On 06/11/2020 08:20, Martin Brown wrote:
On 05/11/2020 21:46, PeterC wrote:
Looked at these on SF and the reviews are not good - flimsy etc.

At work we had single-sided one that worked well but it was made 'in
house'.

Any recommendations for a good one, please?

How big a hole and through what sort of material? What is SF?

A fairly basic adjustable one from one of the sheds will do anything up
to about 3" diameter fairly reliably through wood starting from opposite
sides nearly doubles the possible cut depth. Mine is still going strong
after years of heavy use so it can't be all that flimsy.

If you don't tighten it up properly then it will probably self destruct.

Fixed sized core drills can be had for almost any material.
But even they begin to struggle once you go past a certain depth or
diameter.

The guy who cut a hole in my solid Victorian brick wall for the fire
vent destroyed a core drill doing it and damaged a second one. The small
round flints in the handmade bricks jammed it at every opportunity.


Sounds like he was using el-cheapo tungsten carbide core drill and not a
diamond core drill, which has very fine 'teeth' so less likely to
jam.