Thread: HOLE CUTTERS

Originally Posted by Ben Dono

It either works or it does not.

Yeh its not that simple.

It can work at various states of poorly in between working and not working.

I know quite a few people who seem happy to bludgeon their way thru things with blunt drills......they think it is "working".....that is not MY idea of working.

it all depends on your expectations.

I would not be pushing MY step drills thru 10mm steel plate....A/ because they are too expensve to do that with, and B/ because a pliot drill followed by the right sized drill would be the right tool for the job.

cheers

I must admit to just using a 1/2" inch square stone rubbed a few times up the flat to sharpen mine.

> ...............I would not be pushing MY step drills thru 10mm steel plate....A/ because they are too expensve to do that with,
> and B/ because a pliot drill followed by the right sized drill would be the right tool for the job................

Step drills and conical cutters are obviously not suitable for holes less than full diameter in 10mm plate, because they do produce steps or a taper. I have however very successfully used them in 10 and 12mm Aluminium plate to drill holes of the conical cutter's major diameter (meaning pushing the cutter right through the plate leaving parallel walls). The resulting holes are of excellent finish and roundness. Cutting forces are much less than with a drill. You end up with shiny endless long curls as chips, easy to clean away. The cutter does not suffer in the process, provided plenty of WD40 is used for lube and to prevent cutting edge build-up.

The "right sized drill" is not necessarily the "right tool" for this sort of job. A "Rotabroach" (aka annular cutter) will cut a plug with reduced cutting power requirement compared to a drill. You are left with a plug, very much as with a circular saw. These tools are usually used in magnetic stand drills, but can very well also be used in a drill press or mill or from the tailstock in a lathe. Downside these must be guided and the workpiece clamped, no pilot:
slugger.jpg


Another great tool is the trepanning tool. There are many variations, even with a guide bell for freehand use. This here is IMO the king of all trepanning tools, the famous Swiss made Valcut. Arguably something between a boring head and a simple trepanning tool:
valcut1.jpgvalcut2.jpg

Mike,

Try this similar thread from earlier this year.

https://www.woodworkforums.com/f65/drilling-30mm-hole-10mm-plate-182477

A home made "superdrill" was discussed and there was a lot of interest at the time.

Bill