Cutting Down Drill Bits

[Old Son]

I am proposing to fit a fuel gauge. I want to mount it in the top of the tank but I only have 120mm between that and the underside of the deck. My right angle drill is 70mm deep and the drill bit goes in 30mm so my maximum drill length is 80mm, 75mm to be on the safe side.

 

The hole needs to be 12mm so I am thinking a pilot hole, one mid size and the final 12mm.

 

How can I cut down my drill bits to the correct length, alternatively, could I buy short drill bits?

[Guest]

Stub drill bits are available, try ebay etc. or engineering supplies.

I would think a steel cutting disk in an angle grinder would cut a drill bit down.

Edited October 11, 2015 by Guest

[John V]

I've never had need to cut down a drill bit but with them being that hard a grade of steel I would be tempted to try a slitting disc in an angle grinder

 

 

 

 

eta.....blxxdy peeps that can type faster than me again.....pah!!! why do I waste my time,,,,,mutter mutter

Edited October 11, 2015 by John V

[Tiggs]

I usually just put some insulation tape around (like 5-10 turns) them at the depth I want to cut to if cutting too deep would be a problem.

Edited October 11, 2015 by Tiggs

[Old Son]

I usually just put some insulation tape around (like 5-10 turns) them at the depth I want to cut to if cutting too deep would be a problem.

 

If I put a standard drill bit in my drill it wont fit between the top of the tank and the underside of the deck above.

[W+T]

Yes use a cutting disc in the grinder, a plasma.slitting disc is best unless you have a vice to hold the drill bit, which you should use anyway, then any metal cutitng disc will

[Tiggs]

Oh, I see.

 

Well you can get a right angled gear that might help.

 

https://www.machinemart.co.uk/shop/product/details/clarke-rad-2-right-angle-drill-attachment

 

P.

[W+T]

Oh, I see.

 

Well you can get a right angled gear that might help.

 

https://www.machinemart.co.uk/shop/product/details/clarke-rad-2-right-angle-drill-attachment

 

P.

 

They are good aswell, i have one, can be hard in tight places though as to get pressure on the drill still.

[bigste]

A big no for the average person. Once you cut it you then need to sharpen it. Few people can sharpen a drill bit to cut through steel, unless you are trained for it.

[W+T]

A big no for the average person. Once you cut it you then need to sharpen it. Few people can sharpen a drill bit to cut through steel, unless you are trained for it.

 

 

lol you cut the blunt end then.

[John Holden]

 

 

lol you cut the blunt end then.

 

(A greenie for that sir.)

 

Which is usually a lot softer than the cutting end.

[gazza]

A big no for the average person. Once you cut it you then need to sharpen it. Few people can sharpen a drill bit to cut through steel, unless you are trained for it.

I thought you were Mech Eng?.....

 

As W&T says you shorten the shank not the cutting face....

 

 

Drill shanks can easily by turned in a lathe or ground with um, a grinder.....

 

Go for it, no point buying a stub drill if you have a jobber that can be sacraficed.

[furnessvale]

I thought you were Mech Eng?.....

 

As W&T says you shorten the shank not the cutting face....

 

 

Drill shanks can easily by turned in a lathe or ground with um, a grinder.....

 

Go for it, no point buying a stub drill if you have a jobber that can be sacraficed.

Added to which, for 95% of jobs, the cut down drill is still of use.

 

George ex nb Alton retired

[Guest]

Added to which, for 95% of jobs, the cut down drill is still of use.

 

George ex nb Alton retired

And harder to snap when leaning on it.

I thought you were Mech Eng?.....

 

As W&T says you shorten the shank not the cutting face....

 

 

Drill shanks can easily by turned in a lathe or ground with um, a grinder.....

 

Go for it, no point buying a stub drill if you have a jobber that can be sacraficed.

Shortening the shank is obviously favourite, but to be fair, depending on how much the drill needs shortening, there may not be enough shank to cut off, whilst leaving some shank to go in the chuck.

