What are these bit for

[jon burgess]

I have four Irwin bit use for that I do not know what they are used for. Four of them have different numbers. The other two have no writing on them

[comp56]

they are known as fostner bits, for drilling  thru or flat bottom holes...not that terribly old they were designed long ago to remove knots in wood so the hole could be refilled....but they are used for more and more things 

and the straight one are called straight flute reamers.....used for very tight tolerance holes 

[jon burgess]

Are used on a regular drill or hammer drill

[DR99]

Regular drill. They do not have carbide tips for masonry use.

[jon burgess]

I was clean out my grandfather tools, and I thought they where for anther tool that was near it so I thought that those bit went with that tool. I get that they make hole but why would someone need these bit

[comp56]

Are used on a regular drill or hammer drill

well you can use either but Ideally a drill press if the hole needs to be perfectly 90 degrees to surface.......

[Atlas2000]

Forstner Bits and two reamers

[jon burgess]

what are reamers used for?

[comp56]

what are reamers used for?

I posted what they are for in first post..

 

http://professional-power-tool-guide.com/power-tool-forum/index.php?/topic/7546-what-are-these-bit-for/?p=82157

[RickyMcGrath]

Yup. Forstner bits. Lots of uses. It can be quite challenging to use in a hand drill as they tend to skip. If you must use in a hand drill, and you have the depth to work with, a pilot hole of the exact same diameter will help with alignment and flatten out the bottom of the hole.

[Conductor562]

Forstner's works best in a press

[EEtwidget]

Forstner bits are used when you need a hole that doesn't go all the way through the material. Using a forstner bit will ensure the bottom of the hole is smooth and the bit will not 'pull through'

If you try do drill a hole halfway through material with a regular 'twist' bit, the bit will mostlikly 'pull' too far through the material. A similar bit know as a hole saw is used when you want to bore large holes all the way through material.

As for the reamer, ... Drill bits are not exactly precise in diameter. If you needed a hole with a precision tolerance, you would first drill with appropriate twist bit, then come back and 'drill' with the reamer.

I assume you're grandfather did some metal work? Often those tools are used with mills & drill-press

[Conductor562]

I didn't even catch the reamer. Good catch EET