Hints and Tips - Thread Repair

Bill Hoskins wrote:

David

In re: your problem with the Lancia engine studs. There is available, in the U.S.A. (and allegedly world-wide) a marvelous invention known as the Rosa'n Insert. These come in a variety of configurations, but my personal favorite is what is called the "Slimsert"...in most cases, it requires drilling and tapping the hole in question one thread-size over the original (the hole *does* require counter-boring with their special drill), tapping, and then installing the insert. I have used these little gems for years, and have *never* had a failure. If you would like, I can provide you with their address. The device was originally developed during WW2 as a repair for aircraft parts. The beauty of it is that it puts an (accurate) steel thread in alloy material. It works a treat!

Regards,

Bill Hoskins


From: David Laver
Date: Mon, 19 Jan 1998
Subject: Slimserts

Bill,

I'd be most gratefull for details. They sound like 'helicoils' we have over here. My problem is with an Austin 7 engine - the Lancia Aprilia is of sterner stuff - hence its selection for long term reliable grunt, originally for this car but not for a new car all its own, but alas not in the short term. I must learn not to ramble...

Much of the problem was with me putting it togeather in a rush, I knew some were loose in the block and I couldn't get the nuts properly tight. The other 'progress' I've made is to get proper spanners to reach all the studs and some locknuts. It was a case of race stresses being much harder on it than pottering and a couple of hill climbs. I'm starting to understand why the serious racers strip and inspect so regularly.

David


Date: Mon, 19 Jan 1998
From: William Hoskins
Subject: Re: Slimserts

David:

Helicoils (a dirty word in my vocabulary!) are a wire-type spiral that one threads into a hole for an *emergency* repair! Rosans are full-bodied, steel (your choice of alloy) inserts that provide a proper thread (with a self-locking feature if you so desire). I'll dig out the address for you over the next day or so and send it to you via e-mail.

Regards,

Bill


Date: Mon, 19 Jan 1998
From: William Hoskins
Subject: Rosan...

David:

Write (or FAX):

Rosan/Aerospace Fastener Division
Fairchild Fastener Group
3130 West Harvard Street
Santa Ana, California 92704
U.S.A.

Phone: (714) 641-8800
FAX: (714) 641-8801

Request their Master Catalog. They may charge you for this monster (it's a loose-leaf binder, about 3 inches thick!). I would also *strongly* recommend that you suddenly become the Chief Engineer for some prestigous-sounding aerospace firm, otherwise, they're liable to ignore you.

If you don't want to put p with the main catalog, ask for the technical brocure on the "Slimsert" line of inserts. They also manufacture a little item known as a "Studsert"...just what you think it might be. Most items are available in SAE and/or Metric sizes. They are *not* cheap, but you'll never he to replace one, providing you follow the instructions!! |-) Plan on getting their special step-drills for the sizes you want (unless you've got a very friendly tool-maker that can grind a "special" drill for you), as well as their setting tool. I think if you buy the tools, they may just "sample" you the inserts themselves! I've dealt with these folks for years, and they are always right on the money! If you run into any problems, let me know, and I'll see what I can do from this end.

Regards,

Bill


Home | Hints & Tips | Suppliers | Engineering Data | Links | Events | For Sale | Gallery | Books | Videos | About Us