Keenserts -- the industrial alternative to Heli-Coils

[goodfellow]

These are Keenserts -- I have been using these for high strength repairs for the last two decades. I believe that they were originally developed by Fairchild. Then the technology was picked up by ALCOA and marketed as "Tridair-Keenserts". For repairing heads, these are a stronger alternative to traditional Heli-Coil fasteners.

Here is a good "How-To" PDF, that explains the install and the benefits --

http://www.mediafire.com/?sharekey=77da8fd4484b5e25312dbd5f2bdc5062ec150950fe7248a45621d66e282a0ee8

[Uncle Buck]

Man, if that is your assortment that could not have been cheap at the time of purchase!

[goodfellow]

Man, if that is your assortment that could not have been cheap at the time of purchase!

I got lucky -- bought it for a song off a shop that was closing about 20 years ago.

[Papaw]

I used some in motorcycle repair, but found Helicoils to be quicker and easier for me.

[gtermini]

Awful, vile little things! 

I never have like the way they fit in the tapped hole, plus you have to put a giant hole in a part to install them. It's a white knuckle experience using a piece of keystock to wind them in a 2B tapped hole without bending the tabs off, because there's no where else to drive them from. I did 750 of the 1/2NC x 3/4NF blind in a job once. Probably 25% of the locking tabs bent off wrong when I was setting them, and I had the collared tool. I had to go back with a pin punch and set every single of the 4 tabs on every insert to get them flush with the surface and not catch on anything!

I will never voluntarily install them. Helicoils win hands down. You can buy spiral point gun taps for the insert size to power tap the holes, and the inserts go in with a cordless drill faster than you can say helicoil.

Greyson

[goodfellow]

Pretty sad experience I admit Greyson, and it just goes to show that no one tool or product is the answer. I only have used these serts on automotive projects (mostly cylinder headbolt and manifold repairs) and in all cases they did the job well. Unlike many techs, I have not had good luck with heli-coils in high stress components and these serts have "saved my bacon" numerous times. The install tool seemed to work well for me --

Also -- I just have used this set that is a 1980's vintage; thus I can't vouch for more recent production of these serts.

[gtermini]

I won't disagree with them being stronger. They do serve a purpose, and have a place in the world. I mainly run helicoils in plastics and aluminum that either sees repeated assembly or thermal cycling.

There's another large body, double threaded insert that installs with a flat blade screwdriver. They have the advantage that you can replace them if the inner threads get buggered. They either get red loctite or have a nylon plug embedded in the side to retain them. I forget the trade name. They are my go-to flavor for high strength.

Greyson

[muddy]

I've had to use helicoils more then I'd like to admit

[Uncle Buck]

I have used Heli-Coils only a few times, but I will admit when I did they worked like a charm and made a fan of me.

[slip knot]

Ever ran an aluminum outboard motor in saltwater? You will learn all about inserts. I bought a kit from the Johsnson dealer. it was OMC branded and it worked really well. had a big plastic insert tool shaped like a key. The easiest ones I ever used. Wish I knew who made them. I'm sure OMC just repackaged them.

[skfarmer]

I have used Heli-Coils only a few times, but I will admit when I did they worked like a charm and made a fan of me.

same here. the keenserts look like a sturdier setup  though.

[fatfillup]

I haven't had great luck with heli coils but I likely don't have enough experience.  On one job in particular that we used to see often was broken exhaust stud bolts on 13 hp honda engines.  I find it much easier to drill out the hole for a 3/8 bolt and tap it.  You also have to drill out the manifold and exhaust gasket but for me, it makes a more confident repair

[Matt_T]

I won't disagree with them being stronger. They do serve a purpose, and have a place in the world. I mainly run helicoils in plastics and aluminum that either sees repeated assembly or thermal cycling.

There's another large body, double threaded insert that installs with a flat blade screwdriver. They have the advantage that you can replace them if the inner threads get buggered. They either get red loctite or have a nylon plug embedded in the side to retain them. I forget the trade name. They are my go-to flavor for high strength.

Agreed on the keenserts. Too much trouble for most applications.

I've used the other style you mention. They already had a red threadlocker on them which was about useless. Knocked it off with a wire wheel then used activator and 271. I've also made basically the same thing by D&Ting bolts. If you've got clearance on the back side leave the head on. Gets you a deeper thread and will never pull out.

Timesert is another style of solid insert which looks useful for applications that require a seal.

http://www.timesert.com/