On 2009-03-05, wrote:
I have never had much luck in using Helicoil thread inserts - even
when I used a kit. Now I am trying to do so without buying a kit.

I am trying to install (1) 1/4-28 thread insert. Because of a

[ ... ]

No luck in fumbling thru with it. I tried to twist the insert to
reduce the OD, I tried to deform the end of the insert to make it
undersize, I tried to install the insert backwards, I threaded the
insert on a short 1/4-28 SHCS to use as an install tool. Looking in
the McMaster catalog, I see that the installation tool for the 1/4-28
is a winder style to reduce the OD of the insert for $32+. For those
of you who use these regularily and know what you are doing - advice
please. Obviously, I am not overly interested in spending more money
to install one insert.


Turn a shaft a bit smaller than the ID of the insert as
installed (smaller than the minor diameter of the 1/4-28 thread as
tapped in solid metal) -- probably the tap drill diameter for 1/4-28.

Cut a notch in the end of it about twice the thickness of the
bent cross section.

Cross drill near the other end and put in a crank handle.

Bore a tube into which the insert will slide, and leave the last
1/4" or so tap size for the insert tap.

Tap the last 1/4" or so with the tap you use for the inserts (28
TPI, but something larger in diameter). (You *might* be able to get away
with just turning this last part to the OD of the tap you used for the
insert installation.)

Slide the insert, with the cross bent end first, into the tube,
Follow it with the notched shaft and engage the cross bent end. Start
to crank clockwise until the insert just shows flush with the threaded
end.

Official versions have a window near the reduced diameter end
half the diameter and long enough to allow the longest insert to be
installed without fully withdrawing the crank, which is typically
captive.

Place the end against the tapped hole in your workpiece, and
wind the insert out of the tube and into the workpiece thread.

Once it is in place, withdraw the slotted crank, and using a
smaller diameter pin and a small hammer, break off the cross-pin and
withdraw it with a magnet.

This is based on several Helicoil install kits which I have
acquired at a hamfest.

Good Luck,
DoN.

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