Technical Threaded insert

Hi gents... I really like threaded inserts and I think they are much better than Heli-coils if you have the room. Generally speaking they come in two basic categories: heavy wall and thin wall. Lots of variants i.e metric, stainless etc. The thin wall insert typically has a standard thread OD... 7/16 X 14 or whatever. Now her is the rub: if you use a drill guide and drill and tap the hole for the correct 7/16" thread then you will never be able to screw in the thin wall insert! Look up the part online and it will give you the correct drill size. Example: 7/16 X 14 takes a "U" drill pilot however a thin wall threaded insert requires a drill about .397 or so. Don't axe me how I know...

 

Goodnews. I've had trouble with them spinning.

 

Don't use aluminum inserts unless you're selling the car later that day ...

 

Enlighten us less educated guys. What's the difference between the insert and a helicoil?

 

Google "keensert". As Gene Boul says, better than helicoils, follow the manufacturer's installation instructions. Best to get their tool for driving the keys in.

 

Nutserts are valuable in both aluminum and steel. HRP

http://avdelusallc.com/products/nutsert.shtml

 

Helicoil is basically a piece of diamond cross section wire wrapped up in a spiral so is pretty thin and not very rigid outside of a hole. The outside and inside pitch are the same.
Inserts like Keen-serts have solid walls so can have the inside and outside threads different pitches, and are more rigid. However they have a larger OD than Helicoils so there is not always room for them.
Helicoils require special Helicoil taps, whereas the Keen-sert type use standard (usually NF) taps. There are four little "stakes" on the top of the Keen-sert which are hammered down once the insert is fitted. These positively prevent the insert from spinning. Maybe other imitations don't have these stakes.

 

Thanks you, very informative.

 

I'm not a big fan of inserts... A insert is larger in diameter compared to a Helicoil, so in many applications they just won't fit or you'll have to drill such a large hole that you'll weaken the area where the insert goes. The thinwall inserts aren't as strong as a Helicoil IMO. One application where they can be superior to Helicoils is where you need a 'sealed' thread as fluids or air pressure can 'wick' through a Helicoil, although a liberal application of sealer during installation will usually stop this. But if you find a Helicoil that somebody has managed to pull out or damage, a insert can be a viable repair if the hole is now too large for the right size Helicoil.

I've never had a properly-installed Helicoil fail...

 

Inserts are usually like a captured nut, but are a unit that is inserted thru a prescribed hole size and crimped in place with the corresponding tool. They come in steel or aluminum and in many thread sizes. One brand is Nutsert.
Helicoils are thread repairs. You drill out and rethread a stripped whatever and wind a coil spring into the new thread then break off the winding tab, leaving new original size threads where the damaged threads were.
You can buy kits with multiple thread sizes or single size kits for most uses.
Just remembered another brand name - Timesert.

 

This very helpful

to a bunch of us.

 

Helicoils are OK provided that the hole is barely "wallered" out (to use an expression I learned after moving to the midwest). If the hole is beat up too badly a Keensert or Timesert is the best option due to the larger od and the more rigid thread structure. The other thing that I like about the Timesert is that it locks into place when the installation tool expands the lower part of the insert--no staking required as with a Keensert. I have seen Helicoils come out with the stud/bolt in applications where heat has reduced the retaining ability of Loctite to hold the insert in place. I have rarely found that there was not enough material surrounding a hole to be able to use them rather than helicoils. The stuff that rfraze is talking about (nutserts etc) is aimed more at providing a threaded location in thinner sheetmetal or frame rails etc where there is not enough material to thread .

Roo

 

Just thought I'd mention Allennuts. They are threaded inserts but have a female hex socket on one end to fit an allen wrench. If you insert them in a properly sized hole, they will bite in, since they are knurled on the outside. As an added advantage, they are made from high quality steel, just like socket head capscrews. I use them on the topside of boxed frames and tack weld them in place so I can bolt the body down. See them in McMaster-Carr.

 

In the past I have used helicoils in the ex studs on my HD.
Never have had a problem with them coming out. All my cycles get red lined every time I ride, I don't think there is a worse environment than the heat and shaking of a Harley.
Another area I had a problem with on one SBF was the alternator bolt that goes to the head. Helicoil worked great
On a BMW boxer I bought once ( I got screwed ) the cyclinder studs also hold the heads , the case had helicoils and the repair just couldn't hold the cyclinder pressure and I used Timeserts which lasted about 6 weeks.It was very marginal as to the remaining material. Welding up the deep holes and taping was not an option for me to risk. I found some used cases.
They all have there place and use. The laws of physics always win.

 

These work great and I use them a lot but they are not for thread repair

 

Good luck trying to get a tap out of a helicoil if you happen to chase your threads and don't know it's in there.

 

Keen Serts work well for me. I've been buying them from McMaster Carr, under the MIL part number series MS51830, when I have to sell off a repair to a military customer.

 

Might look up time serts