self tapping threaded insert - how to i install this

[simonfraser]

M3 x 5.2
the external thread measures 4.7mm

all sorts of insert guidance on google, but not clear to me

its going in aluminium

what drill size to use for the hole ?

and screwing it in, do i put an M3 bolt in with a nut at the end and use that as an insertion tool ?

tnx

 

[waynes world]

Have you a link to the insert you want to use.

 

[simonfraser]

SELF TAPPING THREADED INSERTS CORROSION RESISTANT INSERTS FOR ALLOY TRISERT-3 ® | eBay

 

[Talulah]

M3 x 5.2
the external thread measures 4.7mm

all sorts of insert guidance on google, but not clear to me

its going in aluminium

what drill size to use for the hole ?

and screwing it in, do i put an M3 bolt in with a nut at the end and use that as an insertion tool ?

tnx

Probably a 4mm drill required but you could test it on something else. The insertion method I use is as per your message. 3mm bolt with nut about 10mm along. Insert bolt into thread and tighten nut up against insert.

 

[VicS]

The form of the hole and its dimensions are shown below. There is a special tool for inserting the Trisert ... I guess you could improvise as you suggest but be sure to insert the Trisert squarely.

https://www.tappex.co.uk/wp-content/uploads/2017/04/ETP41-Hand-Tools.pdf

 

[simonfraser]

tnx all, will drill this in the next week or so, external, so not today

 

[Refueler]

I know its a bit late and OP is using the threaded type .... but thought it may interest some :

When the bolts started pulling out of the GRP on my stanchions .... (its an old boat with thick grp !) ... I tried threaded inserts but in the end opted to use expanding inserts.



They have proven to hold and after a number of years - absolutely no play or movement at all.

 

[DownWest]

I know its a bit late and OP is using the threaded type .... but thought it may interest some :

When the bolts started pulling out of the GRP on my stanchions .... (its an old boat with thick grp !) ... I tried threaded inserts but in the end opted to use expanding inserts.



They have proven to hold and after a number of years - absolutely no play or movement at all.

False ceiling hangers?

 

[Norman_E]

I would be wary of using those on a boat as zinc passivated steel will rust. If you are putting fittings into a mast or boom use nutserts instead, as they can be bought in aluminium alloy or stainless steel.

 

[halcyon]

I would be wary of using those on a boat as zinc passivated steel will rust. If you are putting fittings into a mast or boom use nutserts instead, as they can be bought in aluminium alloy or stainless steel.

Also is steel and aluminium compatible ? galvanic corrosion.

Brian

 

[Refueler]

False ceiling hangers?

No idea what they are called .... but they are a brass alloy and non corrosive ... the steel bolt is purely as example to show the action of the insert. On the boat I used Stainless - actually the original stanchion bolts cleaned up.

Builders merchants sell them in various sizes for blind fittings into literally any material ... and rated for serious loads.

 

[Refueler]

I would be wary of using those on a boat as zinc passivated steel will rust. If you are putting fittings into a mast or boom use nutserts instead, as they can be bought in aluminium alloy or stainless steel.

Where did I say use on a mast or boom ?

 

[Norman_E]

No idea what they are called .... but they are a brass alloy and non corrosive ... the steel bolt is purely as example to show the action of the insert. On the boat I used Stainless - actually the original stanchion bolts cleaned up.

Builders merchants sell them in various sizes for blind fittings into literally any material ... and rated for serious loads.

The things that the OP linked to are passivated steel Quote for description "Self-tapping threaded inserts made from case hardened steel with a zinc nickel passivated finish. " As such they will not be suitable for marine use.

 

[Norman_E]

Where did I say use on a mast or boom ?

I said "If you are........" The things you linked will be OK domestically, but are totally unsuitable for marine use.

 

[zoidberg]

There are questions of 'passivating' s/s blind fasteners and s/s fittings going onto/into alloy masts and booms. The aviation industry deals with this routinely, but tends to use treatments too toxic for us mortals.

I've used two layers of parcel tape under mast fittings, successfully, but don't yet have an answer to 'holes drilled' and 'blind fasteners inserted'.

Suggestions, please....

 

[Refueler]

The things that the OP linked to are passivated steel Quote for description "Self-tapping threaded inserts made from case hardened steel with a zinc nickel passivated finish. " As such they will not be suitable for marine use.

Wasn't clear - looked like you were referencing my inserts ... which are suitable for marine use ....

Its been over 10years since I used them to refit my stanchions and today they still are in excellent condition ...

 

[VicS]

No idea what they are called .... but they are a brass alloy and non corrosive ... the steel bolt is purely as example to show the action of the insert. On the boat I used Stainless - actually the original stanchion bolts cleaned up.

Builders merchants sell them in various sizes for blind fittings into literally any material ... and rated for serious loads.

Where did I say use on a mast or boom ?

The things that the OP linked to are passivated steel Quote for description "Self-tapping threaded inserts made from case hardened steel with a zinc nickel passivated finish. " As such they will not be suitable for marine use.

I said "If you are........" The things you linked will be OK domestically, but are totally unsuitable for marine use.

Wasn't clear - looked like you were referencing my inserts ... which are suitable for marine use ....

Its been over 10years since I used them to refit my stanchions and today they still are in excellent condition ...

The OP is proposing to fit these into aluminium ........... but probably not into a mast or boom because he has a mobo and mobos tend not to have masts or booms

Passivated case hardened steel will not be suitable for marine use as Norman_E points out. However the same inserts are available in both 304 and 316 stainless steel. He would be well advised to use 316 stainless , especially if his boat is sea going, and to fit them with some Duralac or Tef- Gel to minimise any interaction with the aluminium.

I would not use the brass inserts in aluminium although they would be OK in GRP for use with stainless steel screws and fittings.

 

[Refueler]

Thank you Vic ...

Might be good idea if OP says where he's going to use them - maybe there's better way ?