[Bod]

I am proposing to fit a fuel gauge. I want to mount it in the top of the tank but I only have 120mm between that and the underside of the deck. My right angle drill is 70mm deep and the drill bit goes in 30mm so my maximum drill length is 80mm, 75mm to be on the safe side.

 

The hole needs to be 12mm so I am thinking a pilot hole, one mid size and the final 12mm.

 

How can I cut down my drill bits to the correct length, alternatively, could I buy short drill bits?

Dependant on how thick the metal you wish to drill through, then a step drill may work.

 

Bod

[AndrewIC]

Have a google for Rotabroach mini cutters. They may have something that will bit the gap you have to work in.

 

Andrew

[BGA]

I am proposing to fit a fuel gauge. I want to mount it in the top of the tank but I only have 120mm between that and the underside of the deck. My right angle drill is 70mm deep and the drill bit goes in 30mm so my maximum drill length is 80mm, 75mm to be on the safe side.

 

The hole needs to be 12mm so I am thinking a pilot hole, one mid size and the final 12mm.

 

How can I cut down my drill bits to the correct length, alternatively, could I buy short drill bits?

Has the dip stick stopped working?

[MHS]

Has the dip stick stopped working?

If made from cheap softwood, they can be quite unreliable.

[Guest]

As Bod said a stepped drill is the most likely.

Search ebay for stepped drill!

Once you have one (or a set) you will wonder how you managed without.

As a bonus they cut more smoothly and are hence are much less likely to snag.

Pretty handy if you are working in a tight space.

 

John

Edited October 12, 2015 by Floating Male

[Guest]

As Bod said a stepped drill is the most likely.

Search ebay for stepped drill!

Once you have one (or a set) you will wonder how you managed without.

As a bonus they cut more smoothly and are hence are much less likely to snag.

Pretty handy if you are working in a tight space.

 

John

Never come across these. That is something else I will have to buy now...

[John V]

Have a google for Rotabroach mini cutters. They may have something that will bit the gap you have to work in.

 

Andrew

 

When we were drilling the hundreds of holes for the inspection plates on all of Sabina's tanks we hired one of them (or to be more exact a copy one).

Fantastic bit of kit but eyewateringly expensive

[John Holden]

As Bod said a stepped drill is the most likely.

Search ebay for stepped drill!

Once you have one (or a set) you will wonder how you managed without.

As a bonus they cut more smoothly and are hence are much less likely to snag.

Pretty handy if you are working in a tight space.

 

John

 

I don't see how a stepped bit will help with limited room!

[nicknorman]

Has the dip stick stopped working?

I'm sure your post was somewhat tongue in cheek but for the record, not all boat fuel tanks can be dipped. On ours, the fuel tank is under the engine whilst the filler is on the gunnels, with a long and curving pipe in between, making dipping to measure contents an impossibility. This is why I eventually got around to fitting a fuel gauge.

Edited October 12, 2015 by nicknorman

[Guest]

I'm sure your post was somewhat tongue in cheek but for the record, not all boat fuel tanks can be dipped. On ours, the fuel tank is under the engine whilst the filler is on the gunnels, with a long and curving pipe in between, making dipping to measure contents an impossibility. This is why I eventually got around to fitting a fuel gauge.

Seen a couple of boats like yours where a dipstick wouldn't be feasible.

We can use a dipper on ours, but to be honest I can estimate the amount of fuel left reasonably accurately by observing the rudder tip.

[Bod]

 

I don't see how a stepped bit will help with limited room!

 

For the diameter they will cut up to, they are very short in length, the compromise is that they only drill through about 3-4mm thick steel for a given hole diameter.

 

Bod

 

PS Buy good quality, use very slow drill speed(count revolutions by eye), use cutting fluid, and DON'T put your finger in the hole!

Edited October 12, 2015 by Bod