DIY Threaded insert (Helicoil)

[kess]

How to make your own Threaded insert (Helicoil)
Using a cheap drill press,
a M12 bolt,
Ø 8.5mm & Ø 10.2mm drill bits,
M10 & M12 taps.
By following the same way,
you can make any helicoil with an acceptable combination of threads.

[DIYer]

Thanks kess! We've added your Threaded Insert to our Tapping and Threading category, as well as to your builder page: kess' Homemade Tools. Your receipt:

Threaded Insert by kess

tags: threading

[Frank S]

I've done this many times. One word of advice is to use the highest grade of bolt you can buy.The threads will be cleaner and stronger for the repair.
I usually like to drill a couple of 1/16" or 1.5 mm holes in thread line of the insert and the part being retreaded then driving in a short piece of rod into the drilled holes this will lock the insert into the part. Another advantage of using these DIY inserts is you can make a much longer insert than even an extended length coil thread.
The solid wall DIY inserts will resemble Ez-lock inserts more than the heli coil brand Both have advantages and disadvantages
Advantage of the Heli coil style is the thread will be the same pitch both inside and out side.
advantage of a solid wall type insert is any outside pitch may be used. This helps when you need to repair a fine thread that has been stripped simply use a large enough coarse thread bolt that will have sufficient wall thickness to leave a solid wall in the insert after the inside thread is tapped.

[Wmrra13]

Brilliant!
Wish I'd thought of this, especially the centering method.
Thanks,
Tyler

[kess]

Thanks for your time to complete my post.
Yes I know your method and I have used it many times at past, making two holes one the start and the other at the end point of the diameter at the line circle of thread insert and body.
Usually I use stainless steel rods but if haven't ss at the needed dia, then use hardened steel nails of cable retainer clips.
The video was produced with two basic aims,
i. A how to set up a cheap drill press (all these cheap drill presses working out of 0 point at least by 1~2 degrees)
ii. A how to drill a bold absolutely center without a lathe, and make your own threaded insert.
Happy New Year
Bill

[imohtep56]

Interesting- but there is no way to guarantee that the internal and external threads will be "in sync" (peak to peak and valley to valley) as your diagram shows.
If you try for the thinnest insert - you might end up going through a lot of bolts...

[olderdan]

I think Frank S covered that in his reply, I to have used this method on an XT Yamaha which had all the engine cover threads just about stripped out in the soft alloy crankcase. I used 8mm down to 6mm in brass inserts but I had the benefit of a lathe.

[kess]

Hi imohtep56
You are right there is no way to sync the threads and especially when the inner and outer thread has different pitch (M10x1.5mm /M12x1.75mm).
The thickness between threads it was very thin but I decided to give a try and see if can be done.
The closer shop it was 150 km away from my place and for only one threaded insert it was waste of time. I had used two bolts M12x1.75x35mm for one correct threaded inserts at about 17~18mm length from each one. We have sync (peak /valley) about every 17mm with a random distance from the start point of cutting.

[brianhw]

A great video, Kess. It could not be clearer. I will be using your method the next time I need to repair a stripped thread..
Thanks for posting this.

brianhw

[kess]

Hi brianhw,
Glad that you like it.