Technical Helicoil installation tool

I broke the plastic Helicoil installation tool while restoring an old Edmunds manifold. I have been looking for a replacement, but they don't seem to be available. The current kits advertised have a different tool than what I had. It looks to be a simple steel rod with a slot in the end and a couple of strategically placed bends. If this is truly what it is, I can easily make my own. If someone has one of these for a 3/8-16" helicoil, could you put a calipers on it and tell me the actual diameter of the rod? I know it has to be smaller so the Helicoil can "wind up" and get a little smaller so it will screw in easier. I use the longer (3/4") inserts whenever possible, and I think the old "diamond-headed" plastic tool was only intended for use with the short inserts.

 

Simple steel rod, can be made from an old bolt. The slot is used to wind them in then give it a tap to shear off the tag. Diameter needs to be a snug fit down the helicoil to shear off properly

 

It's really not that simple. I bought a nylon 3/8-16 bolt and made a duplicate of the plastic tool. Because that had the actual bolt diameter, it did not work at all, as the standard bolt kept the OD of the helicoil too large. Notice the part about winding up and getting smaller. That's why I need the actual diameter of that particular tool. I could guess but would rather not because a few thousandths in a case like this could be the difference between a tool that works and one that doesn't.

 

We purchased our helicoil repair kit from McMaster Carr. The winder tool is made of steel and is a specific diameter for the insert size as you know. Ours is for the 5/16-18 thread insert so the measurement you want isn’t the same. Try looking for it in their website….it’s not terribly expensive.

 

That's an alternative. It's just that I have a lathe and some 3/8" steel rod. If I could get the measurement, I could probably make what I need in a few minutes and be on my way.

Surely someone out there has one and can throw a calipers on it.

 

I’m getting .350 on a fairly new steel installation tool. The threads are cut deeper. It’s hard to get a good read on the diameter at the base of the threads as my callipers are a little wide plus the angle but .300 is close. If you have a lathe you could easily cut that thread and grind the profile on the end to grab the tang.

 

There are several types of installation tools for helicoil style inserts. The simplest type is like the red one here, just a round bar with a groove in the end, the diameter does not seem to be precisely engineered because it's rather loose inside the insert even as installed.
The upper tool is a Helicoil brand one, same basic idea to grab and turn the insert, but the tool has an internal thread at the mouth so you actually have to screw the insert through the end of the tool. Not sure what difference that is supposed to make, other than that you can't drop the insert as long as it's still partially inside that thread.

Then there's the tool type SEAAIRE354 shows, I have not used any of those. Most of the time I use the red one. Simple, and gets the job done.

 

minor diameter of 3/8-16 thread is 0.300"

 

@G-son, the diameter on the end of the tool with the red handle is the number I'm looking for. Thanks for the picture, it's more detailed than others I have found. The slot at the bottom is deeper than I thought.

 

BTTT - For the evening crowd.

 

@tubman I know this isn't exactly what your wanting but here is a picture of a 3/8" helicoil with the tool inserted and it doesn't look like that tool is a specific diameter.

Seems to be a lot of space between tool and insert....

...

 

copy the dimensions from your broken plastic tool...

LynnW

 

3/8-16 steel helicoil tool measures
.350 major
.298 minor

 

Thanks guys, I think I have what I need.

 

Success. I always appreciate it when others come back and "tie the bow" on a thread, so I will. I made a tool out of a six inch 3/8" carriage bolt that I had lying around. I ground the last inch of threads off to .030" under the minor dimension of a 3/8-16 thread. I also cut the head off a junk 3/8" bolt to make a "T" handle. I used my Dremel to put a slot in the end and it worked great. When I do a manifold, I like to use the extra long Helicoils (.76") wherever possible for extra hold. Their extra length makes them more difficult to install than the shorter ones. I also use red Loctite on them to make sure they stay put. One thing I hate is an "almost installed" Helicoil that just stops turning. Here is a picture of the tool I made and the installed Helicoil : .

 

Thanks for the update. I had checked my installation tools, back when you posted, and they were plastic, threaded, with a metal tab on the bottom. So, I didn't reply with picture or dimensions.

 

The plastic installation tool had worked great with the short inserts, but broke on the second long one. I don't know if it was cause and effect, but the all-steel tool is clearly superior.

 

Loctite on helicoil type inserts is a double edged sword. It may help lock the insert in place, but remember, the insert is an open coil, anything you put on the outside will bleed through and end up on the inside too, possibly making the insert stick to the screw and come out with the screw the next time you remove it.
As I understand it, the manufacturer does not recommend adding thread locker to these inserts. I usually don't, and so far haven't had any issues with them moving.

 

I don't think it will be a problem, because I NEVER assemble these things anytime close to when I fix them. I do run a bolt in and out, but that's it.

 

I see you have a Edmunds 4 bolt intake. I had to helicoil all the carb holes in my brothers intake.

 

Is this a coprolite buyout problem? Helicoil was in Bethel, Ct. one town over, called them and the recording said the number was not in service. Used their products in the past and liked them.

 

Odd, all of the carb holes were good. I had to do both generator mount holes and both water outlet holes.

 

I had to do the Generator mount as well as the fuel pump mount. I just looked at his intake, we don't have that bolt boss you put your helicoil in. His is Edmunds Racing manifold.

 

I worked at a machine shop that started in the 1950s. It had some older heli-coil kits that had a sheet metal forked blade to push the insert down while winding the insert in with the slotted rod.

Just now I could not find a picture on line amongst all the E-bay postings for seriously old looking kits, so I must have dreamed it.

 

Swap meet finds-

1/4-20 inserter.

3/8-16 inserter.

7/16 to 1” extractor.

 

Lemme guess; he had a Edmunds racing 4-bolt manifold for a flathead. This one if for an Olds Rocket.

 

i'll say this helicoil "thread" has been a 'pitched' battle judging by the amt of re's!!

 

Tubman, I guess I did not look at your manifold close enough! Yes, ours is flathead.