# A HUGE forstner bit?



## angboy (Jun 10, 2007)

I need to find a way to hollow out a big round piece of wood. I need something along the lines of about a 2" round circle hollowed out of it. How would people go about doing that? Are there forstner bits that large? There's probably some really easy method or tool to use to do this that I just don't know about...


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## Dario (Jun 10, 2007)

Angela,

Yes I have fostner bits bigger than that.  Check HF...they are not the best but if you know how to sharpen, they work great.


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## Rudy Vey (Jun 10, 2007)

You can get Forstnerbits that size, and larger. Works for me for hollowing of boxes sometimes.


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## Rifleman1776 (Jun 10, 2007)

Yes, they do come that large and larger. You could also use a lathe and hollow with proper bowl scrapers or hollowing tools.


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## GaryMGg (Jun 10, 2007)

Depending on the depth, if you can't use a lathe to treat like a bowl, you could use a bit like used for installing doorknobs, a circle-cutting bit, or a router with a pattern.


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## woodwish (Jun 10, 2007)

I "cheat" and start a lot of my hollowing with a large forstner bit, have some as big as 3.5" for making tukey pot calls.  Always use them slowly on the lathe but they do build up some heat fast, turn slowly and back out often to clear.  Once you hollow you can finish bottom with a scraper and even the purists can't tell it was done with a bit.  I regularly use up to 1.75" as deep as 10" for my k'scope bodies with little trouble but recently bought a set from MCLS that looks more a conventional twist drill but much bigger.  Haven't tried them out yet but high on my to-do list when I can get back into shop.


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## Gary Max (Jun 10, 2007)

Another thing to think about-----it takes a BIGGGGG drill press to power the bigggg bits and they can be very dangerous if the grab the wood. Gary's ideal is about the lathe is the safest way to fly.


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## skiprat (Jun 10, 2007)

Hi Ang, if you give us some more clues as to what you want to do, I'm sure someone will point out the correct tool / method for the job.[]
Depending on the depth of your hole, you could use a holesaw. I like using them, as the piece that is cut out can often be used on something else. []


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## angboy (Jun 10, 2007)

Thanks everybody! I'm wanting this to hollow out for a kaleidoscope so I guess I may be making a trip to HF. Thanks for the pointers about using the lathe to do this. I actually wonder if my DP would even be large enough for a bit the size I'd need.


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## wdcav1952 (Jun 10, 2007)

Angela, your obsession with size is disturbing. [}][]


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## skiprat (Jun 10, 2007)

Here's a pic of how I would set it up in a bench drill press. However, if I had a 3 wheel lathe steady then I'd do it on the lathe.
Let us know how you solve it.




<br />


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## leehljp (Jun 10, 2007)

MLCS, a division in the same company as PSI (pens) has a <b>forstner bit extender</b> that is helpful if you are turning/drilling out longer sections. I made some duck calls and the regular forstners would not drill/cut all the way through the 4 inch length. I had to reverse the blanks and drill from the other end.
Then I ordered the forstner bit extender. It works great now. I don't know if you want one that long or not but in case you do here is the answer to longer kaleidoscopes.

Forstner bit extender here! Look at the bottom of the page.


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## LEAP (Jun 10, 2007)

Angela, I've done a few kaleidoscopes by drilling on the lathe with a 5" forstner bit extension. I clamp the square block in the chuck then drill on the lathes slowest speed. Clear the chips often. I stop drilling a little short of the chuck and cut off the last 1/4" or so.


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## woodwish (Jun 10, 2007)

Angela, I make probably 100+ k'scopes per year that require anywhere from 1 1/16" to 1 3/4" boring up to 10" deep.  I do the same as Phil above, and would never try this on a drill press.  It's a fair amount of work but if you turn the lathe down slow, a good 4 jaw chuck, and the bit in a drill chuck on the tail stock it can be done.  Clear the chips often, and each species of wood behaves differently.

One bit of advice- bore out the center, rough turn it round and set aside to fully dry a while before finish turning and assembly.  After it dries a while I always run the bit in it one more time, the wood almost always shrinks no matter how dry it was when you started and this will save a lot of trouble getting the mirrors in it.  It almost always ends up oval shaped when it shrinks also, reboring solves that problem also.


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## angboy (Jun 10, 2007)

> _Originally posted by wdcav1952_
> <br />Angela, your obsession with size is disturbing. [}][]



UUuhhhh.. thanks for pointing that out Cav[:0][:0]!!! And thanks to the others who had helpful words to offer. OK, OK, Cav's were helpful too- good for a laugh!![][][]


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## Doghouse (Jun 13, 2007)

I purchased a 2 1/2 and a 3" from Lee Valley.  It works great!  The one trick is that you want to chuck the bit in the tail stock so that you can spin the workpiece slow enough for the bit to bite without stalling.  The drill press does  not get slow enough for that big of a bit.  (JMHO)


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## Phil Joines (Jun 16, 2007)

Most fostner bits have a 3/8" shaft. You can make any length extension using 3/8" drill rod and a 3/8" shaft coupler. The couplers are available from MSC, Enco, Etc.


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