Thread: Threaded Inserts

Your local Cat dealer will have them

If it's only one and you're in a hurry, make one. Tap the hole to whatever convenient oversize bolt you've got, drill and tap the centre of said bolt to the thread you need. Cut off the tapped bit and install with loctite 243. Works best on lower tension grades of bolt but is still stronger than the alloy.

depends on what sort of insert your after,

if a helicoil has been inserted incorrectly or damaged there is a proper removal tool for them which 9/10 leaves the original oversize thread ready for a nw helicoil.

if your;re going to go for one of the screw in and lock type inserts (threaded on the outside and the inside and has top collar to hold it) be very careful with it. they are generally about 4mm larger than the normal thread and some spots on the rover heads will fail once you drill it out and wind it in. If you dont insert it properly they have been known to work themselves loose and in some instances will sit proud of the face and prevent the manifold from sitting flush on the gasket.

Originally Posted by Blknight.aus

depends on what sort of insert your after,

if a helicoil has been inserted incorrectly or damaged there is a proper removal tool for them which 9/10 leaves the original oversize thread ready for a nw helicoil.

if your;re going to go for one of the screw in and lock type inserts (threaded on the outside and the inside and has top collar to hold it) be very careful with it. they are generally about 4mm larger than the normal thread and some spots on the rover heads will fail once you drill it out and wind it in. If you dont insert it properly they have been known to work themselves loose and in some instances will sit proud of the face and prevent the manifold from sitting flush on the gasket.

Thanks Dave - we are taking the later type not helicoil. It is the threaded insert that pulled out of the head not the stud out of the insert.





Garry

Got a lathe or a friend with one? Make a stud with one end oversize to suit whatever you tap the head to.

Thanks to all for the pointers.

The original stud is M8 and the insert was M10 so the next metric size is M12 (looked at 9/16 UNC bit was a tad too small) looked as if it was doable with still about 2.5mm around the hole. Bought a couple of M12 1.5 bolts and tapped the hole in the head to take the bolt - all seemed to go OK.

Went up to my neighbour who has a lathe and turned down one end of the bolt to take an M8 thread(the other M12 end will go into the head. When we came to cut the M8 thread it was hard going and with the M12 end in the lathe chuck, the stud turned and damaged the M12 thread which needs to be perfect to hold in the head.

The bolt I got was high tensile and hand thread cutting was hard work. I just assume the old stud was high tensile but does an inlet manifold stud really need to be high tensile as it really doesn't carry much load?

So back to the drawing board and tomorrow buy a non hi tensile bolt and do the same as we did today or instead of making a new M12/M8 stud just make a new M12/M8 insert and use the M8 stud I have.

So does an inlet manifold stud need to be hi tensile if it does not carry much weight.

Oh this is no on a Rover engine but a Vw style engine.

Thanks

Garry

Last job at strut regas we had thread adaptors made to allow use to get the correct lengths or sizes for replacement gas springs. not hi-tensile but very easy to find in a big city


work has box of metric and imperial CAT inserts. I recently used a 1/2 bolt to replace a exhaust manifold stud on a Honda compressor motor.


had a rep selling a drill, tap and insert unit , was flogging tubes of glues and potions.

Originally Posted by garrycol

Thanks to all for the pointers.

The original stud is M8 and the insert was M10 so the next metric size is M12 When we came to cut the M8 thread it was hard going and with the M12 end in the lathe chuck, the stud turned and damaged the M12 thread which needs to be perfect to hold in the head.

Thanks

Garry

There are 11 mm x 1.5 taps and dies available but too late for you.

Get a piece of hex bar long enough to sit and grip properly in a three jaw chuck. Drill and tap it to the thread on the stud end, screw the stud in and then cut the 8 mm thread. Are you screw cutting or using a die? I should have mentioned this first up but I tend to forget I am not preaching to fitter-machinists.