please, when I read stuff like;-
drmini in aust wrote:
It's a 5/8 UNC thread and yes, it is a pretty close fit.
Well, depends on your description of 'close' but as I said earlier, these are not precision threads, like say a micrometer. Grab a UNC Blot and wind a nut down on it. Then wobble it. There is a fair amount of movement there, eh?
I'm sure if you Googled it, you'd find out what the clearances are.
The correct re-threading system will give the same clearances as the original threaded hole in the sump.
moemoke wrote:
I think helicoils are mainly desidned to work in blind holes and not holes that
go through metal or alloy like a sump. on my moke it's helicoil was becoming tighter and tighter to get the sump plug in or out and I had a good look one day and the helicoil
had wound itself into the sump by 5-10mm and was only gripping the alloy by a couple of turns and some of these where broken, I managed to dig it all out then re threaded the hole and had a friend make up a new sump plug in a slighty bigger diameter, I retapped the sump in the car but was about 0.0005° out of square so has a slight oil leak
(just like the new then
)
What size helicoil do you guys use? I did look at using another but I think the guy said I'd need to drill the sump out quite a bit bigger or maybe that was the only sizr they had
These re-threading systems are very good, although there might be some rubbish ones out there.
There could be a number of reasons for this to occur, some like;-
Using a Whitworth system instead of UNC,
Not cutting the thread correctly,
Using the wrong tap,
Using the wrong system. There are some that are designed for blind holes, some for through holes and
some that are thread locking types, so just don't buy re-threading kit without know what you are buying!
These are the ones I use (and some educational reading);-
http://www.alcoa.com/fastening_systems/ ... cat_id=685
I would have done more than a dozen of these over the years and never had trouble. I do also have a very long T tap handle that makes it easy to get in there and get it reasonably square - square enough that they do seal. Also, guys, try aneiling the copper washer, they do work harden and then they don't seal.
The factory used these systems, when required, on the Gold range of reconditioned gearboxes too (and reading between the lines, I think Matt Read uses them).
Please, don't give a great system a bad name because of misunderstand it or incorrect use. Any tool or system that is not used as intended will give bad results and this is no different.
You're losing me... and perhaps the above does not reflect what you are trying to say????
