Home made dremel bits

[Matador]

I have made some home made dremel bits from old broken drill bits.
I use the drill press and a file to get them down the size to fit into a
dremel and a 3 corner file to made the cutting edge. So no need to
throw the old broken drill bits away.

399685399684

Graham.

[Robson Valley]

Question, Matador: What sort of speed do you think they can take?
My electric drill does maybe 2,500rpm, I rarely run the drill press over 1200.

My Dremel runs 15k max. My RotoZip runs 30k rpm (yes, a real screamer).
How well do you think those bits will stand up?

The main reason I ask is that there are no accessory bits for the RotoZip at all.

[BobL]

A good idea Graham, but if you were able to use an ordinary file to shape the bits I wonder how good the original bits were to start with?

I use Tek and various long shank hardened steel screws to make custom bits. They are soft enough to shape with a dremel/file etc but hard enough for wood.
My favourite ones are reverse countersinks (CS). This is where you need a CS on the opposite side of the hole you just drilled and don't have enough space to get a drill into.

The reverse CSs are made using long shafted CS bugle headed Tek screws.
I cut the thread off and cut and shape two perpendicular slots across the top of the head using a dremel and thin cutting wheel.

The bits are used by placing the shank through the hole from the back of the hole and then attached to a power drill chuck and instead of pushing the drill is pulled and activated.
I find them especially useful for removing mild steel burs in tight spaces.

[Matador]

Hi BobL,

Those broken drill bits I can't think what the steel they are made from it those gold drill bits. Some of them took a bit of to take down with file on the drill press and I was using damp cloth to keep them cool while I was taking them down. To square the ends up I used the dremel and the sharpening stone and used three corner file to the cut the cutting edge into them. I made them so when I do tea bag boxes I can carve tea box into them and also use them to carve a patterns into jewellery boxes. Plus I made myself a pantograph for the dremel and I use the bits in that to do letters. I will have to try your way using tek screws.

Graham.