bubble level...!

[lastminute]

Once had a cordless drill with built in bubble level...very handy for drilling straight, vertically and horizontally ...are there any on the market now?
...tried sticking a bulls eye level on...not the same!

Gerry

 

[Sideways]

I always thought that a 43mm drill collar with bubble levels in 3 axes would be useful. Never found one :-(

The best trick I picked up to help me drill vertical holes handheld is to put an engineers square on the surface next to the hole, blade sticking up. It helps me to judge what is square.

 

[Sideways]

But - it turns out you can get something from Europe ...
https://www.google.com/imgres?imgurl=ht ... A..i&w=400
or
https://www.ebay.ch/itm/Profi-Bohrhilfe ... 1595703837

 

[AES]

They look clever, a bit like the level built into my camera tripod, but I've never seen them "all alone" like that before. Good idea.

Personally I use several large LEGO bricks set up in an "L" shape stuck in a "bricklayer's bond" onto a thin flat LEGO baseplate. Works fine for small holes (up to about 3 or 4 mm) but of course that flat baseplate is sacrificial and needs replacing after you've moved around the "L" several times.