Breaking M20 bolt

[Lewis_RX8]

What about hiring a hydraulic torque wrench? The kind of things they use to do up flange bolts on pipelines, I think the really big ones claim tens of thousands of newton-meters.

At work our flange bolting procedure has u use these hydraulic torque wrenchs anything over 500 ft lbs IIRC

 

[mtt.tr]

I can't see that a hex bit won't either sheer first or round the hole out!


Why do they need to be sheered as opposed taken out.


Impacts are ok but smaller ones are defeated by harmonic as evidence by the 1" air gun used by the tyre guy, his stopped turning but my multiplier could make it turn

For reference this is on a truck.
Impact stopped but my multiplier could still turn it, not enough mass in the impact and like I said harmonics defeat them.




I would be looking at a 3/4 to 1" multiplier myself


2500nm output capacity,.and that is constant pressure at about 210nm input 12:1

Britool Expert HXT28 Torque Multiplier 1/2" to 1" (E100104) 5024344934390 | eBay

Britool Expert HXT28 Torque Multiplier. Equivalent to Expert model E100104. Straight reaction arm. Reaction arm at 90°.

www.ebay.co.uk

Here a suitable bit aswell

ISS 1" Drive Male Hexagon Drivers Metric 100mm Long

Buy ISS 1" Drive Male Hexagon Drivers Metric 100mm Long From ToolsToday.co.uk

www.toolstoday.co.uk

 

[stuvy]

I’ve got access to a 1” m18 if you want me to see if I can set up some sort of test?

It’ll shift big boy nuts and bolts no bother but I’m not certain it would snap them. M22 is truck wheelnuts and I’ve never known it snap them. Even the seized trailer ones. Either the nut gives up or nothing happens.

@James1979 id be really interested in what yours will break

M20! cant grind them off?

Or drill the tops off? Or O/A the head off?

Can’t use a grinder as they are recessed and need to salvage the part they are bolting into

Could it be a left hand thread?

Defo not I bolted them up myself

 

[stuvy]

Will a mini-ductor do it?

Never used one

Are you able to say what the application is?

Can you turn a shear line on them, then wind them in? They should snap with less force.

I’m assuming you’ve got the ability to remove them first etc.

Wondered what the application is because I’m thinking that a shear force might equate to a thread stripping force??

The M20’s bolt through and into S355, they have been through a heat cycle then into heat treatment but they really don’t want to come out

is it just me but the thought of nay job that will involve shearing m20 just makes me feel not well thou thought of doing it by accident is bad enugh never mind on purpose..
also makitas biggest battery impact wont snap a new 8.8 i know that much

They were specced by someone else.
My job is to remove the mistakes they make

Would be helpful to have a bit more detail of the actual job.
Even a photo or two would help.

Sorry, no can do on the pics

We got to two pages without any info

Bob

I like to keep an air of mystery about me

@Barking Mat I think this is the man who's signed a 'non disclosure agreement'.
Yepp your correct indeed

To shear that grade of fastener off your going to need at least 1500nm. If it’s a cap screw you should get it with a suitably sized 1” drive impact slug. Anything smaller you’ll probably shear the square drive. You do run the risk of rounding the hex though, although a 12.9 grade fastener will be almost as hard as the slug so you might end up damaging that instead.

Will try it both ways

My recommendation is either a long thick walled tube (scaffold not man enough) with an alien key cut short so you limit the twisting force reducing the likelihood of damaging the fastener. Otherwise it’s the same Allen key or an allen flogging spanner (or a short bit of Allen key and a flogging spanner) and smack it numerous times with a 14lb hammer.

I can forward the details of the 8000nm gun?

Yes please

What about a torque multiplier? Never used one myself, but I remember someone removing lorry wheel nuts saying you have to make sure you’re going the right way or else you’ll shear the stud off.

How do the hydraulics get powered?

You said no heat allowed but as already mentioned above would you get away with drilling into the bolt to reduce it's effective diameter and weaken it?
Slow and steady with lube to keep it cool.

I’m going to look at this tomorrow

They are not shouldered bolts that have rusted in are they ?
The TQ multiplier idea
Sit down first

https://www.tester.co.uk/norbar-htx-x-handtorquer-standard-multipliers-with-awur?gclid=EAIaIQobChMInOPF6vK8-AIViO7tCh2C4QjhEAQYAiABEgKpnPD_BwE

The drill sounds the way to go you can buy a lot of drills

100% not

They were fitted a few days ago but need to come out to free a work piece off

 

[stuvy]

I can't see that a hex bit won't either sheer first or round the hole out!


