Thread inserts

[Bryan]

I don't mean those useless helicoil inserts, I was thinking Time-Sert or Kerb Konus. There are others too I'm sure.

Care to expand on that Greg? Have you had failures?

[Greg Q]

Yes Bryan, both during installation and in service. I am referring the coil spring type with the special installation tool.

Greg

[Bryan]

Interesting. Up to now I've believed their advertising. Only used them a handful of times myself, without a problem.
I just looked at http://timesert.com/. If you click on the main pic there's a heap of videos. Clearly a better solution.

[Michael G]

A previous employer was in the defence game. While some wound wire (WW - the term Greg mentioned is a brand name) thread inserts were used there, for critical applications the solid types were specified. The WW type rely very much on having a really good tapped hole and a good fastener in the insert as they only stay put because there is nowhere for the wire to go. Once some of the wire comes loose, failure becomes so much more likely as it just pulls out. Although not obvious at first a lot of the solid types have a locking mechanism that is there primarily to hold the insert in place when there is little or no tension on the fastener. Once tension is applied the friction of the outer thread in the base material is the thing supplying most of the resisting torque
One of the inserts went under the brand name of "Rosan". Originally developed by a company that was subsequently bought out by Alcoa they had a sleeve that locked everything in place. We had problems with them because they had gone out of patent and so had been copied by companies all over the place. It was remarkable how some batches would install beautifully and some would not simply because the copying manufacturer had not thought enough about the sleeve clearances and tolerances.

Michael

[Anorak Bob]

Interesting. Up to now I've believed their advertising. Only used them a handful of times myself, without a problem.
I just looked at ++ TIME-SERT Threaded inserts for stripped threads, threaded inserts, thread repair stripped sparkplug's, Ford sparkplug blowouts, threaded inserts threaded, repair stripped threads, stripped threads, inserts threaded inserts, Ford spark plug repair,. If you click on the main pic there's a heap of videos. Clearly a better product.

Thanks for the link Bryan. I just waded through the videos, the fifth of which (IMO) is both the driest and most informative. I was watching the bloke drilling the hole on a skew with his cordless and was encouraged when I found that an alignment jig was offered in their head repair kit. Like all this stuff, you have to know it exists.

BT

[Greg Q]

I was having speaks with Anorak Bob today and mentioned that Amazon has the inserts for his application here:E-Z LOK Threaded Insert For Metal,Metric,M12-1.75 Int Thread,3/4-10 Ext Thread - 303 Stainless (Pack of 5): Amazon.com: Industrial & Scientific

I tried to buy them but shipping is not available to my country. So in my case I can wait the two months for them to show up from my forwarder, but that doesn't help BT. I know they are available here in onsey-twosey orders, but I don't know where. More sleuthing...

Greg

For Bob's application I now think that a larger homemade insert with a large flange inserted into a bored and counterbored and staked or keyed to prevent rotation. An even cooler variation would be LH threads on the OD and standard RH threads on the ID.

I will say that threaded inserts work a treat in engines. I have two stories about this: I used to fly an aeroplane that would pull 54" of boost on take-off when we could find real high octane fuel (145). We never had a failure with the studs set in inserts. On a similar unmodified plane pulling maybe 34" at take off I once had a cylinder, head and push rod tubes grenade right through the cowling. At about 110 cu in. per cylinder it made an unmistakeable sound. Explosion even. I dropped my cigarette and everything.

8 gallons of engine oil finds its way out of a canned-ham sized hole in no time at all, BTW. I could have been a poster boy for J.R.Ewing.

54" is about 1.8 bar, 34" is around 1.1 or so.

I know that one anecdotal story does not a trend make, but there are plenty more in the alu block motor car racing world to convince me. When I make (steal) my version of the euro-mill adapter plate I will copy what Bob does. WWBD?

Greg

[QC Inspector]

I was an aircraft mechanic for a fire bombing outfit once upon a time. The DC6 tankers pulled 56 inches wet (water-methanol injection) with 100/130 fuel to make 2400 HP for takeoff. Those jugs were 155 cu in (18 of them) and they also would occasionally fail but I can't say I ever saw any go through the cowling. The ignition leads, intake and exhaust pipes held more or less held them in place. I have seen the master rod fail and cut through three cylinders and the crankcase before the pilots shut it down though.

Some of the inserts being discussed wouldn't resemble Keenserts would they? They are used a lot at work in the machining fixtures.

Keenserts® Keylocking Thread Inserts

Pete

[rogerbaker]

Back in my younger days I used to prepare competition engines using genuine "Helicoils" and "Recoils". Aluminium Blocks running to 10,000RPM.
Never had a problem.

