hints for identifying thread repair inserts.......

[brino]

Hi All,

I picked up a small parts cabinet with hundreds of the spiral spring type thread repair inserts. Like heli-coil but likely from another manufacturer. I think I got a good deal as the whole lot was just $50. However, it did NOT include all the required drill bits, oversize taps, and installation tools.
(it also had a few pem-nut inserts and other stuff)



(Note all the labels and bolts in the bins are my first pass attempt at identifying them.....)





Once I started going thru it, I realized that it's difficult to determine exactly what threads they are meant to repair!

Why?
When I try a similar thread repair insert from the kit shown below on a bolt of the marked size, I notice:
1) it spreads the inserts coils as I thread it on. That is, the collapsed or "un-sprung" insert looks to be a different thread count than the bolt it is sized for, and
2) the insert seem loose on the bolt. I think the insert gets smaller diameter when installed into a hole.

So the insert looks off in both thread-count and diameter from the thread they are made for!

Here's the type of kits they try to sell for $180 regular price, I got this one on sale:


Things I have noticed:
I believe that the determination of coarse vs. fine thread can be made by looking at the "gauge" of wire used for the inserts.

I suppose I could:

• go and order one each of a bunch of new ones for comparison purposes, as the new ones would be labelled
• try to find fully dimensioned catalog drawings of similar inserts and spend a day measuring
  
• go drill and tap a bunch of holes and try a bunch of these inserts as "practice" to ID them

Anyone have any hints, tricks, thoughts, wisdom on how to identify all these?

Thanks!
-brino

 

[RandyWilson]

If you're lucky, there won't be any metric in the mix.

 

[brino]

If you're lucky, there won't be any metric in the mix.

Yeah, that did occur to me, too.
It makes the job harder.......

-brino

 

[Rustrp]

This a good deal and I hope you never need to use all those.

It's been a while and I only purchased a kit with limited pieces. Okay, I'm going off of memory but I think the taps that come with the heli-coil are not standard threads and are made specifically for the heli-coil kit you're using. I'm not sure if they are standard across the industry. Good luck in you're sorting and you got a good deal.

Edit; I just had to include this. I think the guy needs to get a drill that turns a little faster though.

 

[RandyWilson]

In an old day job, I went through a lot fo M6 and M8 inserts, plus a fair quanitity of 1/4 and 5/16. I would buy the inserts by the pound from a local bolt jobber, who packaged them in brown paper lunch bags with the size scrawled on the outside. Imagine the fun when a new saleman decided to "straighten up" the stock room and combined all the bags into a single box.

 

[hman]

That one sounds worthy of the "Goofs and blunders you should avoid" forum!

 

[Dave Smith]

being a maintenance mechanic I dealt a lot with heli-coils---at times for repairing problem holes they are great, but when used regular to build setups in aluminum--they can be nothing but problems----I concluded that if it is for a one time they are a good fix, but if bolts are required to be removed and replaced often that is where the problems occur----hardened cap screws would bind and snap when workers were removing them and then you had a problem trying to remove the broken bolt and the hardened coil----I have heli coils and while I feel good about having a good assortment----I find that I really don't use them unless it is for a one time fix----this thread made me realize that I should gather all of mine and special taps and organize them in one location at least--I do have many and a lot are not marked-----hope you get all yours identified-----Dave

 

[RandyWilson]

I agree fully. Helicoils, any spring wire insert, does not take kindly to repeated untorquings. They shift and then make like a Chinese finger trap. For high cycle usage, or hgh loads such as head studs, I use Time-serts.

 

[kd4gij]

I always use helicoils with red lock tight in aluminum and never have a problem. So long as you don't over torque the bolts.

 

[Randall Marx]

I see that McMaster has product details for their helical thread inserts that detail OD, intended thread size and pitch, and overall length. They also have a 3D models for downloading from which you could measure wire size and such. Hopefully, this will help in the sorting.