Helicoil advice

[Pete.]

I'd be tempted to run a M8x1.25 tap in, wind in a M7x 1 helicoil and loctite the stud in with permanent loctite.

 

[defender dan]

Well seeing as this is a welding forum, I vote to tack it on

 

[northwest]

Loctite that into the casing and away you go, none of that will take long on a lathe.

Here we go again. Bloke comes on here (sorry I am assuming it's a bloke, could be anything nowadays!) enquiring about a helicoil and already he is buying a lathe. But then, why not!

 

[northwest]

I'd be tempted to run a M8x1.25 tap in, wind in a M7x 1 helicoil and loctite the stud in with permanent loctite.

Loctite and Helicoils, now there is a recipe for disaster. Whoever may pull that stud out in the future is in for a nasty surprise.

 

[Pete.]

Loctite and Helicoils, now there is a recipe for disaster. Whoever may pull that stud out in the future is in for a nasty surprise.

Perhaps but right now the OP is talking about scrapping it. If the choice is between making an irreversible repair whilst giving it a new lease of life and chucking the lot in a skip, surely making it useful one more time is the better option.

 

[northwest]

Perhaps but right now the OP is talking about scrapping it. If the choice is between making an irreversible repair whilst giving it a new lease of life and chucking the lot in a skip, surely making it useful one more time is the better option.

I get that and I am in full agreement with you. It does however go completely against my principles (though I would do it myself if that was the only realistic option). I would caution anybody against taking my advice or following my techniques as I have lost a great deal of sleep over the years in pursuit of "perfection"!

Edit: It has also cost me a great deal of money.

 

[not done it yet]

Find a nut that fits your bolt and then try it on the stud. If it fits both then it’s m7x1

Acquiring a set of thread gauges would, IMO, be the best plan of action.

 

[Bullet2012]

Acquiring a set of thread gauges would, IMO, be the best plan of action.

Agree , for the long term but trying to assist op with what he has to hand

 

[Marcas]

Thanks again for all the suggestions. I knew 7mm was an odd size and I've learned that 7mm X 1.25 is very odd indeed. Creating some sort of specialist stud or insert seems to be the way to go but may not be worth the effort/money for a 20yr old moped

 

[Pete.]

Put up a photo of the hole it goes into - and measure the depth of it!

 

[Keithmac]

To be fair the stud should never need to come back out of the casing so a permanent repair is fair game imho.

Some Chinesium mopeds have "normal" M8 one end and M7 the other.

Piaggio Zips have M7 stus but can't recall if the the base is M8?.

 

[Marcas]

 

[Marcas]

The depth is 21mm. However, please don't waste a lot of time thinking about this. It would appear that it will require somebody with equipment not available to me if I decide it's worth fixing.

 

[Keithmac]

Something like this would do the job, tap case out to M8 and fit the stud..

 

[Pete.]

Yep there's plenty of meat there. Run a M8 tap into the hole and use the 5 quid stud.

 

[highseas]

Cheapest option is to make your own insert using a short bit of thread off something like an m9 or m10 bolt , drill/tap the casing to suit and drill/tap the bolt to m7x1.25. Loctite that into the casing and away you go, none of that will take long on a lathe.

Bob

I can see this descending into a “you need a lathe” thread

 

[Marcas]

That sounds like a good solution that wouldn't cost more than the moped is worth. Many thanks.

 

[hotponyshoes]

If they are prone to ripping out it might be worth replacing all 4 with m8 for 20 quid..

 

[Bornfree]

I can see this descending into a “you need a lathe” thread

And a milling machine

 

[8ob]

I can see this descending into a “you need a lathe” thread

No Most folk that don't have one will know someone that does.

Bob