Why do they need to be sheered as opposed taken out.


Impacts are ok but smaller ones are defeated by harmonic as evidence by the 1" air gun used by the tyre guy, his stopped turning but my multiplier could make it turn

For reference this is on a truck.
Impact stopped but my multiplier could still turn it, not enough mass in the impact and like I said harmonics defeat them.
View attachment 352169View attachment 352170



I would be looking at a 3/4 to 1" multiplier myself


2500nm output capacity,.and that is constant pressure at about 210nm input 12:1

Britool Expert HXT28 Torque Multiplier 1/2" to 1" (E100104) 5024344934390 | eBay

Britool Expert HXT28 Torque Multiplier. Equivalent to Expert model E100104. Straight reaction arm. Reaction arm at 90°.

www.ebay.co.uk

Here a suitable bit aswell

ISS 1" Drive Male Hexagon Drivers Metric 100mm Long

Buy ISS 1" Drive Male Hexagon Drivers Metric 100mm Long From ToolsToday.co.uk

www.toolstoday.co.uk

The piece they are bolted into will be sacrificial as the threads have stretched

When I’m back in tomorrow I will take some pics of the 5 bolts I managed to get out by hand the rest are stuck fast but need to come out

 

[badabec]

Defo not I bolted them up myself

My mum would have asked why you did them up so tight in the first place.

 

[stuvy]

My mum would have asked why you did them up so tight in the first place.

Your mums a funny one

They were torqued up below the manufacturers spec

Some of the chaps on here have met me and know what I do for work but sadly I can’t say too much as it’s all cloaks and daggers

We have to deal with heat input and then the fall out from shrinkage that renders the bolts knackered, no matter what size they are

 

[Beanwood]

All I can say is that for £40 on amazon you're getting a torque multiplier that claim 3400Nm
If it's tighter than that, yes you can spend big money, but my cheapie scoffed at the nut that snapped my 1" breaker bar knuckle. Like it wasn't even tight!

If you haven't tried one you might be surprised.

If it's not man enough go for one of @500e suggestions...

 

[scottmk1]

Can you use a rotabroach and cut the heads off with it?

 

[Bullet2012]

Just torque to them nicel

 

[stuvy]

Can you use a rotabroach and cut the heads off with it?

That’s what I’m going to use today

 

[pressbrake1]

I have a carbide drill modified to fit a mag drill I use for such situations regularly . Quite a lot of hgv calliper bolts

 

[stuvy]

I have a carbide drill modified to fit a mag drill I use for such situations regularly . Quite a lot of hgv calliper bolts

Don’t suppose you could pop a picture up please

 

[pressbrake1]

Here
I’ve cut the dodgy adapter off the end that was welded on that fits the rotabroach as I needed to put the drill in a Weldon shank adapter on the borer
It’s a nice positive rake carbide so the mag drill can handle it and less heat production

 

[Morris]

I used to work for a company that made bubble wrap, the co-extrusion dies had the same issue. They had about 30 M20 cap heads that had to come out annually for cleaning etc.
We used a mag drill and reground masonry bits (really, they worked great) and drilled the heads off. Strange thing is the stubs would come out by hand but we're totally immovable in the torqued up state.

 

[J1nx]

This is the most powerful battery impact available I believe, a fair bit more poke than the Milwaulkee…
https://www.amazon.co.uk/dp/B09CM14R8J?ref_=cm_sw_r_ud_dp_E5GMD2BQVEZR2MTHE3R6

 

[stuvy]

I tried a 14mm rotabroach but it’s not enough to budge still

Im gonna hire a 3/4” Milwaukee and try that with an impact socket

 

[stuvy]

This is the most powerful battery impact available I believe, a fair bit more poke than the Milwaulkee…
https://www.amazon.co.uk/dp/B09CM14R8J?ref_=cm_sw_r_ud_dp_E5GMD2BQVEZR2MTHE3R6

For that money I’d buy a compressor and an 1” truck gun

 

[mtt.tr]

For that money I’d buy a compressor and an 1” truck gun

That still won't sheer them

 

[stuvy]

That still won't sheer them

Need to at least try

I’m gonna hire the 1” Milwaukee gun and drill them with the mag drill and see if that can help break them out