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Where to buy a left hand drill bit
nick205 - 4/9/18 at 01:28 PM

Afternoon all,

I need to remove a bolt from a cast iron exhaust hanifold. The bolt head has sheared off so I'm left with the M6 bolt body flush in the manifold.

I'm thinking centre punch and a use a left hand drill bit to bite into it and hopefully undo it.

Can anyone recommend somewhere online to source a Ø2.5-3.5mm left hand drill bit please?

Thanks,
Nick


I'm also open to people's suggestions for other ways to remove the bolt!

[Edited on 4/9/18 by nick205]

PAULD - 4/9/18 at 02:59 PM

I have ground a normal drill to cut left handed before and it has always worked but the screws I have removed were not corroded in. Might be worth a try.

nick205 - 4/9/18 at 03:01 PM

Have an angle grinder, but not a bench grinder so probably not an option.

It's fair to say the mild steel bolt remains are pretty corroded in the cast iron exhaust manifold as well.

Slimy38 - 4/9/18 at 04:52 PM

Sealey have a set, AK8189. Although it's a bit expensive considering you'll only use the smallest one.

All the other ones I can see are tapered, which I could never get to work properly.

David Jenkins - 4/9/18 at 05:01 PM

Is it worth taking it to a machine shop and asking them to get it out with a spark erosion machine? I did this when I broke a tap while threading the last hole on a complex part of a model steam engine. I think it only cost me a few pounds.

Depends on the value of the manifold, I suppose...

r1_pete - 4/9/18 at 05:44 PM

How about trying the blob of weld followed by another blob of weld then a nut trick.

The local ferocious heat helps too, and as cast is difficult to weld too.......

tims31 - 4/9/18 at 05:51 PM

quote:
Originally posted by nick205
Afternoon all,

I need to remove a bolt from a cast iron exhaust hanifold. The bolt head has sheared off so I'm left with the M6 bolt body flush in the manifold.

I'm thinking centre punch and a use a left hand drill bit to bite into it and hopefully undo it.

Can anyone recommend somewhere online to source a Ø2.5-3.5mm left hand drill bit please?

Thanks,
Nick


I'm also open to people's suggestions for other ways to remove the bolt!

[Edited on 4/9/18 by nick205]


I've always drilled out using a cobalt drill bit and then easy out or screw extractors. Pre-soak with a penetrating oil for 12 hrs or so too to help with extraction.

The key to cobalt drills is to use at very slow speed and let it chip away at the material if you've never used before.

nick205 - 5/9/18 at 07:56 AM

quote:
Originally posted by David Jenkins
Is it worth taking it to a machine shop and asking them to get it out with a spark erosion machine? I did this when I broke a tap while threading the last hole on a complex part of a model steam engine. I think it only cost me a few pounds.

Depends on the value of the manifold, I suppose...



A 2nd hand exhaust manifold is about £50 so it's an option. I'm just one to try and fix things myself first though

nick205 - 5/9/18 at 08:00 AM

quote:
Originally posted by r1_pete
How about trying the blob of weld followed by another blob of weld then a nut trick.

The local ferocious heat helps too, and as cast is difficult to weld too.......



Used this technique to MIG weld some M12 nuts to locking wheel bolts when I had no removal tool. It worked perfectly and is certainly an option.

The engine's still in the car and the left hand drill bit idea I can do without removing the engine or manifold

ReMan - 5/9/18 at 09:49 AM

as mentioned use a normal drip and an ez out.
less? likely to break the easy out if it does grip

steve m - 5/9/18 at 09:54 AM

I would use a normal drill, and an easy out, there real useful tools!
Alternatively drill out and helicoil or drill out and tap it to 8mm,

steve

nick205 - 5/9/18 at 11:00 AM

quote:
Originally posted by steve m
I would use a normal drill, and an easy out, there real useful tools!
Alternatively drill out and helicoil or drill out and tap it to 8mm,

steve



Considered these options.

If I can get the bolt remains out then I'll certainly run an M6 tap down to clean the threads.

There's not enough material in the exhaust manifold boss to open up to M8 though.

The bolt is used to fix a metal support bracket for the air filter canister. Not really load bearing and ultimately I may be able to find another way to fix the bracket - just trying to retain the OEM/factory look.

David Jenkins - 5/9/18 at 11:25 AM

As it's not really load-bearing I suppose you could drill it out over-size, braze in a steel plug, then drill and tap a replacement hole. Hopefully brazing wouldn't cause the cast iron to crack.

Still prefer the spark erosion option myself. It's one of those jobs where the machinist spends 5 or 10 minutes aligning the job and setting the controls, then goes away and does other work while the machine is running. Hopefully they wouldn't charge you too much as it is unlikely to disrupt other paying jobs.

