Left-handed drill bits

[TheOtherLeft]

Hiya all,

Does anyone know where to buy left-handed drill bits?

I have a snapped bolt and there is no material left above the face of the hole so I can't use vicegrips or weld a nut into the remainder of the bolt.

I have heard Ezyouts/extractors are the work of the devil due to the risk of them snapping so thought using a left-handed drill bit might unscrew the remainder of the bolt. I'm going to use some Freeze & Release as well to help it out as well.

I think Blackwoods sell them but would need to ebay a kidney to buy from them.

Do you know of any other places that sell them? Either here or overseas???

Thanks,
Ben

[pipeclay]

What size drill or bolt.

[Karl Robbers]

Do you have a bench grinder?
What I have done before is to sharpen a standard drill bit the opposite way, yes I know that the spiral will be incorrect, but it still works well enough.
The only other source that I am aware of is Snap On - Blackwoods will require a kidney sold, Snap On is more like a heart or lung.:D

Why did the bolt snap - is there corrosion involved?

Another extremely effective method is to use a TIG welder, (a stick welder will even work IF you are steady enough), to build up a knob on the bolt that can be grasped with vice grips. This is my preferred option usually as the heat input and expansion and contraction will break even the most stubborn bolt free.
If you end up using a screw extractor, the best are the square section ones produced by proto, they do not expand the bolt like the tapered, spiral fluted ones will.

[TheOtherLeft]

What size drill or bolt.

It's only about 5 or 7mm diameter. It's the bolt holding on my heatshield to my exhaust manifold so it's a little hard to get to.

[pipeclay]

There are quite a few on ebay rangeing from $13 to $35.
They are in the US but these prices include postage,will just take a while to get here.

[.RC.]

A drill will snap before an easyout will....

However given this is an exhaust manifold bolt, it is probably frozen solid..

Good luck....

[ravna]

Hiya all,

so thought using a left-handed drill bit might unscrew the remainder of the bolt.going to

What on earth makes you think a drill bit , left or right hand will unscrew a frozen bolt?

If you use a LH bit it will just keep on drilling...what is there to make it bite.

As Karl said, get some of the spline type 'Easy outs' drill the correct size hole and then heat the area as much as possible preferably with a oxy torch, immediately spray with Wd 40 or similar, as the area cools it will drag the lubricant into the threads, tap the easy out in and work the bolt backward and forwards until it starts to move and try unscrewing...if it starts to bind again, keep moving both ways until it comes out, hopefully.

The only other option is to drill the bolt to the minor tread diameter and re-tap.

[Karl Robbers]

What on earth makes you think a drill bit , left or right hand will unscrew a frozen bolt?
As a matter of interest it does work in the right circumstances - a bolt that has snapped due to overtightening. Personally I doubt it will work in this case, but it is a very useful tool in the arsenal - Snapon actually make a set of extractors with a LH drill bit that leads into a tapered lh threaded screw extractor, often the bolt is removed before the screw extractor section bites home.

If you use a LH bit it will just keep on drilling...what is there to make it bite.
What makes it bite is the load that is applied cutting the metal plus there is heat input that loosens the bolt to some degree.

The only other option is to drill the bolt to the minor tread diameter and re-tap.
This is a little bit dangerous as one of two things can go wrong.

1/ The tap may not start at the same spot and you can lose your threads altogether.
2/ The bolt can collapse and lock the tap totally, rare but can happen.

If you have the access, skills and equipment my preferred option in this case would be to weld a knob on the bolt and turn it out with vise grips.
If not, don't forget to centerpunch the bolt and drill nice and true, if all else fails, drill the hole right out and use a keysert.

[Jekyll and Hyde]

As a matter of interest it does work in the right circumstances - a bolt that has snapped due to overtightening. Personally I doubt it will work in this case, but it is a very useful tool in the arsenal - Snapon actually make a set of extractors with a LH drill bit that leads into a tapered lh threaded screw extractor, often the bolt is removed before the screw extractor section bites home.

What makes it bite is the load that is applied cutting the metal plus there is heat input that loosens the bolt to some degree.


