Drilling A Snapped Bolt

[Resurrection]

As the title suggests i had a bolt that was connected to my foot plate snap off inside the housing

Now after getting the bike towed home as the footplate is linked to my gear lever and were both flapping round like a pair of dogs nuts in a strong breeze i got it in my garage and had a look

The bolt had snapped off just inside the housing so i decided to drill the sod out re thread it and put some new bolts in

In theory cracking idea. In reality ive gone through about 6 drills bits (3 of em titanium). Now i'm not that daft and have been using smaller drill bits for a pilot hole and oiling the drill bits to keep em cool but nothings working

Short of grinding and welding the belt im stumped,


HELP

Res
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ZX9r

[firefox]

how far have you got into the screw / bolt ?

[Resurrection]

Erm i reckon about halfway through it but its labouress to say the least

Just winding me up to the point where i make things up to do so i dont have to go near it

Res
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ZX9r

[firefox]

screw extractor, the spiral type, you put it in the drill then fit it into the bolt that is left, if theres a gap in the centre for it to grip if not drill a hole down the centre, then push the extractor on and put the drill in reverse and it should get it out. i did this with a snapped spark plug in the head.

https://imageserver.isnweb.com/KDT2419.jpg

[Resurrection]

Sorry mate didnt mention i'd try this and it hasnt worked



Its not the best one in the world but its worked before

Res
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ZX9r

[stinkwheel]

Either your drill bits are pish or you are trying to use them at too fast a drilling speed.

A good quality HSS drill bit should almost suck itself into the metal, throwing off spiraling loops of swarf as it goes. No need for fancy coated crap, you'll never see that sort of thing in a machine shop. Buy them from an agricultural supplier or a metal stockholder, they will sell them individually.

You need to drill this sort of thing using a SLOW drill speed. If you are trying to use a single speed electric drill, you will instantly overheat the bit, rob its temper and heat harden the steel you are trying to drill into. You need a variable speed electric drill set as slow as it goes. Or use a hand brace.

I would drill a small pilot hole using a hand brace anyway to ensure the hole was absolutley bang on centre.

[Resurrection]

I was going slow when i started out using a 3mm hss bit. piloted a hole but two of em snapped so moved up to 4 and then 5 which both snapped, my mate came round with a 3mm and two 4mm titanium drill bits which is about as sharp as a fried egg now

Bolt has rounded perfectly inside and im not even getting swarf out of it anymore


GRRRRRR

Res
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ZX9r

[stinkwheel]

If you are snapping drill bits, they are either crap, or you are trying to bully them in too hard or too fast.

My vote is still for too fast a drill speed. It is only a bolt, which will be a maximum of 12,9 grade steel, a good quality drill bit should make mincemeat of it. Buy a brand new bit (or sharpen your old one), centre-punch the hole you are trying to drill (to break through the layer of hardened metal you have created by spinning a drill bit on top of it) and use a hand drill. Take your time.

Make sure you are applying force to the drill vertically. Don't press to hard, if you are doing it properly with a good, sharp drill bit, it will pull itself into the metal.

You should note that in my experience, you can't buy a good quality drill bit in a hardware shop. Go to a trade suppliers or even somewhere like machine mart. They should be able to sell you them individually, or you might even like to buy a full set of decent bits in a tin box. They should be sharp enough to cut your finger on when you get them. Avoid gimicky coatings.

[Jubal]

The best and cheapest coolant in this situation is plain water, oil squirted on every now and again does not cool sufficiently, a constant dribble of water over the drill bit will do it, backing off every 5-10 seconds to put the tip of the drill under the flow of water.

Get a decent quality bit and don't electrocute yourself!

[cestrian]

This brings back not so fond memories of last week.
You may recall I snapped a bolt when trying to remove the exhaust of my GS500.
Decent drill bits should go through a bolt quite easily unless its the ultra strong type used on camshaft journals etc. As already stated, keep the bits cool and lubed and do NOT drill too fast. My 14volt cordless drill did a sterling job as it spins quite slowly. I ended up drilling out a snapped screw extractor, the drills I used were decent quality Bosch drilss bought from B&Q for a few quid each. I tried some cheaper drills from my local hardware store but they were crud.

Good luck

g)

[Jubal]

Lubricant factor of the coolant not really crucial in this case, the important bit is not to allow the drill to get hot.
The lubricant in emulsion based coolants helps to prevent metal adhesion to whatever tool you're using whether it be a drill or single point tool etc, also aiding the swarfe to get away cleanly and preventing rust.
Lubricant very necessary on things like taps, reamers etc where you have large hi load areas of contact between work and tool.

[Gradog]

I am struggling to understand why your having a problem with Titataniium tipped.
I appreciate the comments above and would say your wasting your time with HSS. Carbide tipped may work with extreme caution , a slow speed and coolant. TCT drills should piss through it.
They are not cheap at around £6 - £10 each, but they work where everything else fails. Do not try using a pilot drill all the way through. It is called a pilot drill to get you started, but the deeper you go, and the slightest twist and it will snap.
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Grey haired bikers don't get that way from pure luck. Only a biker knows why a dog sticks his head out of the car window.

[stinkwheel]

You wont see titanium tipped drills in a machine shop. Bog standard, carbon steel drills all the way.

I know this because I had a summer job working in a machine shop, drilling holes in metal plates.

[Finglonga]

[Gradog]

They were the only ones I could get to touch a snapped exhaust stud.
standard carbon would not touch it.
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Grey haired bikers don't get that way from pure luck. Only a biker knows why a dog sticks his head out of the car window.

[bish777]

i did have a left hand drill bit a while back but it went awol.

drilling left hand can loosen the bolt and actually get it to come out, especially with some hammer action goodness.
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GSXR1100J

[Jubal]

Those Gold coloured so called Titanium drill bits are nothing more than Titanium Nitrided Carbon Steel and are next to useless, the Nitriding is a few microns thick just to make them look pretty and encourage people to buy, just another crap gimmick IMHO.

If you have access to a Green grit wheel, Tungsten Carbide masonry drills can be ground to cut metal and work well.

Quality Titanium Carbide or Tungsten Carbide tipped engineering drills get expensive, solid Tungsten Carbide drills are as brittle as hell and not good for use in a pistol drill.

Decent HSS drills, not Carbon Steel and not bought from the pound shop or market used at the correct speed with coolant will work, high tensile bolts are not the easiest thing to drill out due to their high shear strength, but they're not the worst either!