Just bent a drill bit

[Sutol]

To Sutol
I spotted that first off when you mentioned the carbide insert. I use drills similiar to yours to drill into concrete. A slang in the trade is it is called a Carboly. That describes a drill with a soft steel shank with a rough turned spiral flute and on the end is silver soldered a solid carbide insert. The carbide insert is ground for a percussion point that is why the drill is placed in hammer and drill at the same time. These drills come in 1/4", 3/8"
, 1/2" shank, the larger ones are SDS ( splined drill shank ) and SDS MAX.
Now there is a trick and that is to resharpen the percussion point to a twist drill profile. This can only be done on a GREEN STONE wheel , these are the only wheels that can touch carbide.
It is possible to have a twist drill point with a carbide insert but I have not seen them .
A fellow at the plant did order a solid carbide drill to remove a very tough bolt and it was costly and it looked like a regular twist drill except it was black and looked expensive.

Look at all the fun we are have drilling a hole in a ball bearing.

Craig Clayton

Well you're right of course and I haven't had to sharpen any of mine yet and that is the first one I have had any trouble with.

Here is the finished trophy for my friend who wrote his car off on a wet roundabout.
You can see the size of the ballbearing in this pic, I drilled into it just over an inch and it isn't just case hardened steel it is stainless steel (not magnetic and very hard)
The bit on top is a piece of his wheel that was picked up off the road, we are to present it to him tomorrow together with a photo of him alongside his wrecked pride and joy with his head in his hands:laughing:

All in good fun and he will treasure the trophy I'm sure.


Serves him write for not buying a Lotus, he went for the cheaper Vauxhall alternative

(you may have noticed that Sutol is Lotus backwards)

 

[SPYDERLK]

I can only think that the bit was so hot that its shaft was softened allowing it to deform after the hardened cutting edge had snapped off.

Unless anyone has a better explanation:anyone:

Bound to have been a carbide tipped bit.
larry

To Sutol
I spotted that first off when you mentioned the carbide insert. I use drills similiar to yours to drill into concrete. A slang in the trade is it is called a Carboly. That describes a drill with a soft steel shank with a rough turned spiral flute and on the end is silver soldered a solid carbide insert. The carbide insert is ground for a percussion point that is why the drill is placed in hammer and drill at the same time. These drills come in 1/4", 3/8"
, 1/2" shank, the larger ones are SDS ( splined drill shank ) and SDS MAX.
Now there is a trick and that is to resharpen the percussion point to a twist drill profile. This can only be done on a GREEN STONE wheel , these are the only wheels that can touch carbide.
It is possible to have a twist drill point with a carbide insert but I have not seen them .
A fellow at the plant did order a solid carbide drill to remove a very tough bolt and it was costly and it looked like a regular twist drill except it was black and looked expensive.

Look at all the fun we are have drilling a hole in a ball bearing.

Craig Clayton

Diamond sharpens carbide just fine. Green wheels [silicon carbide] would be 2nd choice.
larry