3" deep hole

[DaveW]

So anyway, I was at HD last night, and a guy was asking the HD employee about making a 3" deep hole with a 1-1.5" diameter. The guy (not the HD employee) wanted to use a router to do all of it...

To me, that's just a frightening concept... I suggested using a forstner bit, but he didn't want "the pilot hole". I'm guessing he was talking about the point in the middle. So, out of curiosity, how would you guys do that?

My thought is to still use the forstner (at least most of the way), but I wouldn't have a clue as to how you'd clean out the bottom.

[Black wallnut]

A person could grind the point off once the hole is started.........

[Tequila]

When you've only got a hammer, everything looks like a nail. I'm betting the guy just got a new router and just wanted to use it. Plus I gotta wonder what he wanted to do with that hole.

I'd probably use a forstner for most of it, and a router to clean the bottom. 3" doesn't seem that deep if you're just skimming a little at a time for cleanout. I'm not sure if there's bits available that long, or if you'd need one of those bit extenders to get to the bottom.

There's no reason it couldn't all be done with a router, it would just take a whole lot longer.

[LarryG]

A "pilot hole" at the bottom of a 3" deep hole that's only 1" or 1-1/2" in diameter? I wouldn't worry about it.

While they may exist, I don't know of a router bit long enough to go that deep. Maybe with a collet extender, assuming it was smaller in diameter than the bit's flutes. (If the collet or extender infringed into the hole, even a little bit, the bit diameter would have to be the same size as the hole, and have end cutters, in order to produce a perfectly flat bottom.)

I don't know how I'd do it, especially in the absence of more information. For instance if the workpiece was thick enough, I might drill a 4" deep hole and then insert a 1" long piece of dowel to bring the depth back to the desired 3". Or drill the hole all the way through the 3" thick piece and then glue it to another, undrilled piece. Probably some other methods available but, as Joe says, it'd help to know what he plans to do with that hole.

[LCHIEN]

I'd still do it with a Forstner bit.
To take care of the dimple, Either
1) drill to depth and use some wood putty to fill the "pilot hole" dimple if that was objectionable,
or
2) drill to about 1/8th of final depth then use a router with a top bearing 1/2" dia straight bit and an extender to make a matching flat bottom.

Seeing as how I don't have an extender and am not sure it my top bearing bit is flat bottomed and it takes an extra setup, I'd be tempted to do 1), its much easier.

[Jim Boyd]

I'd use a forstner bit and not worry about the dimple. Heck, it is going to be behind a 3" long dowel why worry?

[WEG]

Hi guys;
How 'bout this; first the forster then follow up with a 3/4 or 1" dowel with some sandpaper stuck to the end, the other end cut down to fit your VS hand drill and have at it... or do it by hand...probably would take about 2 or 3 innings to get this done
WEG

[sergei]

I make 3 1/8" diameter holes that are 1 3/4" deep all the time when I make clocks. The wood is usually walnut, ash, maple or a combination of the three (when I feel like getting "fancy"). I use a forstner bit on my drill press and have never had a problem.


Not quite a 3" DEEP hole 1.5" in diameter, but you get the picture....

[DaveW]

The other thing that scared the pants off me was that he had a 1/4" router and wanted a collet extender that would accept a 1/2" bit!

[Stytooner]

Do most of it with a forstner and then chuck up an end mill. No dimple that way.

[monte]

I'd go with the forstner as well.

[Pappy]

quote:Originally posted by DaveW

The other thing that scared the pants off me was that he had a 1/4" router and wanted a collet extender that would accept a 1/2" bit!

With this added information, I would recommend a check of his insurance policies and a call to 911 before turning on the router....

[Stytooner]

Thanks Pappy.
Please don't use a router to drive a Forstner bit or an end mill of that size unless you don't mind extra 3" holes in yourself. [:0]
A slow electric drill or drill press is suggested as the drive.

[DaveW]

quote:Originally posted by Stytooner

Do most of it with a forstner and then chuck up an end mill. No dimple that way.

Pardon my ignorance - is an end mill just like a drill bit that leaves a flat bottom?

[BobSch]

quote:Originally posted by DaveW

quote:Originally posted by Stytooner

Do most of it with a forstner and then chuck up an end mill. No dimple that way.

Pardon my ignorance - is an end mill just like a drill bit that leaves a flat bottom?

More like a router bit. Usually used at slower speeds in metal.