zim Posted March 14, 2012 Share Posted March 14, 2012 Morning, I bought my winches second had and found that they had helicoils in them. I put it down to the previous owner being a bit rough handed and stripping threads, then helicoiling them. But speaking to AlanK a couple weeks ago, he said from factory they came with helicoils. What would the reason be ? For those that don't know the winch, they've got aluminium housings / end plates, and the mounting bolts screw into these. They are drilled and tapped (unlike other winches which you put a thin nut on the inside of the casing. Could it be due to them being ally ? Meaning the thread that you're constantly working on is steel and the helicoil isn't removed meaning the ally thread is not 'worked' ? G Quote Link to comment Share on other sites More sharing options...
ejparrott Posted March 14, 2012 Share Posted March 14, 2012 Probably because they're ali. We do a lot of gas turbine casing work, and a lot of threads are helicoiled from new, even in iron and steel castings, and in some nimonic bits we did recently. Quote Link to comment Share on other sites More sharing options...
zim Posted March 14, 2012 Author Share Posted March 14, 2012 Cheers. Back's up what i thought. Next question, looking at helicoil kits they have a "special" tap that comes with them. Are they actually any different to a normal tap ? I've got a good selection of taps G Quote Link to comment Share on other sites More sharing options...
landroversforever Posted March 14, 2012 Share Posted March 14, 2012 Its done here at work for ali things that are taken apart lots, stops the thread being stripped. Helicoil taps are specific to the size of helicoil. Normal taps do not work. Can't really describe how they are different.... like a normal tap but larger with the same pitch I think. Quote Link to comment Share on other sites More sharing options...
ejparrott Posted March 14, 2012 Share Posted March 14, 2012 yup Quote Link to comment Share on other sites More sharing options...
mickeyw Posted March 14, 2012 Share Posted March 14, 2012 Helicoil taps are larger than nominal diameter, but retain the thread pitch. So an M10x1.5 Helicoil will need a special tap large enough to create the thread for the insert, but still be 1.5 pitch. Normally a larger size screw will have a coarser pitch. Hope that makes sense. Quote Link to comment Share on other sites More sharing options...
Team Idris Posted March 15, 2012 Share Posted March 15, 2012 Mines the same with 3/8" unc helicoils. Except in the front, where they are M10 helicoils, which was due to an instalation error on my part resulting in some in-event damage So if you do kill the threads I'll vouch that they will helicoil M10 even if its a bit naughty. They partly work like studs, in that the aluminium thread is only recieving a pulling force rather than the pulling and sliding force of a bolt placed direct into the ally. (same effect seems to apply to tracks?) And they also work because the thread in the ally might be about 12mm for an M10 bolt, so the pull force is spread over more aluminium area. Being able to stand more removals is a good argument, but only if they don't rust. I hate them I'd rather have a threaded nut insert with the location spikes Quote Link to comment Share on other sites More sharing options...
bluespanner Posted March 15, 2012 Share Posted March 15, 2012 If you look at the air con mounts of a tdi engine on the timing case, you will see the holes are helicoiled. Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted March 15, 2012 Share Posted March 15, 2012 If you look at the air con mounts of a tdi engine on the timing case, you will see the holes are helicoiled. My 300 tdi ones don't appear to be Quote Link to comment Share on other sites More sharing options...
bluespanner Posted March 16, 2012 Share Posted March 16, 2012 pfft always one CW. at least i got you out to have a look! Quote Link to comment Share on other sites More sharing options...
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