There’s many ways to repair threads going in a casing.

  • Helicoils
  • Timeserts
  • Tapex
  • MB Specials
  • Welding

Theres an in depth article on all these and how to fit them which you can read here

I’ve regularly fitted Helicoils and Timeserts over the years, both work, but have their faults – mainly they are not deep enough to work well in a Lambretta casings. If they were longer they would be much better. Tapex I hate with a passion, these are far to fat and there are not many places they fit and work especially if fitted wrong which most are and causes more after repairs than anything else.

Because of this we made our own bespoke inserts to fit everywhere from the smallest 4mm to the largest 12mm.

Our inserts are the correct width to really clean out the old alloy and long enough to be deep enough to make a repaired casing perfect and longer lasting.

As with other inserts you need to drill center of the thread and 90 degrees to the casing. Then you need to tap deep enough with the correct tap. Then the casing needs counter boring to suit the size of locking taper on the insert. Use some loctite, run the insert down a screw and nut and screw tight in place.

Easy when you know how and with the correct tools. All our fitted inserts are done on a milling machine to keep every thing true to the casing faces where the casing is mounted on our special fixtures. Of course they can be fitted by hand but care is needed to get to 90 degrees. If not and you get 80 degrees the side cover doesn’t fit and you have to bend a stud or drill out a side cover.

I’ve done these jobs daily for over 40 years. Most are straight forward, but so many people do inserts wrong or try to drill out a stud and the drill goes half into a casing and half into the stud – it takes skill to get the hole repair back in center without welding.


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