907 - 5/9/18 at 11:26 AM

Drill it out with a 4.8mm / 3/16" and run a tap in to remove the thread.

When at the taping stage in a couple of threads, remove and blow the hole out, repeat as necessary.




If you have easy outs then go to a bridge over deep water and drop them in. Shout "Geronimo" as they drop.

A bloke I know once did this but came back with the easy outs.

Why bring them back I said?

He said, I forgot the name of that f'in injun.



Paul G

[Edited on 5/9/18 by 907]

matt5964 - 5/9/18 at 11:27 AM

We sell various versions

Www.cromwell.co.uk

pM me you address and I will see what I can find in my samples 😉

nick205 - 5/9/18 at 11:52 AM

quote:
Originally posted by matt5964
We sell various versions

Www.cromwell.co.uk

pM me you address and I will see what I can find in my samples 😉



U2U sent and thank you kind sir!

matt5964 - 6/9/18 at 11:53 AM

quote:
Originally posted by nick205
quote:
Originally posted by matt5964
We sell various versions

Www.cromwell.co.uk

pM me you address and I will see what I can find in my samples 😉



U2U sent and thank you kind sir!


In the post today recorded delivery 📦 🤓

nick205 - 7/9/18 at 01:38 PM

Received today and a massive thank you for sending it.

ReMan - 7/9/18 at 02:37 PM

Come on then, video the job

With sound!

matt5964 - 7/9/18 at 03:51 PM

quote:
Originally posted by nick205
Received today and a massive thank you for sending it.


Your welcome 😎

Happy to assist a fellow in need.


We do an impressive range of tools and bits

owelly - 7/9/18 at 05:02 PM

I've never had any success with Easy-outs on small stuff! The hole required to fit the Easy-out weakens the sides of the broken stud enough to cause it to expand as you apply the torque required to shift the stud.....then the Easy-out snaps. Now you have a very hard bit of Easy-out jammed in the middle of the buggered stud so it can't be drilled.
I have drilled a hole, then gently knocked a spline bit into the hole. The heat from drilling, plus the percussion from knocking he spline bit in is often enough to get things moving. I usually go straight for the MIG welder......

nick205 - 10/9/18 at 10:29 AM

quote:
Originally posted by ReMan
Come on then, video the job

With sound!



The car is still tucked away in storage at the moment. Skip being moved off the drive today to make room for the car to come home this coming weekend.

Job to be tackled once the car is home

Not sure I'll video it, but I'll certainly report back on how it goes with before/after photos.

nick205 - 10/9/18 at 10:31 AM

quote:
Originally posted by matt5964
quote:
Originally posted by nick205
Received today and a massive thank you for sending it.


Your welcome 😎

Happy to assist a fellow in need.


We do an impressive range of tools and bits



Not visited a Cromwell store before, but looking at th website they do indeed seem to have a great range of tools! I shall certainly keep them in mind going forward.

nick205 - 10/9/18 at 10:34 AM

quote:
Originally posted by owelly
I've never had any success with Easy-outs on small stuff! The hole required to fit the Easy-out weakens the sides of the broken stud enough to cause it to expand as you apply the torque required to shift the stud.....then the Easy-out snaps. Now you have a very hard bit of Easy-out jammed in the middle of the buggered stud so it can't be drilled.
I have drilled a hole, then gently knocked a spline bit into the hole. The heat from drilling, plus the percussion from knocking he spline bit in is often enough to get things moving. I usually go straight for the MIG welder......



I have a set of Easy-Outs, but just don't trust them on stuff this small.

I certianly used my MIG to overcome locking wheel bolts when I didn't have the locking wheel bolt tool. Worked perfectly, but again on stuff this small I'd rather try the left hand drill first. Not sure I can get in there properly with the MIG.

ReMan - 10/9/18 at 09:25 PM

quote:
Originally posted by nick205
quote:
Originally posted by ReMan
Come on then, video the job

With sound!



The car is still tucked away in storage at the moment. Skip being moved off the drive today to make room for the car to come home this coming weekend.

Job to be tackled once the car is home

Not sure I'll video it, but I'll certainly report back on how it goes with before/after photos.


Good call.
Only wanted the sound to see if you swear better than me

nick205 - 11/9/18 at 02:59 PM

quote:
Originally posted by ReMan
quote:
Originally posted by nick205
quote:
Originally posted by ReMan
Come on then, video the job

With sound!



The car is still tucked away in storage at the moment. Skip being moved off the drive today to make room for the car to come home this coming weekend.

Job to be tackled once the car is home

Not sure I'll video it, but I'll certainly report back on how it goes with before/after photos.


Good call.
Only wanted the sound to see if you swear better than me




Like most I have my share of swear words and uncouth phrases, particlarly when things aren't going the way you want them to.

Let's hope the job goes the right way and I get the bolt out