I'd like to drill a stepped hole in one go. Stacking forstner bits?

[Luke Pighetti]

Hey guys.

I just realized that my life would be so much easier with a product I make if I had a stacked drill bit. I have to do a stepped hole a lot and right now I use a CNC router, but I'm thinking more and more that going back to basics is a better idea.

The drill can be used on a press or on the lathe, as the parts are always turned afterwards.

I could buy three drill presses and do them assembly line style, but I believe there is a better way that I just haven't thought of (or don't know about) yet.

I don't need it to turn the outside also, but that would be pretty incredible. That would just be icing on the cake, and I almost considered not even mentioning it because I don't want that to detract from the important discussion of how to drill out the inside in a single go.

I don't mind making something if anyone has any ideas.

The parts are made of various exotic burls and hardwood. The bit needs to cut well. The bit is 1" diameter at the smallest and about 2.25" diameter at the largest (estimate).

Edit: I added a sketch of a quick idea of what the drill bit might look like.

[Chris Fournier]

Looks like something that a custom tool could do. $$$

[Joe Jensen]

I agree. I'd look into a custom bit if this is something you will do a lot of. Assuming if buying three drill presses is an option there will be some volume.

[Luke Pighetti]

Not sure where to even begin looking for someone to make a custom bit. If there are some ideas I don't mind having a go at it myself.

[pat warner]

And piloted cutters won't get you there fast enough?
(Such as, upper left (http://patwarner.com/images/drilling_tools.jpg)). Pilots of essentially any diameter are cheap, & will track the bottom or seconday hole.\
The 3 wing cutters are not cheap but do get big. Believe Forest City's go to 3.0".

[keith micinski]

I would guess most local machine shops would be able to manufacture a High speed steel cutter to start with pretty much like what you have there in your photo. I wonder though if it wouldn't be better to make it like a router bit where as there is a slot cut in the side and then a Piece of carbide is put on the slot on two side of the bit. Also cutting the outside I think would be easy to do by making a cup that fits your dimensions. Think of an upside down whole saw that has an adjustable collet on it with an Allen so you can slide it up and down the shaft of the custom but then you could change the height of the outside shoulder if needed. I think it would also be nice here to mill the cup out and the shop could braze carbide cutters onto the bottom of the cup to form the teeth.

[Alan Melbourne]

how about building a drill press workbench. mount one of those self centering vices to it adn drill all the first holes then change bits and drill again.

also you couldcreate a jig that droped into a recess in the table. a square of mdf etc would work. make enough for each of your workpieces. then attach your workpiece to them (screws,glue togle clamps etc) . drill the holes seperatly

[Chris Fournier]

I would think that a tool body that held carbide inserts at the correct geometry would do nicely. Chip extraction would require some serious thought.

[Alan Melbourne]

how about drilling th esmaller hole first then going in there with a rebating bit to creat the steps

[Peter Quinn]

Not sure where to even begin looking for someone to make a custom bit. If there are some ideas I don't mind having a go at it myself.


This is where (http://www.morriswoodtool.com) . They specialize in drilling bits, and they specialize in custom tooling. They would be a good starting point. I was referred to them by several other manufacturers in a search for something odd a few years back, the bits I got from them drill like no other. Thats quite a large piece of steel you will end up spinning, I'm hoping you have a pretty stout drill press?

[Mike Cutler]

WL Fuller will have, or make what you need.
You probably want a style 4 or 7 step drill.
The only products that WL Fuller makes are drill bits, and mills.

Do you have a drill press that can swing the bit you're looking for?
I imagine it will have to be able to go less than 100 RPM for a bit like you spec'd.

[Jerry Bruette]

You could contact the folks at Great Lakes Carbide Tooling www.glct.com (http://www.glct.com) and see if they could make a cutter for you.

Jerry

[Mike Heidrick]

Work hold down is what I am thinking will be a challenge.

[Jordan Lane]

There's a video on the Popular Woodworking site called Ladderbacks, with Brian Boggs. In that video Brian uses a drill bit exactly what you are talking about. Perhaps he could reveal where he got the tooling. It was a huge bit.

[Myk Rian]

Multi head drilling attachment.