Roger

[Greg Q]

I was an aircraft mechanic for a fire bombing outfit once upon a time. The DC6 tankers pulled 56 inches wet (water-methanol injection) with 100/130 fuel to make 2400 HP for takeoff. Those jugs were 155 cu in (18 of them) and they also would occasionally fail but I can't say I ever saw any go through the cowling. The ignition leads, intake and exhaust pipes held more or less held them in place. I have seen the master rod fail and cut through three cylinders and the crankcase before the pilots shut it down though.

Some of the inserts being discussed wouldn't resemble Keenserts would they? They are used a lot at work in the machining fixtures.

Keenserts® Keylocking Thread Inserts

Pete

Hi Pete. The failure I had was in 1978 on a R-985 Wasp Jr. In a Beech 18 D in Mad River, Oh in 1974. I saw someone else at CYYZ a couple of years later in an H model with the same puckering event. I flew the Wasp, the Cyclone, R-2000 and R-2800 with no problems* after cutting my teeth on the Wasp Jr. That said, I do like my CF-6s just fine

* except for that one twat who gave us a load of Jet-A after seeing the "turbo"decal by the door. Luckily we were held on the ground due ATC delays until the engines quit. Everything from 1978 to now has been on borrowed time.

The inserts are all variations on the Keensert. The variations seem to be on OD dimension and anchoring scheme. They all seem to have some gee-whiz locking idea. I find that loctite is sure-fire absolution for dimensional sins. At least at ambient temps it is. Obviously not so much in cyl heads.

GQ

[Greg Q]

Back in my younger days I used to prepare competition engines using genuine "Helicoils" and "Recoils". Aluminium Blocks running to 10,000RPM.
Never had a problem.

Roger

I think there are two issues with the wire wound thread restorer devices: the thread in the parent material, and the ability to cleanly break off the drive tail of the insert (I forget the term for that, if there is one) Inserts are often meant for blind holes, or critical applications such as spark plug bores, stud holes in alloy cases etc. The very idea of banging a break-away hardened wire into a recess from which you may not be able to extract same leaves me cold. The solid threaded bushing type insert is miles aheadof the wire wound type at similar costs. Why screw around?

[Greg Q]

I was an aircraft mechanic for a fire bombing outfit once upon a time. The DC6 tankers pulled 56 inches wet (water-methanol injection) with 100/130 fuel to make 2400 HP for takeoff. Those jugs were 155 cu in (18 of them) and they also would occasionally fail but I can't say I ever saw any go through the cowling. The ignition leads, intake and exhaust pipes held more or less held them in place. I have seen the master rod fail and cut through three cylinders and the crankcase before the pilots shut it down though.

Some of the inserts being discussed wouldn't resemble Keenserts would they? They are used a lot at work in the machining fixtures.

Keenserts® Keylocking Thread Inserts

Pete

Pete...BTW...when I flew Trackers on fire bombing in Ontario in 1979 we had jugs of tetraethyl lead additive that we would pour willy-nilly into the drums of 100-130 we had. We convinced ourselves that max boost was a safe option with all of that Nascar racer magic in the tanks. never had occasion to give the message to the engine room on that tour. I wonder what would have happened? Remind me to tell the story of dumping a load of borate into an otherwise unoccupied OPP car on the TCH.

GQ

[Anorak Bob]

Pratt & Whitney R-985 Wasp Junior nine-cylinder radial .

4828336192_7d7a1acb56.jpg

Do you miss this stuff GQ?

[Greg Q]

Yes, I surely do. I recall buzzing my first girlfriend's house when I was 18 doing the night mail to Toronto. Those engines made a delightful roar...450hp each, with two bladed props that would go supersonic at the tips on take-off. Great roar, very dude-like.

Back then we used to do a lot of all night single pilot flights, no autopilot, a thermos of java, a deck of smokes and a sure-fire zippo. On the very odd occasion my bud Dean would give hookers a free Detroit-Toronto trip for professional courtesy. My avatar is almost exactly what it looked like, only it was dark.

Those old airplanes had real (not synthetic) loop antennae which would allow us to tune in any good AM station in eastern North America and jive to the tunes of the era...BeeGees in my time, listening to WNBC. Sometimes there would be inflight entertainment. See: Dean.

Greg. off to have peaked so early.

[SurfinNev]

Now you guys have got me worried. I will be attempting a repair on a 1KZ-TE engine, intake manifold today, using the helicoil type inserts. Will not know how bad the manifold is until I remove the venturi. I know two studs at least will need helicoils. One is still good. The fourth stud may break as it is well and truly stuck. Two are blind holes (the stripped ones) and two are through holes. If it fails then it's replacement manifold time, which is a bugger of a job.

Nev

[TED C]

Greg,
I think I have missed the start of the thread, however If you are looking for good inserts [not necesarily timeserts] try a Caterpillar dealer, they stock keenserts.
Ted