Agreed. Doesn't happen with great regularity, but in my experience, bolts definitely can and do come loose when being drilled, particularly exhaust bolts. And when a blind hole is involved, its most certainly of advantage to use a LH drill bit if you can, because a RH bit winds the stump straight to the bottom of the hole, and can make it harder to get out (DAMHIKT). Although, if that does occur, often the bolt is loose enough to knock a torx bit or similar into the hole you've just drilled, and wind it out.


I have heard Ezyouts/extractors are the work of the devil due to the risk of them snapping so thought using a left-handed drill bit might unscrew the remainder of the bolt. I'm going to use some Freeze & Release as well to help it out as well.

I have a passionate hatred of Ezyouts for that reason - about the only way to get the buggers out when broken is to drill a bunch of really small holes around the broken piece, and wiggle it out - like pulling teeth. In the size you're talking, I wouldn't even look at the Ezyout set (well, except to grab the LH drill bit out of it :D).

I'd drill it out to just under the thread size, then use a small screwdriver and hammer to collapse the thread of the bolt onto itself, allowing it to be picked out. If you don't quite get centre of the bolt in this case (I often fail at this part!), it's probably helpful, as it makes it easier to knock the remaining piece into the centre of the hole. Sure, you take out a little thread on one side, but if its only holding a heatshield on it won't really matter. Run a tap into it, and good to go. If it were a more critical application, I'd helicoil it if the original threads are compromised to any great extent.

[3RU]

Yes the exhaust system is a heat and rust prone area and have experienced it myself in aluminum (British) too. Tried to drill with the plan to pick out the thread but missed the centre. Best solution was helicoil and it fixed the thread a treat.

Have a go but if things turn pear shaped use the Helicoil solution as the backup.

Dave

[rogerbaker]

However you remove the offending bolt, when you have finished coat all of the bolts with Never-Seez or similar heat resistant lubricant. I havent had a seized or broken bolt since I started using never-seez 40 years ago.

Roger

[Metmachmad]

Hiya all,

Does anyone know where to buy left-handed drill bits?

I have a snapped bolt and there is no material left above the face of the hole so I can't use vicegrips or weld a nut into the remainder of the bolt.

I have heard Ezyouts/extractors are the work of the devil due to the risk of them snapping so thought using a left-handed drill bit might unscrew the remainder of the bolt. I'm going to use some Freeze & Release as well to help it out as well.

I think Blackwoods sell them but would need to ebay a kidney to buy from them.

Do you know of any other places that sell them? Either here or overseas???

Thanks,
Ben
Is the stud hole blind or open?

[kraits]

going with what ravna posted and if you can get your hand on an oxy set try heating the bolt first until its red hot, don't quench it at this stage, let it cool and with any luck it will anneal, making drilling your hole for the eze out that much easier. then reheat it and quech, water will do the trick and give it a wack with a hammer to losen up, not much to hit then use a centre punch or a small drift, anything you can get onto it. if that fails just drill it out and tap the next size up, should be pleanty of meat on the manifold.

[unixbigot]

It's only about 5 or 7mm diameter. It's the bolt holding on my heatshield to my exhaust manifold so it's a little hard to get to.

If you decide on a lefthand drill as the best option, mcjing.com.au have them for about $6 ea and they ship express post next day.

[TheOtherLeft]

If you decide on a lefthand drill as the best option, mcjing.com.au have them for about $6 ea and they ship express post next day.

Thanks for the link to that shop. They are a few suburbs away from me so I might pop around.

I think left-handed drill bits and some heat will be my first attempt.

[TheOtherLeft]

Is the stud hole blind or open?

it's a blind hole.

[Karl Robbers]

On the subject of quenching, proceed with caution, just remember that this snapped bolt is in an exhaust manifold, typically cast iron and that doesn't like heating and quenching at all.
A good tactic can also be the application of crc or wd40 to a warm, (not red hot!), component, as it will definitely penetrate better.
The best success I have had with such situations has always been using the welding methods described earlier.

[Stustoys]

You could try some of this to help things along.
Welcome to: Loctite® Freeze & Release (http://www.loctitefreezeandrelease.com/)

BTW you did snap it trying to undo it? I think everyone is assuming that.

Stuart

[TheOtherLeft]

You could try some of this to help things along.
Welcome to: Loctite® Freeze & Release (http://www.loctitefreezeandrelease.com/)

BTW you did snap it trying to undo it? I think everyone is assuming that.

