looks low quality - its not a proper tap.
These are used but good, got one last week.
Its really old cheap taps. I dont think it says.
ajlelectronics
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Take a good, matching bolt and grind some vertical grooves in it, then round off the start of the thread. You now have a thread cleaning tool which will not cut a new thread.
Munkul
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Regular taps should only cut enough clearance for a bolt to wind in nicely by hand. I'd have no problem using a standard tap to clean out a threaded hole.
If its cutting a large hole, there's something wrong with either your tap, or you're cutting squint/crossthreading?
I'm very surprised that your tap managed to cut material off the threads of a nut, they usually have more clearance than a tapped hole to start with...
If its cutting a large hole, there's something wrong with either your tap, or you're cutting squint/crossthreading?
I'm very surprised that your tap managed to cut material off the threads of a nut, they usually have more clearance than a tapped hole to start with...
zx9
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Probably not the case but you have to ask.
Are you sure it is not 5/16 BSF ie 22 tpi ?
Age and country of origin of the parts may give a clue, also there have been lots of obscure threads used up to mid last century.
MattF
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If you're using the correct tap, it won't cut any extra metal. It'll simply clear out the crud from the threads.
If threads are damaged will it not just cut threads away rather than push them into place like a chaser or whatever its called.
8ob
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There are a few options, thread files, thread reclaimers/chasers like the snapon set that also covers UNF( can get cheap sets of the bay) and these natty little gadgets that you insert into an internal thread, expand and wind out, they are very good.
Thread files
And these gadgets that expand in the internal threadnand turn out.
Munkul
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Sounds like your taps are a bit off, then!
MattF
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If the threads are damaged/distorted, they're also weakened. I'd have no qualms about those portions being cut, personally.
