View Full Version : Thread inserts
11-19-2009, 01:07 PM
I need your input comparing Keen-Serts, Time-Serts and other thread repair or thread strengthening systems. Cost, special tools and availability are concerns.
11-19-2009, 03:10 PM
For run-of-the-mill work, I favor EZ-Lok thread repair inserts. Widely available (most mill-supply and fastener houses, Fastenal, MSC, and many "professional" auto supply stores), inexpensive, and no special tools are needed. The biggest downside is that the EZ-Lok insert is retained by adhesive, and it takes time for that adhesive to cure.
A similar insert, but using a nylon retainer pellet instead of adhesive, is the Re-Nu-Thread insert from Northwestern Tools, a major maker of jig-and-fixture components. The Re-Nu-Thread inserts don't seem to be as readily available as the EZ-Lok inserts, but most mill supply houses should be able to get them without any trouble. Like the EZ-Lok, the Re-Nu-Thread doesn't need any special tools.
The "key-locking thread repair insert" -- commonly identified by the tradename KeenSert -- is a good insert, and fairly readily available, but setting the tangs pretty much requires a special tool.
The Time-Sert is a good product, but availability is limited and a number of special tools are needed to install one correctly.
The wound-wire insert . . . I don't like them, and avoid 'em whenever possible.
11-19-2009, 06:09 PM
What did you do? Blow a sparkplug out of your Ford?
Time-serts were designed specifically for re-threading Ford Modular engine spark plug holes...The bad news is Time-Sert kits run about $400.
A lot of Ford mechanics buy 'em, and usually can repair enough popped spark plugs to pay for the kit and the refills.
11-19-2009, 06:57 PM
Keenserts can be a HD repair comparable to original material holding ability, lots of useage in the heavy equipment industry.
11-19-2009, 08:08 PM
Sorry for not looking up the brands you list, but just a comment of sorts. I often use solid inserts brand wise I don't care. They work well if you have enough
(meat) around the insert. A few years ago on a Massey Combine with a Perkins 540 V8 Diesel, We dropped a valve and trashed the engine. When they rebuilt it, they pulled the threads from the block on the main bearings. The suggestions on repair were $16000.00 for a new block or put Heli-Coils (coil inserts) in the block. The repair company quaranteed the repair. I've used Heli-Coil Inserts for years but I would have never considered them for crankshaft mains, but the repair ran for years with no problems that I was aware of. They are good stuff in my opinion. John
11-19-2009, 08:12 PM
John Garner: Why don't you like coiled inserts? Localy iv only seen the coiled ones and was considering them as they only needed a flat head screwdriver to insert iirc and once inserted the spring action basicly locks them in place (you 'uncoil' them a little while inserting)
I guess removal might be a little bit of a pain...
11-19-2009, 10:41 PM
Black Moons --
Conventional "tang type" wound-wire thread repair inserts need special tools -- each size takes its own tap, insert installation tool, tang removal punch, and possibly insert removal tool; the good news being that all except the tap can be improvised fairly easily.
Breaking off and then keeping track of the tangs is a pain. I operate in a hi-rel environment, and if you've "been there, done that", you know how much commotion a lost tang can cause.
Beyond that, I've encountered a fair number of wound-wire inserts that wanted to stick to the fastener instead of the hole, sometimes on installing the screw (driving the insert deeper into the hole, and engaging only a short length of screw), sometimes on removing the screw.
For those times that I have to use a wound-wire insert, I LOVE Kato's "Tangless" inserts . . . but the installation tools -- which can't be faked easily -- runs well over US$ 100 each.
11-19-2009, 10:43 PM
I have seen elsewhere that people don't like HeliCoils and I don't know why. They bitch about the special STI tap and that seems to be it. I have always had the best of luck with HeliCoils and never any luck with the others (they come out). Why other than you are too cheap to buy the tap do you not like them?
11-20-2009, 12:57 AM
Old-time ditty I need to remember:
Be careful of the words you say
Keep them short and sweet
You never know from day to day
Which ones you'll need to eat
I've eaten my earlier words because they expressed unwarranted and inappropriate bitchiness.
11-20-2009, 08:35 AM
+1 For Ez-locs,with the right turn count on the tap they can be jammed home flush in the hole,a little 271 loctite and they ain't coming out by themselves.
I have also made my own inserts from NF B-7 all thread for places where a thinner wall is needed.
I will use Helicoils where I have to,but they aren't as strong as solid inserts especially in soft materials.
Hey Saltmine, I swore off of fords when the plug blew out of a new truck and they wouldn't do anything about it. I talked to a ford mechanic and he even knew which plug blew out. Back plug on drivers side.
Patrick :mad: :mad:
11-20-2009, 09:10 AM
Look at the times of my post and yours.
Two minutes apart.
I never saw your post because I was typing mine.
You just posted yours as I hit the send button on my post.
Consider some of the technicalities of posting on a bulletin board before you go off half-cocked.
11-20-2009, 09:12 AM
While "Time-Serts" are used for Ford spark plugs, they also come in a variety of sizes. The smallest being a #4-40 thread and pretty well cover the most common sizes.
For "Keen-Serts" the trick is using the recomended tap drill which is slightly oversize. The insert tool is something you can build pretty easy.
My application is repair of aftermarket Hardley-Davidson parts and are non-engine related.
Thanks to all for the input.
11-20-2009, 10:32 AM
You're right . . . I erred, and I do apologize.
11-20-2009, 11:33 AM
John- Your post had some very valid points and good information. Retrieving tangs can be a pain in a production environment. And yes, you have to remember they are SS and subject to galling. They do come with a powdery red coating, a dry lubricant of sorts, to prevent this galling when you buy them by the 100's. I used to deal with them in a production environment as well. Many times a minimum wage operator had the damn coils jammed up in the pneumatic installation tool, and had them cross-threaded into the parts. As toolroom mechanic, I would usually be the one who un-jammed up the machines and salvaged product (not really my job, but no one else had the patience to do it.) I also had the pleasure of dealing with metric helicoils installed in inch holes and vice-versa. I got good at removing them, not by choice. When word spread that I was good at removing buggered up helicoils, a lot of production personnel would feed me if I removed their bungered helicoils for them :).
Aside from the problems, they were usually operator error. I personally have had very good luck using helicoils, and rather like them. I have seen many of the other keensert or similar variety come out with the fastener. If I have a stripped thread in a machine, I usually use a helicoil. If I had to use a keensert, I would always use green loctite to affix it.