Stuart

Hi Stuart. I mentioned using Freeze & Release in my original thread, and yes I snapped it trying to undo the bolt. Not trying to be sarcastic but is there any other way to snap it, unless it's in tension from a compinent hanging of it I suppose.

I'm still unsure about using heat or cold? Everyone mentions using heat but then there's products like Freeze & Release. I suppose they both work the same, i.e. thermal shock and then using a penetrating oil of some sort.

[pipeclay]

The main problem I can see with using heat,is trying to contain most of the heat to the Bolt and transferring to rapidly to the other part.
Did the bolt start to move at all when you were trying to undo it.
You said you didnt have much room to work with,could you give a bit more area size.

[Stustoys]

Hi Stuart. I mentioned using Freeze & Release in my original thread,
:doh:Omg sorry I would have read that when you first posted but I've obviously forgotten.

]
and yes I snapped it trying to undo the bolt. Not trying to be sarcastic but is there any other way to snap it, unless it's in tension from a compinent hanging of it I suppose.
.
Sure, doing it up or maybe even doing it up when you thought you were undoing it.



I'm still unsure about using heat or cold? Everyone mentions using heat but then there's products like Freeze & Release. I suppose they both work the same, i.e. thermal shock and then using a penetrating oil of some sort.
I've only ever used the spray once. I was very impressed, it worked amazingly well(on a MT3 drill chuck). Its certainly easier to use than heat, not exactly cheap though.

Stuart

[3RU]

However you remove the offending bolt, when you have finished coat all of the bolts with Never-Seez or similar heat resistant lubricant. I havent had a seized or broken bolt since I started using never-seez 40 years ago.

Roger

On ya Rog. Good to hear from you.

Dave

[rusty steel]

Hello T.O.L.,
I assume that there is some space beyond the end of the bolt so if you drill the bolt out as accurately as you can to the minor Dia. and then grind a fine tooth hacksaw blade down so that you can cut through the remaining threads in two opposite places you should be able to collapse the bolt and pick out some of the threads with a scriber and then use a tap to remove the remaining threads if necessary. A very slow process but it has worked for me. Good luck.
Russell

[Ashore]

Not trying to be sarcastic but is there any other way to snap it, unless it's in tension from a compinent hanging of it I suppose.
.
As Stuart said you can snap the bolt off tightening it up , if this happens then an ezyout is the go , unless you have bottomed the bolt. Otherwise ezyouts for small bolts are fraught with danger.
For a 5-7mm bolt that has seized before you do anything else build a dam around the bolt with plastercine, fill it up with penatrine or wd 40 and leave for 24 hours, with a small punch give the centre on the bolt ( dont damage the threads in the block ) a solid belt every couple of hours . This helps the penatrant get down into the threads.

Another method for small bolts like yours is to drill a 2.5mm hole through a block of wood and relieve the end of the hole to 5mm . clamp it directly over the bolt and use it as a guide for a 2.5mm welding rod. It welds onto the end of the bolt , switch off welder and remove the gun , leaving the welding rod welded to the end of the bolt. remove the wood. Repeat the soaking with penatrant and allow the bolt to cool, the welding rod gives a heat shock to the bolt but the heat also expands the bolt so you need to cool it down. Grip the rod as close as possable to the bolt with vice grips and gently remove :rolleyes:

[machined]

I had a small rusty bolt snap off in a downward facing direction under the front sill of my car. I ended up drilling it out and the new bolt went in fine, I must have got the hole just the right size and centred well enough for the old thread to fall out (with some WD40). I drilled a 2mm hole in the centre first using a cheap imitation 'Dremel' tool then drilled the larger hole with a cordless drill. Had to jack the side of the car right up.

[TheOtherLeft]

Thanks for the tips so far gents.

My plan is to heat up the area using a blowtorch - butane as I don't have an oxy or LPG torch, then when it's still hot spray some RP7 and let it soak for a while. I may do this a few times just to be sure. Then I'm going to belt it with a hammer and pin punch and then drill it out using some left-handed drill bits. When I get close to the original diamater I'll try and collapse the remaining bolt material or even jam an allen key in there and try to unwind it.

If need be I'll just retap it. It's not a critical component as it's only holding the heatshield to the exhaust manifold and the bolts been broken for a few years. it's certainly not something I want to pay a professional for but will treat it as a learning experience.