Just pre drill a small hole in the timber to allow clearance around most of the worm thread - that will reduce (or eliminate if you prefer) the pull from the thread without trashing a perfectly good auger.
More milk tibbles?
An angle grinder would soon fix that.... ;-)
TMH:
Cash:
I think that's slightly missing the, er, point.
The screw point on the traditional auger is a primitive form of auto-feed, intended to pull the bit through the wood without the user having to lean hard on the brace-and-bit (much though that tones up the stomach muscles).
The main problem is that it never worked all that well, because the optimum feed rates for hard wood or soft, close grained or open, are all different. Sometimes it's necessary to haul back on the brace to prevent it smashing through the wood.
And that's the second problem: put the same tool in "a suitably powerful mains drill" and it *will* smash straight through the wood - always at its own chosen feed rate.
"Trashing" is far too strong a word. If the threaded point is regularly forcing you to do two drilling operations instead of one, then grinding the thread off is a perfectly reasonable modification.
You can certainly get 300mm long non HSS twist drills - I have a set (5,8,10mm) bought off a market stall. I'd guess HSS might break too easily at this sort of length. Another perhaps more useful thing from the same source was 300mm extensions for flat wood bits - they have a collar which uses allen head grub screws to lock the bit in place and can be daisy chained together. Can't remember the brand - probably BlackForge or some other impressive sounding name but I'd bet Draper do something similar. Check their website.
I can think of one instance where a brace and screwdriver bit is the
*only* tool to use, and that is for shifting old, corroded screws, especially the 6" x 14 type. There is a knack to setting the handle at 3 o' clock and whipping it up to 2 o'c. For some reason the impact shifts things that would never move with just pressure
Impact driver is even better. Even the little Makita is brilliant for removing slot head screws you just know are going to be a problem.
To be fair it works well in some cases, and poorly in others. It much depends on the wood type and direction of cut. Drilling into end grain on soft wood (say a 50mm hole in a newel post), you want all the pull you can get.
That is the problem the hole solves for you. If you pre drill a small hole (say 5mm) it will greatly reduce the pull from the worm. 8mm will probably eliminate it altogether, 3mm will leave you a fair bit etc.
At least that way you have the choice of retaining the pull for when you do want it.
No need to force it using the technique described. If you were drilling
100's of holes in the same timber and situation etc, then it might be worth modding the bit - but its not a general solution since the problem is a moving target.
To help prevent this happening, just pull the drill back out of the hole to let the saw dust out. It is the saw dust that grips the twist drill that lets the torque to go up to the twist drill's breaking point. Just drill for a maximum of 2 inches at a time and then pull out.
Dave
I was thinking more of bending type breaking than twisting with a very long smallish HSS.
I see what you mean. This is a common problem with a pistol type drill handle. The way to get round this, if you are right handed. (If you are left handed, just change hands and follow this with your left hand doing the pushing.)...
In your normal way, start the hole off. Now stop drilling and change hands. Hold the pistol grip in your left hand with only your first finger and thumb, using your finger to press the start switch, while you press at the back of the body of the drill with only the palm of your hand, directly behind and in line with the chuck to start cutting the hole. Do not use your fingers at all while pushing. This puts all the pressure along the line of the twist drill.
It is the act of holding the pistol grip with your full hand grip that puts a bend in the twist drill, as the pressure is put on the drill below the axis of the twist drill.
I'm sure that you knew this Dave, but it is surprising how many drills are snapped by holding and pressing with the handle of the drill.
Dave
[Snip]
I hardly ever use HSS drills in a hand drill - I have a drill press which would be used for steel, etc.
Wouldn't that be difficult to use to drill horizontally through wood? :-)
Sorry, couldn't resist.
Sorry
Dave
You just turn the wood round. ;-)
I don't have a problem breaking twist drills in a hand drill.
Except tungsten ones for PCB use. So I have a special drill press for those. ;-)
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